Choppy playback of VC1 video

[pearlblack15]

I have a situation here. And I don't know who could be causing the real problem while playing the video. The video doesn't play well. It plays slow, like how a high end graphic hungry game would run on a low end system. Here are the instances and the result of playback.

1. LAV video (QuickSync for HW Acceleration with VC1 enabled) + madVR => Choppy playback.

2. LAV video (QuickSync for HW Acceleration with VC1 enabled) + EVR Custom==> Normal Playback

3. LAV video (VC1 deselected under QS decoding option)+ madVR => Playback normal.

So, is it VC1 codec of QS that is creating problem or madVR ?

Sample Video included.

MediaInfo included.

[Island_Dweller]

Maybe your madVR settings are too high for Quicksync VC-1 hardware decoding?

EVR Custom only uses nearest neighbor, bilinear or bicubic for resizing. So, it's not very demanding on the GPU, compared to madVR.

Notice that when you let the CPU decode the video (#3), the GPU can cope with your madVR settings.

[pearlblack15]

That could be a good reason but I have another VC-1 (960x540 @ 3000 kbps) video which plays fine though except that the seeking is slow with that particular video.

madVR is using bicubic 75 for both chroma and luma and all other HD videos play smooth!

I shall find a different VC-1 video to check the problem again. Intel QS decoding is not optimal for VC-1 video I guess.

Thanks anyway

[El Heggunte]

That could be a good reason but I have another VC-1 (960x540 @ 3000 kbps) video which plays fine though except that the seeking is slow with that particular video.

Do you realize that VC-1@960x540@30fps can be played smoothly even on a Pentium-4 with an nVidia 6200 card and without hardware video decoding?

[pearlblack15]

Yea I didn't give a thought to that fact cuz I was thinking of HW decoding. So, the problem is with the crappy intel GPU which is not powerful enough to decode the video while madVR is using the GPU along with QS decoder? But the video isn't that complex..

[El Heggunte]

Hummm, then MAYBE the file was *improperly-muxed*, I think.

TOO MANY ASFs/WMVs are by-default poorly muxed or joined, which can cause jerky playback and/or sync issues with certain decoders or splitters.

You can remux WMV files with AsfBin, ffmpeg, ffmbc, or SolveigMM ASF multiplexer. The bad news is, the ASF container is so pesky, that what works for fixing one file, not always can fix other files, so you've got to keep trying until you find the right tool(s) and/or the right method.

[pearlblack15]

okay, thank you. I'll try once I encounter another VC-1 video like that. For now, I have encoded the video to MPEG4/AVC to get rid of such playback.

[El Heggunte]

1. LAV video (QuickSync for HW Acceleration with VC1 enabled) + madVR => Choppy playback.

3. LAV video (VC1 deselected under QS decoding option)+ madVR => Playback normal.

The author of the LAV Filters says:

LAV uses the frame timestamps from the source to time video and audio. In Audio its important that "Auto A/V Sync" is turned on (default is on), or the audio decoder can run out of sync.

When testing, please use software or DXVA, not QuickSync or CUVID. The last two are more or less blackboxes that may or may not internally behave properly when dropping corrupted frames (especially QS is a bit unreliable there)

{ source: http://forum.doom9.org/showthread.php?p=1621532#post1621532 }

[Island_Dweller]

When testing, please use software or DXVA, not QuickSync or CUVID. The last two are more or less blackboxes that may or may not internally behave properly when dropping corrupted frames (especially QS is a bit unreliable there)

El Heggunte, you know I'm your biggest fan , but it clearly says "When testing" (debug builds) and "when dropping corrupted frames" (dvb-related). Pearlblack is not testing and his video doesn't have corrupted frames. I've used CUVID on at least a dozen computers with Nvidia GPUs and there were no issues. Some even managed to play 1080p60 VC-1 at the highest madVR settings.

Pearlblack's issue is the intel gpu he has can't handle both decoding (Quicksync) and rendering (madVR) of VC-1. LAV also has support for software decode of VC-1 via ffmpeg or microsoft dmo something.

[El Heggunte]

Okay, I SHOULD have said only this:

...... QuickSync or CUVID. The last two are more or less blackboxes that may or may not internally behave properly

FYI, ffdshow's WMV decoders had (and possibly still have) issues with ASF files muxed incorrectly. It's not impossible/improbable that the QS decoder has a similar flaw, which appears only when connected to a resource-hungry video renderer like madVR.