DebugWindow Timing Skew?

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DannyM
Posts: 3
Joined: Fri Feb 03, 2006 5:27 pm

DebugWindow Timing Skew?

Post by DannyM » Fri Feb 03, 2006 5:47 pm

Question: I usually use the debug window to verify the cutpoints for all my recorded shows. Occasionally (about half the time) the .mpg file will open fine, but when I progress through the file (toward the end) the video will black out before I reach the end, and when I go back toward the beginning, all the timing of the video/cutpoints seems to have been skewed somehow.

Is this a problem that's been seen before? How do I resolve it? I'm using a Hauppauge PVR500 with hardware encoding, and I'm running the latest version of ComSkip on the resulting .mpg.

Thanks!
-Daniel

erik
Site Admin
Posts: 3298
Joined: Sun Aug 21, 2005 3:49 pm

Post by erik » Fri Feb 03, 2006 6:25 pm

The preview blacks out when the end of the mpeg is reached.
This happens when the timeline is corrupt.
Can you use mpgtx.exe inside comclean.zip to check the timeline of your recording?

mpgtx -i filename.mpg

It will tell you if the timeline has problems.

If mpgtx responds that all is well (or otherwise anyway) I would like to receive the first few 100MByte of your recording because my mpeg decoder may make a mistake.
PM me for the upload details.

DannyM
Posts: 3
Joined: Fri Feb 03, 2006 5:27 pm

Post by DannyM » Fri Feb 03, 2006 7:03 pm

Thanks for the reply!

Here's what I get:

Mpeg 2 Program Stream File [Video/Audio]
Muxrate : 7.03 Mbps
Estimated Duration: 01:46:54.22s
Checking all time stamps (This may take a while.) ...
Time stamps jumped from 22913.448767 to 209.142267 at position 6413000
Time stamps jumped from 44510.675867 to 1004.503511 at position 1e11b800
Time stamps jumped from 74846.396233 to 1113.212089 at position 214fb800
Time stamps jumped from 55761.557367 to 1444.242800 at position 2b37b800
Time stamps jumped from 33555.072067 to 1489.488000 at position 2c938800
Time stamps jumped from 77453.564444 to 2108.840044 at position 3f1cc000
Time stamps jumped from 52431.534156 to 3253.783867 at position 61608800
Time stamps jumped from 30346.365244 to 6060.654578 at position b556e000
Time stamps jumped from 53195.251911 to 6279.940311 at position bbe83000
Time stamps jumped from 34661.378667 to 6367.861511 at position be869800
Time line is interupted at 10 times.
That means at these points the time stamp is earlier than the previous one.
You may have problems in joining and splitting this file, sorry.
Aspect ratio 4/3 (TV)
Not interlaced, chroma format: 4:2:0
Size [720 x 480] 29.97 fps 5.25 Mbps
Audio : Mpeg 1 layer 2
224 kbps 48000 Hz
Stereo, No emphasis

The strange thing is that sometimes it works fine! Just for kicks, I doublechecked another file that works correctly in the debugwindow, and that also had timestamp errors. Look below for that output:

Mpeg 2 Program Stream File [Video/Audio]
Muxrate : 7.03 Mbps
Estimated Duration: 32:58.59s
Checking all time stamps (This may take a while.) ...
Time stamps jumped from 59880.429811 to 64.964889 at position 1f08800
Time stamps jumped from 23173.046433 to 358.758400 at position abc0000
Time stamps jumped from 55647.865967 to 1155.888089 at position 229b6800
Time stamps jumped from 37326.932800 to 1521.419911 at position 2d864000
Time line is interupted at 4 times.
That means at these points the time stamp is earlier than the previous one.
You may have problems in joining and splitting this file, sorry.
Aspect ratio 4/3 (TV)
Not interlaced, chroma format: 4:2:0
Size [720 x 480] 29.97 fps 5.25 Mbps
Audio : Mpeg 1 layer 2
224 kbps 48000 Hz
Stereo, No emphasis

Any ideas? If there's a way that I can 'repair' the timelines prior to running comskip, and if you think that will help, let me know.

Thanks!

erik
Site Admin
Posts: 3298
Joined: Sun Aug 21, 2005 3:49 pm

Post by erik » Fri Feb 03, 2006 9:44 pm

I also see the same.
Some files work, some don't

On my download site you can find retime.zip
http://mk.kaashoek.com/gbpvr/retime.zip
Instructions are inside the zip file.
If you run retime on the mpeg file before you use the comskip debugwindow things may work.

Make sure you also rename the .csv and the .txt otherwise you won't see anything.

In case you find a file without errors that does not work with comskip I would like to receive the file.

DannyM
Posts: 3
Joined: Fri Feb 03, 2006 5:27 pm

Post by DannyM » Mon Mar 06, 2006 6:35 pm

Now that I'm retiming all my .mpg files, I'm seeing kind of the opposite problem. Occasionally (50-60% of the time) I open a {mpg_file}.txt in the debug viewer window, and instead of it ending short, it seems to go long, and I can't even navigate to the end of the mpg file.

In other words, if I scroll to the end of the file in the debug window, it's still several minutes before the REAL end of the file (when I open it in Windows Media Player).

Any ideas?

Thanks again for a great program.

erik
Site Admin
Posts: 3298
Joined: Sun Aug 21, 2005 3:49 pm

Post by erik » Mon Mar 06, 2006 8:17 pm

Do the cutpoints appear to be at the right position?
If yes its a problem with the length algorithm.
Do you have a not too long file showing this problem you can upload?

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