How can i recompress from H264 to H265 with no quality loss in FFMPEG?

[Unknown01]

What the title says basically.

I have read H264 is the same as H265 but that H265 compression is much better, advanced and saves far more space in the disk. So i want to recompress my videos from H264 to H265 without any kind of quality loss, to optimize my space usage.

However, i cannot find a way to do so.

I tried this:

No lossless h265:

ffmpeg -i input.mkv -c:v libx265 -vtag hvc1 output.mkv

Lossless h265:

ffmpeg -i input.mkv -c:v libx265 -vtag hvc1 -lossless 1 output.mkv

But neither is truly lossless, check this out:



At first sight it might look as if the h265 recode was flawless (and the size went down by 50%!) but if pay attention there IS a loss, even with -lossless 1. Check the eyebrow here, the original has it well defined, while the h265 recoding has them blurry:



The original is a well-defined line while the other 2 are blurry.

Which syntax should i use to go from h264 to h265 without any loss of quality AND ending with a smaller file?

[october262]

try this - https://superuser.com/questions/1380946/how-do-i-convert-10-bit-h-265-hevc-videos-to-h...t-quality-loss

[Unknown01]

try this - https://superuser.com/questions/1380946/how-do-i-convert-10-bit-h-265-hevc-videos-to-h...t-quality-loss

Ehhh...are you sure that's the correct link? It says from H265 to H264.

[poisondeathray]

Don't bother

Re-encoding using lossless profile will make the filesize larger than the original, because input video is decoded to uncompressed data, then recompressed

for ffmpeg libx264 -qp 0 ; for ffmpeg libx265 -x265-params lossless=1

[VoodooFX]

Which syntax should i use to go from h264 to h265 without any loss of quality AND ending with a smaller file?

If h264 file is not lossless then it's usually impossible to do lossless encoding and get a smaller file.