[FFmpeg-user] ac3 frame sync errors mpegts->webm chunks

Wed Aug 3 20:44:29 EEST 2016

On Wed, Aug 3, 2016 at 11:33 AM, Carl Eugen Hoyos <ceffmpeg at gmail.com>
wrote:

> 2016-08-03 17:15 GMT+02:00 Sam Gardner <lwnexgen at gmail.com>:
> > Yes, the frame sync error is the last line when using the (eng) channel -
> > is there any way I can get more verbose output about what's going on? The
> > encode process just seems to hang.
>
> This sounds different from what I understood so far:
> Did you wait?
>
> > I've attacted a file that exhibits all behavior - as you can see from the
> > earlier logs, an identically-compiled/configured ffmpeg 2.8.7 has the
> same
> > behavior on the same input.
> >
> > Thanks for any help, and sorry for the earlier.
> >
> >  capture.ts
> > <
> https://drive.google.com/file/d/0B4fu8KZMt9qnek9oeFFWaUszX0k/view?usp=drive_web
> >
>
> I see a crash here, but you don't, is that correct?

Could you try to simplify your command line, i.e. remove everything that is
> not
> necessary to reproduce the issue you see?
> Is it also reproducible with audio-only? Or with -vcodec libvpx
> (instead of vp9)?
>

Ah ha, you are correct - I was accidentally suppressing output with my
wrapper. I can reproduce reliably like this:

*Invocation*
/home/sam/bin/ffmpeg -i capture.ts -map i:0x34 -c:a libvorbis -b:a 128k -af
'pan=stereo|c0=FL|c1=FR' -f webm_chunk -audio_chunk_duration 2000 -header
/var/www/html/webm_live/tuner_128.hdr -chunk_start_index 1
/var/www/html/webm_live/tuner_128_%d.chk

*Output*
ffmpeg version N-81210-gfd4eb56 Copyright (c) 2000-2016 the FFmpeg
developers
  built with gcc 4.8.3 (GCC) 20140911 (Red Hat 4.8.3-7)
  configuration: --prefix=/home/sam/ffmpeg_build
--extra-cflags=-I/home/sam/ffmpeg_build/include
--extra-ldflags=-L/home/sam/ffmpeg_build/lib --bindir=/home/sam/bin
--pkg-config-flags=--static --enable-gpl --enable-nonfree
--enable-libfdk-aac --enable-libfreetype --enable-libmp3lame
--enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264
--enable-libx265
  libavutil      55. 28.100 / 55. 28.100
  libavcodec     57. 51.100 / 57. 51.100
  libavformat    57. 44.100 / 57. 44.100
  libavdevice    57.  0.102 / 57.  0.102
  libavfilter     6. 49.100 /  6. 49.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
[mpeg2video @ 0x373a060] Invalid frame dimensions 0x0.
    Last message repeated 3 times
[mpeg2video @ 0x373a060] skipped MB in I-frame at 83 43
[mpeg2video @ 0x373a060] Warning MVs not available
[mpeg2video @ 0x373a060] concealing 86 DC, 86 AC, 86 MV errors in I frame
[mpegts @ 0x3735580] PES packet size mismatch
    Last message repeated 3 times
Input #0, mpegts, from 'capture.ts':
  Duration: 00:00:30.90, start: 92067.130322, bitrate: 12148 kb/s
  Program 3
    Stream #0:0[0x31]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002),
yuv420p(tv), 1920x1080 [SAR 1:1 DAR 16:9], Closed Captions, 29.97 fps,
29.97 tbr, 90k tbn, 59.94 tbc
    Stream #0:1[0x34](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz,
5.1(side), fltp, 384 kb/s
    Stream #0:2[0x35](spa): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz,
stereo, fltp, 96 kb/s
[Parsed_pan_0 @ 0x3797c00] Pure channel mapping detected: 0 1
[webm_chunk @ 0x3794c20] Using AVStream.codec to pass codec parameters to
muxers is deprecated, use AVStream.codecpar instead.
Output #0, webm_chunk, to '/var/www/html/webm_live/tuner_128_%d.chk':
  Metadata:
    encoder         : Lavf57.44.100
    Stream #0:0(eng): Audio: vorbis (libvorbis), 48000 Hz, stereo, fltp,
128 kb/s
    Metadata:
      encoder         : Lavc57.51.100 libvorbis
Stream mapping:
  Stream #0:1 -> #0:0 (ac3 (native) -> vorbis (libvorbis))
Press [q] to stop, [?] for help
[ac3 @ 0x373d060] frame sync error
Error while decoding stream #0:1: Invalid data found when processing input
zsh: segmentation fault (core dumped)  /home/sam/bin/ffmpeg -i
/mnt/megapenthes/Development/py_hdhomerun/capture.ts

*GDB stack trace*
Program received signal SIGSEGV, Segmentation fault.
0x000000000061cebc in mkv_write_flush_packet (s=0x2725200,
pkt=0x7fffffffd330) at libavformat/matroskaenc.c:2111
2111        if (s->pb->seekable)
Missing separate debuginfos, use: debuginfo-install
SDL-1.2.15-13.fc19.x86_64 alsa-lib-1.0.27.2-1.fc19.x86_64
bzip2-libs-1.0.6-8.fc19.x86_64 freetype-2.4.11-7.fc19.x86_64
glibc-2.17-21.fc19.x86_64 libX11-1.6.0-1.fc19.x86_64
libXau-1.0.8-1.fc19.x86_64 libXext-1.3.2-1.fc19.x86_64
libXv-1.0.9-1.fc19.x86_64 libgcc-4.8.3-7.fc19.x86_64
libstdc++-4.8.3-7.fc19.x86_64 libxcb-1.9-3.fc19.x86_64
zlib-1.2.7-10.fc19.x86_64
(gdb) bt
#0  0x000000000061cebc in mkv_write_flush_packet (s=0x2725200,
pkt=0x7fffffffd330) at libavformat/matroskaenc.c:2111
#1  0x00000000006e0f6e in webm_chunk_write_packet (s=0x26b1c00,
pkt=0x7fffffffd330) at libavformat/webm_chunk.c:209
#2  0x00000000006591e2 in write_packet (pkt=0x7fffffffd330, s=0x26b1c00) at
libavformat/mux.c:732
#3  av_interleaved_write_frame (s=s at entry=0x26b1c00, pkt=0x0,
pkt at entry=0x7fffffffd670)
at libavformat/mux.c:1184
#4  0x0000000000497f4d in write_frame (s=s at entry=0x26b1c00,
pkt=pkt at entry=0x7fffffffd670,
ost=ost at entry=0x26b31e0) at ffmpeg.c:762
#5  0x000000000049f5cd in do_audio_out (frame=0x273b520, ost=0x26b31e0,
s=0x26b1c00) at ffmpeg.c:840
#6  reap_filters (flush=flush at entry=0) at ffmpeg.c:1376
#7  0x0000000000482be1 in transcode_step () at ffmpeg.c:4119
#8  transcode () at ffmpeg.c:4163
#9  main (argc=<optimized out>, argv=<optimized out>) at ffmpeg.c:4356

Thank you, Carl Eugen
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