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-   -   MythTV VDPAU tearing on Recorded and Live TV on startup of playing (http://www.nvnews.net/vbulletin/showthread.php?t=133103)

tmelhiser 05-19-09 12:51 AM

MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
Configuration:

Mythbuntu: 8.10 amd64
Memory: 4Gb
CPU: AMD X2 4400
GPU: NVidia 8200 IGP
DeInterlacing: Temporal 1x
Driver: NVidia 180.51
Kernel: 2.6.27-11-generic #1 SMP

Window Manager: ratpoison
Composite: Disabled
Connection: HDMI
Resolution: 1920x1080

Problem: During the initial start up of playing an HD stream (either live or recorded) the initial stream has tearing all over the screen. If I pause the input for a few seconds, and then let it resume, the tearing slowly stops and becomes stable. Occasionally this tearing will creep back in from time to time but the pause trick seems to correct it.


This problem is most pronounced primarily only on the start of watching live TV, however can be seen when viewing a previously recorded HD stream. I have 2 diskless frontends that are configured in the same way. The issue exists with them as well.

Thanks,

-T

Stephen Warren 05-19-09 12:00 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
You are most likely using the blit-based presentation queue (do you have the X composite extension turned on)?

If that's the case, trying the latest 185.18.* beta release should solve the problem for you; sync-to-VBLANK (which prevents tearing) was only recently implemented.

tmelhiser 05-19-09 01:27 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
I believe the composite extension is turned off:

Code:

Section "Extensions"
        Option  "Composite"  "Disable"
EndSection

How can I determine what presentation queue I am using? The VDPAU config in MythTV is set to Temporal 1x, but I am not sure if this is the the presentation queue you are talking about.

Regards

-Travis

Quote:

Originally Posted by Stephen Warren (Post 2010907)
You are most likely using the blit-based presentation queue (do you have the X composite extension turned on)?

If that's the case, trying the latest 185.18.* beta release should solve the problem for you; sync-to-VBLANK (which prevents tearing) was only recently implemented.


Stephen Warren 05-19-09 01:31 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
Hmm. There are a few other things that force the blit-based presentation queue; check the VDPAU section in the README for details. Or, if the problem goes away in the latest 185.* driver, that's it. The "temporal 1x" selection is de-interlaced type, not presentation queue type.

By the way, just so I'm clear what you're seeing, can you describe what you mean by "tearing".

tmelhiser 05-19-09 01:38 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
The "tearing" is pretty hard to describe, but I will give it a try:

Looking at a scene with the backdrop of a desert with mountains in the background and the actors in the foreground; as the actors walk and interact, those portions of the screen most static (the mountains/trees/etc) remain unchanged and clear. The actors, however, have banded lines through them that are about 10-20 pixels tall and only as wide as the character themselves. The actors/things in motion have this tearing effect on them.

-Travis

Stephen Warren 05-19-09 01:44 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
Oh, that sounds like something different then. At a guess, I'd personally describe this as "corruption".

"tearing" usually means perfectly decoded pictures, but there's a single line all the way across the image, above which you see the new picutre, and below which you see the old picutre, simply because switching to a new picutre isn't synchronized to your TV's VSYNC signal.

Can you upload the file you're having problems with to the file drop mentioned in the VDPAU sticky. If it's too big, try truncating it to a shorter file, provided the issue still repros clearly.

Thanks.

tmelhiser 05-19-09 02:11 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
I just upgraded to the 185.18 Beta and it seems to have helped immensely. I am now working on pushing this through to my diskless stations.

As for the video being corrupt, no, I don't believe it is. Since I can force the "artifact/
tearing" by starting the stream in different spots.

For example: If I start playback 15 minutes into the clip, the effects will happen from that point forward until I pause the video. Once I pause the video and then resume, the effects are no longer present. But from Time index of 15 minutes until 15 minutes 20 seconds, there are these effects.

If I start the playback at 10 minutes the effect will be from the 10 minute mark until I pause and resume a few times. At which time it will play smoothly again... all the way past the 15 minute mark... with no issues.

-T

Stephen Warren 05-19-09 06:08 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
Quote:

Originally Posted by tmelhiser (Post 2011036)
As for the video being corrupt, no, I don't believe it is. Since I can force the "artifact/tearing" by starting the stream in different spots.

Sorry, I didn't mean the clip was corrupt, but that the decoded result showed visual corruption.

This almost sounds normal; any time one jumps into the middle of a stream, if one isn't careful to jump to a legal "reference frame", then the decoded result may be corrupted.

Also note that MythTV contains a very old snapshot of ffmpeg, which is certainly missing some fixes for the code that calls VDPAU. This might also be related to your issue. I believe somebody is working on pulling in a new fffmpeg into MythTV, but I have no idea about the status of that project.

tmelhiser 05-19-09 07:53 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
Yes, I believe this is true. There is visual corruption; if I do not do pause the input at least 1 time, it will never correct itself.

Pausing the playback seems to correct it.

After having moved to 185.18, there is far less corruption on the screen. However, I now know how to distinguish "tearing" from corruption. The 185.18 driver has significant more tearing in the play back. It looks as if the screen is ripped right down the middle, horizontally.

I will be going back to the 180.51 driver since I have not found a way to get the tearing to quit, where the corruption can be corrected with a pause of the playback. I guess the ffmpeg may not be seeking to the correct I-Frame or some other marker in the TS stream...

Thanks,

-T


Quote:

Originally Posted by Stephen Warren (Post 2011253)
Sorry, I didn't mean the clip was corrupt, but that the decoded result showed visual corruption.

This almost sounds normal; any time one jumps into the middle of a stream, if one isn't careful to jump to a legal "reference frame", then the decoded result may be corrupted.

Also note that MythTV contains a very old snapshot of ffmpeg, which is certainly missing some fixes for the code that calls VDPAU. This might also be related to your issue. I believe somebody is working on pulling in a new fffmpeg into MythTV, but I have no idea about the status of that project.


seth_keith 06-15-09 01:08 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
I think I am getting actual tearing. Only playing back HD content on mplayer-svn w/ vdpau. The symptoms appear sometimes, and not reproducibly. They seem to be related to the particular movie, but not reproducibly, so I get tearing more frequently on some movies in some scenes, but if I go back and try to get it again I cannot reliably do so in the same scene.

My tearing appears as a horizontal line across the entire screen, about 1/4th of the way from the top. It looks like the upper portion is slightly offset from the lower one. Picture looks perfect, except it looks like it was cut horizontally 1/4th of the way down, and rejoined slightly off.

I have seen this problem on and off through many different NV and mplayer releases. Currently I am using NV version 185.18.14. I have an GeForce 8200 chipset, and I am playing on mplayer SVN 29333 with FFmpeg SVN 19012 patched to add multi-threading

Can anyone recommend something to try?

tww1fa 06-15-09 01:33 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
Do you see the same problem if you bring up the OSD? If so, you're seeing the same thing I was when I was using my 8200IGP to play h264 1080i video. After the OSD went away it took a second or two to "clear up." If I played 1080i MPEG2 video there was no corruption. I think the issue may be that the 8200IGP just doesn't have quite the horsepower to handle both h264 decoding and the OSD.

In my case, upgrading to a 9500GT fanless solved the problem completely.

seth_keith 06-15-09 03:03 PM

Re: MythTV VDPAU tearing on Recorded and Live TV on startup of playing
 
I see the problem without OSD, and turning it on does not seem to make it worse. I tend to think that horsepower is not an issue, because the CPU is at like 10%. How do I monitor the GPU? Also some movies always play well, like BBC planet earth, you would think that if anything would bog down the GPU it would be this stuff, but I never see a tear...


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