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• How to increase the compression ratio of a JPEG2000 file with "avenc_jpeg2000" GStreamer encoder ?

  10 juillet 2023, par qfr.bertin.group

  I'm using the plugin avenc_jpeg2000, from gst-libav module, combined with videotestsrc and filesink plugins for encoding a raw picture to a JPEG2000 picture :

  


  gst-launch-1.0 videotestsrc num-buffers=1 ! avenc_jpeg2000 ! filesink location=/tmp/picture-ref.jp2


  


  This pipeline works and produce a 31.85 KiB (32,616) file.

  


  Pipeline graph

  


  Now, I want to divide the size of my output file by two by increasing the compression ratio of the encoder avenc_jpeg2000. To achieve this, I want to minimize the number of bits required to represent the image with an allowable level of distortion. I know JPEG2000 standard support lossless and lossy compression mode. For my use case, the lossy compression mode is acceptable.

  


  How should I proceed to increase the compression of my output file ? What encoder's properties should I play with for doing that ?

  


  My test configuration :

  


  


  • i.MX 8M Plus

    


  


  • GStreamer 1.18.0

    


  


  • libav 1.18.0 (Release date : 2020-09-08)

    


  


  


  I tried to play with "bitrate" and "bitrate-tolerance" properties, but it seems to have no effect on the size of the output file :

  


  gst-launch-1.0 videotestsrc num-buffers=1 ! avenc_jpeg2000 bitrate=100000 bitrate-tolerance=10000 ! filesink location=/tmp/picture-test-01.jp2


  


  I compare files by doing a checksum with sha224sum command :

  


  d0da9118a9c93a0420d6d62f104e0d99fe6e50cda5e87a46cef126f9  /tmp/picture-ref.jp2

d0da9118a9c93a0420d6d62f104e0d99fe6e50cda5e87a46cef126f9  /tmp/picture-test-01.jp2


  


• R "only" substitute of the av package to split and convert an mp4 into multiple mp3 [closed]

  9 février 2024, par Bakaburg

  I am developing an R package that requires splitting an mp4 file into multiple segments and converting these segments into mp3 format. Currently, I use the av package for this task. However, av depends on the external ffmpeg tool, necessitating separate installation. This dependency complicates the setup for non-expert users of my package.

  


  I am seeking an alternative approach that either uses only R or incorporates a low-level solution directly within the package, eliminating the need for external tool installations. The goal is to streamline the user experience by minimizing setup complexity.

  


  Does anyone know of such a solution or approach that can substitute the functionality provided by av without external dependencies ?

  


• FFmpeg : "filter_complex" results in worse quality than "vf"

  16 novembre 2016, par Dasmowenator

  I’m trying to use FFmpeg to do some complex video transcoding (such as concatenating multiple files). To do this, I’ve been trying to use the filter_complex, but I’ve noticed a slight drop in quality from what I saw earlier using the normal video filter.

  To double-check, I boiled down my command to a simple transcode — one using filter_complex and one just using the vf — and I’ve confirmed that the output of the complex filter is noticeably blurry compared to the output of the normal video filter. I can’t find any FFmpeg documentation explaining this... does anyone know why this is happening and how I can get filter_complex to output the same quality video as vf ?

  Command using the normal video filter (vf) :

  ffmpeg -i input.ts -map_chapters -1 -f mpegts -an -sn -map 0:0 -vf "[in]yadif=deint=interlaced[out]" -vcodec libx264 -profile:v baseline -level 2 -b:v 800k output.ts

  FFmpeg Output :

  ffmpeg version 3.0 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 4.1.2 (GCC) 20070626 (Red Hat 4.1.2-14)
  
    configuration: --enable-gpl --enable-nonfree --enable-libx264 --enable-libfdk-aac --enable-libfaac --enable-libvpx --enable-encoder=vorbis --enable-libvorbis --enable-libmp3lame --enable-libspeex --disable-decoder=prores --disable-decoder=prores_lgpl --disable-ffplay --disable-ffserver --disable-shared --enable-static --extra-cflags=-I/local/build/include --extra-libs=-lfdk-aac --extra-ldflags=-L/local/build/lib --prefix=/local/build/install
  
    libavutil      55. 17.103 / 55. 17.103
  
    libavcodec     57. 24.102 / 57. 24.102
  
    libavformat    57. 25.100 / 57. 25.100
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 31.100 /  6. 31.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'clip01.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.41.100
  
    Duration: 00:00:10.02, start: 0.023220, bitrate: 741 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 854x480 [SAR 1:1 DAR 427:240], 604 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  [libx264 @ 0x138a99e0] No 608/708 caption insertion into sei user data.
  
  [libx264 @ 0x138a99e0] using SAR=1/1
  
  [libx264 @ 0x138a99e0] frame MB size (54x30) > level limit (396)
  
  [libx264 @ 0x138a99e0] MB rate (48600) > level limit (11880)
  
  [libx264 @ 0x138a99e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64
  
  [libx264 @ 0x138a99e0] profile Constrained Baseline, level 2.0
  
  Output #0, mpegts, to 'output.ts':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.25.100
  
      Stream #0:0(und): Video: h264 (libx264), yuv420p, 854x480 [SAR 1:1 DAR 427:240], q=-1--1, 800 kb/s, 30 fps, 90k tbn, 30 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
        encoder         : Lavc57.24.102 libx264
  
      Side data:
  
        unknown side data type 10 (24 bytes)
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  
  Press [q] to stop, [?] for help
  
  frame=  300 fps=179 q=-1.0 Lsize=    1059kB time=00:00:10.03 bitrate= 864.9kbits/s speed=   6x    
  
  video:949kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 11.660099%
  
  [libx264 @ 0x138a99e0] frame I:2     Avg QP:23.16  size: 26978
  
  [libx264 @ 0x138a99e0] frame P:298   Avg QP:23.09  size:  3079
  
  [libx264 @ 0x138a99e0] mb I  I16..4: 44.3%  0.0% 55.7%
  
  [libx264 @ 0x138a99e0] mb P  I16..4:  1.1%  0.0%  0.5%  P16..4: 28.7%  8.4%  2.1%  0.0%  0.0%    skip:59.3%
  
  [libx264 @ 0x138a99e0] final ratefactor: 22.63
  
  [libx264 @ 0x138a99e0] coded y,uvDC,uvAC intra: 30.8% 62.8% 23.0% inter: 7.2% 14.8% 0.3%
  
  [libx264 @ 0x138a99e0] i16 v,h,dc,p: 25% 39% 11% 24%
  
  [libx264 @ 0x138a99e0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 29% 16%  5%  6%  7%  6%  4%  5%
  
  [libx264 @ 0x138a99e0] i8c dc,h,v,p: 45% 29% 18%  8%
  
  [libx264 @ 0x138a99e0] kb/s:777.19

  Command using the complex filter :

  ffmpeg -i input.ts -map_chapters -1 -f mpegts -filter_complex "[0:v:0]yadif=deint=interlaced[v0];[v0]concat=n=1:v=1:a=0[cat_v]" -an -sn -map "[cat_v]" -vcodec libx264 -profile:v baseline -level 2 -b:v 800k output.ts

  FFmpeg Output :

  ffmpeg version 3.0 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 4.1.2 (GCC) 20070626 (Red Hat 4.1.2-14)
  
    configuration: --enable-gpl --enable-nonfree --enable-libx264 --enable-libfdk-aac --enable-libfaac --enable-libvpx --enable-encoder=vorbis --enable-libvorbis --enable-libmp3lame --enable-libspeex --disable-decoder=prores --disable-decoder=prores_lgpl --disable-ffplay --disable-ffserver --disable-shared --enable-static --extra-cflags=-I/local/build/include --extra-libs=-lfdk-aac --extra-ldflags=-L/local/build/lib --prefix=/local/build/install
  
    libavutil      55. 17.103 / 55. 17.103
  
    libavcodec     57. 24.102 / 57. 24.102
  
    libavformat    57. 25.100 / 57. 25.100
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 31.100 /  6. 31.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'clip01.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.41.100
  
    Duration: 00:00:10.02, start: 0.023220, bitrate: 741 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 854x480 [SAR 1:1 DAR 427:240], 604 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  [libx264 @ 0x81f5200] No 608/708 caption insertion into sei user data.
  
  [libx264 @ 0x81f5200] using SAR=1/1
  
  [libx264 @ 0x81f5200] frame MB size (54x30) > level limit (396)
  
  [libx264 @ 0x81f5200] MB rate (48600) > level limit (11880)
  
  [libx264 @ 0x81f5200] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64
  
  [libx264 @ 0x81f5200] profile Constrained Baseline, level 2.0
  
  Output #0, mpegts, to 'output.ts':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.25.100
  
      Stream #0:0: Video: h264 (libx264), yuv420p, 854x480 [SAR 1:1 DAR 427:240], q=-1--1, 800 kb/s, 30 fps, 90k tbn, 30 tbc (default)
  
      Metadata:
  
        encoder         : Lavc57.24.102 libx264
  
      Side data:
  
        unknown side data type 10 (24 bytes)
  
  Stream mapping:
  
    Stream #0:0 (h264) -> yadif
  
    concat -> Stream #0:0 (libx264)
  
  Press [q] to stop, [?] for help
  
  frame=  300 fps=179 q=-1.0 Lsize=    1059kB time=00:00:10.03 bitrate= 864.9kbits/s speed=   6x    
  
  video:949kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 11.660099%
  
  [libx264 @ 0x81f5200] frame I:2     Avg QP:23.16  size: 26978
  
  [libx264 @ 0x81f5200] frame P:298   Avg QP:23.09  size:  3079
  
  [libx264 @ 0x81f5200] mb I  I16..4: 44.3%  0.0% 55.7%
  
  [libx264 @ 0x81f5200] mb P  I16..4:  1.1%  0.0%  0.5%  P16..4: 28.7%  8.4%  2.1%  0.0%  0.0%    skip:59.3%
  
  [libx264 @ 0x81f5200] final ratefactor: 22.63
  
  [libx264 @ 0x81f5200] coded y,uvDC,uvAC intra: 30.8% 62.8% 23.0% inter: 7.2% 14.8% 0.3%
  
  [libx264 @ 0x81f5200] i16 v,h,dc,p: 25% 39% 11% 24%
  
  [libx264 @ 0x81f5200] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 29% 16%  5%  6%  7%  6%  4%  5%
  
  [libx264 @ 0x81f5200] i8c dc,h,v,p: 45% 29% 18%  8%
  
  [libx264 @ 0x81f5200] kb/s:777.19