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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. //#define DEBUG

  23. //#define DEBUG_SEEK

  24. 

  25. #include "libavutil/intreadwrite.h"

  26. #include "libavutil/bswap.h"

  27. #include "avformat.h"

  28. #include "avi.h"

  29. #include "dv.h"

  30. #include "riff.h"

  31. 

  32. #undef NDEBUG

  33. #include <assert.h>

  34. 

  35. typedef struct AVIStream {

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

  37.                          (used to compute the pts) */

  38.     int remaining;

  39.     int packet_size;

  40. 

  41.     int scale;

  42.     int rate;

  43.     int sample_size; /* size of one sample (or packet) (in the rate/scale sense) in bytes */

  44. 

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

  46. 

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

  48.     int prefix_count;

  49.     uint32_t pal[256];

  50.     int has_pal;

  51. } AVIStream;

  52. 

  53. typedef struct {

  54.     int64_t  riff_end;

  55.     int64_t  movi_end;

  56.     int64_t  fsize;

  57.     int64_t movi_list;

  58.     int64_t last_pkt_pos;

  59.     int index_loaded;

  60.     int is_odml;

  61.     int non_interleaved;

  62.     int stream_index;

  63.     DVDemuxContext* dv_demux;

  64. } AVIContext;

  65. 

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

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

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

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

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

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

  72.     { 0 }

  73. };

  74. 

  75. static int avi_load_index(AVFormatContext *s);

  76. static int guess_ni_flag(AVFormatContext *s);

  77. 

  78. #ifdef DEBUG

  79. static void print_tag(const char *str, unsigned int tag, int size)

  80. {

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

  82.            str, tag & 0xff,

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

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

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

  86.            size);

  87. }

  88. #endif

  89. 

  90. static int get_riff(AVFormatContext *s, ByteIOContext *pb)

  91. {

  92.     AVIContext *avi = s->priv_data;

  93.     char header[8];

  94.     int i;

  95. 

  96.     /* check RIFF header */

  97.     get_buffer(pb, header, 4);

  98.     avi->riff_end = get_le32(pb);   /* RIFF chunk size */

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

  100.     get_buffer(pb, header+4, 4);

  101. 

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

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

  104.             break;

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

  106.         return -1;

  107. 

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

  109.         av_log(s, AV_LOG_INFO, "This file has been generated by a totally broken muxer.\n");

  110. 

  111.     return 0;

  112. }

  113. 

  114. static int read_braindead_odml_indx(AVFormatContext *s, int frame_num){

  115.     AVIContext *avi = s->priv_data;

  116.     ByteIOContext *pb = s->pb;

  117.     int longs_pre_entry= get_le16(pb);

  118.     int index_sub_type = get_byte(pb);

  119.     int index_type     = get_byte(pb);

  120.     int entries_in_use = get_le32(pb);

  121.     int chunk_id       = get_le32(pb);

  122.     int64_t base       = get_le64(pb);

  123.     int stream_id= 10*((chunk_id&0xFF) - '0') + (((chunk_id>>8)&0xFF) - '0');

  124.     AVStream *st;

  125.     AVIStream *ast;

  126.     int i;

  127.     int64_t last_pos= -1;

  128.     int64_t filesize= url_fsize(s->pb);

  129. 

  130. #ifdef DEBUG_SEEK

  131.     av_log(s, AV_LOG_ERROR, "longs_pre_entry:%d index_type:%d entries_in_use:%d chunk_id:%X base:%16"PRIX64"\n",

  132.         longs_pre_entry,index_type, entries_in_use, chunk_id, base);

  133. #endif

  134. 

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

  136.         return -1;

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

  138.     ast = st->priv_data;

  139. 

  140.     if(index_sub_type)

  141.         return -1;

  142. 

  143.     get_le32(pb);

  144. 

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

  146.         return -1;

  147.     if(index_type>1)

  148.         return -1;

  149. 

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

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

  152.         if(base>>32 == (base & 0xFFFFFFFF) && (base & 0xFFFFFFFF) < filesize && filesize <= 0xFFFFFFFF)

  153.             base &= 0xFFFFFFFF;

  154.         else

  155.             return -1;

  156.     }

  157. 

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

  159.         if(index_type){

  160.             int64_t pos= get_le32(pb) + base - 8;

  161.             int len    = get_le32(pb);

  162.             int key= len >= 0;

  163.             len &= 0x7FFFFFFF;

  164. 

  165. #ifdef DEBUG_SEEK

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

  167. #endif

  168.             if(url_feof(pb))

  169.                 return -1;

  170. 

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

  172.                 avi->non_interleaved= 1;

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

  174.                 av_add_index_entry(st, pos, ast->cum_len, len, 0, key ? AVINDEX_KEYFRAME : 0);

  175. 

  176.             if(ast->sample_size)

  177.                 ast->cum_len += len;

  178.             else

  179.                 ast->cum_len ++;

  180.             last_pos= pos;

  181.         }else{

  182.             int64_t offset, pos;

  183.             int duration;

  184.             offset = get_le64(pb);

  185.             get_le32(pb);       /* size */

  186.             duration = get_le32(pb);

  187. 

  188.             if(url_feof(pb))

  189.                 return -1;

  190. 

  191.             pos = url_ftell(pb);

  192. 

  193.             url_fseek(pb, offset+8, SEEK_SET);

  194.             read_braindead_odml_indx(s, frame_num);

  195.             frame_num += duration;

  196. 

  197.             url_fseek(pb, pos, SEEK_SET);

  198.         }

  199.     }

  200.     avi->index_loaded=1;

  201.     return 0;

  202. }

  203. 

  204. static void clean_index(AVFormatContext *s){

  205.     int i;

  206.     int64_t j;

  207. 

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

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

  210.         AVIStream *ast = st->priv_data;

  211.         int n= st->nb_index_entries;

  212.         int max= ast->sample_size;

  213.         int64_t pos, size, ts;

  214. 

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

  216.             continue;

  217. 

  218.         while(max < 1024) max+=max;

  219. 

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

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

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

  223. 

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

  225.             av_add_index_entry(st, pos+j, ts+j, FFMIN(max, size-j), 0, AVINDEX_KEYFRAME);

  226.         }

  227.     }

  228. }

  229. 

  230. static int avi_read_tag(AVFormatContext *s, const char *key, unsigned int size)

  231. {

  232.     ByteIOContext *pb = s->pb;

  233.     char *value;

  234. 

  235.     size += (size & 1);

  236. 

  237.     if (size == UINT_MAX)

  238.         return -1;

  239.     value = av_malloc(size+1);

  240.     if (!value)

  241.         return -1;

  242.     get_strz(pb, value, size);

  243. 

  244.     return av_metadata_set2(&s->metadata, key, value,

  245.                                   AV_METADATA_DONT_STRDUP_VAL);

  246. }

  247. 

  248. static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)

  249. {

  250.     AVIContext *avi = s->priv_data;

  251.     ByteIOContext *pb = s->pb;

  252.     unsigned int tag, tag1, handler;

  253.     int codec_type, stream_index, frame_period, bit_rate;

  254.     unsigned int size;

  255.     int i;

  256.     AVStream *st;

  257.     AVIStream *ast = NULL;

  258.     int avih_width=0, avih_height=0;

  259.     int amv_file_format=0;

  260.     uint64_t list_end = 0;

  261. 

  262.     avi->stream_index= -1;

  263. 

  264.     if (get_riff(s, pb) < 0)

  265.         return -1;

  266. 

  267.     avi->fsize = url_fsize(pb);

  268.     if(avi->fsize<=0)

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

  270. 

  271.     /* first list tag */

  272.     stream_index = -1;

  273.     codec_type = -1;

  274.     frame_period = 0;

  275.     for(;;) {

  276.         if (url_feof(pb))

  277.             goto fail;

  278.         tag = get_le32(pb);

  279.         size = get_le32(pb);

  280. #ifdef DEBUG

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

  282. #endif

  283. 

  284.         switch(tag) {

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

  286.             list_end = url_ftell(pb) + size;

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

  288.             tag1 = get_le32(pb);

  289. #ifdef DEBUG

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

  291. #endif

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

  293.                 avi->movi_list = url_ftell(pb) - 4;

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

  295.                 else     avi->movi_end = url_fsize(pb);

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

  297.                 goto end_of_header;

  298.             }

  299.             break;

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

  301.             avi->is_odml = 1;

  302.             url_fskip(pb, size + (size & 1));

  303.             break;

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

  305.             amv_file_format=1;

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

  307.             /* AVI header */

  308.             /* using frame_period is bad idea */

  309.             frame_period = get_le32(pb);

  310.             bit_rate = get_le32(pb) * 8;

  311.             get_le32(pb);

  312.             avi->non_interleaved |= get_le32(pb) & AVIF_MUSTUSEINDEX;

  313. 

  314.             url_fskip(pb, 2 * 4);

  315.             get_le32(pb);

  316.             get_le32(pb);

  317.             avih_width=get_le32(pb);

  318.             avih_height=get_le32(pb);

  319. 

  320.             url_fskip(pb, size - 10 * 4);

  321.             break;

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

  323.             /* stream header */

  324. 

  325.             tag1 = get_le32(pb);

  326.             handler = get_le32(pb); /* codec tag */

  327. 

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

  329.                 url_fskip(pb, size - 8);

  330.                 break;

  331.             }else{

  332.                 stream_index++;

  333.                 st = av_new_stream(s, stream_index);

  334.                 if (!st)

  335.                     goto fail;

  336. 

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

  338.                 if (!ast)

  339.                     goto fail;

  340.                 st->priv_data = ast;

  341.             }

  342.             if(amv_file_format)

  343.                 tag1 = stream_index ? MKTAG('a','u','d','s') : MKTAG('v','i','d','s');

  344. 

  345. #ifdef DEBUG

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

  347. #endif

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

  349.                 int64_t dv_dur;

  350. 

  351.                 /*

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

  353.                  * have to support anything but DV in type1 AVIs.

  354.                  */

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

  356.                     goto fail;

  357. 

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

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

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

  361.                    goto fail;

  362. 

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

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

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

  366.                 s->nb_streams = 0;

  367.                 if (CONFIG_DV_DEMUXER) {

  368.                     avi->dv_demux = dv_init_demux(s);

  369.                     if (!avi->dv_demux)

  370.                         goto fail;

  371.                 }

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

  373.                 url_fskip(pb, 3 * 4);

  374.                 ast->scale = get_le32(pb);

  375.                 ast->rate = get_le32(pb);

  376.                 url_fskip(pb, 4);  /* start time */

  377. 

  378.                 dv_dur = get_le32(pb);

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

  380.                     dv_dur *= AV_TIME_BASE;

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

  382.                 }

  383.                 /*

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

  385.                  *      will make a guess based on bitrate.

  386.                  */

  387. 

  388.                 stream_index = s->nb_streams - 1;

  389.                 url_fskip(pb, size - 9*4);

  390.                 break;

  391.             }

  392. 

  393.             assert(stream_index < s->nb_streams);

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

  395. 

  396.             get_le32(pb); /* flags */

  397.             get_le16(pb); /* priority */

  398.             get_le16(pb); /* language */

  399.             get_le32(pb); /* initial frame */

  400.             ast->scale = get_le32(pb);

  401.             ast->rate = get_le32(pb);

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

  403.                 av_log(s, AV_LOG_WARNING, "scale/rate is %u/%u which is invalid. (This file has been generated by broken software.)\n", ast->scale, ast->rate);

  404.                 if(frame_period){

  405.                     ast->rate = 1000000;

  406.                     ast->scale = frame_period;

  407.                 }else{

  408.                     ast->rate = 25;

  409.                     ast->scale = 1;

  410.                 }

  411.             }

  412.             av_set_pts_info(st, 64, ast->scale, ast->rate);

  413. 

  414.             ast->cum_len=get_le32(pb); /* start */

  415.             st->nb_frames = get_le32(pb);

  416. 

  417.             st->start_time = 0;

  418.             get_le32(pb); /* buffer size */

  419.             get_le32(pb); /* quality */

  420.             ast->sample_size = get_le32(pb); /* sample ssize */

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

  422. //            av_log(s, AV_LOG_DEBUG, "%d %d %d %d\n", ast->rate, ast->scale, ast->start, ast->sample_size);

  423. 

  424.             switch(tag1) {

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

  426.                 codec_type = CODEC_TYPE_VIDEO;

  427. 

  428.                 ast->sample_size = 0;

  429.                 break;

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

  431.                 codec_type = CODEC_TYPE_AUDIO;

  432.                 break;

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

  434.                 //FIXME

  435.                 codec_type = CODEC_TYPE_DATA; //CODEC_TYPE_SUB ?  FIXME

  436.                 break;

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

  438.                 codec_type = CODEC_TYPE_DATA;

  439.                 break;

  440.             default:

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

  442.                 goto fail;

  443.             }

  444.             if(ast->sample_size == 0)

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

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

  447.             url_fskip(pb, size - 12 * 4);

  448.             break;

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

  450.             /* stream header */

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

  452.                 url_fskip(pb, size);

  453.             } else {

  454.                 uint64_t cur_pos = url_ftell(pb);

  455.                 if (cur_pos < list_end)

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

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

  458.                 switch(codec_type) {

  459.                 case CODEC_TYPE_VIDEO:

  460.                     if(amv_file_format){

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

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

  463.                         st->codec->codec_type = CODEC_TYPE_VIDEO;

  464.                         st->codec->codec_id = CODEC_ID_AMV;

  465.                         url_fskip(pb, size);

  466.                         break;

  467.                     }

  468.                     get_le32(pb); /* size */

  469.                     st->codec->width = get_le32(pb);

  470.                     st->codec->height = (int32_t)get_le32(pb);

  471.                     get_le16(pb); /* panes */

  472.                     st->codec->bits_per_coded_sample= get_le16(pb); /* depth */

  473.                     tag1 = get_le32(pb);

  474.                     get_le32(pb); /* ImageSize */

  475.                     get_le32(pb); /* XPelsPerMeter */

  476.                     get_le32(pb); /* YPelsPerMeter */

  477.                     get_le32(pb); /* ClrUsed */

  478.                     get_le32(pb); /* ClrImportant */

  479. 

  480.                     if (tag1 == MKTAG('D', 'X', 'S', 'B') || tag1 == MKTAG('D','X','S','A')) {

  481.                         st->codec->codec_type = CODEC_TYPE_SUBTITLE;

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

  483.                         st->codec->codec_id = CODEC_ID_XSUB;

  484.                         break;

  485.                     }

  486. 

  487.                     if(size > 10*4 && size<(1<<30)){

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

  489.                         st->codec->extradata= av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);

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

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

  492.                             return AVERROR(ENOMEM);

  493.                         }

  494.                         get_buffer(pb, st->codec->extradata, st->codec->extradata_size);

  495.                     }

  496. 

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

  498.                         get_byte(pb);

  499. 

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

  501.                     /* This code assumes that extradata contains only palette. */

  502.                     /* This is true for all paletted codecs implemented in FFmpeg. */

  503.                     if (st->codec->extradata_size && (st->codec->bits_per_coded_sample <= 8)) {

  504.                         st->codec->palctrl = av_mallocz(sizeof(AVPaletteControl));

  505. #if HAVE_BIGENDIAN

  506.                         for (i = 0; i < FFMIN(st->codec->extradata_size, AVPALETTE_SIZE)/4; i++)

  507.                             st->codec->palctrl->palette[i] = bswap_32(((uint32_t*)st->codec->extradata)[i]);

  508. #else

  509.                         memcpy(st->codec->palctrl->palette, st->codec->extradata,

  510.                                FFMIN(st->codec->extradata_size, AVPALETTE_SIZE));

  511. #endif

  512.                         st->codec->palctrl->palette_changed = 1;

  513.                     }

  514. 

  515. #ifdef DEBUG

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

  517. #endif

  518.                     st->codec->codec_type = CODEC_TYPE_VIDEO;

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

  520.                     st->codec->codec_id = ff_codec_get_id(ff_codec_bmp_tags, tag1);

  521.                     st->need_parsing = AVSTREAM_PARSE_HEADERS; // This is needed to get the pict type which is necessary for generating correct pts.

  522.                     // Support "Resolution 1:1" for Avid AVI Codec

  523.                     if(tag1 == MKTAG('A', 'V', 'R', 'n') &&

  524.                        st->codec->extradata_size >= 31 &&

  525.                        !memcmp(&st->codec->extradata[28], "1:1", 3))

  526.                         st->codec->codec_id = CODEC_ID_RAWVIDEO;

  527. 

  528.                     if(st->codec->codec_tag==0 && st->codec->height > 0 && st->codec->extradata_size < 1U<<30){

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

  530.                         st->codec->extradata= av_realloc(st->codec->extradata, st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);

  531.                         if(st->codec->extradata)

  532.                             memcpy(st->codec->extradata + st->codec->extradata_size - 9, "BottomUp", 9);

  533.                     }

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

  535. 

  536. //                    url_fskip(pb, size - 5 * 4);

  537.                     break;

  538.                 case CODEC_TYPE_AUDIO:

  539.                     ff_get_wav_header(pb, st->codec, size);

  540.                     if(ast->sample_size && st->codec->block_align && ast->sample_size != st->codec->block_align){

  541.                         av_log(s, AV_LOG_WARNING, "sample size (%d) != block align (%d)\n", ast->sample_size, st->codec->block_align);

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

  543.                     }

  544.                     if (size%2) /* 2-aligned (fix for Stargate SG-1 - 3x18 - Shades of Grey.avi) */

  545.                         url_fskip(pb, 1);

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

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

  548.                     st->need_parsing = AVSTREAM_PARSE_TIMESTAMPS;

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

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

  551.                      * fail. */

  552.                     if (st->codec->codec_id == CODEC_ID_AAC && st->codec->extradata_size)

  553.                         st->need_parsing = AVSTREAM_PARSE_NONE;

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

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

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

  557.                         st->codec->codec_id  = CODEC_ID_XAN_DPCM;

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

  559.                     }

  560.                     if (amv_file_format)

  561.                         st->codec->codec_id  = CODEC_ID_ADPCM_IMA_AMV;

  562.                     break;

  563.                 default:

  564.                     st->codec->codec_type = CODEC_TYPE_DATA;

  565.                     st->codec->codec_id= CODEC_ID_NONE;

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

  567.                     url_fskip(pb, size);

  568.                     break;

  569.                 }

  570.             }

  571.             break;

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

  573.             i= url_ftell(pb);

  574.             if(!url_is_streamed(pb) && !(s->flags & AVFMT_FLAG_IGNIDX)){

  575.                 read_braindead_odml_indx(s, 0);

  576.             }

  577.             url_fseek(pb, i+size, SEEK_SET);

  578.             break;

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

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

  581.                 AVRational active, active_aspect;

  582. 

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

  584.                 get_le32(pb);

  585.                 get_le32(pb);

  586.                 get_le32(pb);

  587.                 get_le32(pb);

  588.                 get_le32(pb);

  589. 

  590.                 active_aspect.den= get_le16(pb);

  591.                 active_aspect.num= get_le16(pb);

  592.                 active.num       = get_le32(pb);

  593.                 active.den       = get_le32(pb);

  594.                 get_le32(pb); //nbFieldsPerFrame

  595. 

  596.                 if(active_aspect.num && active_aspect.den && active.num && active.den){

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

  598. //av_log(s, AV_LOG_ERROR, "vprp %d/%d %d/%d\n", active_aspect.num, active_aspect.den, active.num, active.den);

  599.                 }

  600.                 size -= 9*4;

  601.             }

  602.             url_fseek(pb, size, SEEK_CUR);

  603.             break;

  604.         case MKTAG('I', 'N', 'A', 'M'):

  605.             avi_read_tag(s, "Title", size);

  606.             break;

  607.         case MKTAG('I', 'A', 'R', 'T'):

  608.             avi_read_tag(s, "Artist", size);

  609.             break;

  610.         case MKTAG('I', 'C', 'O', 'P'):

  611.             avi_read_tag(s, "Copyright", size);

  612.             break;

  613.         case MKTAG('I', 'C', 'M', 'T'):

  614.             avi_read_tag(s, "Comment", size);

  615.             break;

  616.         case MKTAG('I', 'G', 'N', 'R'):

  617.             avi_read_tag(s, "Genre", size);

  618.             break;

  619.         case MKTAG('I', 'P', 'R', 'D'):

  620.             avi_read_tag(s, "Album", size);

  621.             break;

  622.         case MKTAG('I', 'P', 'R', 'T'):

  623.             avi_read_tag(s, "Track", size);

  624.             break;

  625.         default:

  626.             if(size > 1000000){

  627.                 av_log(s, AV_LOG_ERROR, "Something went wrong during header parsing, "

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

  629.                 avi->movi_list = url_ftell(pb) - 4;

  630.                 avi->movi_end  = url_fsize(pb);

  631.                 goto end_of_header;

  632.             }

  633.             /* skip tag */

  634.             size += (size & 1);

  635.             url_fskip(pb, size);

  636.             break;

  637.         }

  638.     }

  639.  end_of_header:

  640.     /* check stream number */

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

  642.     fail:

  643.         return -1;

  644.     }

  645. 

  646.     if(!avi->index_loaded && !url_is_streamed(pb))

  647.         avi_load_index(s);

  648.     avi->index_loaded = 1;

  649.     avi->non_interleaved |= guess_ni_flag(s);

  650.     if(avi->non_interleaved) {

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

  652.         clean_index(s);

  653.     }

  654. 

  655.     return 0;

  656. }

  657. 

  658. static int get_stream_idx(int *d){

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

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

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

  662.     }else{

  663.         return 100; //invalid stream ID

  664.     }

  665. }

  666. 

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

  668. {

  669.     AVIContext *avi = s->priv_data;

  670.     ByteIOContext *pb = s->pb;

  671.     int n, d[8];

  672.     unsigned int size;

  673.     int64_t i, sync;

  674.     void* dstr;

  675. 

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

  677.         int size = dv_get_packet(avi->dv_demux, pkt);

  678.         if (size >= 0)

  679.             return size;

  680.     }

  681. 

  682.     if(avi->non_interleaved){

  683.         int best_stream_index = 0;

  684.         AVStream *best_st= NULL;

  685.         AVIStream *best_ast;

  686.         int64_t best_ts= INT64_MAX;

  687.         int i;

  688. 

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

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

  691.             AVIStream *ast = st->priv_data;

  692.             int64_t ts= ast->frame_offset;

  693.             int64_t last_ts;

  694. 

  695.             if(!st->nb_index_entries)

  696.                 continue;

  697. 

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

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

  700.                 continue;

  701. 

  702.             ts = av_rescale_q(ts, st->time_base, (AVRational){FFMAX(1, ast->sample_size), AV_TIME_BASE});

  703. 

  704. //            av_log(s, AV_LOG_DEBUG, "%"PRId64" %d/%d %"PRId64"\n", ts, st->time_base.num, st->time_base.den, ast->frame_offset);

  705.             if(ts < best_ts){

  706.                 best_ts= ts;

  707.                 best_st= st;

  708.                 best_stream_index= i;

  709.             }

  710.         }

  711.         if(!best_st)

  712.             return -1;

  713. 

  714.         best_ast = best_st->priv_data;

  715.         best_ts = av_rescale_q(best_ts, (AVRational){FFMAX(1, best_ast->sample_size), AV_TIME_BASE}, best_st->time_base);

  716.         if(best_ast->remaining)

  717.             i= av_index_search_timestamp(best_st, best_ts, AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);

  718.         else{

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

  720.             if(i>=0)

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

  722.         }

  723. 

  724. //        av_log(s, AV_LOG_DEBUG, "%d\n", i);

  725.         if(i>=0){

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

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

  728.             url_fseek(s->pb, pos + 8, SEEK_SET);

  729. //        av_log(s, AV_LOG_DEBUG, "pos=%"PRId64"\n", pos);

  730. 

  731.             assert(best_ast->remaining <= best_ast->packet_size);

  732. 

  733.             avi->stream_index= best_stream_index;

  734.             if(!best_ast->remaining)

  735.                 best_ast->packet_size=

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

  737.         }

  738.     }

  739. 

  740. resync:

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

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

  743.         AVIStream *ast= st->priv_data;

  744.         int size, err;

  745. 

  746.         if(ast->sample_size <= 1) // minorityreport.AVI block_align=1024 sample_size=1 IMA-ADPCM

  747.             size= INT_MAX;

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

  749.             size= 64*ast->sample_size;

  750.         else

  751.             size= ast->sample_size;

  752. 

  753.         if(size > ast->remaining)

  754.             size= ast->remaining;

  755.         avi->last_pkt_pos= url_ftell(pb);

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

  757.         if(err<0)

  758.             return err;

  759. 

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

  761.             void *ptr= av_realloc(pkt->data, pkt->size + 4*256 + FF_INPUT_BUFFER_PADDING_SIZE);

  762.             if(ptr){

  763.             ast->has_pal=0;

  764.             pkt->size += 4*256;

  765.             pkt->data= ptr;

  766.                 memcpy(pkt->data + pkt->size - 4*256, ast->pal, 4*256);

  767.             }else

  768.                 av_log(s, AV_LOG_ERROR, "Failed to append palette\n");

  769.         }

  770. 

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

  772.             dstr = pkt->destruct;

  773.             size = dv_produce_packet(avi->dv_demux, pkt,

  774.                                     pkt->data, pkt->size);

  775.             pkt->destruct = dstr;

  776.             pkt->flags |= PKT_FLAG_KEY;

  777.         } else {

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

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

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

  781.             if(ast->sample_size)

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

  783. //av_log(s, AV_LOG_DEBUG, "dts:%"PRId64" offset:%"PRId64" %d/%d smpl_siz:%d base:%d st:%d size:%d\n", pkt->dts, ast->frame_offset, ast->scale, ast->rate, ast->sample_size, AV_TIME_BASE, avi->stream_index, size);

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

  785. 

  786.             if (st->codec->codec_type == CODEC_TYPE_VIDEO) {

  787.                 AVIndexEntry *e;

  788.                 int index;

  789.                 assert(st->index_entries);

  790. 

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

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

  793. 

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

  795.                     if (e->flags & AVINDEX_KEYFRAME)

  796.                         pkt->flags |= PKT_FLAG_KEY;

  797.                 }

  798.             } else {

  799.                 pkt->flags |= PKT_FLAG_KEY;

  800.             }

  801.             if(ast->sample_size)

  802.                 ast->frame_offset += pkt->size;

  803.             else

  804.                 ast->frame_offset++;

  805.         }

  806.         ast->remaining -= size;

  807.         if(!ast->remaining){

  808.             avi->stream_index= -1;

  809.             ast->packet_size= 0;

  810.         }

  811. 

  812.         return size;

  813.     }

  814. 

  815.     memset(d, -1, sizeof(int)*8);

  816.     for(i=sync=url_ftell(pb); !url_feof(pb); i++) {

  817.         int j;

  818. 

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

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

  821.         d[7]= get_byte(pb);

  822. 

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

  824. 

  825.         n= get_stream_idx(d+2);

  826. //av_log(s, AV_LOG_DEBUG, "%X %X %X %X %X %X %X %X %"PRId64" %d %d\n", d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);

  827.         if(i + (uint64_t)size > avi->fsize || d[0]<0)

  828.             continue;

  829. 

  830.         //parse ix##

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

  832.         //parse JUNK

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

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

  835.             url_fskip(pb, size);

  836. //av_log(s, AV_LOG_DEBUG, "SKIP\n");

  837.             goto resync;

  838.         }

  839. 

  840.         //parse stray LIST

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

  842.             url_fskip(pb, 4);

  843.             goto resync;

  844.         }

  845. 

  846.         n= get_stream_idx(d);

  847. 

  848.         if(!((i-avi->last_pkt_pos)&1) && get_stream_idx(d+1) < s->nb_streams)

  849.             continue;

  850. 

  851.         //detect ##ix chunk and skip

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

  853.             url_fskip(pb, size);

  854.             goto resync;

  855.         }

  856. 

  857.         //parse ##dc/##wb

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

  859.             AVStream *st;

  860.             AVIStream *ast;

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

  862.             ast = st->priv_data;

  863. 

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

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

  866.                 AVIStream *ast1= st1->priv_data;

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

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

  869.                    && n==0

  870.                    && st ->codec->codec_type == CODEC_TYPE_VIDEO

  871.                    && st1->codec->codec_type == CODEC_TYPE_AUDIO

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

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

  874.                   ){

  875.                     n=1;

  876.                     st = st1;

  877.                     ast = ast1;

  878.                     av_log(s, AV_LOG_WARNING, "Invalid stream + prefix combination, assuming audio.\n");

  879.                 }

  880.             }

  881. 

  882. 

  883.             if(   (st->discard >= AVDISCARD_DEFAULT && size==0)

  884.                /*|| (st->discard >= AVDISCARD_NONKEY && !(pkt->flags & PKT_FLAG_KEY))*/ //FIXME needs a little reordering

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

  886.                 if(ast->sample_size) ast->frame_offset += pkt->size;

  887.                 else                 ast->frame_offset++;

  888.                 url_fskip(pb, size);

  889.                 goto resync;

  890.             }

  891. 

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

  893.                 int k = get_byte(pb);

  894.                 int last = (k + get_byte(pb) - 1) & 0xFF;

  895. 

  896.                 get_le16(pb); //flags

  897. 

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

  899.                     ast->pal[k] = get_be32(pb)>>8;// b + (g << 8) + (r << 16);

  900.                 ast->has_pal= 1;

  901.                 goto resync;

  902.             } else if(   ((ast->prefix_count<5 || sync+9 > i) && d[2]<128 && d[3]<128) ||

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

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

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

  906. 

  907. //av_log(s, AV_LOG_DEBUG, "OK\n");

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

  909.                     ast->prefix_count++;

  910.                 else{

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

  912.                     ast->prefix_count= 0;

  913.                 }

  914. 

  915.                 avi->stream_index= n;

  916.                 ast->packet_size= size + 8;

  917.                 ast->remaining= size;

  918. 

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

  920.                     uint64_t pos= url_ftell(pb) - 8;

  921.                     if(!st->index_entries || !st->nb_index_entries || st->index_entries[st->nb_index_entries - 1].pos < pos){

  922.                         av_add_index_entry(st, pos, ast->frame_offset, size, 0, AVINDEX_KEYFRAME);

  923.                     }

  924.                 }

  925.                 goto resync;

  926.             }

  927.         }

  928.     }

  929. 

  930.     return AVERROR_EOF;

  931. }

  932. 

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

  934.    for each stream. */

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

  936. {

  937.     AVIContext *avi = s->priv_data;

  938.     ByteIOContext *pb = s->pb;

  939.     int nb_index_entries, i;

  940.     AVStream *st;

  941.     AVIStream *ast;

  942.     unsigned int index, tag, flags, pos, len;

  943.     unsigned last_pos= -1;

  944. 

  945.     nb_index_entries = size / 16;

  946.     if (nb_index_entries <= 0)

  947.         return -1;

  948. 

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

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

  951.         tag = get_le32(pb);

  952.         flags = get_le32(pb);

  953.         pos = get_le32(pb);

  954.         len = get_le32(pb);

  955. #if defined(DEBUG_SEEK)

  956.         av_log(s, AV_LOG_DEBUG, "%d: tag=0x%x flags=0x%x pos=0x%x len=%d/",

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

  958. #endif

  959.         if(i==0 && pos > avi->movi_list)

  960.             avi->movi_list= 0; //FIXME better check

  961.         pos += avi->movi_list;

  962. 

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

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

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

  966.             continue;

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

  968.         ast = st->priv_data;

  969. 

  970. #if defined(DEBUG_SEEK)

  971.         av_log(s, AV_LOG_DEBUG, "%d cum_len=%"PRId64"\n", len, ast->cum_len);

  972. #endif

  973.         if(url_feof(pb))

  974.             return -1;

  975. 

  976.         if(last_pos == pos)

  977.             avi->non_interleaved= 1;

  978.         else if(len || !ast->sample_size)

  979.             av_add_index_entry(st, pos, ast->cum_len, len, 0, (flags&AVIIF_INDEX) ? AVINDEX_KEYFRAME : 0);

  980.         if(ast->sample_size)

  981.             ast->cum_len += len;

  982.         else

  983.             ast->cum_len ++;

  984.         last_pos= pos;

  985.     }

  986.     return 0;

  987. }

  988. 

  989. static int guess_ni_flag(AVFormatContext *s){

  990.     int i;

  991.     int64_t last_start=0;

  992.     int64_t first_end= INT64_MAX;

  993.     int64_t oldpos= url_ftell(s->pb);

  994. 

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

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

  997.         int n= st->nb_index_entries;

  998.         unsigned int size;

  999. 

  1000.         if(n <= 0)

  1001.             continue;

  1002. 

  1003.         if(n >= 2){

  1004.             int64_t pos= st->index_entries[0].pos;

  1005.             url_fseek(s->pb, pos + 4, SEEK_SET);

  1006.             size= get_le32(s->pb);

  1007.             if(pos + size > st->index_entries[1].pos)

  1008.                 last_start= INT64_MAX;

  1009.         }

  1010. 

  1011.         if(st->index_entries[0].pos > last_start)

  1012.             last_start= st->index_entries[0].pos;

  1013.         if(st->index_entries[n-1].pos < first_end)

  1014.             first_end= st->index_entries[n-1].pos;

  1015.     }

  1016.     url_fseek(s->pb, oldpos, SEEK_SET);

  1017.     return last_start > first_end;

  1018. }

  1019. 

  1020. static int avi_load_index(AVFormatContext *s)

  1021. {

  1022.     AVIContext *avi = s->priv_data;

  1023.     ByteIOContext *pb = s->pb;

  1024.     uint32_t tag, size;

  1025.     int64_t pos= url_ftell(pb);

  1026.     int ret = -1;

  1027. 

  1028.     if (url_fseek(pb, avi->movi_end, SEEK_SET) < 0)

  1029.         goto the_end; // maybe truncated file

  1030. #ifdef DEBUG_SEEK

  1031.     printf("movi_end=0x%"PRIx64"\n", avi->movi_end);

  1032. #endif

  1033.     for(;;) {

  1034.         if (url_feof(pb))

  1035.             break;

  1036.         tag = get_le32(pb);

  1037.         size = get_le32(pb);

  1038. #ifdef DEBUG_SEEK

  1039.         printf("tag=%c%c%c%c size=0x%x\n",

  1040.                tag & 0xff,

  1041.                (tag >> 8) & 0xff,

  1042.                (tag >> 16) & 0xff,

  1043.                (tag >> 24) & 0xff,

  1044.                size);

  1045. #endif

  1046.         switch(tag) {

  1047.         case MKTAG('i', 'd', 'x', '1'):

  1048.             if (avi_read_idx1(s, size) < 0)

  1049.                 goto skip;

  1050.             ret = 0;

  1051.                 goto the_end;

  1052.             break;

  1053.         default:

  1054.         skip:

  1055.             size += (size & 1);

  1056.             if (url_fseek(pb, size, SEEK_CUR) < 0)

  1057.                 goto the_end; // something is wrong here

  1058.             break;

  1059.         }

  1060.     }

  1061.  the_end:

  1062.     url_fseek(pb, pos, SEEK_SET);

  1063.     return ret;

  1064. }

  1065. 

  1066. static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)

  1067. {

  1068.     AVIContext *avi = s->priv_data;

  1069.     AVStream *st;

  1070.     int i, index;

  1071.     int64_t pos;

  1072.     AVIStream *ast;

  1073. 

  1074.     if (!avi->index_loaded) {

  1075.         /* we only load the index on demand */

  1076.         avi_load_index(s);

  1077.         avi->index_loaded = 1;

  1078.     }

  1079.     assert(stream_index>= 0);

  1080. 

  1081.     st = s->streams[stream_index];

  1082.     ast= st->priv_data;

  1083.     index= av_index_search_timestamp(st, timestamp * FFMAX(ast->sample_size, 1), flags);

  1084.     if(index<0)

  1085.         return -1;

  1086. 

  1087.     /* find the position */

  1088.     pos = st->index_entries[index].pos;

  1089.     timestamp = st->index_entries[index].timestamp / FFMAX(ast->sample_size, 1);

  1090. 

  1091. //    av_log(s, AV_LOG_DEBUG, "XX %"PRId64" %d %"PRId64"\n", timestamp, index, st->index_entries[index].timestamp);

  1092. 

  1093.     if (CONFIG_DV_DEMUXER && avi->dv_demux) {

  1094.         /* One and only one real stream for DV in AVI, and it has video  */

  1095.         /* offsets. Calling with other stream indexes should have failed */

  1096.         /* the av_index_search_timestamp call above.                     */

  1097.         assert(stream_index == 0);

  1098. 

  1099.         /* Feed the DV video stream version of the timestamp to the */

  1100.         /* DV demux so it can synthesize correct timestamps.        */

  1101.         dv_offset_reset(avi->dv_demux, timestamp);

  1102. 

  1103.         url_fseek(s->pb, pos, SEEK_SET);

  1104.         avi->stream_index= -1;

  1105.         return 0;

  1106.     }

  1107. 

  1108.     for(i = 0; i < s->nb_streams; i++) {

  1109.         AVStream *st2 = s->streams[i];

  1110.         AVIStream *ast2 = st2->priv_data;

  1111. 

  1112.         ast2->packet_size=

  1113.         ast2->remaining= 0;

  1114. 

  1115.         if (st2->nb_index_entries <= 0)

  1116.             continue;

  1117. 

  1118. //        assert(st2->codec->block_align);

  1119.         assert((int64_t)st2->time_base.num*ast2->rate == (int64_t)st2->time_base.den*ast2->scale);

  1120.         index = av_index_search_timestamp(

  1121.                 st2,

  1122.                 av_rescale_q(timestamp, st->time_base, st2->time_base) * FFMAX(ast2->sample_size, 1),

  1123.                 flags | AVSEEK_FLAG_BACKWARD);

  1124.         if(index<0)

  1125.             index=0;

  1126. 

  1127.         if(!avi->non_interleaved){

  1128.             while(index>0 && st2->index_entries[index].pos > pos)

  1129.                 index--;

  1130.             while(index+1 < st2->nb_index_entries && st2->index_entries[index].pos < pos)

  1131.                 index++;

  1132.         }

  1133. 

  1134. //        av_log(s, AV_LOG_DEBUG, "%"PRId64" %d %"PRId64"\n", timestamp, index, st2->index_entries[index].timestamp);

  1135.         /* extract the current frame number */

  1136.         ast2->frame_offset = st2->index_entries[index].timestamp;

  1137.     }

  1138. 

  1139.     /* do the seek */

  1140.     url_fseek(s->pb, pos, SEEK_SET);

  1141.     avi->stream_index= -1;

  1142.     return 0;

  1143. }

  1144. 

  1145. static int avi_read_close(AVFormatContext *s)

  1146. {

  1147.     int i;

  1148.     AVIContext *avi = s->priv_data;

  1149. 

  1150.     for(i=0;i<s->nb_streams;i++) {

  1151.         AVStream *st = s->streams[i];

  1152.         av_free(st->codec->palctrl);

  1153.     }

  1154. 

  1155.     if (avi->dv_demux)

  1156.         av_free(avi->dv_demux);

  1157. 

  1158.     return 0;

  1159. }

  1160. 

  1161. static int avi_probe(AVProbeData *p)

  1162. {

  1163.     int i;

  1164. 

  1165.     /* check file header */

  1166.     for(i=0; avi_headers[i][0]; i++)

  1167.         if(!memcmp(p->buf  , avi_headers[i]  , 4) &&

  1168.            !memcmp(p->buf+8, avi_headers[i]+4, 4))

  1169.             return AVPROBE_SCORE_MAX;

  1170. 

  1171.     return 0;

  1172. }

  1173. 

  1174. AVInputFormat avi_demuxer = {

  1175.     "avi",

  1176.     NULL_IF_CONFIG_SMALL("AVI format"),

  1177.     sizeof(AVIContext),

  1178.     avi_probe,

  1179.     avi_read_header,

  1180.     avi_read_packet,

  1181.     avi_read_close,

  1182.     avi_read_seek,

  1183. };