pvr150 video timing bug

[wtg]

There is no header that contains the duration in the MPG file. The duration is derived from the presentation time stamps that are spread throughout the file (thousands of them). When people remux the file, this as the side effect of rebuilding these timestamps.

I don't know enough to argue with you even if I wanted to, but how does a player show you the length of the video right as it opens? Obviously it doesn't read the entire file. Does it just read the end of the file too, or does each PTS have the full duration in it? Just curious.

If you're timestamps are 'broken' then the PVR150 drivers are probably to blame. GB-PVR just saves the MPEG stream byte for byte as its generated by the drivers. Somewhere in amongst all that data is the timestamps, but at record time GB-PVR has no knowledge of which bytes are what, and doesnt manipulate them in any way.

I know its not a gbpvr thing... definitely the drivers. I had no trouble at all until my pvr250 broke and I replaced it with the 150. It's frustrating that they've not fixed such an obvious problem.

[wtg]

Not really had this myself, but did a bit of searching and found this:

http://www.digitalfaq.com/dvdguides/capt...stream.htm

Restream looks like it may well be the tool for the job... if it does commandline of course...

Thanks for the info. I just found that one and a couple others a few minutes ago myself. I'll try them later tonight when I have a chance and post the results.

[sub]

I don't know enough to argue with you even if I wanted to, but how does a player show you the length of the video right as it opens? Obviously it doesn't read the entire file. Does it just read the end of the file too, or does each PTS have the full duration in it? Just curious.

It depends on the player, but I often read the first and last presentation timestamp and calculate the duration from the difference. That said, if the other timestamps during the show are incorrect, you could get one or all of the following problems - hanging, stuttering, audio/video out of sync, finishing early. These presentation timestamps are very important and used to tell the system when audio of heard or video seen.

[wtg]

I tried a couple utilities, mixed results.

I tried restream mentioned above and it requires demux'ing first, so it's no better than what I already have.

Next, I tried MPEG-Corrector http://www.dvdhelp.us/index.html?html/tutmpegheadercorrector.html~mainFrame
. This is nice because it's one simple executable and doens't require temp files, but it has a couple problems. First, it's GUI-only so it's no good for a batch process. Second, even though it did rewrite the file with correct time stamps, it tagged the file at MPEG1 instead of MPEG2. Realplayer and Windows Media Player choked on it because of that, Nero's Showtime handled it ok. I didn't bother in gbpvr.

So, still looking...

[wtg]

I did find one easy solution... mencoder. Most people use it to make an avi, but it can make an mpeg file too. The following command line makes it rebuild the mpeg file, simply copying the input's video and audio stream without re-encoding: mencoder -of mpeg -ovc copy -oac copy input.mpg -o output.mpg

This reset the timestamps and didn't require demux'ing. I'll play around with it some more, but this might be the best option.

[groover km]

I have checked my PVR-150 driver version, and it is 2.0.30.23123 ...I'm pretty sure that this is the one off the CD, and I have tweaked the settings with the tweak tool from SHS.

The current version on the hauppauge website is 2.2.23257 ... I never updated as I read too many 'horror' stories on shspvr forum and I thought if it's not broke...

However if it's the driver causing me a problem, I'm willing to try it. What version driver do you guys use? Any recommendations, suggestions, thoughts?

[wtg]

I'm using the latest from the Hauppauge website. They don't work consistently either.

[wtg]

The following command line makes it rebuild the mpeg file, simply copying the input's video and audio stream without re-encoding:

mencoder -of mpeg -ovc copy -oac copy input.mpg -o output.mpg

I've done some more experimenting and I'm liking this option even more. On my wee 1.1 GHz Celeron it does 1 hr of video in about 8 minutes (input and output to the same disk too), plus you can start watching the video in gbpvr or on the MVP as soon as you start the process. Since the PC is converting it much faster than realtime, by the time you get to a commercial, enough video has been converted that you can skip it.

This is a much better solution that demux'ing and remux'ing.

[Lindsay]

sub pointed me to this thread. Below find a description of a problem I have had. Does this sound like the problem you are discussing?

The mpg file was the right length but it was handled as follows:- GBPVR played a few seconds, WMP took about 10 sec to move the place-holder to the right-hand end then continued to play the file, VideoRedo Plus played 12 sec and stopped but the commercial finder read the whole file!

I use a pvr150, dvr ver 23258.

Thanks.

[groover km]

It doesn't sound 'exactly' the same, but it certainly could be related to the timestamps distributed throughout the file.

Typically, I open the recorded file to play, look at the OSD, and rather than showing the correct duration (say 1:00 Hour) it shows a funky number - 23minutes 14 seconds, or whatever). If I leave the file to play without touching the remote it will play fine, sometimes I can FF and RW, but any attempt to skip around the file goes haywire.

Maybe try some of the suggested fixes in this thread and see if it has an affect?