Bug 254731 - [GTK][GStreamer] VA+DMABuf higher than expected usage for AV1 videos
Summary: [GTK][GStreamer] VA+DMABuf higher than expected usage for AV1 videos
Status: RESOLVED WORKSFORME
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebKitGTK (show other bugs)
Version: WebKit Nightly Build
Hardware: PC Linux
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-03-30 04:19 PDT by Kdwk
Modified: 2023-03-31 00:41 PDT (History)
2 users (show)

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Description Kdwk 2023-03-30 04:19:27 PDT 
On an AV1-hardware-decoding-capable machine,
1. Go to YouTube -> Settings -> Performance and Playback -> Always prefer AV1
2. Load an AV1 video
3. Observe the CPU usage of the WebProcess
It needs around 5% for (suspected) VA+DMABuf AV1 decoding. This is much higher than confirmed hardware decoding (Clapper with vaav1dec uses about 2-3% CPU) but also significantly lower than confirmed software decoding (~13%). VP9 works as expected at 2-3%.
Comment 1 Philippe Normand 2023-03-30 04:41:54 PDT 
If you set GST_DEBUG="va*:6" do you see the vaav1dec element emitting logs?

Might be useful to have a pipeline dump too, set GST_DEBUG_DUMP_DOT_DIR=/some/dir/ephy/can-write-on/ and attach dot files here.
Comment 2 Kdwk 2023-03-31 00:41:09 PDT 
After further testing, CPU usage of AV1 videos seem to stabilize at the expected 2-3% after quite some time, so it appears that it is indeed using vaav1dec. Closing this for now