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• Problem accessing audio track from mp4 file

  20 décembre 2019, par Thomas Spycher

  For a TV Project we want to transcode the source videofiles to other formats. The Sourcefiles are fragmented mp4 files. Destination format could be mp4 or any other format.
  The sourcefile contains multiple audio tracks for different codes (aac, eac3, aac-otherlanguage).

  Something with this files is odd. I can play them without problems on quicktime or VLC. Import them into Premiere for example ends up with the video but without sound.

  Converting them on AWS MediaConvert results in weird issues as well like (depending on the settings) :

  • No audio frames decoded on [selector-(Audio Selector 1)-track-1-drc] (selecting aac audiotrack (Track:1))
  • Decoder : [Dolby decoder error : failed to configure to stream in first 100 frames] (selecting eac3 audiotrack (Track:2) )

  I’m able to convert the files with Handbreak and the result is a MP4 file with one audiotrack which is working everywhere. I’m trying to figure out whats odd with this file to make them working with AWS MediaConvert.

  Here is the ffprobe output of one of the files :

  ffprobe version 4.1 Copyright (c) 2007-2018 the FFmpeg developers
  
    built with Apple LLVM version 10.0.0 (clang-1000.10.44.4)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gpl --enable-libmp3lame --enable-libopus --enable-libsnappy --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfreetype --enable-opencl --enable-videotoolbox
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '123893.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42isomiso2iso5dashavc1dby1mp41
  
    Duration: 00:01:24.02, start: 0.000000, bitrate: 5600 kb/s
  
      Stream #0:0(deu): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 4869 kb/s, 50 fps, 50 tbr, 1k tbn, 100 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(deu): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
      Stream #0:2(deu): Audio: eac3 (ec-3 / 0x332D6365), 48000 Hz, 5.1(side), fltp, 256 kb/s
  
      Metadata:
  
        handler_name    : SoundHandler
  
      Side data:
  
        audio service type: main

  An example file can get downloaded here : https://wilmaa-rnd.s3-eu-west-1.amazonaws.com/124041.mp4

• avcodec/wmadec : Keep track of exponent initialization per channel

  30 novembre 2019, par Michael Niedermayer

  avcodec/wmadec : Keep track of exponent initialization per channel
  Fixes : division by 0
  
  Fixes : 19123/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMAV2_fuzzer-5655493121146880
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/wma.h
  • [DH] libavcodec/wmadec.c

• FFmpeg : How can I loop a single frame of video to cover the length of audio track

  6 avril 2020, par John Bergqvist

  I have a VOB file holding an MPEG-2 video track with an AC-3 audio track. The video track of that VOB file consists of a single frame, which when played in a DVD player, holds that still frame until the audio track has finished.

  



  How can I (with FFMPEG ideally), loop that frame to make a "normal" video track that lasts for the length of the audio track, rather than just a single frame ?

  



  ffmpeg version N-91999-g148a21611d Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 8.2.1 (GCC) 20180813
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
  libavutil      56. 19.101 / 56. 19.101
  libavcodec     58. 30.100 / 58. 30.100
  libavformat    58. 18.102 / 58. 18.102
  libavdevice    58.  4.103 / 58.  4.103
  libavfilter     7. 32.100 /  7. 32.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
  libpostproc    55.  2.100 / 55.  2.100
Input #0, mpeg, from '.\SINGLEFRAME.VOB':
  Duration: 00:00:47.94, start: 0.336711, bitrate: 439 kb/s
    Stream #0:0: Data: dvd_nav_packet
    Stream #0:1: Video: mpeg2video (Main), yuv420p(tv), 720x576 [SAR 16:15 DAR 4:3], 8000 kb/s, 25 tbr, 90k tbn, 50 tbc
    Stream #0:2: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s