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by Kayou 4377 days ago
Thank you! I was gonna post the exact same thing. Nice website, though.

I encoded the gif in 420 (subsampling), 422 and 444, having a nice quality with 444 with VLC, I embed the three different videos in a web page and when playing in my browser, they are all as bad as the twitter video! I thought that Firefox was using a standard library to play MP4?
1 comments
ferongr 4377 days ago
Firefox uses the Windows-bundled decoder on Windows Vista or later. Chroma upsampling happens after decoding so it's the renderer's responsibility (Firefox, Chrome, VLC, madVR etc).

Depending on the webpage you uploaded them, the videos could be re-encoded (or VLC's options could be no-ops and the artifacts hidden when played back in VLC due to better chroma upsampling) hence the problem.

link
Kayou 4377 days ago
Okay, thanks for the explanation on the chroma upsampling! I use Linux but it should work all the same.

When I said that I embedded the videos in a web page, I wrote a small page from scratch to display them in my browser, locally, without any server. So no re-encoding. I think that VLC just has a better chroma upsampling.

link