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Alkl58 / NotEnoughAV1Encodes

GUI for AV1 (aomenc, rav1e & svt-av1)
MIT License
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Container Aspect Ratio #90

Closed Ichisich closed 2 years ago

Ichisich commented 2 years ago

NEAV1E 2.0.5 Windows 10

When using native encoders (aom/rav1e/svt-av1) some aspect ratios get distorted on the container level. FFmpeg's encoders are not affected, so I guess the problem lies in the external muxing process. I guess you're using mkvtoolnix?

Some examples------

Original cropped video (1600x1080)pixel/scaled: mpv-shot0002

Encoded with aomenc (1600x1080)pixel (1620x1080)scaled: 1600aom

Encoded with FFmpeg's aomenc (1600x1080)pixel/scaled: 1600ffmpeg

Using .mp4 and .webm bears the same results as .mkv. Given, this problem only affects media players which obtain the aspect ratio from the container and not the bitstream directly, like VLC or mpv with default setting.

Ichisich commented 2 years ago

I found the culprit. It's DisplayHeight/Width https://www.matroska.org/technical/elements.html#PixelWidth

MkvToolNix standard integer value was Video Display Width=3 and Video Display Height=2 which resulted in a botched 1,5 aspect ratio and thus 1620x1080 instead of the correct 1600x1080 PixellWidth/Height. FFmpeg on the other hand doesn't even bother with those two entries (you could also just set them to 0) forcing the actual pixel count as parameter.

I changed the values both to 0 and voilà: 1600aom

Out of curiosity, because I'm not really familiar with MkvToolNix. Is there are a reason you're using MkvToolNix as a muxer for native clients instead of ffmpeg? MkvToolNix comes with a whooping extra 156mb.

Alkl58 commented 2 years ago

MKVToolnix is used to support VFR and Subtitle Support.

FFmpeg has problems regarding PGS Subtitles.

I think the problem in this particular case is this commit: Use Aspect Ratio of Source if external encoder is used

This "feature" / "bug" was added, as piping to the external encoder would lead to it defaulting to a 1:1 pixel aspect ratio, which resulted in DVD encodes not having the correct aspect ratio.

I think the easiest solution would be, to only set the aspect ratio, if it detects that it's not the default 1:1 pixel aspect ratio.

Alkl58 commented 2 years ago

This issue should be fixed in the v2.0.6 release.

Feel free to open a new issue if you think it still exists.