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• How to remove tx3g stream from m4a file [closed]

  12 novembre 2023, par KWottrich

  I have an audiobook that I'm trying to play on my phone. My audio app of choice is struggling with the file, and I think it's because there's an additional stream in the file that it can't handle. VLC for Android plays the file without issue, but I'd rather use my audio app of choice.

  


  When I open the m4a file in VLC for Windows, I see two streams :

  


  

  


  I want to get rid of the tx3g stream, and just keep the audio stream. So I turned to ffmpeg to try to copy over only the audio stream. However, no matter what I try, the tx3g stream seems to come along for the ride. I referred to this post to figure out how to remove the tx3g stream, but so far I've been unsuccessful. Can anyone help me figure out how to remove just the tx3g track ? Ideally, I'd like to keep the metadata and album art as well.

  


  I tried to run ffmpeg -i input.m4a -map 0:a:0 -sn -dn -c copy output.m4a, but the tx3g stream is still there. Here is the command output :

  


  ffmpeg version 2021-12-06-git-ef00d40e32-essentials_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 11.2.0 (Rev2, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
  libavutil      57. 10.101 / 57. 10.101
  libavcodec     59. 14.100 / 59. 14.100
  libavformat    59.  9.102 / 59.  9.102
  libavdevice    59.  0.101 / 59.  0.101
  libavfilter     8. 19.100 /  8. 19.100
  libswscale      6.  1.101 /  6.  1.101
  libswresample   4.  0.100 /  4.  0.100
  libpostproc    56.  0.100 / 56.  0.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 000002773b2db200] stream 0, timescale not set
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '.\input.m4a':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    artist          : [removed]
    title           : [removed]
    album           : [removed]
    date            : 2020
    genre           : Audiobook
    track           : 1/22
    disc            : 1/1
    comment         : [removed]
    copyright       : [removed]
    encoder         : Lavf58.29.100
  Duration: 00:01:45.14, start: 0.000000, bitrate: 132 kb/s
  Chapters:
    Chapter #0:0: start 0.000000, end 105.000000
      Metadata:
        title           : [removed]
  Stream #0:0[0x1](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]
  Stream #0:1[0x2](und): Data: bin_data (text / 0x74786574), 0 kb/s
    Metadata:
      creation_time   : 2021-11-29T16:23:41.000000Z
  Stream #0:2[0x0]: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/unknown), 500x500 [SAR 1:1 DAR 1:1], 90k tbr, 90k tbn (attached pic)
Output #0, ipod, to 'output.m4a':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    artist          : [removed]
    title           : [removed]
    album           : [removed]
    date            : 2020
    genre           : Audiobook
    track           : 1/22
    disc            : 1/1
    comment         : [removed]
    copyright       : [removed]
    encoder         : Lavf59.9.102
  Chapters:
    Chapter #0:0: start 0.000000, end 105.000000
      Metadata:
        title           : [removed]
  Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
size=    1632kB time=00:01:45.11 bitrate= 127.2kbits/s speed=1.48e+04x
video:0kB audio:1612kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.233040%


  


• ffmpeg H.264 to VP9 always creates larger output files on Zoom Meeting Recordings

  22 avril 2022, par Sam

  ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 0 -crf 30 -pass 1 -an -f null -row-mt 1 NUL && ^
ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 0 -crf 30 -pass 2 -c:a libopus -row-mt 1 output.webm


  


  input.mp4 file size is 197,007 KiB and output.webm is 197,132 KiB.

  


  For context, we have approx. 9TB of Zoom Meeting Recordings stored in AWS S3. My goal is to optimize the storage consumption by converting to VP9. I'm willing to sacrifice a bit of quality to optimize storage.

  


  I am seeing better results on some other (non-Zoom) H.264 files (reduced from 88MiB in H.264 to 11MiB in VP9) with the exact same ffmpeg options.

  


  Here's the details on the input file :

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2022-03-17T16:20:43.000000Z
  Duration: 01:14:31.74, start: 0.000000, bitrate: 360 kb/s
  Chapters:
    Chapter #0:0: start 0.000000, end 755.480000
      Metadata:
        title           : Recording Started
    Chapter #0:1: start 755.480000, end 4465.840000
      Metadata:
        title           : Sharing Started
    Chapter #0:2: start 4465.840000, end 4471.720000
      Metadata:
        title           : Sharing Stopped
  Stream #0:0[0x1](und): Audio: aac (LC) (mp4a / 0x6134706D), 32000 Hz, mono, fltp, 126 kb/s (default)
    Metadata:
      creation_time   : 2022-03-17T16:20:43.000000Z
      handler_name    : AAC audio
      vendor_id       : [0][0][0][0]
  Stream #0:1[0x2](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 1920x1040, 232 kb/s, 25 fps, 25 tbr, 30k tbn (default)
    Metadata:
      creation_time   : 2022-03-17T16:20:43.000000Z
      handler_name    : H.264/AVC video
      vendor_id       : [0][0][0][0]
      encoder         : AVC Coding
  Stream #0:2[0x3](und): Data: bin_data (text / 0x74786574)
    Metadata:
      creation_time   : 2022-03-17T16:20:43.000000Z
      handler_name    : Text


  


  Output file :

  


  Input #0, matroska,webm, from 'output.webm':
  Metadata:
    COMPATIBLE_BRANDS: isommp42
    MAJOR_BRAND     : mp42
    MINOR_VERSION   : 0
    ENCODER         : Lavf59.22.100
  Duration: 01:14:31.75, start: -0.003000, bitrate: 361 kb/s
  Chapters:
    Chapter #0:0: start 0.000000, end 755.480000
      Metadata:
        title           : Recording Started
    Chapter #0:1: start 755.480000, end 4465.840000
      Metadata:
        title           : Sharing Started
    Chapter #0:2: start 4465.840000, end 4471.720000
      Metadata:
        title           : Sharing Stopped
  Stream #0:0: Video: vp9 (Profile 0), yuv420p(tv, progressive), 1920x1040, SAR 1:1 DAR 24:13, 25 fps, 25 tbr, 1k tbn (default)
    Metadata:
      HANDLER_NAME    : H.264/AVC video
      VENDOR_ID       : [0][0][0][0]
      ENCODER         : Lavc59.26.100 libvpx-vp9
      DURATION        : 01:14:31.727000000
  Stream #0:1: Audio: opus, 48000 Hz, mono, fltp (default)
    Metadata:
      HANDLER_NAME    : AAC audio
      VENDOR_ID       : [0][0][0][0]
      ENCODER         : Lavc59.26.100 libopus
      DURATION        : 01:14:31.752000000


  


  I'm noticing that H.264/AVC is still listed in the metadata for Stream #0:0 in the output file, but I don't see this same detail on my successfully-reduced VP9 files.

  


• avformat/matroskaenc : Don't check twice whether to write tags

  15 juin 2022, par Andreas Rheinhardt

  avformat/matroskaenc : Don't check twice whether to write tags
  Because not all metadata is written as tags, the Matroska muxer
  
  filters out the tags that are not written as tags.
  
  Therefore the code first checks whether a Tag master element
  
  needs to be opened for a given stream/chapter/attachment/global
  
  metadata. If the answer turns out to be yes, it is checked again
  
  whether a given AVDictionaryEntry is written as a tag.
  
  This commit changes this : The Tag element is opened unconditionally
  
  and in case it turns out that it was unneeded, it is discarded again.
  
  This is possible because the Tag element is written into its own
  
  dynamic buffer.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavformat/matroskaenc.c