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View Full Version : Skipping in Mpeg - Difference with PVRX2 and MVPMC Filesystem?



psycik
2008-02-18, 07:25 PM
Hi, I've been on digital for a while using the ATI mux. Have found in PVRX2 using mvpmc that skipping in a digital recorded video is very erratic. Press the 1 min skip, sometimes goes backwards, skips erratic amounts, skips back to the same point etc.

By chance, because I was playing with the mvpmc config file I set up some file shares to my recordings directory and played a digital based recording using the Filesystem mode of mvpmc, skipping around in this I didn't have any of these issues.

Does anyone know what the differences are?

mvallevand
2008-02-19, 12:07 AM
I can't answer why there are problems, but I can tell you the main difference is that mvpmc natively can control the entire mpeg playing process, the dynamci bi-way file positioning the demux and it has all the timestamp information (both hardware and file based) that it needs do to this.

With Hauppauge protocol mvpmc is just a sequential file player, each time you reposition the file (or change the channel) it is a a new file starting a zero. GBPVR is demuxing the file as it plays but the actual location is not accurate. When you add some slightly erratic network behaviour small skips will be approximations. Even with all this it still has to be feed into the mpvmc demux and then demuxed and played. The something applies to comsip, resume etct it is all tricking mvpmc into playing a new file at the correct point. Frankly I am surprised it works as well as it does. Maybe sub is physic too?

There is also just plain difference is the demux, mvpmc can do file positioning on mpeg-1 files as an example. Maybe the mvpmc logic is a little better suited to the data contained in the ATI muxed files?

One of the things that I hoped a couple of years ago was to glue the GBPVR UI and use the mvpmc file player, adding in vlc for good measure, to get the best of both worlds, but PVRx2 was born instead which is a more important direction.

I should add that mvpmc would probably even do better on your digital recordings with mpeg-ts file since the time stamps would would be that much more accurate.

Martin

psycik
2008-02-19, 12:45 AM
So you can think of no solution?


Maybe sub is physic too?

I'm sure in the past I've said he is!! :D

mvallevand
2008-02-19, 02:58 AM
So you can think of no solution?



I'm sure in the past I've said he is!! :D


No real solutions. My recommendations are don't be too fast with skip/next, use short skip instead of FF and use mvpmc's Go FF to move forward at 2x when possible. I find everything works a little better with logging level's turned down too but that can be tough when debugging.

Martin

psycik
2008-02-19, 04:21 AM
and use mvpmc's Go FF to move forward at 2x when possible.

How do I turn this on??



I find everything works a little better with logging level's turned down too but that can be tough when debugging.

Martin

Hmm, should look at this too, I always leave my logging all the way on...

mvallevand
2008-02-19, 04:27 AM
Hit the Go key then hit then the FF key. The Play key will put it back to normal.

Martin

clifford
2008-02-19, 06:59 AM
Yah i have this problem too. I tried the mvpmc solution as above, but the problem remained. seems though the first skip i try always works (or at least is in the ballpark). the problem occurs if i try to rrwd or skip 1/2 way through the file