I've been uploading some videos to Youtube and unfortunately just today I noticed that they are being handled wrong by their converters.
For some reason, Youtube is not expanding the levels of my videos so they look opaque. This is one of them: https://www.youtube.com/watch?v=rSILf3Y2JcY
I thought that I could be doing something wrong but the source videos actually look fine on computer (right levels). They are 4:2:0 according to MediaInfo, so Youtube for some reason is handling them as if they were full range and not limited.
Reading another forum, Poisondeathray mentioned that there's a flag aside from the actual range of the video that Youtube is taking into account to determine if the video is going to be expanded to full levels or converted like mine. I want to know if this is possible to do with an MKV container. I'm using MKVToolnix GUI to convert the videos I'm uploading by the way.
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Can be edited using mkvtoolnix' header editor, propedit or mkvmerge. But I don't know if Youtube cares about it.
Aside from container there is also flag in the bitstream of some codecs
For already encoded H.264 see: https://forum.doom9.org/showthread.php?t=152419
With x264 and x265 you can set during encoding.
4:2:0 indicates chroma subsampling, it's independent of full vs. limited range
Your video looks fine to me on youtube. Black is black. White is white. Maybe you have a configuration/playback problem?
When you download the video, the levels are correct too Y~16 black, Y~235 white . It's easy to tell because at the very beginning there is a "black" section, and at the very end there is a fade to "white" . So that suggests a playback configuration problem on your end. Check your graphics card settings
If your upload has a full range flag, youtube will clamp the re-encode, regardless of what the actual levels are. But that's NOT what's happening here. If there was 8bit clamping, there would be evidence banding in the histogram and no overshoots >235 (it's smooth, and there are overshoots present) . So that suggests you uploaded normal range video, unflagged.
Yes, looks fine here, too. (Should have watched before posting.)
Thank you. I'm going to try with the MKV header only. Hope it works.
You are right. It looks fine on my cellphone. I don't know what's going on, but at least the uploaded video is ok, and that's what matters.