[mythtv] VAAPI2 improvements

Andreas Mayer and.mayer at aon.at
Wed Nov 14 22:02:27 UTC 2018

On 08.11.2018 23:00 Andreas Mayer wrote:
> On 07.11.2018 20:42 Peter Bennett wrote:
>> There are some further improvements that will reduce CPU usage with 
>> VAAPI2. Please try the latest master commit 
>> (9d627fe9eec3aca85e7ae62ada8f04b2cf26fc83) and see if it helps.
> I have tried the latest commit yesterday with LiveTV and the test 
> video using mythavtest, VAAPI2 works even better now (but VAAPI 
> playback is still a bit smoother, although with VAAPI I'm getting 
> sometimes a black flashing screen, I guess because of some frame flips 
> not in sync with vsync).
> With VAAPI/avsync2 and -v playback I see repeating lines during playback:
> Player(0): dropping frame to catch up, lateness=51000 usec
> With VAAPI2/avsync2 and -v playback I see repeating lines during 
> playback:
> Player(0): Waiting for video buffers...
> Player(0): dropping frame to catch up, lateness=48000 usec
> For VAAPI2 FE cpu went up to 90%, intel_gpu_top shows: render busy 60% 
> GAM 85% CS 55% TSG 40% VFE 40% GAFS 20%
> So both cpu and gpu show higher utilization now.
> I have tried with display 1920x1080 at 50 and 3840x2160 at 30 (HDMI 1.4)
> I will continue testing VAAPI2/avsyc2 with LiveTV (SD, HD and UHD) 
> using 3840x2160 at 30 to see if this configuration works stable now (I 
> think I noticed audio not starting yesterday sometimes)
I was now finally able to catch frontend log with -v 
playback,audio,timestamp while audio playback was not starting when 
starting LiveTV using VAAPI2 and AVsync2.

AFD: Already opened codec not matching (H265 vs H265). Reopening
AFD: Could not open codec 0x61aa840, id(MP2) type(Audio) ignoring. 
reason Das Argument ist ungültig (this translates to invalid argument)

I have tried to playback the same recording using mythavtest and audio 
started without any problems.

My display is now set to 1920x1080 at 50, I was not able to reproduce with 

Do you think it would be possible to enhance VAAPI(2) any futher to get 
2160p HEVC playback without frame drops?
It looks like I'm currently unable to get Deep Color (10bpc) working 
using Intel UHD graphics on Linux, with Nvidia GT 1030 I was able to use 
10bpc, but since VDPAU does not support HEVC main 10 decoding I'm not 
able to use the Nvidia card (would require mythtv to support CUDA/NVDEC).
It's not that I really would need Deep Color support currently, but I 
would like to get HEVC main 10 hardware accellerated smooth playback 
working without frame drops.

Thank you!


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