4:4:4 never in full range

[Former user]

Hello,

Looks like there is a problem with encoding to main444-8 profile. In every way I tried the output is not full range even if the source is. Tried many various sources and combinations. My sources were x264 4:2:0; x264 4:4:4; x265 4:2:0; x265 4:2:0 10bit - those tried with help of a few external software (VirtualDub, ffmpeg, StaxRip) and also tried raw YUV file source 4:2:0 and 4:4:4. No matter what I tried I could never get a full range 4:4:4 output file.

I have tried mainly those command line combinations:

--crf 26 --input-res 1920x1080 --fps 23.976 -o "Converted.hevc" --input-csp i444 --profile main444-8 --preset veryslow --tune zerolatency --me 3 --merange 64

(blacks are gray on the output)

--crf 26 --input-res 1920x1080 --fps 23.976 -o "Converted.hevc" --input-csp i444 --profile main444-8 --preset veryslow --tune zerolatency --me 3 --merange 64 --range limited

(blacks are gray on the output)

--crf 26 --input-res 1920x1080 --fps 23.976 -o "Converted.hevc" --profile main444-8 --preset veryslow --tune zerolatency --me 3 --merange 64

(this one gave me flickering output, even with 4:4:4 source)

I'm using version number 2.8.0.40

Would appreciate some help. Thank you.

[Radhakrishnan Venugopal Rajaganesan]

x265 doesn't do any chroma subsampling conversion. See the docs " The chroma subsampling format of your input must match your desired output chroma subsampling format (libx265 will not perform any chroma subsampling conversion), and it must be supported by the HEVC profile you have specified."

To get 444 output input should be a 444 source

[Mangusta]

Yes, I tried that as well. No luck.

[Radhakrishnan Venugopal Rajaganesan]

Can you brief the problems you are facing with 444 input?

[Mangusta]

Output video is not full range, I get gray instead of pure black, input file is fine.

[Radhakrishnan Venugopal Rajaganesan]

If you could share the input clips it would be helpful to reproduce?

[Mangusta]

Sure: AVI x264 4:4:4 - https://expirebox.com/download/bc88e5e653e59f9b33ce0d564d364f96.html YUV - https://expirebox.com/download/4c7faf5bf3bd74af9f5153295342b7ee.html PS: Those files will expire after 2 days (service limitation).

[Mangusta]

Looks like it was a decoder fault (ffdshow problem when using filters ffdshow converts the color space). I guess this issue can be closed. Thank you.