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• FFMPEG Select audio stream by Codec or Bitrate

  25 juillet 2018, par CRS

  I’m trying to convert some TV recorded videos with ffmpeg.
  Target format should be : MP4/H264/AAC
  Most movies are in TS/MPEG2/MPEG2 audio

  Some movies also have an AC3 stereo or AC3 surround track.

  I want the ffmpeg to always prefer the AC3 track as a source if it exists because this usually has a better quality. If the Video is multichannel, that works anyway since ffmpeg automatically selects the track with the most channels. But if it is only 2 channels, often the MPEG2 Audio Track is used.

  Of course, I could achieve that for each movie individually with the map option, but I want to convert a few hundred movies by batch and the stream IDs are mixed thoroughly so I want ffmpeg to automatically select either the AC3 Track or the Track with the highest bitrate for conversion.

  Another Solution would be : Always convert the MPEG Stream to AAC and copy the AC3 one to the output file if it exists. I just don’t want to lose the AC3 Stream.

• Converting DTS to AAC with ffmpeg shifts spoken audio to the right

  18 août 2018, par Giuseppe

  I am using ffmpeg to convert mkv movies to mp4, like so :

  $ ffmpeg -i source.mkv -c:v copy -c:a aac destination.mp4

  By doing this, the audio stream gets converted from the original DTS :

  Stream #0:1: Audio: dts (DTS), 48000 Hz, 5.1(side), fltp, 1536 kb/s (default)

  To AAC :

  Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 394 kb/s (default)

  The resulting file plays just fine, except that the spoken audio (what I am assuming would be sent to the central channel in a 5.1 configuration) sounds clearly shifted to the right, when listening through the MacBook’s built-in speakers or my stereo headphones. Note that music and other sound effects appear unaffected, properly balanced. Also note that I have been able to reproduce this behavior with a variety of source files.

  Here’s ffmpeg’s banner :

  ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with Apple LLVM version 9.1.0 (clang-902.0.39.2)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.0.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  
    libavutil      56. 14.100 / 56. 14.100
  
    libavcodec     58. 18.100 / 58. 18.100
  
    libavformat    58. 12.100 / 58. 12.100
  
    libavdevice    58.  3.100 / 58.  3.100
  
    libavfilter     7. 16.100 /  7. 16.100
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  1.100 /  5.  1.100
  
    libswresample   3.  1.100 /  3.  1.100
  
    libpostproc    55.  1.100 / 55.  1.100

• Rotate Video- Could not write header for output file #0 (incorrect codec parameters ?)

  26 août 2018, par varmashrivastava

  I am using below command to rotate video-

  {"-y", "-ss", "" + startMs / 1000, "-t", "" + (endMs - startMs) / 1000, "-i", inputPath, "-vf", "transpose=" + type,"-c:a", "copy", outputPath}

  I am getting below failure message in Android Oreo-

  "ffmpeg version n3.0.1 Copyright (c) 2000-2016 the FFmpeg developers\n
  built with gcc 4.8 (GCC)\n configuration : —target-os=linux
  —cross-prefix=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/bin/arm-linux-androideabi-
  —arch=arm —cpu=cortex-a8 —enable-runtime-cpudetect —sysroot=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/sysroot
  —enable-pic —enable-libx264 —enable-libass —enable-libfreetype —enable-libfribidi —enable-libmp3lame —enable-fontconfig —enable-pthreads —disable-debug —disable-ffserver —enable-version3 —enable-hardcoded-tables —disable-ffplay —disable-ffprobe —enable-gpl —enable-yasm —disable-doc —disable-shared —enable-static —pkg-config=/home/vagrant/SourceCode/ffmpeg-android/ffmpeg-pkg-config —prefix=/home/vagrant/SourceCode/ffmpeg-android/build/armeabi-v7a —extra-cflags=’-I/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/include
  -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fno-strict-overflow -fstack-protector-all’ —extra-ldflags=’-L/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/lib
  -Wl,-z,relro -Wl,-z,now -pie’ —extra-libs=’-lpng -lexpat -lm’ —extra-cxxflags=\n libavutil 55. 17.103 / 55. 17.103\n libavcodec 57. 24.102 / 57. 24.102\n libavformat 57. 25.100 /
  57. 25.100\n libavdevice 57. 0.101 / 57. 0.101\n libavfilter 6. 31.100 / 6. 31.100\n libswscale 4. 0.100 / 4. 0.100\n libswresample 2. 0.101 / 2. 0.101\n libpostproc 54. 0.100 /
  54. 0.100\nInput #0, mov,mp4,m4a,3gp,3g2,mj2, from ’/storage/emulated/0/Download/dolbycanyon.3gp’ :\n Metadata :\n
  major_brand : 3gp4\n minor_version : 512\n
  compatible_brands : isomiso23gp4\n Duration : 00:00:38.07, start :
  0.006250, bitrate : 402 kb/s\n Stream #0:0(und) : Video : h263 (s263 / 0x33363273), yuv420p, 704x576 [SAR 12:11 DAR 4:3], 384 kb/s, 29.97
  fps, 29.97 tbr, 30k tbn, 29.97 tbc (default)\n Metadata :\n
  handler_name : VideoHandler\n Stream #0:1(und) : Audio : amr_nb
  (samr / 0x726D6173), 8000 Hz, mono, flt, 12 kb/s (default)\n
  Metadata :\n handler_name : SoundHandler\n[libx264 @
  0xf64e5400] using SAR=11/12\n[libx264 @ 0xf64e5400] using cpu
  capabilities : none !\n[libx264 @ 0xf64e5400] profile High, level
  3.1\n[libx264 @ 0xf64e5400] 264 - core 148 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options :
  cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1
  psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1
  8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2
  threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1
  interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2
  b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250
  keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf
  mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40
  aq=1:1.00\n[mp4 @ 0xf64a8600] Could not find tag for codec amr_nb in
  stream #1, codec not currently supported in container\nOutput #0, mp4,
  to ’/storage/emulated/0/Movies/rotate_video4.mp4’ :\n Metadata :\n
  major_brand : 3gp4\n minor_version : 512\n
  compatible_brands : isomiso23gp4\n encoder : Lavf57.25.100\n
  Stream #0:0(und) : Video : h264 (libx264) ([33][0][0][0] / 0x0021),
  yuv420p, 576x704 [SAR 11:12 DAR 3:4], q=-1—1, 29.97 fps, 30k tbn,
  29.97 tbc (default)\n Metadata :\n handler_name : VideoHandler\n encoder : Lavc57.24.102 libx264\n Side
  data :\n unknown side data type 10 (24 bytes)\n Stream
  0:1(und) : Audio : amr_nb (samr / 0x726D6173), 8000 Hz, mono, 12 kb/s (default)\n Metadata :\n handler_name : SoundHandler\nStream
  mapping :\n Stream #0:0 -> #0:0 (h263 (native) -> h264 (libx264))\n
  Stream #0:1 -> #0:1 (copy)\nCould not write header for output file #0
  (incorrect codec parameters ?) : Invalid argument\n"

  Why am i getting this error and how can i resolve it ?