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• avutil/hwcontext_videotoolbox : BGRA should be full range

  3 janvier 2023, par Zhao Zhili

  avutil/hwcontext_videotoolbox : BGRA should be full range
  HEVC alpha layer encoding is broken without the patch.
  Signed-off-by : Zhao Zhili <zhilizhao@tencent.com>
  

  • [DH] libavutil/hwcontext_videotoolbox.c

• pgssubdec : fix subpicture output colorspace and range

  24 avril 2016, par Jan Ekström

  pgssubdec : fix subpicture output colorspace and range
  Functionality used before didn’t widen the values from limited to
  
  full range. Additionally, now the decoder uses BT.709 where it
  
  should be used according to the video resolution.
  Default for not yet set colorimetry is BT.709 due to most observed
  
  HDMV content being HD.
  BT.709 coefficients were gathered from the first two parts of BT.709
  
  to BT.2020 conversion guide in ARIB STD-B62 (Pt. 1, Chapter 6.2.2).
  
  They were additionally confirmed by manually calculating values.
  Fixes #4637
  

  • [DH] libavcodec/pgssubdec.c
  • [DH] libavutil/colorspace.h

• Why convert wav to mp3 get different length

  13 avril 2022, par sybil

  I use NAudio and NAudio.Lame to convert a wav file to mp3 file,code like that :

  


  using var reader = new WaveFileReader(file);
using var ms = new MemoryStream();
var writer = new LameMP3FileWriter(ms, reader.WaveFormat, 32);
reader.CopyTo(writer);
writer.Flush();
File.WriteAllBytes(file.Replace("wav", "mp3"), ms.ToArray());


  


  the wav file length is 1500ms,but the mp3 file length is 1557ms.

  


  And I do the same thing by using ffmpeg.exe,command like that :

  


  ffmpeg -i c:\2\xxx.wav c:\2\xxx.mp3


  


  the output info :

  


  ffmpeg version 5.0.1-essentials_build-www.gyan.dev Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 11.2.0 (Rev7, 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. 17.100 / 57. 17.100
  libavcodec     59. 18.100 / 59. 18.100
  libavformat    59. 16.100 / 59. 16.100
  libavdevice    59.  4.100 / 59.  4.100
  libavfilter     8. 24.100 /  8. 24.100
  libswscale      6.  4.100 /  6.  4.100
  libswresample   4.  3.100 /  4.  3.100
  libpostproc    56.  3.100 / 56.  3.100
Guessed Channel Layout for Input Stream #0.0 : mono
Input #0, wav, from 'c:\2\xxx.wav':
  Duration: 00:00:01.50, bitrate: 768 kb/s
  Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, mono, s16, 768 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, mp3, to 'c:\2\xxx.mp3':
  Metadata:
    TSSE            : Lavf59.16.100
  Stream #0:0: Audio: mp3, 48000 Hz, mono, s16p
    Metadata:
      encoder         : Lavc59.18.100 libmp3lame
size=      12kB time=00:00:01.51 bitrate=  66.2kbits/s speed= 137x
video:0kB audio:12kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.928711%


  


  And I get a mp3 file which length is 1536ms.
So,why the length changed ?
Thanks for reading.