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ValveSoftware / SteamOS

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Steam deck gpu driver ignores qp for CQP rate control mode in vaapi video encoding #1609

Open dec05eba opened 2 months ago

dec05eba commented 2 months ago

I'm not sure where to report this issue as I dont see any place to report technical issues specifically with the custom AMD gpu used on steam deck.

Your system information

Please describe your issue in as much detail as possible:

When recording gameplay and choosing CQP (constant-quality) rate control mode in any screen recording software (obs, gpu screen recorder, etc) the qp (Constant QP) is ignored by the gpu driver, resulting in extremely large file size (12gb file for recording 10 minutes of gameplay at 1280x800 resolution, no matter what the QP value is). This issue doesn't happen with desktop amd gpus and neither does it with other rate control modes, such as CBR (constant bitrate). If it's the case that steam deck amd gpu doesn't support CQP then it shouldn't report that it does (via VA_RC_CQP, as reported by vainfo -a).

I also dont think that this has always been the case. It seems like this issue started happening in recent months.

Steps for reproducing this issue:

  1. Install obs (flatpak) from discovery application
  2. Go to settings -> output -> and select Advanced output mode and then in Recording tab select FFMPEG vaapi (either h264 or hevc).
  3. In the encoder settings at the bottom select CQP for rate control and set QP to 51 for the worst possible quality (smallest filesize).
  4. Start recording and move windows around for 10 seconds or so and see the extremely large file size even at 1280x800, at around 30-40mb which would normally be 1mb or lower at lower quality (higher QP value). Changing the QP value has no effect on quality nor filesize, it's always at the max possible quality (0).
jojommeke commented 2 months ago

I can confirm this is a huge issue for me, I can't record anything without it getting huge Filesize which is frustrating

jojommeke commented 2 months ago

i can also confirm this is still the issue in steamos 3.6

zqpvr commented 1 month ago

I also have this.