[FFmpeg-user] Concat and extract image cause FFmpeg to hang in 3.3 and 3.4

[Jeff Wang]

> In addition to the command line, could you kindly also post the

> complete, uncut console output of a working and a non-working attempt?
> Even if you have no warning or error messages, the outputs contain
> valuable information.

Please see the complete console output at the end of this message.


> Furthermore, instead of (or in addition to) testing releases, please
> also try latest git master

I've try the latest release ffmpeg version N-89803-g856b7cae9f-tessus. Same behavior.


> Does removing "-threads 0" help?

It does not help. Exactly same behavior.


> Why are you updating to 3.3 and not 3.4.x? While I can understand why
> you may want to stick to releases, why an older one?

Good point. I will bring it up with the team today. However, 3.4 seems to hang at the same line at the console output (but Lavc version is different).


> P.S.: With my artificially created input, I couldn't reproduce.

My inputs can be found here https://s3.amazonaws.com/it6dc/public/ffmpeg-cat/inputs.zip Is there anyway I can get your artificially created input also?


Please see the complete output from FFmpeg below:

ffmpeg -i topia.flac -i topia_png.flac -threads 0 -map_chapters -1 -f flac -filter_complex "[0:a:0][1:a:0]concat=n=2:v=0:a=1[cat_a]" -map "[cat_a]" -acodec flac -sample_fmt s16 -ac 2 -ar 44100 -sn -vn topia.flac+topia_png.flac.flac -map 1:1 -f image2 -vcodec copy -frames:v 1 extract.png


ffmpeg version 3.3-tessus Copyright (c) 2000-2017 the FFmpeg developers
  built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-libzvbi --enable-version3 --disable-ffplay --disable-indev=qtkit
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
Input #0, flac, from 'topia.flac':
  Metadata:
    MAJOR_BRAND     : dash
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: iso6mp41
    ENCODER         : Lavf57.25.100
  Duration: 00:00:05.00, start: 0.000000, bitrate: 678 kb/s
    Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
Input #1, flac, from 'topia_png.flac':
  Metadata:
    MAJOR_BRAND     : dash
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: iso6mp41
    ENCODER         : Lavf57.25.100
  Duration: 00:00:05.00, start: 0.000000, bitrate: 961 kb/s
    Stream #1:0: Audio: flac, 44100 Hz, stereo, s16
    Stream #1:1: Video: png, rgba(pc), 300x300, 90k tbr, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
Output #1, image2, to 'extract.png':
  Metadata:
    MAJOR_BRAND     : dash
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: iso6mp41
    encoder         : Lavf57.71.100
    Stream #1:0: Video: png, rgba(pc), 300x300, q=2-31, 90k tbr, 90k tbn, 90k tbc
    Metadata:
      comment         : Cover (front)
Stream mapping:
  Stream #0:0 (flac) -> concat:in0:a0
  Stream #1:0 (flac) -> concat:in1:a0
  concat -> Stream #0:0 (flac)
  Stream #1:1 -> #1:0 (copy)
Press [q] to stop, [?] for help
Output #0, flac, to 'topia.flac+topia_png.flac.flac':
  Metadata:
    MAJOR_BRAND     : dash
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: iso6mp41
    encoder         : Lavf57.71.100
    Stream #0:0: Audio: flac, 44100 Hz, stereo, s16, 128 kb/s (default)
    Metadata:
      encoder         : Lavc57.89.100 flac


Thanks,
Jeff