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• avformat/movenc : allow writing out channel count in MP4 and 3GP

  7 février 2023, par Jan Ekström

  avformat/movenc : allow writing out channel count in MP4 and 3GP
  ISOBMFF (14496-12) made this field ('channelcount') in the
  
  AudioSampleEntry structure non-template¹ somewhere before the
  
  release of the 2022 edition. As for ETSI TS 126 244 AKA 3GPP
  
  file format (V16.1.0, 2020-10), it does not seem contain any
  
  references limiting the channelcount entry in AudioSampleEntry
  
  or in its own definition of EVSSampleEntry.
  fate-mov-mp4-chapters test had to be adjusted as it output a
  
  mono vorbis stream, which would now be properly marked as such
  
  in the container.
  1 : As per 14496-12 :
  
     Fields shown as “template” in the box descriptions are fields
  
     which are coded with a default value unless a derived
  
     specification defines their use and permits writers to use
  
     other values than the default.
  

  • [DH] libavformat/movenc.c
  • [DH] tests/ref/fate/mov-mp4-chapters

• PGS subtitle track is out of sync after extracting then adding to another video file

  23 décembre 2022, par Diericx

  I have the Japanese and English version of a show. I am attempting to extract the subtitles and audio from the English version and add them to the Japanese version.

  


  The video in both files seems to be exactly the same.

  


  Here is the info for the streams contained in the english file. When playing this source video file Track 2 subtitles seem to be almost empty while Track 1 contains all of them forced.

  


  Stream #0:1(eng): Audio: dts (DTS-HD MA), 48000 Hz, stereo, s32p (24 bit) (default)
    Metadata:
      title           : Stereo
      BPS-eng         : 1572054
      DURATION-eng    : 00:29:08.789333333
      NUMBER_OF_FRAMES-eng: 163949
      NUMBER_OF_BYTES-eng: 343648948
      SOURCE_ID-eng   : 001100
      _STATISTICS_WRITING_APP-eng: MakeMKV v1.17.2 darwin(arm64-release)
      _STATISTICS_WRITING_DATE_UTC-eng: 2022-12-18 02:20:00
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES SOURCE_ID
  Stream #0:2(eng): Audio: dts (DTS), 48000 Hz, stereo, fltp, 1536 kb/s
    Metadata:
      title           : Stereo
      BPS-eng         : 1509000
      DURATION-eng    : 00:29:08.789333333
      NUMBER_OF_FRAMES-eng: 163949
      NUMBER_OF_BYTES-eng: 329865388
      SOURCE_ID-eng   : 001100
      _STATISTICS_WRITING_APP-eng: MakeMKV v1.17.2 darwin(arm64-release)
      _STATISTICS_WRITING_DATE_UTC-eng: 2022-12-18 02:20:00
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES SOURCE_ID
  Stream #0:3(eng): Subtitle: hdmv_pgs_subtitle
    Metadata:
      BPS-eng         : 22140
      DURATION-eng    : 00:28:47.454895833
      NUMBER_OF_FRAMES-eng: 836
      NUMBER_OF_BYTES-eng: 4780741
      SOURCE_ID-eng   : 001200
      _STATISTICS_WRITING_APP-eng: MakeMKV v1.17.2 darwin(arm64-release)
      _STATISTICS_WRITING_DATE_UTC-eng: 2022-12-18 02:20:00
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES SOURCE_ID
  Stream #0:4(eng): Subtitle: hdmv_pgs_subtitle
    Metadata:
      BPS-eng         : 1770
      DURATION-eng    : 00:28:39.655437500
      NUMBER_OF_FRAMES-eng: 62
      NUMBER_OF_BYTES-eng: 380532
      SOURCE_ID-eng   : 001201
      _STATISTICS_WRITING_APP-eng: MakeMKV v1.17.2 darwin(arm64-release)
      _STATISTICS_WRITING_DATE_UTC-eng: 2022-12-18 02:20:00
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES SOURCE_ID


  


  I extract the english audio

  


  ffmpeg -i s01e01_ja.mkv \
-muxdelay 0 \
-map 0:1 \
-vn \
-acodec copy \
s01e01_en_audio.dts


  


  I extract the english subtitles

  


  ffmpeg -i s01e01_en.mkv \
-muxdelay 0 \
-map 0:3 \
-vn \
-c copy \
s01e01_en_sub.sup


  


  I add the english audio track to the japanese video

  


  ffmpeg -i s01e01_ja.mkv \
-i s01e01_en_audio.dts \
-muxdelay 0 \
-map 0 \
-map 1:a \
-c copy \
-shortest \
s01e01_en_ja.mkv


  


  And finally add the english subtitles to the new japanese video that contains english audio

  


  ffmpeg -i s01e01_en_ja.mkv \
-itsoffset 6 \
-i future_boy_conan_s01e01_en_sub.sup \
-muxdelay 0 \
-map 0 \
-map 1:s \
-c copy \
-shortest \
s01e01_en_ja_subs.mkv


  


  As you can see I need to offset the subtitles by 6 seconds in order to get the subtitles to sync with the audio. The english audio is in sync with the video.

  


  I do not know how to debug this in order to tell if the subtitles are extracted or injected incorrectly causing the time offset. Any help would be appreciated !

  


• ffmpeg works with laptop webcam but not with android camera

  28 février 2023, par Rajkumar Somasundaram

  I am working on Macbook with M1 Chip with this ffmpeg version locally installed.

  


  ffmpeg version 5.1.2 Copyright (c) 2000-2022 the FFmpeg developers 
built with Apple clang version 14.0.0 (clang-1400.0.29.202)


  


  With this, I am able to use my laptop's webcam as input and do my ffmpeg work.

  


  Following command is what worked (avfoundation was needed for OSX)

  


  ffmpeg -f avfoundation -framerate 30 -i 0:0 \
-map 0:v:0 -map 0:a:0 \
-pix_fmt yuv420p \
-c:v libx264 -profile:v high \
-crf 32 -ar 44100 \
-c:a aac \
-filter:v:0 scale=w=480:h=360 \
-utc_timing_url "https://time.akamai.com/?iso" \
-segment_time 8 \
-f dash ${path.join(__dirname, "/output/sample.mpd")}


  


  Now, I am trying to use my android front camera as an input.

  


  But, it is not working. (Errors are mainly in & around camera_index)

  


  I am trying the following command and facing error.

  


  ffmpeg -f android_camera -camera_index 0 -framerate 30 -map 0:v -map 0:a -c:v\
libx264 -profile:v high -c:a aac -filter:v:0 scale=w=480:h=360 \
-utc_timing_url "https://time.akamai.com/?iso" -segment_time 8 \
-f dash ${path.join(__dirname, "/output/sample.mpd")}


  


  This is the stacktrace of the whole error log : https://www.diffchecker.com/Mnnghg7M/

  


  

  1. What is the correct command for android camera as input ?

  


  2. Do all stable versions of ffmpeg work with android or any limitations ?