PSNR, color pre- and post- spitzer |
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Issue descriptionVersion: 50.0.2661.9 OS: Android Nexus 5: Without Spitzer flag: Avg PSNR is 36.64 (https://av-analysis.corp.google.com/#/get-testpass-details/2/Video%20Stack/96681) With Spitzer flag: Avg PSNR is 30.55 (https://av-analysis.corp.google.com/#/get-testpass-details/2/Video%20Stack/96682) If you look at the videos, you can see that the color is hugely different between the two videos. I assume that this is the reason for the PSNR difference. I manually reviewed results for Samsung Galaxy S3 and saw the same difference. Color is complicated because it is subjective to some extent. I have added hubbe@ and cliffordcheng@, our resident color experts, to weigh in.
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Mar 10 2016
Oh sorry, yes, this is only for VP9 content (We don't have any automated VP8 tests).
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Mar 10 2016
Yeah, I think this is most likely a difference in what color space is assumed in the absence of metadata. Spitzer will default to BT709 for HD content. Presumably MediaPlayer is assuming BT601. Even if re-encode the test videos to contain the metadata, I have no idea whether MediaPlayer will respect it. Its libvpx could be too old, and even if it's not, it might ignore it.
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Mar 10 2016
One way to test would be to add a BT601 flag to the test video and see if the colors match. I can't test it right now, but if someone else wants to, I believe the vpxenc flag is --color-space=bt601
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Mar 12 2016
I'm going to close this bug as expected behavior. Thanks for looking into it, watk@.
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Mar 12 2016
Which one looks better? :)
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Apr 28 2016
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Comment 1 by dalecur...@chromium.org
, Mar 10 2016