Thank you very much for the test build
Dunno how detailed feedback you want so let it be '-verbose'. I use Windows 7 x64 with disabled DWM. The E-450 APU has dual core CPU @1,6 GHz, graphics is HD6320 with 512MB (384MB by default, I use my custom unlocked bios) video memory taken from RAM. First I closed all apps possible except ESET, then I have changed values one by one and restarted after every single change. Values which didn't work - extreme shuttering
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mcorruptframes.init -1
mcorruptframes.presentedframes -1
mcorruptframes.mean 11
So I decided to try those
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mcorruptframes.init 2147483647
mcorruptframes.presentedframes 2147483647
mcorruptframes.mean 10
to be absolutely sure nothing will trigger the fallback. Those worked, I have not noticed the fallback.
300 instead of max int worked as well. Even at 4k@60fps there was less than
100% dropped frames (of course 4k@60fps is way too much to handle by my E-450).
So this is a good thing... and here comes the bad thing, not directly related to the test build.
In Firefox builds >37.0.2 the statistics functions which counts decoded/displayed/corrupted/dropped frames as well as those checking functions if x >= y if to trigger the fallback works all the time and may increase CPU usage.
Could this be the reason why video playback is not as smooth as using Firefox 37.0.2 x86?
Firefox 37.0.2 x86 does not have the video decoding fallback and related statistics functions implemented (except dropped frames counter for stats for nerds). At the beginning of the video when I switch to full screen mode I have like 20-30 dropped frames total for first few seconds. Then the playback is butter smooth (0-5 dropped frames for next 10 seconds). When I move playback forwards/backwards I have some (~10-15) dropped frames one second later, then the playback is butter smooth again.
Using your pcxFirefox44 x86 test build I had more dropped frames during normal (not moving around) playback, 1-5 frames every 2-5 seconds. That was bit weird. I have noticed the same thing using Firefox Nightly builds (but those differ way too much).
As long as video decoding fallback function does not trigger, which is very easy for me, the native Firefox 44 x64 seems to perform sightly (a little bit lower CPU usage/less CPU usage spikes) than x86 version. However I will probably never get rid of 100% dropped frames thanks to bad AMD drivers...
//edit@:
xunxun1982 wrote:
1) keep the default value, dxva enabled or disabled?
2) set the three about:config to 0 or 1, dxva enabled or disabled?
3) set the three about:config to a larger value, dxva enabled or disabled?
I'll test a bit more with those values.
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Using Firefox Nightly builds there is a (hidden?)
preference, which if is set up to '-1', it overrides all blacklists. Just saying.