cytopia/ffscreencast

Post record optimisation

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#11 opened on 2016年8月26日

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enhancementhelp wanted

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説明

From personal experience it's a tall ask to record in one step on low performance computers. Suggest add option to post-optimise the original 'uncompressed' file recorded Here is what is used (...before finding ffscreencast)

  • i record in as efficient a format as I could find for low performance cpu AND _drive. i could be wrong about libx264 and rgb24 usage.
  • i also record only 640x480/vga/sntsc at 20 fps then reduce to 10
  • 18MB -> 1.1MB
  • libopus support for mono 16-20 kbps is very efficient for voiceovers
  • i've also been looking for a way to record 'faked' mouseclick sounds and keypresses into a channel so it's not using the microphone to record the typing. could use same solution to show modifier and function keys pressed on overlay see https://github.com/wavexx/screenkey

#my 60 second test record ffmpeg -f x11grab -framerate 20 -video_size 640X480 -i :0.0 -c:v libx264rgb -pix_fmt rgb24 -tune animation -crf 0 -preset ultrafast -t 60 raw.mp4

one minute is about 16mb

#my_ re-compress, oddly -crf 35 still looks good. ffmpeg -i raw.mp4 -c:v libx264rgb -r 10 -preset veryslow -crf 35 -tune animation -movflags faststart compressed.mp4

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