[FFmpeg-trac] #3804(avformat:open): FFmpeg process hangs when new subtitle streams are found during encoding

[FFmpeg]

#3804: FFmpeg process hangs when new subtitle streams are found during encoding
------------------------------------+------------------------------------
             Reporter:  mrskman     |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  important   |                Component:  avformat
              Version:  git-master  |               Resolution:
             Keywords:  deadlock    |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  0           |
------------------------------------+------------------------------------
Changes (by cehoyos):

 * status:  new => open
 * reproduced:  0 => 1
 * component:  undetermined => avformat
 * priority:  normal => important
 * version:  2.3 => git-master
 * keywords:   => deadlock


Comment:

 I suspect that parse_packet() loops forever.
 {{{
 (gdb) r -i encoding_hangs_when_new_subtitle_streams_are_found_0-20MB.vob
 -f null -
 Starting program: ffmpeg_g -i
 encoding_hangs_when_new_subtitle_streams_are_found_0-20MB.vob -f null -
 [Thread debugging using libthread_db enabled]
 Using host libthread_db library "/lib64/libthread_db.so.1".
 ffmpeg version N-64967-g2904d05 Copyright (c) 2000-2014 the FFmpeg
 developers
   built on Jul 25 2014 13:18:59 with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl
   libavutil      52. 92.101 / 52. 92.101
   libavcodec     55. 69.100 / 55. 69.100
   libavformat    55. 49.100 / 55. 49.100
   libavdevice    55. 13.102 / 55. 13.102
   libavfilter     4. 11.102 /  4. 11.102
   libswscale      2.  6.100 /  2.  6.100
   libswresample   0. 19.100 /  0. 19.100
   libpostproc    52.  3.100 / 52.  3.100
 Input #0, mpeg, from
 'encoding_hangs_when_new_subtitle_streams_are_found_0-20MB.vob':
   Duration: 00:00:12.51, start: 0.287267, bitrate: 13407 kb/s
     Stream #0:0[0x1bf]: Data: dvd_nav_packet
     Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, smpte170m),
 720x576 [SAR 64:45 DAR 16:9], max. 8000 kb/s, 25 fps, 25 tbr, 90k tbn, 50
 tbc
     Stream #0:2[0x80]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
 [New Thread 0x7ffff1d26700 (LWP 13924)]
 [New Thread 0x7ffff1525700 (LWP 13925)]
 [New Thread 0x7ffff0d24700 (LWP 13926)]
 [New Thread 0x7ffff0523700 (LWP 13927)]
 [New Thread 0x7fffefd22700 (LWP 13928)]
 [New Thread 0x7fffef521700 (LWP 13929)]
 [New Thread 0x7fffeed20700 (LWP 13930)]
 [New Thread 0x7fffee51f700 (LWP 13931)]
 [New Thread 0x7fffedd1e700 (LWP 13932)]
 [New Thread 0x7fffed51d700 (LWP 13933)]
 [New Thread 0x7fffecd1c700 (LWP 13934)]
 [New Thread 0x7fffec51b700 (LWP 13935)]
 [New Thread 0x7fffebd1a700 (LWP 13936)]
 [New Thread 0x7fffeb519700 (LWP 13937)]
 [New Thread 0x7fffead18700 (LWP 13938)]
 [New Thread 0x7fffea517700 (LWP 13939)]
 [New Thread 0x7fffe9d16700 (LWP 13940)]
 [New Thread 0x7fffe9515700 (LWP 13941)]
 [New Thread 0x7fffe8d14700 (LWP 13942)]
 [New Thread 0x7fffe8513700 (LWP 13943)]
 [New Thread 0x7fffe7d12700 (LWP 13944)]
 [New Thread 0x7fffe7511700 (LWP 13945)]
 [New Thread 0x7fffe6d10700 (LWP 13946)]
 [New Thread 0x7fffe650f700 (LWP 13947)]
 [New Thread 0x7fffe5d0e700 (LWP 13948)]
 [New Thread 0x7fffe550d700 (LWP 13949)]
 [New Thread 0x7fffe4d0c700 (LWP 13950)]
 Output #0, null, to 'pipe:':
   Metadata:
     encoder         : Lavf55.49.100
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 720x576
 [SAR 64:45 DAR 16:9], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
     Metadata:
       encoder         : Lavc55.69.100 rawvideo
     Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
     Metadata:
       encoder         : Lavc55.69.100 pcm_s16le
 Stream mapping:
   Stream #0:1 -> #0:0 (mpeg2video (native) -> rawvideo (native))
   Stream #0:2 -> #0:1 (ac3 (native) -> pcm_s16le (native))
 Press [q] to stop, [?] for help
 [null @ 0x1a8eb40] Encoder did not produce proper pts, making some up.
 [mpeg @ 0x1a10d40] New subtitle stream 0:3 at pos:11966478 and
 DTS:0.280633s
 [mpeg @ 0x1a10d40] New subtitle stream 0:4 at pos:11970574 and
 DTS:0.280633s

 Program received signal SIGINT, Interrupt.
 parse_packet (s=s at entry=0x1a10d40, pkt=pkt at entry=0x7fffffffd610,
     stream_index=<optimized out>) at libavformat/utils.c:1355
 1355            pkt->pos = -1;
 (gdb) bt
 #0  parse_packet (s=s at entry=0x1a10d40, pkt=pkt at entry=0x7fffffffd610,
     stream_index=<optimized out>) at libavformat/utils.c:1355
 #1  0x000000000060f80a in read_frame_internal (s=0x1a10d40,
 pkt=0x7fffffffd9f0)
     at libavformat/utils.c:1522
 #2  0x0000000000610446 in av_read_frame (s=0x1a10d40,
 pkt=pkt at entry=0x7fffffffd9f0)
     at libavformat/utils.c:1599
 #3  0x0000000000485b36 in get_input_packet (pkt=0x7fffffffd9f0,
 f=0x1a08240)
     at ffmpeg.c:3281
 #4  process_input (file_index=0) at ffmpeg.c:3318
 #5  0x000000000046bb1f in transcode_step () at ffmpeg.c:3609
 #6  transcode () at ffmpeg.c:3661
 #7  main (argc=<optimized out>, argv=<optimized out>) at ffmpeg.c:3837
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/3804#comment:1>
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