A fix today for GNOME Shell's screen casting/recording service was merged after it was reported that H.264 recordings using the Video Acceleration API (VA-API) are around 18x larger than they should be like when using the VP8 software fallback.

The issue at hand is the GNOME Shell desktop screen casting/recording code wasn't setting any rate control on VA-API H.264 pipelines that led to the file sizes being massively inflated without any noticeable quality benefits. Last week [1]a bug report came in to point out this issue over "~18x larger files" and this problem for VA-API H.264 likely having existed all the way back to GNOME 44.

The bug report noted that VA-API H.264 usage with the Mesa drivers on Radeon graphics were producing around ~12 Mbit/s recordings compared to around ~630 kbit/s when using the software-based VP8 fallback while having similar quality.

Today the two-line fix was [2]merged for setting a proper rate control to avoid the excessively large H.264 captures.



[1] https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/9165

[2] https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/7b6d39c204f2e552af3230c189ef2239e062f995