Glitch in decoding H.264 #3

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Nick007
Posts: 38
Joined: Wed Sep 29, 2010 12:20 pm

Glitch in decoding H.264 #3

Post by Nick007 »

I'm back with the same kind of glitch like before and I hope we finally figure it out this time :-)

I got a 15 frames long glitch caused by decoding of H.264 track from TV capture via DGDecNV. The glitch is not there when I use DirectShowSource or FFVideoSource, or if I play it in mpc-hc with CoreAVC or ffdShow decoder or in VLC. As far as I can tell the capture is glitch-free. I got this kind of unforeseeable glitch few times also on video track from Blu-ray, I do not believe it is HDTV related.

The glitch appears when I play the avisynth script (only with DGSource() in it) in VirtualDub or frame-step in AvsPmod from frame 0. The glitch appears only when the script is played from the beginning, if I seek to some frame and play from there, it doesn't appear! This is the same behaviour like I got few times before already and I believe it is the same exact bug that's causing it.

I replicated the glitch on my desktop pc with GTX 570 (various drivers) and on my laptop with GT 220M, with DGDecNV 2042 and 2043, using decode modes 0,1,0 and 1,1,1. It is there when I index the track in mkv or demuxed h264.

Here's 40sec video from the very beginning of the capture, which is enough to replicate it:
http://www.mediafire.com/?02g61wt751sk9ca

As you can see, it's like it was overlapping with frame from 900 frames before:
Image Image Image Image

The glitch is from frame 889 to frame 903. And like I said, it is there only when it's played/frame-stepped from frame 0, it is not there when seeking to frame X before 889 and frame-stepping from X, or when seeking to frames 889-903 directly.
It is there if I use DGSource("source.mkv").Trim(1, 0), but it isn't there if I use DGSource("source.mkv").Trim(200, 0).

It is really strange and it's bugging me a lot, I hope we'll be able to figure it out soon. If you need any more assistance, please let me now.
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admin
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Re: Glitch in decoding H.264 #3

Post by admin »

I've duplicated this. Investigating...
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admin
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Re: Glitch in decoding H.264 #3

Post by admin »

Doesn't fail with 2,2,2 and use_D3D=true.

I have to ask nVidia about this.
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Nick007
Posts: 38
Joined: Wed Sep 29, 2010 12:20 pm

Re: Glitch in decoding H.264 #3

Post by Nick007 »

Interesting, haven't tried this new mode.

Thanks for digging deeper into it :-)
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admin
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Re: Glitch in decoding H.264 #3

Post by admin »

Update: My contact at nVidia that usually figures these things out really quickly is on vacation until the end of October. He said he will look into this upon his return.
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Nick007
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Re: Glitch in decoding H.264 #3

Post by Nick007 »

Hi admin. Have you got any feedback about this issue?
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kypec
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Joined: Tue Sep 21, 2010 2:37 am

Re: Glitch in decoding H.264 #3

Post by kypec »

Here is a nice sample, confirmed to show glitches for various people with DGDecNV decoder http://forum.doom9.org/showthread.php?p ... ost1624013
Although the last Sulik's comment claims that the stream violates spec I wonder how is that possible, given that it's a straight DVB recording. Do broadcasters violate H.264 specs recently? :o
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admin
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Re: Glitch in decoding H.264 #3

Post by admin »

kypec wrote:Here is a nice sample, confirmed to show glitches for various people with DGDecNV decoder http://forum.doom9.org/showthread.php?p ... ost1624013
Although the last Sulik's comment claims that the stream violates spec I wonder how is that possible, given that it's a straight DVB recording. Do broadcasters violate H.264 specs recently? :o
This one appears to be fixed with the latest nVidia driver and DGDecNV.
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