Disappointing MPEG2 decoding

[dark_half]

This sounds like the quartz.dll problem to me. Have you tried the fix mentioned above by systemshark.

http://support.microsoft.com/kb/919071

Code:

Folks,

Found a microsoft Hotfix which fixes the Quartz.dll issue.

[urlhttp://support.microsoft.com/kb/919071[/url]

It's working fine on my machine...

[martint123]

Yes, I sometimes had the odd stuttering after using skip and the only way to restore viewing was to stop and resume. The quartz fix just mentioned seems to have sorted it out - at least I've not seen it since the M/S patch

[BerkA]

This thread is very long. However, I read it all and tried the things that were recommended here. Rather than add yet another question to it, I thought I would contribute a bit and summarize what I found here. I'll follow up with my question later. The beginning and end of the thread concentrate on the quartz.dll deinterlacing bug, so it's easy to assume that there's nothing more to it. However, there's a lot more in these 21 pages!

So far, in this thread, I found these causes/workarounds for unsatisfactory MPEG2 playback:
- Quartz.dll deinterlacing bug, as described in MS knowledge base article 919071. http://support.microsoft.com/kb/919071
- Problems with video and audio decoders and renderers. Basically, you should try all combinations! (Yeah, that sucks.)
- Other programs interfering with accessing video files (such as virus scanners.)
- Dual core, multi-core, multi-processor systems having stuttering. The "ForceSingleProcessorAffinity" workaround so that GBPVR/PVRX2 run on a single core or processor.
- Some people having playback improvements by increasing GBPVR/PVRX2 process priority. The "ForceHighPriorityRecordingService" config option to achieve this.


I saw that most people who are reporting problems here usually have better luck playing the same files back with other applications -- Windows Media Player (WMP) is the common comparison. Sub says that GBPVR -- like most applications -- use MS DirectShow to play video; the apps don't actually play back the video themselves. So, if two applications have differing performance, the most likely reason is that they are using a different combination of mux/demux, codecs and renderers.

I found out about the Microsoft GraphEdit tool to play with DirectShow's rendering of video. Microsoft claims that GraphEdit can connect to running filter graphs and see what they're doing. However, I couldn't use the GraphEdit "connect to remote graph" as I had hoped. (I had hoped to see how GBPVR and other applications use DirectShow.) However, I found that GBPVR, PVRX2 and the GBPVRrecordingService all touch a file called "lastgraph.grf". This file, as the name implies is the last filter graph these programs used to render or record a video file. The file can be opened with GraphEdit. (Although GraphEdit crashed with long file names... Workaround: I copied the files, renamed them, and opened in GBPVR again as regular video files.) Once I opened the lastgraph.grf file in GraphEdit, I could play the file, see statistics and troubleshoot the playback. I could mess with the graph to pinpoint the source of the problems. I wasn't able to find how WMP renders video, but I was able to get exactly the same result as WMP by using GraphEdit's "File->Render Media File..." menu option.

I hope this summary helps others who are faced with reading through this long thread and debugging "disappointing MPEG2 decoding." Please point to any other issues and hints I may have missed. It'll be nice to have a good summary to keep this thread useful.

Edit: Check following Wiki page for more info on codec setup:
http://gbpvr.com/pmwiki/pmwiki.php/FAQ/Codec

[BerkA]

I've been using GBPVR for almost 4 years, but I only had experience with WinTV PVR350 TV out and more recently MVP. Now I'm trying to get an HD setup going, so I'm back to using GBPVR "natively." I have stuttering MPEG2 playback problems. I've been through this thread and tried just about anything offered, but I can't seem to get relief. The "stuttering" I'm experiencing is not like the "flickering" caused by the quartz.dll deinterlacing bug as described in the MS KB article. (Although I've tried several versions of quartz.dll anyway -- without relief.) The stuttering seems to be caused by dropped frames. Essentially, every second or two, the video freezes for a fraction of a second and resumes. So it goes like "Play for 1sec, pause for 250msec, jump ahead 1 second and repeat..." It's essentially resyncing the video after dropping a few frames. Windows media player plays the same files without any problems, and it looks good too. My CPU usage is around 30% for playing back 1080i HD content on 1920x1080p display, so CPU does not seem to be the bottleneck (in any scenario I've tested.) I considered AGP 8x as the bottleneck, but some back-of-the-envelope calculation suggests it's nowhere near being a limit. Besides, the problems didn't go away when I tried lower resolution MPEG2 video or lower monitor resolution.


Hardware summary:
- Athlon 64 3000+ (Socket 939)
- Nforce3 250/GB ultra-based Motherboard
- 128-bit (dual-channel) memory
- 2GB DDR400 memory.
- Nvidia GeForceFX 5700LE w/128MB RAM (AGP 8x)
- DVI output to 1080p HDTV HDMI input
Oh, I'm using Windows XP SP2.

Some tested combinations:
With PVRX2, VMR9 Custom Renderer
1920x1080 screen resolution (progressive)
- 1920x1080i content: Stuttering
- 720x480i content: stuttering
1280x720 screen resolution (progressive)
- 1920x1080i content: Stuttering
- 720x480i content: Seems OK at first, but still stuttering every 10-15 seconds.


I used GraphEdit to troubleshoot. I couldn't "connect to remote graph" to see what Windows Media Player was doing, but I was able to get identical results by using GraphEdit's "File -> Render Media File" option. Basically, when I used GraphEdit to open the files, they played back just fine, deinterlaced (bob) and without stuttering. When I opened PVRX2's "lastgraph.grf" in GraphEdit, I was able to reproduce the stuttering. The video renderer's statistics showed that over 1/2 the frames were being dropped. The only difference that was immediately visible: Different video renderers. The names of the filters are not very descriptive -- just "Video Renderer." I can't tell exactly which filter was being chosen by GraphEdit, but it's a VMR of some sort -- with a "VMR input0" pin. See attached filter graphs.

So, here's some "side-by-side" comparison of PVRX2 VMR9 Custom Renderer performance and GraphEdit's choice VMR Renderer performance:
Average Frame Rate achieved:
PVRX2: ~23fps GraphEdit's choice: ~30fps
Frames Dropped in Renderer:
PVRX2: ~60% GraphEdit's choice: ~0.3%

One interesting thing that got my attention is that the PVRX2 graph tries to render 60fps while the "GraphEdit's choice" graph only aims for 30fps. The only difference is the Video Renderer. The rest of the graph is the same, and the video decoder tries to do bob de-interlacing in both cases. I expect bob deinterlacing (line doubling) to double the frame rate, but somehow the 'other' renderer gets away with 30fps. My only guess is that the 'other' renderer is "offloading" the deinterlacing in place of the decoder (although changing the decoder setting to bob or weave has an obvious effect on the video output).

In GraphEdit, I started with PVRX2's last graph and swapped out the renderer a few times. Standard VMR9 and PVRX2's custom VMR caused stuttering. The 'other' VMR and some overlayed renderer worked just fine. I wanted to apply this to PVRX2 config, but obviously could only do VMR9 custom and FSE. Neither config removed stuttering. To try the other renderers, I reverted back to GBPVR.exe. I tried all rendrers available to GBPVR.exe, but none of them removed the stutter. (In this paragraph of experiments, I only used 1080i content, and 1920x1080p screen resolution.)


Soooo, does anybody have a recommendation to relieve the stuttering? Does anybody have an explanation for the 30fps vs 60fps difference between renderers? Do other people out there using the VMR9 renderers and bob deinterlacing really achieve 60fps?

I attached representative PVRX2 logs with debug output enabled; I also attached some filter graphs.

[TornadoTJ]

I think it's interesting to read this as I still have stuttering on my system as well. I've all but given up on HD working correctly on the system I have now. Honestly, I have decided to just deal with it. I did notice on another thread that the 3D settings should be turned all the way down for the video card (I have an ATI 9600XT) and I'm going to give that a shot as that's something I've never tried. I truly thought the Athlon x64 3000+ would be enough horsepower for HD, and same for the vid card. For a while I thought maybe it was my hard disks, as they are regular ATA, but they are fast Hitachi (IBM) 7200 drives, one for boot/OS and one for the recordings, and my tests show that the drives are plenty fast and not the bottleneck.

[peter t]

I have used the PVR 350 out sucessfully for three years.
I recently purchased a HD 1080 LCD and have spent many hours followed the good advice in this thread.
I have upgraded codecs and hardware and changed endless settings. I had made gradual progress until last night when I completely solved my problem of jerkiness and occasional freeze frames.
I have not heard any mention of this solution and guess others like me have overlooked such a simple solution.
Being a PAL system country we use a line rate of 50Hz so I changed the monitor refresh rate from 60Hz (the default) to 50Hz.
Problem solved, perfect pictures in fact they are almost as good as my Snazzio HD Net Cinema.
I hope this ramble helps some other person like me who has a tendency to overlook the obvious.

AMD 64 X2 4800, MSI K8NNeo4Platinum, 2G DDR400 RAM, Nova-T-500, (PVR350 to Satellite Box), USBUIRT, WinfastPX8500GTTDH, HDMI to Sony KDL40X3100

[BigMoose]

I am in the same situation - used the pvr350 TV out for years, then bought a 1080p LCD and wanted to make best use of it. I'm pretty much there now with playback (except DVD playback is still poor). Also if I watch the show that's currently being recorded the playback is very choppy (but strangely in timeshift mode, pausing etc, the playback is fine. I thought that was basically recording it and playing it back at the same time? No idea why one is fine and one is so choppy).

Anyway, I digress! I cant persuade it to let me have 50hz at 1080p resolution, but it did at 720p - and that is much smoother. Although I assumed that was due to the lower resolution more than the Hz. Probably both!

[RaulDuke]

OK, I had my machine working well for over a year, but now I have had a problem like this return.

Here is the issue, when I play a show I recorded through Windows Media player it is fine, but recorded shows and live tv through PVRX2 hitch. What I mean by that is every 2 seconds the video stops, though the audio continues. I have tried every combination of ideas in this thread, and cannot for the life of me figure out how I fixed it before. In the Microsoft Video Decoder check, it says Media Player is using "Ligos MPEG Video Decoder", Dscaler Mpeg2 Video Decoder, Cyberlink Video/SP Decoder, and Intervideo NonCSS Video.

I have a Hauppauge 250. Can anyone spot what I am doing wrong?

[RaulDuke]

OK, I had my machine working well for over a year, but now I have had a problem like this return.

Here is the issue, when I play a show I recorded through Windows Media player it is fine, but recorded shows and live tv through PVRX2 hitch. What I mean by that is every 2 seconds the video stops, though the audio continues. I have tried every combination of ideas in this thread, and cannot for the life of me figure out how I fixed it before. In the Microsoft Video Decoder check, it says Media Player is using "Ligos MPEG Video Decoder", Dscaler Mpeg2 Video Decoder, Cyberlink Video/SP Decoder, and Intervideo NonCSS Video.

I have a Hauppauge 250. Can anyone spot what I am doing wrong?

Dear future self, I wanted to take this opportunity to remind you that when this happens, it is because you do not have the intervideo set as the video and audio option. You can obtain that from the Hauppage website. I wish you a long and happy life.

Signed,
Past Self

[marieper]

Like many here I seem to have the stuttering problem with live tv (dvb-t) - I wanted to try out the GraphEdit track, as fiddeling around with the too many codecs does not make any improvement (I can get it worse though) - but I can't find any lastgraph.grf - where is it?

Comparing with the twinhan's supplied DigitalTV, which gives me "perfect" picture, it will possible to do it through pvrx2 as well...