On Thu, Jun 21, 2018 at 2:26 PM Bolik Bom <[email protected]> wrote: > > Hello everyone, > > I have recorded my screen with some recording software, and encoded the video > as lossless h.264, rgb. > > I've saved the file as "source_lossless_rgb.mp4", and then lossy encoded it: > ffmpeg -i source_lossless_rgb.mp4 -c:v libx264rgb rgb.mp4 > > And I've created another lossy version, in yuv420p format: > ffmpeg -i source_lossless_rgb.mp4 -c:v libx264 -pix_fmt yuv420p yuv420p.mp4 > > When playing the two videos using Media Player Classic / VLC, > text and icons in the yuv420 video are a little blurry. > Is it possible to create an exact translation from rgb to yuv420, > so no blur will be introduced?
YUV 4:2:0 will downsample the chroma channel by a factor of two (for every 2x2 luma samples there is only one U and one V sample). YUV 4:2:2 downsamples chroma by a factor of 2, but only horizontally (2x1 luma samples, one U, one V samples) YUV 4:4:4 does not downsample chroma at all, so this is more appropriate for screen capture If you still have to use 4:2:0 sampling then you can work around the downsampling by upscaling the video by a factor of 2 horizontally and vertically before encoding, then there will be no chroma loss due to chroma downsampling Pavel. _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
