[FFmpeg-trac] #3531(undetermined:closed): ffmpeg hangs converting a possibly broken avi file

[FFmpeg]

#3531: ffmpeg hangs converting a possibly broken avi file
-------------------------------------+-------------------------------------
             Reporter:  hxuanyu      |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  important    |                Component:
              Version:  git-master   |  undetermined
             Keywords:  avi          |               Resolution:  fixed
  deadlock regression                |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------

Comment (by DonMoir):

 I ended up changing the following. I tested several avi files and it seems
 to be ok. With the change, lake.avi will open in about 2 seconds with
 about 350 index entries. Need someone to verify. Also, it could be
 last_pos should only be set if an index is added. Does new ticket need to
 be opened?

 {{{
 static int read_braindead_odml_indx(AVFormatContext *s, int frame_num)
 {
     AVIContext *avi     = s->priv_data;
     AVIOContext *pb     = s->pb;
     int longs_pre_entry = avio_rl16(pb);
     int index_sub_type  = avio_r8(pb);
     int index_type      = avio_r8(pb);
     int entries_in_use  = avio_rl32(pb);
     int chunk_id        = avio_rl32(pb);
     int64_t base        = avio_rl64(pb);
     int stream_id       = ((chunk_id      & 0xFF) - '0') * 10 +
                           ((chunk_id >> 8 & 0xFF) - '0');
     AVStream *st;
     AVIStream *ast;
     int i;
     int64_t last_pos = -1;
     int64_t filesize = avi->fsize;

     av_dlog(s,
             "longs_pre_entry:%d index_type:%d entries_in_use:%d "
             "chunk_id:%X base:%16"PRIX64"\n",
             longs_pre_entry,
             index_type,
             entries_in_use,
             chunk_id,
             base);

     if (stream_id >= s->nb_streams || stream_id < 0)
         return AVERROR_INVALIDDATA;
     st  = s->streams[stream_id];
     ast = st->priv_data;

     if (index_sub_type)
         return AVERROR_INVALIDDATA;

     avio_rl32(pb);

     if (index_type && longs_pre_entry != 2)
         return AVERROR_INVALIDDATA;
     if (index_type > 1)
         return AVERROR_INVALIDDATA;

     if (filesize > 0 && base >= filesize) {
         av_log(s, AV_LOG_ERROR, "ODML index invalid\n");
         if (base >> 32 == (base & 0xFFFFFFFF) &&
             (base & 0xFFFFFFFF) < filesize    &&
             filesize <= 0xFFFFFFFF)
             base &= 0xFFFFFFFF;
         else
             return AVERROR_INVALIDDATA;
     }

     for (i = 0; i < entries_in_use; i++) {
         if (index_type) {
             int64_t pos = avio_rl32(pb) + base - 8;
             int len     = avio_rl32(pb);
             int key     = len >= 0;
             len &= 0x7FFFFFFF;

 #ifdef DEBUG_SEEK
             av_log(s, AV_LOG_ERROR, "pos:%"PRId64", len:%X\n", pos, len);
 #endif
             if (url_feof(pb))
                 return AVERROR_INVALIDDATA;

             if (last_pos == pos || pos == base - 8)
                 avi->non_interleaved = 1;
 -            if (last_pos != pos && (len || !ast->sample_size))
 +            if (len && last_pos != pos)
                 av_add_index_entry(st, pos, ast->cum_len, len, 0,
                                    key ? AVINDEX_KEYFRAME : 0);

             ast->cum_len += get_duration(ast, len);
             last_pos      = pos;
         } else {
             int64_t offset, pos;
             int duration;
             offset = avio_rl64(pb);
             avio_rl32(pb);       /* size */
             duration = avio_rl32(pb);

             if (url_feof(pb))
                 return AVERROR_INVALIDDATA;

             pos = avio_tell(pb);

             if (avi->odml_depth > MAX_ODML_DEPTH) {
                 av_log(s, AV_LOG_ERROR, "Too deeply nested ODML
 indexes\n");
                 return AVERROR_INVALIDDATA;
             }

             if (avio_seek(pb, offset + 8, SEEK_SET) < 0)
                 return -1;
             avi->odml_depth++;
             read_braindead_odml_indx(s, frame_num);
             avi->odml_depth--;
             frame_num += duration;

             if (avio_seek(pb, pos, SEEK_SET) < 0) {
                 av_log(s, AV_LOG_ERROR, "Failed to restore position after
 reading index\n");
                 return -1;
             }

         }
     }
     avi->index_loaded = 2;
     return 0;
 }
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/3531#comment:9>
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