Patch for recent dxva stutter/skip problem

WhiningKhan, as Voyager-xbmc points out, the only option for the scaler seems only to be DXVA for the sources I notice stuttering most. I can't change it using the OSD.

Just from my observations that BD sources (at 24Hz) work flawlessly; SD interlaced sources with upscaling (60Hz) drops frames; and SD interlaced sources without upscaling works flawlessly, I take it to mean it's not solely memory b/w limited. The upscaling must be a limiter here, too.

Anyway, I have no evidence other than my observations and you guys know far more about the interworkings of this stuff, so I may be misinterpreting the results.

Thanks,
Doug

dclindner Wrote:Just from my observations that BD sources (at 24Hz) work flawlessly; SD interlaced sources with upscaling (60Hz) drops frames; and SD interlaced sources without upscaling works flawlessly, I take it to mean it's not solely memory b/w limited. The upscaling must be a limiter here, too.

Apparently upscaling with deinterlace increases the processing time per frame enough to cause the skips, then. What happens with SW full rate deinterlace + GPU upscaling (if your CPU can handle the effort)?

WhiningKhan Wrote:Apparently upscaling with deinterlace increases the processing time per frame enough to cause the skips, then. What happens with SW full rate deinterlace + GPU upscaling (if your CPU can handle the effort)?

So, I've set render to SW and full deinterlace, and I get an occassional drop about once every minute or so. Seems fewer drops than with DXVA.

I've also gone to pixel shaders and full deinterlace and I get the same occassional drop as with SW rendering.

Hmm...not sure what any of this really means.

There is certainly a variability that I don't understand. Perhaps it's nothing more than just a CPU on the edge, with marginal GPU performance issues.

However, drops with DXVA seems random--sometimes it's pretty good and other times it seems to start dropping frames every second or two. Perhaps there are still background activities that I can't nail down. I'll keep tweaking.

Thanks for all the suggestions and help. I really appreciate it.

Doug

Voyager-xbmc Wrote:The problem is the high frame rate when doing a full deinterlace (software or dxva), not the scaler.

My experience is that with pixelshaders the upscalers work very well on the ION (no stuttering whatsoever) as long as you do half-rate deinterlacing (frame rate stays at 25 or 30 fps). In the case of pixelshaders I use software deinterlacing (HALF, because the full is too heavy on the CPU). I can use the highest setting for scaling without trouble.

With dxva rendering and deinterlacing, there is no "hardware half" option. The problem is pushed to the hardware, which does a decent job but on low-end ION GPUs (especially 1st gen) the frame blit takes about all the time it has, i.e. 1/50s for double rate PAL (the blit includes the deinterlacing & scaling steps). The slightest glitch in CPU usage causes a frame to be missed.
EDIT: on DXVA rendering, you don't have choice in scalers. The only one is "DXVA".

My conclusion: on IONs the best playback of interlaced DVD/SD material is obtained by using pixelshaders and software half-rate deinterlacing.

I am really struggling with this. I have switched it over to Pixel Shaders in the gui but I still only get DVXA options for deinterlacing, what am I missing here. Running nightly from 20111017.

crystalgipsy Wrote:I am really struggling with this. I have switched it over to Pixel Shaders in the gui but I still only get DVXA options for deinterlacing, what am I missing here. Running nightly from 20111017.

DXVA rendering is forced by default for DXVA decoding (unless otherwise defined in advancedsettings). So what I referred to in my original post is applicable for DVD playback which are forced to software decoding.

Voyager-xbmc Wrote:DXVA rendering is forced by default for DXVA decoding (unless otherwise defined in advancedsettings). So what I referred to in my original post is applicable for DVD playback which are forced to software decoding.

Ok thanks. Can I set it up in advanced settings for SD footage to use software rather than DXVA as I have all my SD DVD's wrapped as MKV's or is it container only that you can specify?

I'm not sure if my problem is related to the exact issue of this thread, but I am getting stuttering on 1080i content using dxva best (vector adaptive) setting on all the betas from the past month or so. The picture stutters every 2-3 seconds constantly and it does not depend on content or bitrate. I know this is not a problem with my ati 5450 video card because vector adaptive works perfect in Windows Media Center and used to work perfect in June "patched" deinterlace builds of xbmc taken from the other thread on this forum. Any idea what could be the problem or a fix for it?

crystalgipsy Wrote:Ok thanks. Can I set it up in advanced settings for SD footage to use software rather than DXVA as I have all my SD DVD's wrapped as MKV's or is it container only that you can specify?

The choice for software decoding of DVDs (ISO, VOB/IFO) is specific to the container (hard coded) and cannot be changed through settings.

In your case, i assume you're playing back an mkv with an MPEG2 video stream. So normally it should be picked up as DXVA decoding if you've enabled dxva. Therefore, it forces also DXVA rendering. You CAN use advancedsettings to force Pixelshaders rendering, but thats not advisable as it means an additional memory copy from video memory (where decoded) to RAM (used by pixelshaders).

You can try this by setting

<forcedxvarenderer>false</forcedxvarenderer>

in the <video> section.

Voyager-xbmc Wrote:The choice for software decoding of DVDs (ISO, VOB/IFO) is specific to the container (hard coded) and cannot be changed through settings.

In your case, i assume you're playing back an mkv with an MPEG2 video stream. So normally it should be picked up as DXVA decoding if you've enabled dxva. Therefore, it forces also DXVA rendering. You CAN use advancedsettings to force Pixelshaders rendering, but thats not advisable as it means an additional memory copy from video memory (where decoded) to RAM (used by pixelshaders).

You can try this by setting

<forcedxvarenderer>false</forcedxvarenderer>

in the <video> section.

Will give it a go, again thanks.

StinDaWg Wrote:I'm not sure if my problem is related to the exact issue of this thread, but I am getting stuttering on 1080i content using dxva best (vector adaptive) setting on all the betas from the past month or so. The picture stutters every 2-3 seconds constantly and it does not depend on content or bitrate. I know this is not a problem with my ati 5450 video card because vector adaptive works perfect in Windows Media Center and used to work perfect in June "patched" deinterlace builds of xbmc taken from the other thread on this forum. Any idea what could be the problem or a fix for it?

After playing more video content it seems that this problem has nothing to do with 1080i content in particular, rather the stuttering affects All HD MPEG2 .ts files whether 720p or 1080i using dxva renderer. It's not a matter of filesize, bitrate, or anything else, they all stutter in the same consistent 2-3 second intervals. It's not a problem with my graphics card or cpu as this never happens in previous or stable builds. This has only been happening with the nightly builds from the past month or so. I have an ATI 5450. Something is wrong with the software or code, I just don't know how to pinpoint it.