I have recently come into possession of a couple of 4k movies with a resolution of 4096x2304. Unfortunately my Samsung 4k TV wont play anything over 3840x2160.

I have managed to re-encode the videos to 3840x2160, unfortunately the bitrate fell to 1/10th of what it was before.

I used:

for %%a in ("*.mkv") do ffmpeg -i "%%a" -s 3840x2610 -q:v 0 -c:v libx264 -acodec copy D:\%%~na.mp4

Original file size was 27.8GB, the re-encoded one was under 8GB.

Is there any way I can re-encode them so I can keep the original bitrate/quality?

Rant: Even my 4 year old computer can play the movie, but that fcking new Samsung TV of course can't /rant-end


Judge based on the quality rather than the bitrate value. Use CRF mode encoding and if the quality isn't what you can accept, decrease the CRF value.

ffmpeg -i "%%a" -s 3840x2610 -c:v libx264 -crf 18 -acodec copy D:\%%~na.mp4
  • Is it possible to say which -crf gets me the same quality as the original? Nov 1 '15 at 16:02
  • CRF 18 is advertised as 'visually lossless', but isn't technically lossless. See slhck.info/articles/crf
    – Gyan
    Nov 1 '15 at 16:07
  • Alternatively you could use -vf scale=3840:-1.
    – llogan
    Nov 1 '15 at 21:02

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