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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.                         if (ff_alloc_extradata(st->codec, st->codec->extradata_size))

  652.                             return AVERROR(ENOMEM);

  653.                         avio_read(pb,

  654.                                   st->codec->extradata,

  655.                                   st->codec->extradata_size);

  656.                     }

  657. 

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

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

  660.                         avio_r8(pb);

  661. 

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

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

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

  665.                      * FFmpeg. */

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

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

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

  669.                         const uint8_t *pal_src;

  670. 

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

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

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

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

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

  676.                         ast->has_pal = 1;

  677.                     }

  678. 

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

  680. 

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

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

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

  684.                                                             tag1);

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

  686.                      * for generating correct pts. */

  687.                     st->need_parsing = AVSTREAM_PARSE_HEADERS;

  688. 

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

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

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

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

  693.                                                st->codec->extradata_size +

  694.                                                FF_INPUT_BUFFER_PADDING_SIZE)) < 0) {

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

  696.                             return ret;

  697.                         } else

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

  699.                                    "BottomUp", 9);

  700.                     }

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

  702. 

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

  704.                     break;

  705.                 case AVMEDIA_TYPE_AUDIO:

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

  707.                     if (ret < 0)

  708.                         return ret;

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

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

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

  712.                         av_log(s,

  713.                                AV_LOG_WARNING,

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

  715.                                ast->sample_size,

  716.                                st->codec->block_align);

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

  718.                     }

  719.                     /* 2-aligned

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

  721.                     if (size & 1)

  722.                         avio_skip(pb, 1);

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

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

  725.                     st->need_parsing = AVSTREAM_PARSE_TIMESTAMPS;

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

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

  728.                      * fail. */

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

  730.                         st->codec->extradata_size)

  731.                         st->need_parsing = AVSTREAM_PARSE_NONE;

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

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

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

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

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

  737.                         ast->dshow_block_align = 0;

  738.                     }

  739.                     if (amv_file_format) {

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

  741.                         ast->dshow_block_align = 0;

  742.                     }

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

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

  745.                         ast->dshow_block_align = 0;

  746.                     }

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

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

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

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

  751.                         ast->sample_size = 0;

  752.                     }

  753.                     break;

  754.                 case AVMEDIA_TYPE_SUBTITLE:

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

  756.                     st->request_probe= 1;

  757.                     avio_skip(pb, size);

  758.                     break;

  759.                 default:

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

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

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

  763.                     avio_skip(pb, size);

  764.                     break;

  765.                 }

  766.             }

  767.             break;

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

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

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

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

  772.                 avio_skip(pb, size);

  773.             } else {

  774.                 uint64_t cur_pos = avio_tell(pb);

  775.                 if (cur_pos < list_end)

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

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

  778. 

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

  780.                     if (ff_alloc_extradata(st->codec, size))

  781.                         return AVERROR(ENOMEM);

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

  783.                 }

  784. 

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

  786.                     avio_r8(pb);

  787.             }

  788.             break;

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

  790.             i = avio_tell(pb);

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

  792.                 avi->use_odml &&

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

  794.                 (s->error_recognition & AV_EF_EXPLODE))

  795.                 goto fail;

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

  797.             break;

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

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

  800.                 AVRational active, active_aspect;

  801. 

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

  803.                 avio_rl32(pb);

  804.                 avio_rl32(pb);

  805.                 avio_rl32(pb);

  806.                 avio_rl32(pb);

  807.                 avio_rl32(pb);

  808. 

  809.                 active_aspect.den = avio_rl16(pb);

  810.                 active_aspect.num = avio_rl16(pb);

  811.                 active.num        = avio_rl32(pb);

  812.                 active.den        = avio_rl32(pb);

  813.                 avio_rl32(pb); // nbFieldsPerFrame

  814. 

  815.                 if (active_aspect.num && active_aspect.den &&

  816.                     active.num && active.den) {

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

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

  819.                             active_aspect.num, active_aspect.den,

  820.                             active.num, active.den);

  821.                 }

  822.                 size -= 9 * 4;

  823.             }

  824.             avio_skip(pb, size);

  825.             break;

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

  827.             if (s->nb_streams) {

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

  829.                 if (ret < 0)

  830.                     return ret;

  831.                 break;

  832.             }

  833.         default:

  834.             if (size > 1000000) {

  835.                 av_log(s, AV_LOG_ERROR,

  836.                        "Something went wrong during header parsing, "

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

  838.                 if (s->error_recognition & AV_EF_EXPLODE)

  839.                     goto fail;

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

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

  842.                 goto end_of_header;

  843.             }

  844.             /* skip tag */

  845.             size += (size & 1);

  846.             avio_skip(pb, size);

  847.             break;

  848.         }

  849.     }

  850. 

  851. end_of_header:

  852.     /* check stream number */

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

  854. 

  855. fail:

  856.         return AVERROR_INVALIDDATA;

  857.     }

  858. 

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

  860.         avi_load_index(s);

  861.     avi->index_loaded    |= 1;

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

  863. 

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

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

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

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

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

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

  870.                 st->need_parsing = AVSTREAM_PARSE_FULL;

  871.         }

  872. 

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

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

  875.         if (st->nb_index_entries)

  876.             break;

  877.     }

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

  879.     // a mis-detection.

  880.     if (avi->dv_demux)

  881.         avi->non_interleaved = 0;

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

  883.         av_log(s, AV_LOG_WARNING,

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

  885.         avi->non_interleaved = 0;

  886.     }

  887. 

  888.     if (avi->non_interleaved) {

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

  890.         clean_index(s);

  891.     }

  892. 

  893.     ff_metadata_conv_ctx(s, NULL, avi_metadata_conv);

  894.     ff_metadata_conv_ctx(s, NULL, ff_riff_info_conv);

  895. 

  896.     return 0;

  897. }

  898. 

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

  900. {

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

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

  903.         uint8_t desc[256];

  904.         int score      = AVPROBE_SCORE_EXTENSION, ret;

  905.         AVIStream *ast = st->priv_data;

  906.         AVInputFormat *sub_demuxer;

  907.         AVRational time_base;

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

  909.                                              pkt->size - 7,

  910.                                              0, NULL, NULL, NULL, NULL);

  911.         AVProbeData pd;

  912.         unsigned int desc_len = avio_rl32(pb);

  913. 

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

  915.             goto error;

  916. 

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

  918.         avio_skip(pb, desc_len - ret);

  919.         if (*desc)

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

  921. 

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

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

  924. 

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

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

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

  928.             goto error;

  929. 

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

  931.             goto error;

  932. 

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

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

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

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

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

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

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

  940.         }

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

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

  943.         return 1;

  944. 

  945. error:

  946.         av_freep(&pb);

  947.     }

  948.     return 0;

  949. }

  950. 

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

  952.                                   AVPacket *pkt)

  953. {

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

  955.     int64_t ts, next_ts, ts_min = INT64_MAX;

  956.     AVStream *st, *sub_st = NULL;

  957.     int i;

  958. 

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

  960.                            AV_TIME_BASE_Q);

  961. 

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

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

  964.         ast = st->priv_data;

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

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

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

  968.                 ts_min = ts;

  969.                 sub_st = st;

  970.             }

  971.         }

  972.     }

  973. 

  974.     if (sub_st) {

  975.         ast               = sub_st->priv_data;

  976.         *pkt              = ast->sub_pkt;

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

  978. 

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

  980.             ast->sub_pkt.data = NULL;

  981.     }

  982.     return sub_st;

  983. }

  984. 

  985. static int get_stream_idx(unsigned *d)

  986. {

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

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

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

  990.     } else {

  991.         return 100; // invalid stream ID

  992.     }

  993. }

  994. 

  995. /**

  996.  *

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

  998.  */

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

  1000. {

  1001.     AVIContext *avi = s->priv_data;

  1002.     AVIOContext *pb = s->pb;

  1003.     int n;

  1004.     unsigned int d[8];

  1005.     unsigned int size;

  1006.     int64_t i, sync;

  1007. 

  1008. start_sync:

  1009.     memset(d, -1, sizeof(d));

  1010.     for (i = sync = avio_tell(pb); !url_feof(pb); i++) {

  1011.         int j;

  1012. 

  1013.         for (j = 0; j < 7; j++)

  1014.             d[j] = d[j + 1];

  1015.         d[7] = avio_r8(pb);

  1016. 

  1017.         size = d[4] + (d[5] << 8) + (d[6] << 16) + (d[7] << 24);

  1018. 

  1019.         n = get_stream_idx(d + 2);

  1020.         av_dlog(s, "%X %X %X %X %X %X %X %X %"PRId64" %u %d\n",

  1021.                 d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);

  1022.         if (i*(avi->io_fsize>0) + (uint64_t)size > avi->fsize || d[0] > 127)

  1023.             continue;

  1024. 

  1025.         // parse ix##

  1026.         if ((d[0] == 'i' && d[1] == 'x' && n < s->nb_streams) ||

  1027.             // parse JUNK

  1028.             (d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K') ||

  1029.             (d[0] == 'i' && d[1] == 'd' && d[2] == 'x' && d[3] == '1')) {

  1030.             avio_skip(pb, size);

  1031.             goto start_sync;

  1032.         }

  1033. 

  1034.         // parse stray LIST

  1035.         if (d[0] == 'L' && d[1] == 'I' && d[2] == 'S' && d[3] == 'T') {

  1036.             avio_skip(pb, 4);

  1037.             goto start_sync;

  1038.         }

  1039. 

  1040.         n = avi->dv_demux ? 0 : get_stream_idx(d);

  1041. 

  1042.         if (!((i - avi->last_pkt_pos) & 1) &&

  1043.             get_stream_idx(d + 1) < s->nb_streams)

  1044.             continue;

  1045. 

  1046.         // detect ##ix chunk and skip

  1047.         if (d[2] == 'i' && d[3] == 'x' && n < s->nb_streams) {

  1048.             avio_skip(pb, size);

  1049.             goto start_sync;

  1050.         }

  1051. 

  1052.         // parse ##dc/##wb

  1053.         if (n < s->nb_streams) {

  1054.             AVStream *st;

  1055.             AVIStream *ast;

  1056.             st  = s->streams[n];

  1057.             ast = st->priv_data;

  1058. 

  1059.             if (!ast) {

  1060.                 av_log(s, AV_LOG_WARNING, "Skiping foreign stream %d packet\n", n);

  1061.                 continue;

  1062.             }

  1063. 

  1064.             if (s->nb_streams >= 2) {

  1065.                 AVStream *st1   = s->streams[1];

  1066.                 AVIStream *ast1 = st1->priv_data;

  1067.                 // workaround for broken small-file-bug402.avi

  1068.                 if (   d[2] == 'w' && d[3] == 'b'

  1069.                    && n == 0

  1070.                    && st ->codec->codec_type == AVMEDIA_TYPE_VIDEO

  1071.                    && st1->codec->codec_type == AVMEDIA_TYPE_AUDIO

  1072.                    && ast->prefix == 'd'*256+'c'

  1073.                    && (d[2]*256+d[3] == ast1->prefix || !ast1->prefix_count)

  1074.                   ) {

  1075.                     n   = 1;

  1076.                     st  = st1;

  1077.                     ast = ast1;

  1078.                     av_log(s, AV_LOG_WARNING,

  1079.                            "Invalid stream + prefix combination, assuming audio.\n");

  1080.                 }

  1081.             }

  1082. 

  1083.             if (!avi->dv_demux &&

  1084.                 ((st->discard >= AVDISCARD_DEFAULT && size == 0) /* ||

  1085.                  // FIXME: needs a little reordering

  1086.                  (st->discard >= AVDISCARD_NONKEY &&

  1087.                  !(pkt->flags & AV_PKT_FLAG_KEY)) */

  1088.                 || st->discard >= AVDISCARD_ALL)) {

  1089.                 if (!exit_early) {

  1090.                     ast->frame_offset += get_duration(ast, size);

  1091.                     avio_skip(pb, size);

  1092.                     goto start_sync;

  1093.                 }

  1094.             }

  1095. 

  1096.             if (d[2] == 'p' && d[3] == 'c' && size <= 4 * 256 + 4) {

  1097.                 int k    = avio_r8(pb);

  1098.                 int last = (k + avio_r8(pb) - 1) & 0xFF;

  1099. 

  1100.                 avio_rl16(pb); // flags

  1101. 

  1102.                 // b + (g << 8) + (r << 16);

  1103.                 for (; k <= last; k++)

  1104.                     ast->pal[k] = 0xFFU<<24 | avio_rb32(pb)>>8;

  1105. 

  1106.                 ast->has_pal = 1;

  1107.                 goto start_sync;

  1108.             } else if (((ast->prefix_count < 5 || sync + 9 > i) &&

  1109.                         d[2] < 128 && d[3] < 128) ||

  1110.                        d[2] * 256 + d[3] == ast->prefix /* ||

  1111.                        (d[2] == 'd' && d[3] == 'c') ||

  1112.                        (d[2] == 'w' && d[3] == 'b') */) {

  1113.                 if (exit_early)

  1114.                     return 0;

  1115.                 if (d[2] * 256 + d[3] == ast->prefix)

  1116.                     ast->prefix_count++;

  1117.                 else {

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

  1119.                     ast->prefix_count = 0;

  1120.                 }

  1121. 

  1122.                 avi->stream_index = n;

  1123.                 ast->packet_size  = size + 8;

  1124.                 ast->remaining    = size;

  1125. 

  1126.                 if (size || !ast->sample_size) {

  1127.                     uint64_t pos = avio_tell(pb) - 8;

  1128.                     if (!st->index_entries || !st->nb_index_entries ||

  1129.                         st->index_entries[st->nb_index_entries - 1].pos < pos) {

  1130.                         av_add_index_entry(st, pos, ast->frame_offset, size,

  1131.                                            0, AVINDEX_KEYFRAME);

  1132.                     }

  1133.                 }

  1134.                 return 0;

  1135.             }

  1136.         }

  1137.     }

  1138. 

  1139.     if (pb->error)

  1140.         return pb->error;

  1141.     return AVERROR_EOF;

  1142. }

  1143. 

  1144. static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)

  1145. {

  1146.     AVIContext *avi = s->priv_data;

  1147.     AVIOContext *pb = s->pb;

  1148.     int err;

  1149. #if FF_API_DESTRUCT_PACKET

  1150.     void *dstr;

  1151. #endif

  1152. 

  1153.     if (CONFIG_DV_DEMUXER && avi->dv_demux) {

  1154.         int size = avpriv_dv_get_packet(avi->dv_demux, pkt);

  1155.         if (size >= 0)

  1156.             return size;

  1157.         else

  1158.             goto resync;

  1159.     }

  1160. 

  1161.     if (avi->non_interleaved) {

  1162.         int best_stream_index = 0;

  1163.         AVStream *best_st     = NULL;

  1164.         AVIStream *best_ast;

  1165.         int64_t best_ts = INT64_MAX;

  1166.         int i;

  1167. 

  1168.         for (i = 0; i < s->nb_streams; i++) {

  1169.             AVStream *st   = s->streams[i];

  1170.             AVIStream *ast = st->priv_data;

  1171.             int64_t ts     = ast->frame_offset;

  1172.             int64_t last_ts;

  1173. 

  1174.             if (!st->nb_index_entries)

  1175.                 continue;

  1176. 

  1177.             last_ts = st->index_entries[st->nb_index_entries - 1].timestamp;

  1178.             if (!ast->remaining && ts > last_ts)

  1179.                 continue;

  1180. 

  1181.             ts = av_rescale_q(ts, st->time_base,

  1182.                               (AVRational) { FFMAX(1, ast->sample_size),

  1183.                                              AV_TIME_BASE });

  1184. 

  1185.             av_dlog(s, "%"PRId64" %d/%d %"PRId64"\n", ts,

  1186.                     st->time_base.num, st->time_base.den, ast->frame_offset);

  1187.             if (ts < best_ts) {

  1188.                 best_ts           = ts;

  1189.                 best_st           = st;

  1190.                 best_stream_index = i;

  1191.             }

  1192.         }

  1193.         if (!best_st)

  1194.             return AVERROR_EOF;

  1195. 

  1196.         best_ast = best_st->priv_data;

  1197.         best_ts  = best_ast->frame_offset;

  1198.         if (best_ast->remaining) {

  1199.             i = av_index_search_timestamp(best_st,

  1200.                                           best_ts,

  1201.                                           AVSEEK_FLAG_ANY |

  1202.                                           AVSEEK_FLAG_BACKWARD);

  1203.         } else {

  1204.             i = av_index_search_timestamp(best_st, best_ts, AVSEEK_FLAG_ANY);

  1205.             if (i >= 0)

  1206.                 best_ast->frame_offset = best_st->index_entries[i].timestamp;

  1207.         }

  1208. 

  1209.         if (i >= 0) {

  1210.             int64_t pos = best_st->index_entries[i].pos;

  1211.             pos += best_ast->packet_size - best_ast->remaining;

  1212.             if (avio_seek(s->pb, pos + 8, SEEK_SET) < 0)

  1213.               return AVERROR_EOF;

  1214. 

  1215.             av_assert0(best_ast->remaining <= best_ast->packet_size);

  1216. 

  1217.             avi->stream_index = best_stream_index;

  1218.             if (!best_ast->remaining)

  1219.                 best_ast->packet_size =

  1220.                 best_ast->remaining   = best_st->index_entries[i].size;

  1221.         }

  1222.         else

  1223.           return AVERROR_EOF;

  1224.     }

  1225. 

  1226. resync:

  1227.     if (avi->stream_index >= 0) {

  1228.         AVStream *st   = s->streams[avi->stream_index];

  1229.         AVIStream *ast = st->priv_data;

  1230.         int size, err;

  1231. 

  1232.         if (get_subtitle_pkt(s, st, pkt))

  1233.             return 0;

  1234. 

  1235.         // minorityreport.AVI block_align=1024 sample_size=1 IMA-ADPCM

  1236.         if (ast->sample_size <= 1)

  1237.             size = INT_MAX;

  1238.         else if (ast->sample_size < 32)

  1239.             // arbitrary multiplier to avoid tiny packets for raw PCM data

  1240.             size = 1024 * ast->sample_size;

  1241.         else

  1242.             size = ast->sample_size;

  1243. 

  1244.         if (size > ast->remaining)

  1245.             size = ast->remaining;

  1246.         avi->last_pkt_pos = avio_tell(pb);

  1247.         err               = av_get_packet(pb, pkt, size);

  1248.         if (err < 0)

  1249.             return err;

  1250.         size = err;

  1251. 

  1252.         if (ast->has_pal && pkt->size < (unsigned)INT_MAX / 2) {

  1253.             uint8_t *pal;

  1254.             pal = av_packet_new_side_data(pkt,

  1255.                                           AV_PKT_DATA_PALETTE,

  1256.                                           AVPALETTE_SIZE);

  1257.             if (!pal) {

  1258.                 av_log(s, AV_LOG_ERROR,

  1259.                        "Failed to allocate data for palette\n");

  1260.             } else {

  1261.                 memcpy(pal, ast->pal, AVPALETTE_SIZE);

  1262.                 ast->has_pal = 0;

  1263.             }

  1264.         }

  1265. 

  1266.         if (CONFIG_DV_DEMUXER && avi->dv_demux) {

  1267.             AVBufferRef *avbuf = pkt->buf;

  1268. #if FF_API_DESTRUCT_PACKET

  1269. FF_DISABLE_DEPRECATION_WARNINGS

  1270.             dstr = pkt->destruct;

  1271. FF_ENABLE_DEPRECATION_WARNINGS

  1272. #endif

  1273.             size = avpriv_dv_produce_packet(avi->dv_demux, pkt,

  1274.                                             pkt->data, pkt->size, pkt->pos);

  1275. #if FF_API_DESTRUCT_PACKET

  1276. FF_DISABLE_DEPRECATION_WARNINGS

  1277.             pkt->destruct = dstr;

  1278. FF_ENABLE_DEPRECATION_WARNINGS

  1279. #endif

  1280.             pkt->buf    = avbuf;

  1281.             pkt->flags |= AV_PKT_FLAG_KEY;

  1282.             if (size < 0)

  1283.                 av_free_packet(pkt);

  1284.         } else if (st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE &&

  1285.                    !st->codec->codec_tag && read_gab2_sub(st, pkt)) {

  1286.             ast->frame_offset++;

  1287.             avi->stream_index = -1;

  1288.             ast->remaining    = 0;

  1289.             goto resync;

  1290.         } else {

  1291.             /* XXX: How to handle B-frames in AVI? */

  1292.             pkt->dts = ast->frame_offset;

  1293. //                pkt->dts += ast->start;

  1294.             if (ast->sample_size)

  1295.                 pkt->dts /= ast->sample_size;

  1296.             av_dlog(s,

  1297.                     "dts:%"PRId64" offset:%"PRId64" %d/%d smpl_siz:%d "

  1298.                     "base:%d st:%d size:%d\n",

  1299.                     pkt->dts,

  1300.                     ast->frame_offset,

  1301.                     ast->scale,

  1302.                     ast->rate,

  1303.                     ast->sample_size,

  1304.                     AV_TIME_BASE,

  1305.                     avi->stream_index,

  1306.                     size);

  1307.             pkt->stream_index = avi->stream_index;

  1308. 

  1309.             if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {

  1310.                 AVIndexEntry *e;

  1311.                 int index;

  1312.                 av_assert0(st->index_entries);

  1313. 

  1314.                 index = av_index_search_timestamp(st, ast->frame_offset, 0);

  1315.                 e     = &st->index_entries[index];

  1316. 

  1317.                 if (index >= 0 && e->timestamp == ast->frame_offset) {

  1318.                     if (index == st->nb_index_entries-1) {

  1319.                         int key=1;

  1320.                         int i;

  1321.                         uint32_t state=-1;

  1322.                         for (i=0; i<FFMIN(size,256); i++) {

  1323.                             if (st->codec->codec_id == AV_CODEC_ID_MPEG4) {

  1324.                                 if (state == 0x1B6) {

  1325.                                     key= !(pkt->data[i]&0xC0);

  1326.                                     break;

  1327.                                 }

  1328.                             }else

  1329.                                 break;

  1330.                             state= (state<<8) + pkt->data[i];

  1331.                         }

  1332.                         if (!key)

  1333.                             e->flags &= ~AVINDEX_KEYFRAME;

  1334.                     }

  1335.                     if (e->flags & AVINDEX_KEYFRAME)

  1336.                         pkt->flags |= AV_PKT_FLAG_KEY;

  1337.                 }

  1338.             } else {

  1339.                 pkt->flags |= AV_PKT_FLAG_KEY;

  1340.             }

  1341.             ast->frame_offset += get_duration(ast, pkt->size);

  1342.         }

  1343.         ast->remaining -= err;

  1344.         if (!ast->remaining) {

  1345.             avi->stream_index = -1;

  1346.             ast->packet_size  = 0;

  1347.         }

  1348. 

  1349.         if (!avi->non_interleaved && pkt->pos >= 0 && ast->seek_pos > pkt->pos) {

  1350.             av_free_packet(pkt);

  1351.             goto resync;

  1352.         }

  1353.         ast->seek_pos= 0;

  1354. 

  1355.         if (!avi->non_interleaved && st->nb_index_entries>1 && avi->index_loaded>1) {

  1356.             int64_t dts= av_rescale_q(pkt->dts, st->time_base, AV_TIME_BASE_Q);

  1357. 

  1358.             if (avi->dts_max - dts > 2*AV_TIME_BASE) {

  1359.                 avi->non_interleaved= 1;

  1360.                 av_log(s, AV_LOG_INFO, "Switching to NI mode, due to poor interleaving\n");

  1361.             }else if (avi->dts_max < dts)

  1362.                 avi->dts_max = dts;

  1363.         }

  1364. 

  1365.         return 0;

  1366.     }

  1367. 

  1368.     if ((err = avi_sync(s, 0)) < 0)

  1369.         return err;

  1370.     goto resync;

  1371. }

  1372. 

  1373. /* XXX: We make the implicit supposition that the positions are sorted

  1374.  * for each stream. */

  1375. static int avi_read_idx1(AVFormatContext *s, int size)

  1376. {

  1377.     AVIContext *avi = s->priv_data;

  1378.     AVIOContext *pb = s->pb;

  1379.     int nb_index_entries, i;

  1380.     AVStream *st;

  1381.     AVIStream *ast;

  1382.     unsigned int index, tag, flags, pos, len, first_packet = 1;

  1383.     unsigned last_pos = -1;

  1384.     unsigned last_idx = -1;

  1385.     int64_t idx1_pos, first_packet_pos = 0, data_offset = 0;

  1386.     int anykey = 0;

  1387. 

  1388.     nb_index_entries = size / 16;

  1389.     if (nb_index_entries <= 0)

  1390.         return AVERROR_INVALIDDATA;

  1391. 

  1392.     idx1_pos = avio_tell(pb);

  1393.     avio_seek(pb, avi->movi_list + 4, SEEK_SET);

  1394.     if (avi_sync(s, 1) == 0)

  1395.         first_packet_pos = avio_tell(pb) - 8;

  1396.     avi->stream_index = -1;

  1397.     avio_seek(pb, idx1_pos, SEEK_SET);

  1398. 

  1399.     if (s->nb_streams == 1 && s->streams[0]->codec->codec_tag == AV_RL32("MMES")) {

  1400.         first_packet_pos = 0;

  1401.         data_offset = avi->movi_list;

  1402.     }

  1403. 

  1404.     /* Read the entries and sort them in each stream component. */

  1405.     for (i = 0; i < nb_index_entries; i++) {

  1406.         if (url_feof(pb))

  1407.             return -1;

  1408. 

  1409.         tag   = avio_rl32(pb);

  1410.         flags = avio_rl32(pb);

  1411.         pos   = avio_rl32(pb);

  1412.         len   = avio_rl32(pb);

  1413.         av_dlog(s, "%d: tag=0x%x flags=0x%x pos=0x%x len=%d/",

  1414.                 i, tag, flags, pos, len);

  1415. 

  1416.         index  = ((tag      & 0xff) - '0') * 10;

  1417.         index +=  (tag >> 8 & 0xff) - '0';

  1418.         if (index >= s->nb_streams)

  1419.             continue;

  1420.         st  = s->streams[index];

  1421.         ast = st->priv_data;

  1422. 

  1423.         if (first_packet && first_packet_pos) {

  1424.             data_offset  = first_packet_pos - pos;

  1425.             first_packet = 0;

  1426.         }

  1427.         pos += data_offset;

  1428. 

  1429.         av_dlog(s, "%d cum_len=%"PRId64"\n", len, ast->cum_len);

  1430. 

  1431.         // even if we have only a single stream, we should

  1432.         // switch to non-interleaved to get correct timestamps

  1433.         if (last_pos == pos)

  1434.             avi->non_interleaved = 1;

  1435.         if (last_idx != pos && len) {

  1436.             av_add_index_entry(st, pos, ast->cum_len, len, 0,

  1437.                                (flags & AVIIF_INDEX) ? AVINDEX_KEYFRAME : 0);

  1438.             last_idx= pos;

  1439.         }

  1440.         ast->cum_len += get_duration(ast, len);

  1441.         last_pos      = pos;

  1442.         anykey       |= flags&AVIIF_INDEX;

  1443.     }

  1444.     if (!anykey) {

  1445.         for (index = 0; index < s->nb_streams; index++) {

  1446.             st = s->streams[index];

  1447.             if (st->nb_index_entries)

  1448.                 st->index_entries[0].flags |= AVINDEX_KEYFRAME;

  1449.         }

  1450.     }

  1451.     return 0;

  1452. }

  1453. 

  1454. static int guess_ni_flag(AVFormatContext *s)

  1455. {

  1456.     int i;

  1457.     int64_t last_start = 0;

  1458.     int64_t first_end  = INT64_MAX;

  1459.     int64_t oldpos     = avio_tell(s->pb);

  1460.     int *idx;

  1461.     int64_t min_pos, pos;

  1462. 

  1463.     for (i = 0; i < s->nb_streams; i++) {

  1464.         AVStream *st = s->streams[i];

  1465.         int n        = st->nb_index_entries;

  1466.         unsigned int size;

  1467. 

  1468.         if (n <= 0)

  1469.             continue;

  1470. 

  1471.         if (n >= 2) {

  1472.             int64_t pos = st->index_entries[0].pos;

  1473.             avio_seek(s->pb, pos + 4, SEEK_SET);

  1474.             size = avio_rl32(s->pb);

  1475.             if (pos + size > st->index_entries[1].pos)

  1476.                 last_start = INT64_MAX;

  1477.         }

  1478. 

  1479.         if (st->index_entries[0].pos > last_start)

  1480.             last_start = st->index_entries[0].pos;

  1481.         if (st->index_entries[n - 1].pos < first_end)

  1482.             first_end = st->index_entries[n - 1].pos;

  1483.     }

  1484.     avio_seek(s->pb, oldpos, SEEK_SET);

  1485.     if (last_start > first_end)

  1486.         return 1;

  1487.     idx= av_calloc(s->nb_streams, sizeof(*idx));

  1488.     if (!idx)

  1489.         return 0;

  1490.     for (min_pos=pos=0; min_pos!=INT64_MAX; pos= min_pos+1LU) {

  1491.         int64_t max_dts = INT64_MIN/2, min_dts= INT64_MAX/2;

  1492.         min_pos = INT64_MAX;

  1493. 

  1494.         for (i=0; i<s->nb_streams; i++) {

  1495.             AVStream *st = s->streams[i];

  1496.             AVIStream *ast = st->priv_data;

  1497.             int n= st->nb_index_entries;

  1498.             while (idx[i]<n && st->index_entries[idx[i]].pos < pos)

  1499.                 idx[i]++;

  1500.             if (idx[i] < n) {

  1501.                 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));

  1502.                 min_pos = FFMIN(min_pos, st->index_entries[idx[i]].pos);

  1503.             }

  1504.             if (idx[i])

  1505.                 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));

  1506.         }

  1507.         if (max_dts - min_dts > 2*AV_TIME_BASE) {

  1508.             av_free(idx);

  1509.             return 1;

  1510.         }

  1511.     }

  1512.     av_free(idx);

  1513.     return 0;

  1514. }

  1515. 

  1516. static int avi_load_index(AVFormatContext *s)

  1517. {

  1518.     AVIContext *avi = s->priv_data;

  1519.     AVIOContext *pb = s->pb;

  1520.     uint32_t tag, size;

  1521.     int64_t pos = avio_tell(pb);

  1522.     int64_t next;

  1523.     int ret     = -1;

  1524. 

  1525.     if (avio_seek(pb, avi->movi_end, SEEK_SET) < 0)

  1526.         goto the_end; // maybe truncated file

  1527.     av_dlog(s, "movi_end=0x%"PRIx64"\n", avi->movi_end);

  1528.     for (;;) {

  1529.         tag  = avio_rl32(pb);

  1530.         size = avio_rl32(pb);

  1531.         if (url_feof(pb))

  1532.             break;

  1533.         next = avio_tell(pb) + size + (size & 1);

  1534. 

  1535.         av_dlog(s, "tag=%c%c%c%c size=0x%x\n",

  1536.                  tag        & 0xff,

  1537.                 (tag >>  8) & 0xff,

  1538.                 (tag >> 16) & 0xff,

  1539.                 (tag >> 24) & 0xff,

  1540.                 size);

  1541. 

  1542.         if (tag == MKTAG('i', 'd', 'x', '1') &&

  1543.             avi_read_idx1(s, size) >= 0) {

  1544.             avi->index_loaded=2;

  1545.             ret = 0;

  1546.         }else if (tag == MKTAG('L', 'I', 'S', 'T')) {

  1547.             uint32_t tag1 = avio_rl32(pb);

  1548. 

  1549.             if (tag1 == MKTAG('I', 'N', 'F', 'O'))

  1550.                 ff_read_riff_info(s, size - 4);

  1551.         }else if (!ret)

  1552.             break;

  1553. 

  1554.         if (avio_seek(pb, next, SEEK_SET) < 0)

  1555.             break; // something is wrong here

  1556.     }

  1557. 

  1558. the_end:

  1559.     avio_seek(pb, pos, SEEK_SET);

  1560.     return ret;

  1561. }

  1562. 

  1563. static void seek_subtitle(AVStream *st, AVStream *st2, int64_t timestamp)

  1564. {

  1565.     AVIStream *ast2 = st2->priv_data;

  1566.     int64_t ts2     = av_rescale_q(timestamp, st->time_base, st2->time_base);

  1567.     av_free_packet(&ast2->sub_pkt);

  1568.     if (avformat_seek_file(ast2->sub_ctx, 0, INT64_MIN, ts2, ts2, 0) >= 0 ||

  1569.         avformat_seek_file(ast2->sub_ctx, 0, ts2, ts2, INT64_MAX, 0) >= 0)

  1570.         ff_read_packet(ast2->sub_ctx, &ast2->sub_pkt);

  1571. }

  1572. 

  1573. static int avi_read_seek(AVFormatContext *s, int stream_index,

  1574.                          int64_t timestamp, int flags)

  1575. {

  1576.     AVIContext *avi = s->priv_data;

  1577.     AVStream *st;

  1578.     int i, index;

  1579.     int64_t pos, pos_min;

  1580.     AVIStream *ast;

  1581. 

  1582.     /* Does not matter which stream is requested dv in avi has the

  1583.      * stream information in the first video stream.

  1584.      */

  1585.     if (avi->dv_demux)

  1586.         stream_index = 0;

  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. 

  1621.         if (avio_seek(s->pb, pos, SEEK_SET) < 0)

  1622.             return -1;

  1623. 

  1624.         /* Feed the DV video stream version of the timestamp to the */

  1625.         /* DV demux so it can synthesize correct timestamps.        */

  1626.         ff_dv_offset_reset(avi->dv_demux, timestamp);

  1627. 

  1628.         avi->stream_index = -1;

  1629.         return 0;

  1630.     }

  1631. 

  1632.     pos_min = pos;

  1633.     for (i = 0; i < s->nb_streams; i++) {

  1634.         AVStream *st2   = s->streams[i];

  1635.         AVIStream *ast2 = st2->priv_data;

  1636. 

  1637.         ast2->packet_size =

  1638.         ast2->remaining   = 0;

  1639. 

  1640.         if (ast2->sub_ctx) {

  1641.             seek_subtitle(st, st2, timestamp);

  1642.             continue;

  1643.         }

  1644. 

  1645.         if (st2->nb_index_entries <= 0)

  1646.             continue;

  1647. 

  1648. //        av_assert1(st2->codec->block_align);

  1649.         av_assert0((int64_t)st2->time_base.num * ast2->rate ==

  1650.                    (int64_t)st2->time_base.den * ast2->scale);

  1651.         index = av_index_search_timestamp(st2,

  1652.                                           av_rescale_q(timestamp,

  1653.                                                        st->time_base,

  1654.                                                        st2->time_base) *

  1655.                                           FFMAX(ast2->sample_size, 1),

  1656.                                           flags |

  1657.                                           AVSEEK_FLAG_BACKWARD |

  1658.                                           (st2->codec->codec_type != AVMEDIA_TYPE_VIDEO ? AVSEEK_FLAG_ANY : 0));

  1659.         if (index < 0)

  1660.             index = 0;

  1661.         ast2->seek_pos = st2->index_entries[index].pos;

  1662.         pos_min = FFMIN(pos_min,ast2->seek_pos);

  1663.     }

  1664.     for (i = 0; i < s->nb_streams; i++) {

  1665.         AVStream *st2 = s->streams[i];

  1666.         AVIStream *ast2 = st2->priv_data;

  1667. 

  1668.         if (ast2->sub_ctx || st2->nb_index_entries <= 0)

  1669.             continue;

  1670. 

  1671.         index = av_index_search_timestamp(

  1672.                 st2,

  1673.                 av_rescale_q(timestamp, st->time_base, st2->time_base) * FFMAX(ast2->sample_size, 1),

  1674.                 flags | AVSEEK_FLAG_BACKWARD | (st2->codec->codec_type != AVMEDIA_TYPE_VIDEO ? AVSEEK_FLAG_ANY : 0));

  1675.         if (index < 0)

  1676.             index = 0;

  1677.         while (!avi->non_interleaved && index>0 && st2->index_entries[index-1].pos >= pos_min)

  1678.             index--;

  1679.         ast2->frame_offset = st2->index_entries[index].timestamp;

  1680.     }

  1681. 

  1682.     /* do the seek */

  1683.     if (avio_seek(s->pb, pos_min, SEEK_SET) < 0) {

  1684.         av_log(s, AV_LOG_ERROR, "Seek failed\n");

  1685.         return -1;

  1686.     }

  1687.     avi->stream_index = -1;

  1688.     avi->dts_max      = INT_MIN;

  1689.     return 0;

  1690. }

  1691. 

  1692. static int avi_read_close(AVFormatContext *s)

  1693. {

  1694.     int i;

  1695.     AVIContext *avi = s->priv_data;

  1696. 

  1697.     for (i = 0; i < s->nb_streams; i++) {

  1698.         AVStream *st   = s->streams[i];

  1699.         AVIStream *ast = st->priv_data;

  1700.         if (ast) {

  1701.             if (ast->sub_ctx) {

  1702.                 av_freep(&ast->sub_ctx->pb);

  1703.                 avformat_close_input(&ast->sub_ctx);

  1704.             }

  1705.             av_free(ast->sub_buffer);

  1706.             av_free_packet(&ast->sub_pkt);

  1707.         }

  1708.     }

  1709. 

  1710.     av_free(avi->dv_demux);

  1711. 

  1712.     return 0;

  1713. }

  1714. 

  1715. static int avi_probe(AVProbeData *p)

  1716. {

  1717.     int i;

  1718. 

  1719.     /* check file header */

  1720.     for (i = 0; avi_headers[i][0]; i++)

  1721.         if (!memcmp(p->buf,     avi_headers[i],     4) &&

  1722.             !memcmp(p->buf + 8, avi_headers[i] + 4, 4))

  1723.             return AVPROBE_SCORE_MAX;

  1724. 

  1725.     return 0;

  1726. }

  1727. 

  1728. AVInputFormat ff_avi_demuxer = {

  1729.     .name           = "avi",

  1730.     .long_name      = NULL_IF_CONFIG_SMALL("AVI (Audio Video Interleaved)"),

  1731.     .priv_data_size = sizeof(AVIContext),

  1732.     .read_probe     = avi_probe,

  1733.     .read_header    = avi_read_header,

  1734.     .read_packet    = avi_read_packet,

  1735.     .read_close     = avi_read_close,

  1736.     .read_seek      = avi_read_seek,

  1737.     .priv_class = &demuxer_class,

  1738. };