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• avformat/matroskadec : Fix probing of unknown-length headers

  17 mai 2019, par Andreas Rheinhardt

  avformat/matroskadec : Fix probing of unknown-length headers
  matroska_probe did not support the case of an unknown-length EBML header
  
  at all ; given that libavformat's Matroska muxer used to produce such
  
  files in the streaming case, support for them has been added.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskadec.c

• FFMPEG color range cropped to 15-235 in RGB

  20 décembre 2017, par Some1Else

  I have a series of BMPs (or PNG) images that I want to convert to XVID and MP5 movie formats.

  Encoding works but the resulting movie has a washed out color look to it and the blacks are somehow moved to RGB 16 and the brightest 255 values are moved down to 235. I want the output movie to use the same 0 to 255 colors as the source frames.

  Now there are all sorts of conflicting doco out there for FFMPEG so I am hopinbg someone has an example command line that does what I need. I have tried all sorts of pix_fmt flags but none of them get the output movie in the full color range.

  For XVID

  ffmpeg.exe -framerate 60 -i "D:\SRC%05d.BMP"  -c:v mpeg4 -vtag xvid -qscale 1 -y "D:\OUTPUT.AVI""

  For H265

  ffmpeg.exe -framerate 60 -i "D:\SRC%05d.BMP" -c:v libx265 -x265-params lossless=1 -s 3840x2160 -pix_fmt yuvj420p -an -y "D:\OUTPUT.MP4""

  The yuvj420p is supposed to give the full color range but ffmpeg complains "Incompatible pixel format ’yuvj420p’ for codec ’libx265’, auto-selecting format ’yuv420p’"

  So, are there any FFMPEG gurus out there that can give me the magic switches to get my output movies with black blacks and colors that maintain the original frame files 0-255 RGB values.

• ffmpeg flac or mp3 to m4a - exactly the same length possible ?

  17 février 2021, par Rumpl

  I'm converting .flac and .mp3 audio files to .m4a using ffmpeg with libfdk_aac (Fraunhofer AAC encoder) like this :

  


  ffmpeg -i "001.flac" -c:a libfdk_aac "001.m4a"

  


  This works fine, but in case of .flac the resulting .m4a files include 0.046 seconds of silence at the start and sometimes a few extra milliseconds at the end. Though, I need the .m4a files to be of exactly(!) the same length without any extra silence. Is there a way to achieve this ?

  


  EDIT : At the moment I'm using an additional step, i.e. cutting the resulting .m4a file works at least in the beginning of the track, but there are still some (varying) extra ms in the end :

  


  ffmpeg -i 001.m4a -ss 0.047 -c:a libfdk_aac 001cut.m4a