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• Revision ad2fa5e7d5 : vp9/vp9_cx_iface : Silence ts_number_layers MSVC warnings Silence signed/unsigne

  13 février 2014, par Tom Finegan

  Changed Paths :
   Modify /vp9/vp9_cx_iface.c

  
  
  vp9/vp9_cx_iface : Silence ts_number_layers MSVC warnings

  Silence signed/unsigned mismatch warnings by adding casts where
  ts_number_layers does not match the sign of the variable to which
  it is being compared.

  Change-Id : Iab25e18c877d158b2b2b417de7da94669648b2fa

• Creating a convertAll() function that converts all .filetype in working directory

  5 janvier 2019, par Risviltsov

  I seem to not know proper bash syntax ; despite this, I’ve tried to create a tool that changes the dimensions of all files of a ffmpeg-accepted filetype in the working directory and converts it to another ffmpeg-accepted filetype. In this instance, this tool converts all .webm files over 1080x720 into 1080x-1 or -1x720 .mp4 files. If the .webm file is under 1080x720, the new .mp4 file will have the same dimensions.

  However, there’s a wrench in the tool.

  convertAll () {
  
  local wantedWidth = 1080
  
  local wantedHeight = 720
  
  for i in *.webm; do
  
  local newWidth = $i.width
  
  local newHeight = $i.height
  
  until [$newWidth <= $wantedWidth && $newHeight <= $wantedHeight]; do
  
  if [$videoWidth > $wantedWidth]; then
  
  newHeight = $newWidth*($wantedWidth/$newWidth)
  
  newWidth = $newWidth*($wantedWidth/$newWidth)
  
  fi
  
  if [$videoHeight > $wantedHeight]; then
  
  newWidth = $newWidth*($wantedHeight/$newHeight)
  
  newHeight = $newHeight*($wantedHeight/$newHeight)
  
  fi
  
  done
  
  ffmpeg -i "$i" -vf scale=$newWidth:$newHeight "${i%.*}.mp4";
  
  done
  
  echo "All files have been converted."
  
  }

  What this returns is a bunch of lines that look like this :

  bash: [: missing ']'
  
  bash: [: missing ']'
  
  bash: =: No such file or directory

  My best guess is that BASH can’t do mathematics, and that I’m declaring and editing my variables incorrectly.

  I’d like some input on this --- my lack of experience is really getting me here.

• Upgrading an existing h.264 solution of Level-4.1 to support 4K(Level-5.2)

  11 août 2015, par Codec Guy

  I am currently studying to support 4K(3840x2160) on H.264 Encoder.
  When I studied the specs of H.264, it says 4K resolution is supported in Level-5.2(XAVC).
  In order to check the implementation I encoded my full HD(1920x1080)bitstream using x264 in FFMPEG for three different levels(Level-4,4.1 and 5.2).

  Here is what I noticed
   All the three Encoded bitstreams, encoded for different levels matched pixel by pixel.
   I was wondering if the encoding is done for different levels(Level-4,4.1 and 5.2), how come there is no change in bitstream.

  • I have a solution of high 422 Level-4.1, are there any changes in the core modules like Transformation, Quantazition, CAVLC to support 4K(3840 x 2160)/XAVC.

  • or the processing of all Level-5.2 is same as Level-4.1.

  It would be very helpful, if somebody can refer me to any documents which explains the diffrence in processing of H.264/AVC and XAVC