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FFmpeg/libavformat/avidec.c

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  1. /*

  2.  * AVI demuxer

  3.  * Copyright (c) 2001 Fabrice Bellard

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * FFmpeg is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with FFmpeg; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. #include "libavutil/avassert.h"

  23. #include "libavutil/avstring.h"

  24. #include "libavutil/bswap.h"

  25. #include "libavutil/opt.h"

  26. #include "libavutil/dict.h"

  27. #include "libavutil/internal.h"

  28. #include "libavutil/intreadwrite.h"

  29. #include "libavutil/mathematics.h"

  30. #include "avformat.h"

  31. #include "avi.h"

  32. #include "dv.h"

  33. #include "internal.h"

  34. #include "riff.h"

  35. 

  36. typedef struct AVIStream {

  37.     int64_t frame_offset;   /* current frame (video) or byte (audio) counter

  38.                              * (used to compute the pts) */

  39.     int remaining;

  40.     int packet_size;

  41. 

  42.     uint32_t scale;

  43.     uint32_t rate;

  44.     int sample_size;        /* size of one sample (or packet)

  45.                              * (in the rate/scale sense) in bytes */

  46. 

  47.     int64_t cum_len;        /* temporary storage (used during seek) */

  48.     int prefix;             /* normally 'd'<<8 + 'c' or 'w'<<8 + 'b' */

  49.     int prefix_count;

  50.     uint32_t pal[256];

  51.     int has_pal;

  52.     int dshow_block_align;  /* block align variable used to emulate bugs in

  53.                              * the MS dshow demuxer */

  54. 

  55.     AVFormatContext *sub_ctx;

  56.     AVPacket sub_pkt;

  57.     uint8_t *sub_buffer;

  58. 

  59.     int64_t seek_pos;

  60. } AVIStream;

  61. 

  62. typedef struct {

  63.     const AVClass *class;

  64.     int64_t riff_end;

  65.     int64_t movi_end;

  66.     int64_t fsize;

  67.     int64_t io_fsize;

  68.     int64_t movi_list;

  69.     int64_t last_pkt_pos;

  70.     int index_loaded;

  71.     int is_odml;

  72.     int non_interleaved;

  73.     int stream_index;

  74.     DVDemuxContext *dv_demux;

  75.     int odml_depth;

  76.     int use_odml;

  77. #define MAX_ODML_DEPTH 1000

  78.     int64_t dts_max;

  79. } AVIContext;

  80. 

  81. 

  82. static const AVOption options[] = {

  83.     { "use_odml", "use odml index", offsetof(AVIContext, use_odml), AV_OPT_TYPE_INT, {.i64 = 1}, -1, 1, AV_OPT_FLAG_DECODING_PARAM},

  84.     { NULL },

  85. };

  86. 

  87. static const AVClass demuxer_class = {

  88.     .class_name = "avi",

  89.     .item_name  = av_default_item_name,

  90.     .option     = options,

  91.     .version    = LIBAVUTIL_VERSION_INT,

  92.     .category   = AV_CLASS_CATEGORY_DEMUXER,

  93. };

  94. 

  95. 

  96. static const char avi_headers[][8] = {

  97.     { 'R', 'I', 'F', 'F', 'A', 'V', 'I', ' '  },

  98.     { 'R', 'I', 'F', 'F', 'A', 'V', 'I', 'X'  },

  99.     { 'R', 'I', 'F', 'F', 'A', 'V', 'I', 0x19 },

  100.     { 'O', 'N', '2', ' ', 'O', 'N', '2', 'f'  },

  101.     { 'R', 'I', 'F', 'F', 'A', 'M', 'V', ' '  },

  102.     { 0 }

  103. };

  104. 

  105. static const AVMetadataConv avi_metadata_conv[] = {

  106.     { "strn", "title" },

  107.     { 0 },

  108. };

  109. 

  110. static int avi_load_index(AVFormatContext *s);

  111. static int guess_ni_flag(AVFormatContext *s);

  112. 

  113. #define print_tag(str, tag, size)                        \

  114.     av_dlog(NULL, "%s: tag=%c%c%c%c size=0x%x\n",        \

  115.             str, tag & 0xff,                             \

  116.             (tag >> 8) & 0xff,                           \

  117.             (tag >> 16) & 0xff,                          \

  118.             (tag >> 24) & 0xff,                          \

  119.             size)

  120. 

  121. static inline int get_duration(AVIStream *ast, int len)

  122. {

  123.     if (ast->sample_size)

  124.         return len;

  125.     else if (ast->dshow_block_align)

  126.         return (len + ast->dshow_block_align - 1) / ast->dshow_block_align;

  127.     else

  128.         return 1;

  129. }

  130. 

  131. static int get_riff(AVFormatContext *s, AVIOContext *pb)

  132. {

  133.     AVIContext *avi = s->priv_data;

  134.     char header[8];

  135.     int i;

  136. 

  137.     /* check RIFF header */

  138.     avio_read(pb, header, 4);

  139.     avi->riff_end  = avio_rl32(pb); /* RIFF chunk size */

  140.     avi->riff_end += avio_tell(pb); /* RIFF chunk end */

  141.     avio_read(pb, header + 4, 4);

  142. 

  143.     for (i = 0; avi_headers[i][0]; i++)

  144.         if (!memcmp(header, avi_headers[i], 8))

  145.             break;

  146.     if (!avi_headers[i][0])

  147.         return AVERROR_INVALIDDATA;

  148. 

  149.     if (header[7] == 0x19)

  150.         av_log(s, AV_LOG_INFO,

  151.                "This file has been generated by a totally broken muxer.\n");

  152. 

  153.     return 0;

  154. }

  155. 

  156. static int read_braindead_odml_indx(AVFormatContext *s, int frame_num)

  157. {

  158.     AVIContext *avi     = s->priv_data;

  159.     AVIOContext *pb     = s->pb;

  160.     int longs_pre_entry = avio_rl16(pb);

  161.     int index_sub_type  = avio_r8(pb);

  162.     int index_type      = avio_r8(pb);

  163.     int entries_in_use  = avio_rl32(pb);

  164.     int chunk_id        = avio_rl32(pb);

  165.     int64_t base        = avio_rl64(pb);

  166.     int stream_id       = ((chunk_id      & 0xFF) - '0') * 10 +

  167.                           ((chunk_id >> 8 & 0xFF) - '0');

  168.     AVStream *st;

  169.     AVIStream *ast;

  170.     int i;

  171.     int64_t last_pos = -1;

  172.     int64_t filesize = avi->fsize;

  173. 

  174.     av_dlog(s,

  175.             "longs_pre_entry:%d index_type:%d entries_in_use:%d "

  176.             "chunk_id:%X base:%16"PRIX64"\n",

  177.             longs_pre_entry,

  178.             index_type,

  179.             entries_in_use,

  180.             chunk_id,

  181.             base);

  182. 

  183.     if (stream_id >= s->nb_streams || stream_id < 0)

  184.         return AVERROR_INVALIDDATA;

  185.     st  = s->streams[stream_id];

  186.     ast = st->priv_data;

  187. 

  188.     if (index_sub_type)

  189.         return AVERROR_INVALIDDATA;

  190. 

  191.     avio_rl32(pb);

  192. 

  193.     if (index_type && longs_pre_entry != 2)

  194.         return AVERROR_INVALIDDATA;

  195.     if (index_type > 1)

  196.         return AVERROR_INVALIDDATA;

  197. 

  198.     if (filesize > 0 && base >= filesize) {

  199.         av_log(s, AV_LOG_ERROR, "ODML index invalid\n");

  200.         if (base >> 32 == (base & 0xFFFFFFFF) &&

  201.             (base & 0xFFFFFFFF) < filesize    &&

  202.             filesize <= 0xFFFFFFFF)

  203.             base &= 0xFFFFFFFF;

  204.         else

  205.             return AVERROR_INVALIDDATA;

  206.     }

  207. 

  208.     for (i = 0; i < entries_in_use; i++) {

  209.         if (index_type) {

  210.             int64_t pos = avio_rl32(pb) + base - 8;

  211.             int len     = avio_rl32(pb);

  212.             int key     = len >= 0;

  213.             len &= 0x7FFFFFFF;

  214. 

  215. #ifdef DEBUG_SEEK

  216.             av_log(s, AV_LOG_ERROR, "pos:%"PRId64", len:%X\n", pos, len);

  217. #endif

  218.             if (url_feof(pb))

  219.                 return AVERROR_INVALIDDATA;

  220. 

  221.             if (last_pos == pos || pos == base - 8)

  222.                 avi->non_interleaved = 1;

  223.             if (last_pos != pos && (len || !ast->sample_size))

  224.                 av_add_index_entry(st, pos, ast->cum_len, len, 0,

  225.                                    key ? AVINDEX_KEYFRAME : 0);

  226. 

  227.             ast->cum_len += get_duration(ast, len);

  228.             last_pos      = pos;

  229.         } else {

  230.             int64_t offset, pos;

  231.             int duration;

  232.             offset = avio_rl64(pb);

  233.             avio_rl32(pb);       /* size */

  234.             duration = avio_rl32(pb);

  235. 

  236.             if (url_feof(pb))

  237.                 return AVERROR_INVALIDDATA;

  238. 

  239.             pos = avio_tell(pb);

  240. 

  241.             if (avi->odml_depth > MAX_ODML_DEPTH) {

  242.                 av_log(s, AV_LOG_ERROR, "Too deeply nested ODML indexes\n");

  243.                 return AVERROR_INVALIDDATA;

  244.             }

  245. 

  246.             if (avio_seek(pb, offset + 8, SEEK_SET) < 0)

  247.                 return -1;

  248.             avi->odml_depth++;

  249.             read_braindead_odml_indx(s, frame_num);

  250.             avi->odml_depth--;

  251.             frame_num += duration;

  252. 

  253.             if (avio_seek(pb, pos, SEEK_SET) < 0) {

  254.                 av_log(s, AV_LOG_ERROR, "Failed to restore position after reading index\n");

  255.                 return -1;

  256.             }

  257. 

  258.         }

  259.     }

  260.     avi->index_loaded = 2;

  261.     return 0;

  262. }

  263. 

  264. static void clean_index(AVFormatContext *s)

  265. {

  266.     int i;

  267.     int64_t j;

  268. 

  269.     for (i = 0; i < s->nb_streams; i++) {

  270.         AVStream *st   = s->streams[i];

  271.         AVIStream *ast = st->priv_data;

  272.         int n          = st->nb_index_entries;

  273.         int max        = ast->sample_size;

  274.         int64_t pos, size, ts;

  275. 

  276.         if (n != 1 || ast->sample_size == 0)

  277.             continue;

  278. 

  279.         while (max < 1024)

  280.             max += max;

  281. 

  282.         pos  = st->index_entries[0].pos;

  283.         size = st->index_entries[0].size;

  284.         ts   = st->index_entries[0].timestamp;

  285. 

  286.         for (j = 0; j < size; j += max)

  287.             av_add_index_entry(st, pos + j, ts + j, FFMIN(max, size - j), 0,

  288.                                AVINDEX_KEYFRAME);

  289.     }

  290. }

  291. 

  292. static int avi_read_tag(AVFormatContext *s, AVStream *st, uint32_t tag,

  293.                         uint32_t size)

  294. {

  295.     AVIOContext *pb = s->pb;

  296.     char key[5]     = { 0 };

  297.     char *value;

  298. 

  299.     size += (size & 1);

  300. 

  301.     if (size == UINT_MAX)

  302.         return AVERROR(EINVAL);

  303.     value = av_malloc(size + 1);

  304.     if (!value)

  305.         return AVERROR(ENOMEM);

  306.     avio_read(pb, value, size);

  307.     value[size] = 0;

  308. 

  309.     AV_WL32(key, tag);

  310. 

  311.     return av_dict_set(st ? &st->metadata : &s->metadata, key, value,

  312.                        AV_DICT_DONT_STRDUP_VAL);

  313. }

  314. 

  315. static const char months[12][4] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",

  316.                                     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };

  317. 

  318. static void avi_metadata_creation_time(AVDictionary **metadata, char *date)

  319. {

  320.     char month[4], time[9], buffer[64];

  321.     int i, day, year;

  322.     /* parse standard AVI date format (ie. "Mon Mar 10 15:04:43 2003") */

  323.     if (sscanf(date, "%*3s%*[ ]%3s%*[ ]%2d%*[ ]%8s%*[ ]%4d",

  324.                month, &day, time, &year) == 4) {

  325.         for (i = 0; i < 12; i++)

  326.             if (!av_strcasecmp(month, months[i])) {

  327.                 snprintf(buffer, sizeof(buffer), "%.4d-%.2d-%.2d %s",

  328.                          year, i + 1, day, time);

  329.                 av_dict_set(metadata, "creation_time", buffer, 0);

  330.             }

  331.     } else if (date[4] == '/' && date[7] == '/') {

  332.         date[4] = date[7] = '-';

  333.         av_dict_set(metadata, "creation_time", date, 0);

  334.     }

  335. }

  336. 

  337. static void avi_read_nikon(AVFormatContext *s, uint64_t end)

  338. {

  339.     while (avio_tell(s->pb) < end) {

  340.         uint32_t tag  = avio_rl32(s->pb);

  341.         uint32_t size = avio_rl32(s->pb);

  342.         switch (tag) {

  343.         case MKTAG('n', 'c', 't', 'g'):  /* Nikon Tags */

  344.         {

  345.             uint64_t tag_end = avio_tell(s->pb) + size;

  346.             while (avio_tell(s->pb) < tag_end) {

  347.                 uint16_t tag     = avio_rl16(s->pb);

  348.                 uint16_t size    = avio_rl16(s->pb);

  349.                 const char *name = NULL;

  350.                 char buffer[64]  = { 0 };

  351.                 size -= avio_read(s->pb, buffer,

  352.                                   FFMIN(size, sizeof(buffer) - 1));

  353.                 switch (tag) {

  354.                 case 0x03:

  355.                     name = "maker";

  356.                     break;

  357.                 case 0x04:

  358.                     name = "model";

  359.                     break;

  360.                 case 0x13:

  361.                     name = "creation_time";

  362.                     if (buffer[4] == ':' && buffer[7] == ':')

  363.                         buffer[4] = buffer[7] = '-';

  364.                     break;

  365.                 }

  366.                 if (name)

  367.                     av_dict_set(&s->metadata, name, buffer, 0);

  368.                 avio_skip(s->pb, size);

  369.             }

  370.             break;

  371.         }

  372.         default:

  373.             avio_skip(s->pb, size);

  374.             break;

  375.         }

  376.     }

  377. }

  378. 

  379. static int avi_read_header(AVFormatContext *s)

  380. {

  381.     AVIContext *avi = s->priv_data;

  382.     AVIOContext *pb = s->pb;

  383.     unsigned int tag, tag1, handler;

  384.     int codec_type, stream_index, frame_period;

  385.     unsigned int size;

  386.     int i;

  387.     AVStream *st;

  388.     AVIStream *ast      = NULL;

  389.     int avih_width      = 0, avih_height = 0;

  390.     int amv_file_format = 0;

  391.     uint64_t list_end   = 0;

  392.     int ret;

  393.     AVDictionaryEntry *dict_entry;

  394. 

  395.     avi->stream_index = -1;

  396. 

  397.     ret = get_riff(s, pb);

  398.     if (ret < 0)

  399.         return ret;

  400. 

  401.     av_log(avi, AV_LOG_DEBUG, "use odml:%d\n", avi->use_odml);

  402. 

  403.     avi->io_fsize = avi->fsize = avio_size(pb);

  404.     if (avi->fsize <= 0 || avi->fsize < avi->riff_end)

  405.         avi->fsize = avi->riff_end == 8 ? INT64_MAX : avi->riff_end;

  406. 

  407.     /* first list tag */

  408.     stream_index = -1;

  409.     codec_type   = -1;

  410.     frame_period = 0;

  411.     for (;;) {

  412.         if (url_feof(pb))

  413.             goto fail;

  414.         tag  = avio_rl32(pb);

  415.         size = avio_rl32(pb);

  416. 

  417.         print_tag("tag", tag, size);

  418. 

  419.         switch (tag) {

  420.         case MKTAG('L', 'I', 'S', 'T'):

  421.             list_end = avio_tell(pb) + size;

  422.             /* Ignored, except at start of video packets. */

  423.             tag1 = avio_rl32(pb);

  424. 

  425.             print_tag("list", tag1, 0);

  426. 

  427.             if (tag1 == MKTAG('m', 'o', 'v', 'i')) {

  428.                 avi->movi_list = avio_tell(pb) - 4;

  429.                 if (size)

  430.                     avi->movi_end = avi->movi_list + size + (size & 1);

  431.                 else

  432.                     avi->movi_end = avi->fsize;

  433.                 av_dlog(NULL, "movi end=%"PRIx64"\n", avi->movi_end);

  434.                 goto end_of_header;

  435.             } else if (tag1 == MKTAG('I', 'N', 'F', 'O'))

  436.                 ff_read_riff_info(s, size - 4);

  437.             else if (tag1 == MKTAG('n', 'c', 'd', 't'))

  438.                 avi_read_nikon(s, list_end);

  439. 

  440.             break;

  441.         case MKTAG('I', 'D', 'I', 'T'):

  442.         {

  443.             unsigned char date[64] = { 0 };

  444.             size += (size & 1);

  445.             size -= avio_read(pb, date, FFMIN(size, sizeof(date) - 1));

  446.             avio_skip(pb, size);

  447.             avi_metadata_creation_time(&s->metadata, date);

  448.             break;

  449.         }

  450.         case MKTAG('d', 'm', 'l', 'h'):

  451.             avi->is_odml = 1;

  452.             avio_skip(pb, size + (size & 1));

  453.             break;

  454.         case MKTAG('a', 'm', 'v', 'h'):

  455.             amv_file_format = 1;

  456.         case MKTAG('a', 'v', 'i', 'h'):

  457.             /* AVI header */

  458.             /* using frame_period is bad idea */

  459.             frame_period = avio_rl32(pb);

  460.             avio_rl32(pb); /* max. bytes per second */

  461.             avio_rl32(pb);

  462.             avi->non_interleaved |= avio_rl32(pb) & AVIF_MUSTUSEINDEX;

  463. 

  464.             avio_skip(pb, 2 * 4);

  465.             avio_rl32(pb);

  466.             avio_rl32(pb);

  467.             avih_width  = avio_rl32(pb);

  468.             avih_height = avio_rl32(pb);

  469. 

  470.             avio_skip(pb, size - 10 * 4);

  471.             break;

  472.         case MKTAG('s', 't', 'r', 'h'):

  473.             /* stream header */

  474. 

  475.             tag1    = avio_rl32(pb);

  476.             handler = avio_rl32(pb); /* codec tag */

  477. 

  478.             if (tag1 == MKTAG('p', 'a', 'd', 's')) {

  479.                 avio_skip(pb, size - 8);

  480.                 break;

  481.             } else {

  482.                 stream_index++;

  483.                 st = avformat_new_stream(s, NULL);

  484.                 if (!st)

  485.                     goto fail;

  486. 

  487.                 st->id = stream_index;

  488.                 ast    = av_mallocz(sizeof(AVIStream));

  489.                 if (!ast)

  490.                     goto fail;

  491.                 st->priv_data = ast;

  492.             }

  493.             if (amv_file_format)

  494.                 tag1 = stream_index ? MKTAG('a', 'u', 'd', 's')

  495.                                     : MKTAG('v', 'i', 'd', 's');

  496. 

  497.             print_tag("strh", tag1, -1);

  498. 

  499.             if (tag1 == MKTAG('i', 'a', 'v', 's') ||

  500.                 tag1 == MKTAG('i', 'v', 'a', 's')) {

  501.                 int64_t dv_dur;

  502. 

  503.                 /* After some consideration -- I don't think we

  504.                  * have to support anything but DV in type1 AVIs. */

  505.                 if (s->nb_streams != 1)

  506.                     goto fail;

  507. 

  508.                 if (handler != MKTAG('d', 'v', 's', 'd') &&

  509.                     handler != MKTAG('d', 'v', 'h', 'd') &&

  510.                     handler != MKTAG('d', 'v', 's', 'l'))

  511.                     goto fail;

  512. 

  513.                 ast = s->streams[0]->priv_data;

  514.                 av_freep(&s->streams[0]->codec->extradata);

  515.                 av_freep(&s->streams[0]->codec);

  516.                 if (s->streams[0]->info)

  517.                     av_freep(&s->streams[0]->info->duration_error);

  518.                 av_freep(&s->streams[0]->info);

  519.                 av_freep(&s->streams[0]);

  520.                 s->nb_streams = 0;

  521.                 if (CONFIG_DV_DEMUXER) {

  522.                     avi->dv_demux = avpriv_dv_init_demux(s);

  523.                     if (!avi->dv_demux)

  524.                         goto fail;

  525.                 } else

  526.                     goto fail;

  527.                 s->streams[0]->priv_data = ast;

  528.                 avio_skip(pb, 3 * 4);

  529.                 ast->scale = avio_rl32(pb);

  530.                 ast->rate  = avio_rl32(pb);

  531.                 avio_skip(pb, 4);  /* start time */

  532. 

  533.                 dv_dur = avio_rl32(pb);

  534.                 if (ast->scale > 0 && ast->rate > 0 && dv_dur > 0) {

  535.                     dv_dur     *= AV_TIME_BASE;

  536.                     s->duration = av_rescale(dv_dur, ast->scale, ast->rate);

  537.                 }

  538.                 /* else, leave duration alone; timing estimation in utils.c

  539.                  * will make a guess based on bitrate. */

  540. 

  541.                 stream_index = s->nb_streams - 1;

  542.                 avio_skip(pb, size - 9 * 4);

  543.                 break;

  544.             }

  545. 

  546.             av_assert0(stream_index < s->nb_streams);

  547.             st->codec->stream_codec_tag = handler;

  548. 

  549.             avio_rl32(pb); /* flags */

  550.             avio_rl16(pb); /* priority */

  551.             avio_rl16(pb); /* language */

  552.             avio_rl32(pb); /* initial frame */

  553.             ast->scale = avio_rl32(pb);

  554.             ast->rate  = avio_rl32(pb);

  555.             if (!(ast->scale && ast->rate)) {

  556.                 av_log(s, AV_LOG_WARNING,

  557.                        "scale/rate is %u/%u which is invalid. "

  558.                        "(This file has been generated by broken software.)\n",

  559.                        ast->scale,

  560.                        ast->rate);

  561.                 if (frame_period) {

  562.                     ast->rate  = 1000000;

  563.                     ast->scale = frame_period;

  564.                 } else {

  565.                     ast->rate  = 25;

  566.                     ast->scale = 1;

  567.                 }

  568.             }

  569.             avpriv_set_pts_info(st, 64, ast->scale, ast->rate);

  570. 

  571.             ast->cum_len  = avio_rl32(pb); /* start */

  572.             st->nb_frames = avio_rl32(pb);

  573. 

  574.             st->start_time = 0;

  575.             avio_rl32(pb); /* buffer size */

  576.             avio_rl32(pb); /* quality */

  577.             if (ast->cum_len*ast->scale/ast->rate > 3600) {

  578.                 av_log(s, AV_LOG_ERROR, "crazy start time, iam scared, giving up\n");

  579.                 return AVERROR_INVALIDDATA;

  580.             }

  581.             ast->sample_size = avio_rl32(pb); /* sample ssize */

  582.             ast->cum_len    *= FFMAX(1, ast->sample_size);

  583.             av_dlog(s, "%"PRIu32" %"PRIu32" %d\n",

  584.                     ast->rate, ast->scale, ast->sample_size);

  585. 

  586.             switch (tag1) {

  587.             case MKTAG('v', 'i', 'd', 's'):

  588.                 codec_type = AVMEDIA_TYPE_VIDEO;

  589. 

  590.                 ast->sample_size = 0;

  591.                 break;

  592.             case MKTAG('a', 'u', 'd', 's'):

  593.                 codec_type = AVMEDIA_TYPE_AUDIO;

  594.                 break;

  595.             case MKTAG('t', 'x', 't', 's'):

  596.                 codec_type = AVMEDIA_TYPE_SUBTITLE;

  597.                 break;

  598.             case MKTAG('d', 'a', 't', 's'):

  599.                 codec_type = AVMEDIA_TYPE_DATA;

  600.                 break;

  601.             default:

  602.                 av_log(s, AV_LOG_INFO, "unknown stream type %X\n", tag1);

  603.             }

  604.             if (ast->sample_size == 0) {

  605.                 st->duration = st->nb_frames;

  606.                 if (st->duration > 0 && avi->io_fsize > 0 && avi->riff_end > avi->io_fsize) {

  607.                     av_log(s, AV_LOG_DEBUG, "File is truncated adjusting duration\n");

  608.                     st->duration = av_rescale(st->duration, avi->io_fsize, avi->riff_end);

  609.                 }

  610.             }

  611.             ast->frame_offset = ast->cum_len;

  612.             avio_skip(pb, size - 12 * 4);

  613.             break;

  614.         case MKTAG('s', 't', 'r', 'f'):

  615.             /* stream header */

  616.             if (!size)

  617.                 break;

  618.             if (stream_index >= (unsigned)s->nb_streams || avi->dv_demux) {

  619.                 avio_skip(pb, size);

  620.             } else {

  621.                 uint64_t cur_pos = avio_tell(pb);

  622.                 unsigned esize;

  623.                 if (cur_pos < list_end)

  624.                     size = FFMIN(size, list_end - cur_pos);

  625.                 st = s->streams[stream_index];

  626.                 switch (codec_type) {

  627.                 case AVMEDIA_TYPE_VIDEO:

  628.                     if (amv_file_format) {

  629.                         st->codec->width      = avih_width;

  630.                         st->codec->height     = avih_height;

  631.                         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

  632.                         st->codec->codec_id   = AV_CODEC_ID_AMV;

  633.                         avio_skip(pb, size);

  634.                         break;

  635.                     }

  636.                     tag1 = ff_get_bmp_header(pb, st, &esize);

  637. 

  638.                     if (tag1 == MKTAG('D', 'X', 'S', 'B') ||

  639.                         tag1 == MKTAG('D', 'X', 'S', 'A')) {

  640.                         st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

  641.                         st->codec->codec_tag  = tag1;

  642.                         st->codec->codec_id   = AV_CODEC_ID_XSUB;

  643.                         break;

  644.                     }

  645. 

  646.                     if (size > 10 * 4 && size < (1 << 30) && size < avi->fsize) {

  647.                         if (esize == size-1 && (esize&1)) {

  648.                             st->codec->extradata_size = esize - 10 * 4;

  649.                         } else

  650.                             st->codec->extradata_size =  size - 10 * 4;

  651.                         st->codec->extradata      = av_malloc(st->codec->extradata_size +

  652.                                                               FF_INPUT_BUFFER_PADDING_SIZE);

  653.                         if (!st->codec->extradata) {

  654.                             st->codec->extradata_size = 0;

  655.                             return AVERROR(ENOMEM);

  656.                         }

  657.                         avio_read(pb,

  658.                                   st->codec->extradata,

  659.                                   st->codec->extradata_size);

  660.                     }

  661. 

  662.                     // FIXME: check if the encoder really did this correctly

  663.                     if (st->codec->extradata_size & 1)

  664.                         avio_r8(pb);

  665. 

  666.                     /* Extract palette from extradata if bpp <= 8.

  667.                      * This code assumes that extradata contains only palette.

  668.                      * This is true for all paletted codecs implemented in

  669.                      * FFmpeg. */

  670.                     if (st->codec->extradata_size &&

  671.                         (st->codec->bits_per_coded_sample <= 8)) {

  672.                         int pal_size = (1 << st->codec->bits_per_coded_sample) << 2;

  673.                         const uint8_t *pal_src;

  674. 

  675.                         pal_size = FFMIN(pal_size, st->codec->extradata_size);

  676.                         pal_src  = st->codec->extradata +

  677.                                    st->codec->extradata_size - pal_size;

  678.                         for (i = 0; i < pal_size / 4; i++)

  679.                             ast->pal[i] = 0xFFU<<24 | AV_RL32(pal_src+4*i);

  680.                         ast->has_pal = 1;

  681.                     }

  682. 

  683.                     print_tag("video", tag1, 0);

  684. 

  685.                     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

  686.                     st->codec->codec_tag  = tag1;

  687.                     st->codec->codec_id   = ff_codec_get_id(ff_codec_bmp_tags,

  688.                                                             tag1);

  689.                     /* This is needed to get the pict type which is necessary

  690.                      * for generating correct pts. */

  691.                     st->need_parsing = AVSTREAM_PARSE_HEADERS;

  692. 

  693.                     if (st->codec->codec_tag == 0 && st->codec->height > 0 &&

  694.                         st->codec->extradata_size < 1U << 30) {

  695.                         st->codec->extradata_size += 9;

  696.                         if ((ret = av_reallocp(&st->codec->extradata,

  697.                                                st->codec->extradata_size +

  698.                                                FF_INPUT_BUFFER_PADDING_SIZE)) < 0) {

  699.                             st->codec->extradata_size = 0;

  700.                             return ret;

  701.                         } else

  702.                             memcpy(st->codec->extradata + st->codec->extradata_size - 9,

  703.                                    "BottomUp", 9);

  704.                     }

  705.                     st->codec->height = FFABS(st->codec->height);

  706. 

  707. //                    avio_skip(pb, size - 5 * 4);

  708.                     break;

  709.                 case AVMEDIA_TYPE_AUDIO:

  710.                     ret = ff_get_wav_header(pb, st->codec, size);

  711.                     if (ret < 0)

  712.                         return ret;

  713.                     ast->dshow_block_align = st->codec->block_align;

  714.                     if (ast->sample_size && st->codec->block_align &&

  715.                         ast->sample_size != st->codec->block_align) {

  716.                         av_log(s,

  717.                                AV_LOG_WARNING,

  718.                                "sample size (%d) != block align (%d)\n",

  719.                                ast->sample_size,

  720.                                st->codec->block_align);

  721.                         ast->sample_size = st->codec->block_align;

  722.                     }

  723.                     /* 2-aligned

  724.                      * (fix for Stargate SG-1 - 3x18 - Shades of Grey.avi) */

  725.                     if (size & 1)

  726.                         avio_skip(pb, 1);

  727.                     /* Force parsing as several audio frames can be in

  728.                      * one packet and timestamps refer to packet start. */

  729.                     st->need_parsing = AVSTREAM_PARSE_TIMESTAMPS;

  730.                     /* ADTS header is in extradata, AAC without header must be

  731.                      * stored as exact frames. Parser not needed and it will

  732.                      * fail. */

  733.                     if (st->codec->codec_id == AV_CODEC_ID_AAC &&

  734.                         st->codec->extradata_size)

  735.                         st->need_parsing = AVSTREAM_PARSE_NONE;

  736.                     /* AVI files with Xan DPCM audio (wrongly) declare PCM

  737.                      * audio in the header but have Axan as stream_code_tag. */

  738.                     if (st->codec->stream_codec_tag == AV_RL32("Axan")) {

  739.                         st->codec->codec_id  = AV_CODEC_ID_XAN_DPCM;

  740.                         st->codec->codec_tag = 0;

  741.                         ast->dshow_block_align = 0;

  742.                     }

  743.                     if (amv_file_format) {

  744.                         st->codec->codec_id    = AV_CODEC_ID_ADPCM_IMA_AMV;

  745.                         ast->dshow_block_align = 0;

  746.                     }

  747.                     if (st->codec->codec_id == AV_CODEC_ID_AAC && ast->dshow_block_align <= 4 && ast->dshow_block_align) {

  748.                         av_log(s, AV_LOG_DEBUG, "overriding invalid dshow_block_align of %d\n", ast->dshow_block_align);

  749.                         ast->dshow_block_align = 0;

  750.                     }

  751.                     if (st->codec->codec_id == AV_CODEC_ID_AAC && ast->dshow_block_align == 1024 && ast->sample_size == 1024 ||

  752.                        st->codec->codec_id == AV_CODEC_ID_AAC && ast->dshow_block_align == 4096 && ast->sample_size == 4096 ||

  753.                        st->codec->codec_id == AV_CODEC_ID_MP3 && ast->dshow_block_align == 1152 && ast->sample_size == 1152) {

  754.                         av_log(s, AV_LOG_DEBUG, "overriding sample_size\n");

  755.                         ast->sample_size = 0;

  756.                     }

  757.                     break;

  758.                 case AVMEDIA_TYPE_SUBTITLE:

  759.                     st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

  760.                     st->request_probe= 1;

  761.                     avio_skip(pb, size);

  762.                     break;

  763.                 default:

  764.                     st->codec->codec_type = AVMEDIA_TYPE_DATA;

  765.                     st->codec->codec_id   = AV_CODEC_ID_NONE;

  766.                     st->codec->codec_tag  = 0;

  767.                     avio_skip(pb, size);

  768.                     break;

  769.                 }

  770.             }

  771.             break;

  772.         case MKTAG('s', 't', 'r', 'd'):

  773.             if (stream_index >= (unsigned)s->nb_streams

  774.                 || s->streams[stream_index]->codec->extradata_size

  775.                 || s->streams[stream_index]->codec->codec_tag == MKTAG('H','2','6','4')) {

  776.                 avio_skip(pb, size);

  777.             } else {

  778.                 uint64_t cur_pos = avio_tell(pb);

  779.                 if (cur_pos < list_end)

  780.                     size = FFMIN(size, list_end - cur_pos);

  781.                 st = s->streams[stream_index];

  782. 

  783.                 if (size<(1<<30)) {

  784.                     st->codec->extradata_size= size;

  785.                     st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);

  786.                     if (!st->codec->extradata) {

  787.                         st->codec->extradata_size= 0;

  788.                         return AVERROR(ENOMEM);

  789.                     }

  790.                     avio_read(pb, st->codec->extradata, st->codec->extradata_size);

  791.                 }

  792. 

  793.                 if (st->codec->extradata_size & 1) //FIXME check if the encoder really did this correctly

  794.                     avio_r8(pb);

  795.             }

  796.             break;

  797.         case MKTAG('i', 'n', 'd', 'x'):

  798.             i = avio_tell(pb);

  799.             if (pb->seekable && !(s->flags & AVFMT_FLAG_IGNIDX) &&

  800.                 avi->use_odml &&

  801.                 read_braindead_odml_indx(s, 0) < 0 &&

  802.                 (s->error_recognition & AV_EF_EXPLODE))

  803.                 goto fail;

  804.             avio_seek(pb, i + size, SEEK_SET);

  805.             break;

  806.         case MKTAG('v', 'p', 'r', 'p'):

  807.             if (stream_index < (unsigned)s->nb_streams && size > 9 * 4) {

  808.                 AVRational active, active_aspect;

  809. 

  810.                 st = s->streams[stream_index];

  811.                 avio_rl32(pb);

  812.                 avio_rl32(pb);

  813.                 avio_rl32(pb);

  814.                 avio_rl32(pb);

  815.                 avio_rl32(pb);

  816. 

  817.                 active_aspect.den = avio_rl16(pb);

  818.                 active_aspect.num = avio_rl16(pb);

  819.                 active.num        = avio_rl32(pb);

  820.                 active.den        = avio_rl32(pb);

  821.                 avio_rl32(pb); // nbFieldsPerFrame

  822. 

  823.                 if (active_aspect.num && active_aspect.den &&

  824.                     active.num && active.den) {

  825.                     st->sample_aspect_ratio = av_div_q(active_aspect, active);

  826.                     av_dlog(s, "vprp %d/%d %d/%d\n",

  827.                             active_aspect.num, active_aspect.den,

  828.                             active.num, active.den);

  829.                 }

  830.                 size -= 9 * 4;

  831.             }

  832.             avio_skip(pb, size);

  833.             break;

  834.         case MKTAG('s', 't', 'r', 'n'):

  835.             if (s->nb_streams) {

  836.                 ret = avi_read_tag(s, s->streams[s->nb_streams - 1], tag, size);

  837.                 if (ret < 0)

  838.                     return ret;

  839.                 break;

  840.             }

  841.         default:

  842.             if (size > 1000000) {

  843.                 av_log(s, AV_LOG_ERROR,

  844.                        "Something went wrong during header parsing, "

  845.                        "I will ignore it and try to continue anyway.\n");

  846.                 if (s->error_recognition & AV_EF_EXPLODE)

  847.                     goto fail;

  848.                 avi->movi_list = avio_tell(pb) - 4;

  849.                 avi->movi_end  = avi->fsize;

  850.                 goto end_of_header;

  851.             }

  852.             /* skip tag */

  853.             size += (size & 1);

  854.             avio_skip(pb, size);

  855.             break;

  856.         }

  857.     }

  858. 

  859. end_of_header:

  860.     /* check stream number */

  861.     if (stream_index != s->nb_streams - 1) {

  862. 

  863. fail:

  864.         return AVERROR_INVALIDDATA;

  865.     }

  866. 

  867.     if (!avi->index_loaded && pb->seekable)

  868.         avi_load_index(s);

  869.     avi->index_loaded    |= 1;

  870.     avi->non_interleaved |= guess_ni_flag(s) | (s->flags & AVFMT_FLAG_SORT_DTS);

  871. 

  872.     dict_entry = av_dict_get(s->metadata, "ISFT", NULL, 0);

  873.     if (dict_entry && !strcmp(dict_entry->value, "PotEncoder"))

  874.         for (i = 0; i < s->nb_streams; i++) {

  875.             AVStream *st = s->streams[i];

  876.             if (   st->codec->codec_id == AV_CODEC_ID_MPEG1VIDEO

  877.                 || st->codec->codec_id == AV_CODEC_ID_MPEG2VIDEO)

  878.                 st->need_parsing = AVSTREAM_PARSE_FULL;

  879.         }

  880. 

  881.     for (i = 0; i < s->nb_streams; i++) {

  882.         AVStream *st = s->streams[i];

  883.         if (st->nb_index_entries)

  884.             break;

  885.     }

  886.     // DV-in-AVI cannot be non-interleaved, if set this must be

  887.     // a mis-detection.

  888.     if (avi->dv_demux)

  889.         avi->non_interleaved = 0;

  890.     if (i == s->nb_streams && avi->non_interleaved) {

  891.         av_log(s, AV_LOG_WARNING,

  892.                "Non-interleaved AVI without index, switching to interleaved\n");

  893.         avi->non_interleaved = 0;

  894.     }

  895. 

  896.     if (avi->non_interleaved) {

  897.         av_log(s, AV_LOG_INFO, "non-interleaved AVI\n");

  898.         clean_index(s);

  899.     }

  900. 

  901.     ff_metadata_conv_ctx(s, NULL, avi_metadata_conv);

  902.     ff_metadata_conv_ctx(s, NULL, ff_riff_info_conv);

  903. 

  904.     return 0;

  905. }

  906. 

  907. static int read_gab2_sub(AVStream *st, AVPacket *pkt)

  908. {

  909.     if (pkt->size >= 7 &&

  910.         !strcmp(pkt->data, "GAB2") && AV_RL16(pkt->data + 5) == 2) {

  911.         uint8_t desc[256];

  912.         int score      = AVPROBE_SCORE_EXTENSION, ret;

  913.         AVIStream *ast = st->priv_data;

  914.         AVInputFormat *sub_demuxer;

  915.         AVRational time_base;

  916.         AVIOContext *pb = avio_alloc_context(pkt->data + 7,

  917.                                              pkt->size - 7,

  918.                                              0, NULL, NULL, NULL, NULL);

  919.         AVProbeData pd;

  920.         unsigned int desc_len = avio_rl32(pb);

  921. 

  922.         if (desc_len > pb->buf_end - pb->buf_ptr)

  923.             goto error;

  924. 

  925.         ret = avio_get_str16le(pb, desc_len, desc, sizeof(desc));

  926.         avio_skip(pb, desc_len - ret);

  927.         if (*desc)

  928.             av_dict_set(&st->metadata, "title", desc, 0);

  929. 

  930.         avio_rl16(pb);   /* flags? */

  931.         avio_rl32(pb);   /* data size */

  932. 

  933.         pd = (AVProbeData) { .buf      = pb->buf_ptr,

  934.                              .buf_size = pb->buf_end - pb->buf_ptr };

  935.         if (!(sub_demuxer = av_probe_input_format2(&pd, 1, &score)))

  936.             goto error;

  937. 

  938.         if (!(ast->sub_ctx = avformat_alloc_context()))

  939.             goto error;

  940. 

  941.         ast->sub_ctx->pb = pb;

  942.         if (!avformat_open_input(&ast->sub_ctx, "", sub_demuxer, NULL)) {

  943.             ff_read_packet(ast->sub_ctx, &ast->sub_pkt);

  944.             *st->codec = *ast->sub_ctx->streams[0]->codec;

  945.             ast->sub_ctx->streams[0]->codec->extradata = NULL;

  946.             time_base = ast->sub_ctx->streams[0]->time_base;

  947.             avpriv_set_pts_info(st, 64, time_base.num, time_base.den);

  948.         }

  949.         ast->sub_buffer = pkt->data;

  950.         memset(pkt, 0, sizeof(*pkt));

  951.         return 1;

  952. 

  953. error:

  954.         av_freep(&pb);

  955.     }

  956.     return 0;

  957. }

  958. 

  959. static AVStream *get_subtitle_pkt(AVFormatContext *s, AVStream *next_st,

  960.                                   AVPacket *pkt)

  961. {

  962.     AVIStream *ast, *next_ast = next_st->priv_data;

  963.     int64_t ts, next_ts, ts_min = INT64_MAX;

  964.     AVStream *st, *sub_st = NULL;

  965.     int i;

  966. 

  967.     next_ts = av_rescale_q(next_ast->frame_offset, next_st->time_base,

  968.                            AV_TIME_BASE_Q);

  969. 

  970.     for (i = 0; i < s->nb_streams; i++) {

  971.         st  = s->streams[i];

  972.         ast = st->priv_data;

  973.         if (st->discard < AVDISCARD_ALL && ast && ast->sub_pkt.data) {

  974.             ts = av_rescale_q(ast->sub_pkt.dts, st->time_base, AV_TIME_BASE_Q);

  975.             if (ts <= next_ts && ts < ts_min) {

  976.                 ts_min = ts;

  977.                 sub_st = st;

  978.             }

  979.         }

  980.     }

  981. 

  982.     if (sub_st) {

  983.         ast               = sub_st->priv_data;

  984.         *pkt              = ast->sub_pkt;

  985.         pkt->stream_index = sub_st->index;

  986. 

  987.         if (ff_read_packet(ast->sub_ctx, &ast->sub_pkt) < 0)

  988.             ast->sub_pkt.data = NULL;

  989.     }

  990.     return sub_st;

  991. }

  992. 

  993. static int get_stream_idx(unsigned *d)

  994. {

  995.     if (d[0] >= '0' && d[0] <= '9' &&

  996.         d[1] >= '0' && d[1] <= '9') {

  997.         return (d[0] - '0') * 10 + (d[1] - '0');

  998.     } else {

  999.         return 100; // invalid stream ID

  1000.     }

  1001. }

  1002. 

  1003. /**

  1004.  *

  1005.  * @param exit_early set to 1 to just gather packet position without making the changes needed to actually read & return the packet

  1006.  */

  1007. static int avi_sync(AVFormatContext *s, int exit_early)

  1008. {

  1009.     AVIContext *avi = s->priv_data;

  1010.     AVIOContext *pb = s->pb;

  1011.     int n;

  1012.     unsigned int d[8];

  1013.     unsigned int size;

  1014.     int64_t i, sync;

  1015. 

  1016. start_sync:

  1017.     memset(d, -1, sizeof(d));

  1018.     for (i = sync = avio_tell(pb); !url_feof(pb); i++) {

  1019.         int j;

  1020. 

  1021.         for (j = 0; j < 7; j++)

  1022.             d[j] = d[j + 1];

  1023.         d[7] = avio_r8(pb);

  1024. 

  1025.         size = d[4] + (d[5] << 8) + (d[6] << 16) + (d[7] << 24);

  1026. 

  1027.         n = get_stream_idx(d + 2);

  1028.         av_dlog(s, "%X %X %X %X %X %X %X %X %"PRId64" %u %d\n",

  1029.                 d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);

  1030.         if (i*(avi->io_fsize>0) + (uint64_t)size > avi->fsize || d[0] > 127)

  1031.             continue;

  1032. 

  1033.         // parse ix##

  1034.         if ((d[0] == 'i' && d[1] == 'x' && n < s->nb_streams) ||

  1035.             // parse JUNK

  1036.             (d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K') ||

  1037.             (d[0] == 'i' && d[1] == 'd' && d[2] == 'x' && d[3] == '1')) {

  1038.             avio_skip(pb, size);

  1039.             goto start_sync;

  1040.         }

  1041. 

  1042.         // parse stray LIST

  1043.         if (d[0] == 'L' && d[1] == 'I' && d[2] == 'S' && d[3] == 'T') {

  1044.             avio_skip(pb, 4);

  1045.             goto start_sync;

  1046.         }

  1047. 

  1048.         n = get_stream_idx(d);

  1049. 

  1050.         if (!((i - avi->last_pkt_pos) & 1) &&

  1051.             get_stream_idx(d + 1) < s->nb_streams)

  1052.             continue;

  1053. 

  1054.         // detect ##ix chunk and skip

  1055.         if (d[2] == 'i' && d[3] == 'x' && n < s->nb_streams) {

  1056.             avio_skip(pb, size);

  1057.             goto start_sync;

  1058.         }

  1059. 

  1060.         // parse ##dc/##wb

  1061.         if (n < s->nb_streams) {

  1062.             AVStream *st;

  1063.             AVIStream *ast;

  1064.             st  = s->streams[n];

  1065.             ast = st->priv_data;

  1066. 

  1067.             if (!ast) {

  1068.                 av_log(s, AV_LOG_WARNING, "Skiping foreign stream %d packet\n", n);

  1069.                 continue;

  1070.             }

  1071. 

  1072.             if (s->nb_streams >= 2) {

  1073.                 AVStream *st1   = s->streams[1];

  1074.                 AVIStream *ast1 = st1->priv_data;

  1075.                 // workaround for broken small-file-bug402.avi

  1076.                 if (   d[2] == 'w' && d[3] == 'b'

  1077.                    && n == 0

  1078.                    && st ->codec->codec_type == AVMEDIA_TYPE_VIDEO

  1079.                    && st1->codec->codec_type == AVMEDIA_TYPE_AUDIO

  1080.                    && ast->prefix == 'd'*256+'c'

  1081.                    && (d[2]*256+d[3] == ast1->prefix || !ast1->prefix_count)

  1082.                   ) {

  1083.                     n   = 1;

  1084.                     st  = st1;

  1085.                     ast = ast1;

  1086.                     av_log(s, AV_LOG_WARNING,

  1087.                            "Invalid stream + prefix combination, assuming audio.\n");

  1088.                 }

  1089.             }

  1090. 

  1091.             if (!avi->dv_demux &&

  1092.                 ((st->discard >= AVDISCARD_DEFAULT && size == 0) /* ||

  1093.                  // FIXME: needs a little reordering

  1094.                  (st->discard >= AVDISCARD_NONKEY &&

  1095.                  !(pkt->flags & AV_PKT_FLAG_KEY)) */

  1096.                 || st->discard >= AVDISCARD_ALL)) {

  1097.                 if (!exit_early) {

  1098.                     ast->frame_offset += get_duration(ast, size);

  1099.                     avio_skip(pb, size);

  1100.                     goto start_sync;

  1101.                 }

  1102.             }

  1103. 

  1104.             if (d[2] == 'p' && d[3] == 'c' && size <= 4 * 256 + 4) {

  1105.                 int k    = avio_r8(pb);

  1106.                 int last = (k + avio_r8(pb) - 1) & 0xFF;

  1107. 

  1108.                 avio_rl16(pb); // flags

  1109. 

  1110.                 // b + (g << 8) + (r << 16);

  1111.                 for (; k <= last; k++)

  1112.                     ast->pal[k] = 0xFFU<<24 | avio_rb32(pb)>>8;

  1113. 

  1114.                 ast->has_pal = 1;

  1115.                 goto start_sync;

  1116.             } else if (((ast->prefix_count < 5 || sync + 9 > i) &&

  1117.                         d[2] < 128 && d[3] < 128) ||

  1118.                        d[2] * 256 + d[3] == ast->prefix /* ||

  1119.                        (d[2] == 'd' && d[3] == 'c') ||

  1120.                        (d[2] == 'w' && d[3] == 'b') */) {

  1121.                 if (exit_early)

  1122.                     return 0;

  1123.                 if (d[2] * 256 + d[3] == ast->prefix)

  1124.                     ast->prefix_count++;

  1125.                 else {

  1126.                     ast->prefix       = d[2] * 256 + d[3];

  1127.                     ast->prefix_count = 0;

  1128.                 }

  1129. 

  1130.                 avi->stream_index = n;

  1131.                 ast->packet_size  = size + 8;

  1132.                 ast->remaining    = size;

  1133. 

  1134.                 if (size || !ast->sample_size) {

  1135.                     uint64_t pos = avio_tell(pb) - 8;

  1136.                     if (!st->index_entries || !st->nb_index_entries ||

  1137.                         st->index_entries[st->nb_index_entries - 1].pos < pos) {

  1138.                         av_add_index_entry(st, pos, ast->frame_offset, size,

  1139.                                            0, AVINDEX_KEYFRAME);

  1140.                     }

  1141.                 }

  1142.                 return 0;

  1143.             }

  1144.         }

  1145.     }

  1146. 

  1147.     if (pb->error)

  1148.         return pb->error;

  1149.     return AVERROR_EOF;

  1150. }

  1151. 

  1152. static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)

  1153. {

  1154.     AVIContext *avi = s->priv_data;

  1155.     AVIOContext *pb = s->pb;

  1156.     int err;

  1157. #if FF_API_DESTRUCT_PACKET

  1158.     void *dstr;

  1159. #endif

  1160. 

  1161.     if (CONFIG_DV_DEMUXER && avi->dv_demux) {

  1162.         int size = avpriv_dv_get_packet(avi->dv_demux, pkt);

  1163.         if (size >= 0)

  1164.             return size;

  1165.     }

  1166. 

  1167.     if (avi->non_interleaved) {

  1168.         int best_stream_index = 0;

  1169.         AVStream *best_st     = NULL;

  1170.         AVIStream *best_ast;

  1171.         int64_t best_ts = INT64_MAX;

  1172.         int i;

  1173. 

  1174.         for (i = 0; i < s->nb_streams; i++) {

  1175.             AVStream *st   = s->streams[i];

  1176.             AVIStream *ast = st->priv_data;

  1177.             int64_t ts     = ast->frame_offset;

  1178.             int64_t last_ts;

  1179. 

  1180.             if (!st->nb_index_entries)

  1181.                 continue;

  1182. 

  1183.             last_ts = st->index_entries[st->nb_index_entries - 1].timestamp;

  1184.             if (!ast->remaining && ts > last_ts)

  1185.                 continue;

  1186. 

  1187.             ts = av_rescale_q(ts, st->time_base,

  1188.                               (AVRational) { FFMAX(1, ast->sample_size),

  1189.                                              AV_TIME_BASE });

  1190. 

  1191.             av_dlog(s, "%"PRId64" %d/%d %"PRId64"\n", ts,

  1192.                     st->time_base.num, st->time_base.den, ast->frame_offset);

  1193.             if (ts < best_ts) {

  1194.                 best_ts           = ts;

  1195.                 best_st           = st;

  1196.                 best_stream_index = i;

  1197.             }

  1198.         }

  1199.         if (!best_st)

  1200.             return AVERROR_EOF;

  1201. 

  1202.         best_ast = best_st->priv_data;

  1203.         best_ts  = best_ast->frame_offset;

  1204.         if (best_ast->remaining) {

  1205.             i = av_index_search_timestamp(best_st,

  1206.                                           best_ts,

  1207.                                           AVSEEK_FLAG_ANY |

  1208.                                           AVSEEK_FLAG_BACKWARD);

  1209.         } else {

  1210.             i = av_index_search_timestamp(best_st, best_ts, AVSEEK_FLAG_ANY);

  1211.             if (i >= 0)

  1212.                 best_ast->frame_offset = best_st->index_entries[i].timestamp;

  1213.         }

  1214. 

  1215.         if (i >= 0) {

  1216.             int64_t pos = best_st->index_entries[i].pos;

  1217.             pos += best_ast->packet_size - best_ast->remaining;

  1218.             if (avio_seek(s->pb, pos + 8, SEEK_SET) < 0)

  1219.               return AVERROR_EOF;

  1220. 

  1221.             av_assert0(best_ast->remaining <= best_ast->packet_size);

  1222. 

  1223.             avi->stream_index = best_stream_index;

  1224.             if (!best_ast->remaining)

  1225.                 best_ast->packet_size =

  1226.                 best_ast->remaining   = best_st->index_entries[i].size;

  1227.         }

  1228.         else

  1229.           return AVERROR_EOF;

  1230.     }

  1231. 

  1232. resync:

  1233.     if (avi->stream_index >= 0) {

  1234.         AVStream *st   = s->streams[avi->stream_index];

  1235.         AVIStream *ast = st->priv_data;

  1236.         int size, err;

  1237. 

  1238.         if (get_subtitle_pkt(s, st, pkt))

  1239.             return 0;

  1240. 

  1241.         // minorityreport.AVI block_align=1024 sample_size=1 IMA-ADPCM

  1242.         if (ast->sample_size <= 1)

  1243.             size = INT_MAX;

  1244.         else if (ast->sample_size < 32)

  1245.             // arbitrary multiplier to avoid tiny packets for raw PCM data

  1246.             size = 1024 * ast->sample_size;

  1247.         else

  1248.             size = ast->sample_size;

  1249. 

  1250.         if (size > ast->remaining)

  1251.             size = ast->remaining;

  1252.         avi->last_pkt_pos = avio_tell(pb);

  1253.         err               = av_get_packet(pb, pkt, size);

  1254.         if (err < 0)

  1255.             return err;

  1256.         size = err;

  1257. 

  1258.         if (ast->has_pal && pkt->size < (unsigned)INT_MAX / 2) {

  1259.             uint8_t *pal;

  1260.             pal = av_packet_new_side_data(pkt,

  1261.                                           AV_PKT_DATA_PALETTE,

  1262.                                           AVPALETTE_SIZE);

  1263.             if (!pal) {

  1264.                 av_log(s, AV_LOG_ERROR,

  1265.                        "Failed to allocate data for palette\n");

  1266.             } else {

  1267.                 memcpy(pal, ast->pal, AVPALETTE_SIZE);

  1268.                 ast->has_pal = 0;

  1269.             }

  1270.         }

  1271. 

  1272.         if (CONFIG_DV_DEMUXER && avi->dv_demux) {

  1273.             AVBufferRef *avbuf = pkt->buf;

  1274. #if FF_API_DESTRUCT_PACKET

  1275. FF_DISABLE_DEPRECATION_WARNINGS

  1276.             dstr = pkt->destruct;

  1277. FF_ENABLE_DEPRECATION_WARNINGS

  1278. #endif

  1279.             size = avpriv_dv_produce_packet(avi->dv_demux, pkt,

  1280.                                             pkt->data, pkt->size, pkt->pos);

  1281. #if FF_API_DESTRUCT_PACKET

  1282. FF_DISABLE_DEPRECATION_WARNINGS

  1283.             pkt->destruct = dstr;

  1284. FF_ENABLE_DEPRECATION_WARNINGS

  1285. #endif

  1286.             pkt->buf    = avbuf;

  1287.             pkt->flags |= AV_PKT_FLAG_KEY;

  1288.             if (size < 0)

  1289.                 av_free_packet(pkt);

  1290.         } else if (st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE &&

  1291.                    !st->codec->codec_tag && read_gab2_sub(st, pkt)) {

  1292.             ast->frame_offset++;

  1293.             avi->stream_index = -1;

  1294.             ast->remaining    = 0;

  1295.             goto resync;

  1296.         } else {

  1297.             /* XXX: How to handle B-frames in AVI? */

  1298.             pkt->dts = ast->frame_offset;

  1299. //                pkt->dts += ast->start;

  1300.             if (ast->sample_size)

  1301.                 pkt->dts /= ast->sample_size;

  1302.             av_dlog(s,

  1303.                     "dts:%"PRId64" offset:%"PRId64" %d/%d smpl_siz:%d "

  1304.                     "base:%d st:%d size:%d\n",

  1305.                     pkt->dts,

  1306.                     ast->frame_offset,

  1307.                     ast->scale,

  1308.                     ast->rate,

  1309.                     ast->sample_size,

  1310.                     AV_TIME_BASE,

  1311.                     avi->stream_index,

  1312.                     size);

  1313.             pkt->stream_index = avi->stream_index;

  1314. 

  1315.             if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {

  1316.                 AVIndexEntry *e;

  1317.                 int index;

  1318.                 av_assert0(st->index_entries);

  1319. 

  1320.                 index = av_index_search_timestamp(st, ast->frame_offset, 0);

  1321.                 e     = &st->index_entries[index];

  1322. 

  1323.                 if (index >= 0 && e->timestamp == ast->frame_offset) {

  1324.                     if (index == st->nb_index_entries-1) {

  1325.                         int key=1;

  1326.                         int i;

  1327.                         uint32_t state=-1;

  1328.                         for (i=0; i<FFMIN(size,256); i++) {

  1329.                             if (st->codec->codec_id == AV_CODEC_ID_MPEG4) {

  1330.                                 if (state == 0x1B6) {

  1331.                                     key= !(pkt->data[i]&0xC0);

  1332.                                     break;

  1333.                                 }

  1334.                             }else

  1335.                                 break;

  1336.                             state= (state<<8) + pkt->data[i];

  1337.                         }

  1338.                         if (!key)

  1339.                             e->flags &= ~AVINDEX_KEYFRAME;

  1340.                     }

  1341.                     if (e->flags & AVINDEX_KEYFRAME)

  1342.                         pkt->flags |= AV_PKT_FLAG_KEY;

  1343.                 }

  1344.             } else {

  1345.                 pkt->flags |= AV_PKT_FLAG_KEY;

  1346.             }

  1347.             ast->frame_offset += get_duration(ast, pkt->size);

  1348.         }

  1349.         ast->remaining -= err;

  1350.         if (!ast->remaining) {

  1351.             avi->stream_index = -1;

  1352.             ast->packet_size  = 0;

  1353.         }

  1354. 

  1355.         if (!avi->non_interleaved && pkt->pos >= 0 && ast->seek_pos > pkt->pos) {

  1356.             av_free_packet(pkt);

  1357.             goto resync;

  1358.         }

  1359.         ast->seek_pos= 0;

  1360. 

  1361.         if (!avi->non_interleaved && st->nb_index_entries>1 && avi->index_loaded>1) {

  1362.             int64_t dts= av_rescale_q(pkt->dts, st->time_base, AV_TIME_BASE_Q);

  1363. 

  1364.             if (avi->dts_max - dts > 2*AV_TIME_BASE) {

  1365.                 avi->non_interleaved= 1;

  1366.                 av_log(s, AV_LOG_INFO, "Switching to NI mode, due to poor interleaving\n");

  1367.             }else if (avi->dts_max < dts)

  1368.                 avi->dts_max = dts;

  1369.         }

  1370. 

  1371.         return 0;

  1372.     }

  1373. 

  1374.     if ((err = avi_sync(s, 0)) < 0)

  1375.         return err;

  1376.     goto resync;

  1377. }

  1378. 

  1379. /* XXX: We make the implicit supposition that the positions are sorted

  1380.  * for each stream. */

  1381. static int avi_read_idx1(AVFormatContext *s, int size)

  1382. {

  1383.     AVIContext *avi = s->priv_data;

  1384.     AVIOContext *pb = s->pb;

  1385.     int nb_index_entries, i;

  1386.     AVStream *st;

  1387.     AVIStream *ast;

  1388.     unsigned int index, tag, flags, pos, len, first_packet = 1;

  1389.     unsigned last_pos = -1;

  1390.     unsigned last_idx = -1;

  1391.     int64_t idx1_pos, first_packet_pos = 0, data_offset = 0;

  1392.     int anykey = 0;

  1393. 

  1394.     nb_index_entries = size / 16;

  1395.     if (nb_index_entries <= 0)

  1396.         return AVERROR_INVALIDDATA;

  1397. 

  1398.     idx1_pos = avio_tell(pb);

  1399.     avio_seek(pb, avi->movi_list + 4, SEEK_SET);

  1400.     if (avi_sync(s, 1) == 0)

  1401.         first_packet_pos = avio_tell(pb) - 8;

  1402.     avi->stream_index = -1;

  1403.     avio_seek(pb, idx1_pos, SEEK_SET);

  1404. 

  1405.     if (s->nb_streams == 1 && s->streams[0]->codec->codec_tag == AV_RL32("MMES")) {

  1406.         first_packet_pos = 0;

  1407.         data_offset = avi->movi_list;

  1408.     }

  1409. 

  1410.     /* Read the entries and sort them in each stream component. */

  1411.     for (i = 0; i < nb_index_entries; i++) {

  1412.         if (url_feof(pb))

  1413.             return -1;

  1414. 

  1415.         tag   = avio_rl32(pb);

  1416.         flags = avio_rl32(pb);

  1417.         pos   = avio_rl32(pb);

  1418.         len   = avio_rl32(pb);

  1419.         av_dlog(s, "%d: tag=0x%x flags=0x%x pos=0x%x len=%d/",

  1420.                 i, tag, flags, pos, len);

  1421. 

  1422.         index  = ((tag      & 0xff) - '0') * 10;

  1423.         index +=  (tag >> 8 & 0xff) - '0';

  1424.         if (index >= s->nb_streams)

  1425.             continue;

  1426.         st  = s->streams[index];

  1427.         ast = st->priv_data;

  1428. 

  1429.         if (first_packet && first_packet_pos) {

  1430.             data_offset  = first_packet_pos - pos;

  1431.             first_packet = 0;

  1432.         }

  1433.         pos += data_offset;

  1434. 

  1435.         av_dlog(s, "%d cum_len=%"PRId64"\n", len, ast->cum_len);

  1436. 

  1437.         // even if we have only a single stream, we should

  1438.         // switch to non-interleaved to get correct timestamps

  1439.         if (last_pos == pos)

  1440.             avi->non_interleaved = 1;

  1441.         if (last_idx != pos && len) {

  1442.             av_add_index_entry(st, pos, ast->cum_len, len, 0,

  1443.                                (flags & AVIIF_INDEX) ? AVINDEX_KEYFRAME : 0);

  1444.             last_idx= pos;

  1445.         }

  1446.         ast->cum_len += get_duration(ast, len);

  1447.         last_pos      = pos;

  1448.         anykey       |= flags&AVIIF_INDEX;

  1449.     }

  1450.     if (!anykey) {

  1451.         for (index = 0; index < s->nb_streams; index++) {

  1452.             st = s->streams[index];

  1453.             if (st->nb_index_entries)

  1454.                 st->index_entries[0].flags |= AVINDEX_KEYFRAME;

  1455.         }

  1456.     }

  1457.     return 0;

  1458. }

  1459. 

  1460. static int guess_ni_flag(AVFormatContext *s)

  1461. {

  1462.     int i;

  1463.     int64_t last_start = 0;

  1464.     int64_t first_end  = INT64_MAX;

  1465.     int64_t oldpos     = avio_tell(s->pb);

  1466.     int *idx;

  1467.     int64_t min_pos, pos;

  1468. 

  1469.     for (i = 0; i < s->nb_streams; i++) {

  1470.         AVStream *st = s->streams[i];

  1471.         int n        = st->nb_index_entries;

  1472.         unsigned int size;

  1473. 

  1474.         if (n <= 0)

  1475.             continue;

  1476. 

  1477.         if (n >= 2) {

  1478.             int64_t pos = st->index_entries[0].pos;

  1479.             avio_seek(s->pb, pos + 4, SEEK_SET);

  1480.             size = avio_rl32(s->pb);

  1481.             if (pos + size > st->index_entries[1].pos)

  1482.                 last_start = INT64_MAX;

  1483.         }

  1484. 

  1485.         if (st->index_entries[0].pos > last_start)

  1486.             last_start = st->index_entries[0].pos;

  1487.         if (st->index_entries[n - 1].pos < first_end)

  1488.             first_end = st->index_entries[n - 1].pos;

  1489.     }

  1490.     avio_seek(s->pb, oldpos, SEEK_SET);

  1491.     if (last_start > first_end)

  1492.         return 1;

  1493.     idx= av_calloc(s->nb_streams, sizeof(*idx));

  1494.     if (!idx)

  1495.         return 0;

  1496.     for (min_pos=pos=0; min_pos!=INT64_MAX; pos= min_pos+1LU) {

  1497.         int64_t max_dts = INT64_MIN/2, min_dts= INT64_MAX/2;

  1498.         min_pos = INT64_MAX;

  1499. 

  1500.         for (i=0; i<s->nb_streams; i++) {

  1501.             AVStream *st = s->streams[i];

  1502.             AVIStream *ast = st->priv_data;

  1503.             int n= st->nb_index_entries;

  1504.             while (idx[i]<n && st->index_entries[idx[i]].pos < pos)

  1505.                 idx[i]++;

  1506.             if (idx[i] < n) {

  1507.                 min_dts = FFMIN(min_dts, av_rescale_q(st->index_entries[idx[i]].timestamp/FFMAX(ast->sample_size, 1), st->time_base, AV_TIME_BASE_Q));

  1508.                 min_pos = FFMIN(min_pos, st->index_entries[idx[i]].pos);

  1509.             }

  1510.             if (idx[i])

  1511.                 max_dts = FFMAX(max_dts, av_rescale_q(st->index_entries[idx[i]-1].timestamp/FFMAX(ast->sample_size, 1), st->time_base, AV_TIME_BASE_Q));

  1512.         }

  1513.         if (max_dts - min_dts > 2*AV_TIME_BASE) {

  1514.             av_free(idx);

  1515.             return 1;

  1516.         }

  1517.     }

  1518.     av_free(idx);

  1519.     return 0;

  1520. }

  1521. 

  1522. static int avi_load_index(AVFormatContext *s)

  1523. {

  1524.     AVIContext *avi = s->priv_data;

  1525.     AVIOContext *pb = s->pb;

  1526.     uint32_t tag, size;

  1527.     int64_t pos = avio_tell(pb);

  1528.     int64_t next;

  1529.     int ret     = -1;

  1530. 

  1531.     if (avio_seek(pb, avi->movi_end, SEEK_SET) < 0)

  1532.         goto the_end; // maybe truncated file

  1533.     av_dlog(s, "movi_end=0x%"PRIx64"\n", avi->movi_end);

  1534.     for (;;) {

  1535.         tag  = avio_rl32(pb);

  1536.         size = avio_rl32(pb);

  1537.         if (url_feof(pb))

  1538.             break;

  1539.         next = avio_tell(pb) + size + (size & 1);

  1540. 

  1541.         av_dlog(s, "tag=%c%c%c%c size=0x%x\n",

  1542.                  tag        & 0xff,

  1543.                 (tag >>  8) & 0xff,

  1544.                 (tag >> 16) & 0xff,

  1545.                 (tag >> 24) & 0xff,

  1546.                 size);

  1547. 

  1548.         if (tag == MKTAG('i', 'd', 'x', '1') &&

  1549.             avi_read_idx1(s, size) >= 0) {

  1550.             avi->index_loaded=2;

  1551.             ret = 0;

  1552.         }else if (tag == MKTAG('L', 'I', 'S', 'T')) {

  1553.             uint32_t tag1 = avio_rl32(pb);

  1554. 

  1555.             if (tag1 == MKTAG('I', 'N', 'F', 'O'))

  1556.                 ff_read_riff_info(s, size - 4);

  1557.         }else if (!ret)

  1558.             break;

  1559. 

  1560.         if (avio_seek(pb, next, SEEK_SET) < 0)

  1561.             break; // something is wrong here

  1562.     }

  1563. 

  1564. the_end:

  1565.     avio_seek(pb, pos, SEEK_SET);

  1566.     return ret;

  1567. }

  1568. 

  1569. static void seek_subtitle(AVStream *st, AVStream *st2, int64_t timestamp)

  1570. {

  1571.     AVIStream *ast2 = st2->priv_data;

  1572.     int64_t ts2     = av_rescale_q(timestamp, st->time_base, st2->time_base);

  1573.     av_free_packet(&ast2->sub_pkt);

  1574.     if (avformat_seek_file(ast2->sub_ctx, 0, INT64_MIN, ts2, ts2, 0) >= 0 ||

  1575.         avformat_seek_file(ast2->sub_ctx, 0, ts2, ts2, INT64_MAX, 0) >= 0)

  1576.         ff_read_packet(ast2->sub_ctx, &ast2->sub_pkt);

  1577. }

  1578. 

  1579. static int avi_read_seek(AVFormatContext *s, int stream_index,

  1580.                          int64_t timestamp, int flags)

  1581. {

  1582.     AVIContext *avi = s->priv_data;

  1583.     AVStream *st;

  1584.     int i, index;

  1585.     int64_t pos, pos_min;

  1586.     AVIStream *ast;

  1587. 

  1588.     if (!avi->index_loaded) {

  1589.         /* we only load the index on demand */

  1590.         avi_load_index(s);

  1591.         avi->index_loaded |= 1;

  1592.     }

  1593.     av_assert0(stream_index >= 0);

  1594. 

  1595.     st    = s->streams[stream_index];

  1596.     ast   = st->priv_data;

  1597.     index = av_index_search_timestamp(st,

  1598.                                       timestamp * FFMAX(ast->sample_size, 1),

  1599.                                       flags);

  1600.     if (index < 0) {

  1601.         if (st->nb_index_entries > 0)

  1602.             av_log(s, AV_LOG_DEBUG, "Failed to find timestamp %"PRId64 " in index %"PRId64 " .. %"PRId64 "\n",

  1603.                    timestamp * FFMAX(ast->sample_size, 1),

  1604.                    st->index_entries[0].timestamp,

  1605.                    st->index_entries[st->nb_index_entries - 1].timestamp);

  1606.         return AVERROR_INVALIDDATA;

  1607.     }

  1608. 

  1609.     /* find the position */

  1610.     pos       = st->index_entries[index].pos;

  1611.     timestamp = st->index_entries[index].timestamp / FFMAX(ast->sample_size, 1);

  1612. 

  1613.     av_dlog(s, "XX %"PRId64" %d %"PRId64"\n",

  1614.             timestamp, index, st->index_entries[index].timestamp);

  1615. 

  1616.     if (CONFIG_DV_DEMUXER && avi->dv_demux) {

  1617.         /* One and only one real stream for DV in AVI, and it has video  */

  1618.         /* offsets. Calling with other stream indexes should have failed */

  1619.         /* the av_index_search_timestamp call above.                     */

  1620.         av_assert0(stream_index == 0);

  1621. 

  1622.         if (avio_seek(s->pb, pos, SEEK_SET) < 0)

  1623.             return -1;

  1624. 

  1625.         /* Feed the DV video stream version of the timestamp to the */

  1626.         /* DV demux so it can synthesize correct timestamps.        */

  1627.         ff_dv_offset_reset(avi->dv_demux, timestamp);

  1628. 

  1629.         avi->stream_index = -1;

  1630.         return 0;

  1631.     }

  1632. 

  1633.     pos_min = pos;

  1634.     for (i = 0; i < s->nb_streams; i++) {

  1635.         AVStream *st2   = s->streams[i];

  1636.         AVIStream *ast2 = st2->priv_data;

  1637. 

  1638.         ast2->packet_size =

  1639.         ast2->remaining   = 0;

  1640. 

  1641.         if (ast2->sub_ctx) {

  1642.             seek_subtitle(st, st2, timestamp);

  1643.             continue;

  1644.         }

  1645. 

  1646.         if (st2->nb_index_entries <= 0)

  1647.             continue;

  1648. 

  1649. //        av_assert1(st2->codec->block_align);

  1650.         av_assert0((int64_t)st2->time_base.num * ast2->rate ==

  1651.                    (int64_t)st2->time_base.den * ast2->scale);

  1652.         index = av_index_search_timestamp(st2,

  1653.                                           av_rescale_q(timestamp,

  1654.                                                        st->time_base,

  1655.                                                        st2->time_base) *

  1656.                                           FFMAX(ast2->sample_size, 1),

  1657.                                           flags |

  1658.                                           AVSEEK_FLAG_BACKWARD |

  1659.                                           (st2->codec->codec_type != AVMEDIA_TYPE_VIDEO ? AVSEEK_FLAG_ANY : 0));

  1660.         if (index < 0)

  1661.             index = 0;

  1662.         ast2->seek_pos = st2->index_entries[index].pos;

  1663.         pos_min = FFMIN(pos_min,ast2->seek_pos);

  1664.     }

  1665.     for (i = 0; i < s->nb_streams; i++) {

  1666.         AVStream *st2 = s->streams[i];

  1667.         AVIStream *ast2 = st2->priv_data;

  1668. 

  1669.         if (ast2->sub_ctx || st2->nb_index_entries <= 0)

  1670.             continue;

  1671. 

  1672.         index = av_index_search_timestamp(

  1673.                 st2,

  1674.                 av_rescale_q(timestamp, st->time_base, st2->time_base) * FFMAX(ast2->sample_size, 1),

  1675.                 flags | AVSEEK_FLAG_BACKWARD | (st2->codec->codec_type != AVMEDIA_TYPE_VIDEO ? AVSEEK_FLAG_ANY : 0));

  1676.         if (index < 0)

  1677.             index = 0;

  1678.         while (!avi->non_interleaved && index>0 && st2->index_entries[index-1].pos >= pos_min)

  1679.             index--;

  1680.         ast2->frame_offset = st2->index_entries[index].timestamp;

  1681.     }

  1682. 

  1683.     /* do the seek */

  1684.     if (avio_seek(s->pb, pos_min, SEEK_SET) < 0) {

  1685.         av_log(s, AV_LOG_ERROR, "Seek failed\n");

  1686.         return -1;

  1687.     }

  1688.     avi->stream_index = -1;

  1689.     avi->dts_max      = INT_MIN;

  1690.     return 0;

  1691. }

  1692. 

  1693. static int avi_read_close(AVFormatContext *s)

  1694. {

  1695.     int i;

  1696.     AVIContext *avi = s->priv_data;

  1697. 

  1698.     for (i = 0; i < s->nb_streams; i++) {

  1699.         AVStream *st   = s->streams[i];

  1700.         AVIStream *ast = st->priv_data;

  1701.         if (ast) {

  1702.             if (ast->sub_ctx) {

  1703.                 av_freep(&ast->sub_ctx->pb);

  1704.                 avformat_close_input(&ast->sub_ctx);

  1705.             }

  1706.             av_free(ast->sub_buffer);

  1707.             av_free_packet(&ast->sub_pkt);

  1708.         }

  1709.     }

  1710. 

  1711.     av_free(avi->dv_demux);

  1712. 

  1713.     return 0;

  1714. }

  1715. 

  1716. static int avi_probe(AVProbeData *p)

  1717. {

  1718.     int i;

  1719. 

  1720.     /* check file header */

  1721.     for (i = 0; avi_headers[i][0]; i++)

  1722.         if (!memcmp(p->buf,     avi_headers[i],     4) &&

  1723.             !memcmp(p->buf + 8, avi_headers[i] + 4, 4))

  1724.             return AVPROBE_SCORE_MAX;

  1725. 

  1726.     return 0;

  1727. }

  1728. 

  1729. AVInputFormat ff_avi_demuxer = {

  1730.     .name           = "avi",

  1731.     .long_name      = NULL_IF_CONFIG_SMALL("AVI (Audio Video Interleaved)"),

  1732.     .priv_data_size = sizeof(AVIContext),

  1733.     .read_probe     = avi_probe,

  1734.     .read_header    = avi_read_header,

  1735.     .read_packet    = avi_read_packet,

  1736.     .read_close     = avi_read_close,

  1737.     .read_seek      = avi_read_seek,

  1738.     .priv_class = &demuxer_class,

  1739. };