Capturing is slightly slower than normal TV

[UkF1]

Hey all.

I'm very much a newbie with regards to tv/video capture. I have just forked out for a WinTV PVR250 which seems a fine card and I get quite nice picture quality.

However I have noticed that there is a delay between what my PC is playing and what my TV in the other room is showing. It's about 1 second, but I've noticed this increases, so my card can end up being 10-15secs behind after an hour or so.

I presume this is to do with the time it take for my computer. Anyone know why this happens?

Also sometimes I get slight glitches in the TV.

Here's an example:
http://www.btinternet.com/~aaron.edwards83/vids/France_03_Barrichello_Spins.mpg

At around the 3.5sec mark there is a glitch and the pictures jumps. How can I stop this?

Any help much appreciated. Thanks! :)

[jggimi]

Welcome to the Forum! I hope you find it useful.

I'm not familiar with your card (or the software you may be using). But based on your description of a "delay" from real-time, your software appears to be caching the captured signals, as your encoding is slower than real-time.

I examined your sample clip. Frame #97 (starting with frame#0) has the problem. The frame is a B-frame. The clip contained 17 I-frames, 81 P-frames, and 193 B-frames. Your MPEG GOP sequence is IBBPBBPBBPBBPBBPBBI... and the error frame did not appear to disturb the sequence.

I ran the clip through a SeparateFields() filter, and it's in both fields. I do not know the cause, but I can only guess that it might be an encoding error, unless it was in the source you captured.

It appears your software captures and encodes directly to MPEG-1. To reduce CPU consumption, you may want to decrease the number of B-frames in each sequence, or remove them entirely. They take a tremendous amount of CPU to encode. P-frames are also CPU intensive, though less-so. When I was capturing directly to MPEG-2, I would set the GOP sequence to 100% I-frames, which consumed the least amount of CPU during capture. If you capture with 100% I-frames, you'll likely "keep up" a little better. If you want more information on GOP frames, see GOP's: I, P, and B frames explained (http://forum.doom9.org/showthread.php?s=&threadid=19436) in the DivX 5 forum. That's an MPEG-4 codec, but the GOP discussion applies to MPEG-1/2 as well.

In addition, you should disable background tasks, network connections, and even USB connected devices (mice, joysticks) that might interfere with capturing.

Good luck, and let us know if this helps.

[Joe_Bloggs]

I have browsed
http://www.hauppauge.co.uk/html/pvr_prod.htm#pvr250
This device has hardware mpeg-1/2 encoder for the analogue
transmissions it can receive. It also has an svideo input for camcorder
and VCR. There is little mention of how it handles the audio so i
assume it relies on the properties of the audio card employed.
This is perhaps the heart of the problem.

I would advise searching for Hauppauge PVR250 audio sync on google.
This turned up at first attempt:-
http://steve.kittelsen.com/pvr250/
This chap ,who is an enthusiast, may be able to help. He takes a
very good picture of a pvr250 at least.

Don't expect the drivers from Hauppauge you get with your card
to be the ones that do the business. Sometimes you have to upgrade
to the latest ones that work for you or at least work for others.

Everything about the Hauppauge PVR250 is digital apart from the
analogue transmissions it can receive.
If UKF1 had bought a digital terrestrial receiver card then another
25 TV channels could be available according to location and ariel.
Only five to seven of them worth watching though.
Regards Joe

[jggimi]

Thanks for the info, Joe. Further research shows the hardware encoding uses an IVAC015 chip (whatever that is).

My advice on GOP settings was for software encoding; however, if continued "glitches" occur in B-frames, I would recommend altering the GOP sequence to disable them, and see if that circumvents the problem.

[UkF1]

Woah, thanks for the response guys!

I have indeed checked out this site - http://steve.kittelsen.com/pvr250/ - he seems to rate the card highly. :)

As for your comments on GOP's well i've really no clue as to what they are, but I will read up on them and see what they are all about/how to edit them etc...

I noticed that capturing is VERY PC hungry, and if I even try to open "My Documents" it's very slow, so I will remove all other programs, remove things from my "Ctrl - alt - del" and do a defrag before I do my next capturing tests.

Thanks guys.

There's so much to read and take in all at once on these forums! :eek: :D

[Joe_Bloggs]

Info on the ITVC15 thing watsit job.
http://www.globespanvirata.com/GV%20iTVC15.pdf

A person either dedicated to the promotion of acronyms or
one totally opposed to their existance wrote this list:-
http://www.ginko.de/user/franz.hamberger/acronyms.txt


GOP appears as a group of pictures.

I have trawled the web and have discovered that the PVR250 has
an audio input and video input they both should remain in sync as
it is all handled on the card by one chip.
It would be wise to quote your OS version, CPU ,relevant hardware
eg motherboard,bios version, soundcard, video card, ram
quantity, CPU type and maybe hardisk/s involved. Just hack it into
a text file and cut and paste it in when relevant to the topic.

This card is quite popular amongst fans of linux who try to make
a PVR (What!! Acronym man has failed me), I'll try that hotdog
geezer next time.
PVR. Personal Video Recorder,I guess as opposed to public video
recorder I assume? I could be wrong maybe jggimi can comment
on the relative merits of Freevo and MythTV, perhaps not in this
forum but in a Linux one. Anyway the users of such software grumble
a bit about sync and trying to read between the lines, they run out
of PCI bandwidth. Maybe some less than perfect soundcard is hogging
the PCI bus for no good reason and making the mpeg decoder struggle
to do its thing.
Updating drivers for your sound card might solve the problem if it
has been reported as an issue in the past.

Without the information it's just speculation.
Regards Joe.
PS is offair playback in sync? Is the sync error in playback varying?

[UkF1]

Hi, sorry for the late reply, I have been desperately trying things, like de-fragging my PC, doing scandisks, diskcleanups and virus checking.

My PC spec is:

1.33 AMD Athlon,
512 ram
GeForce 2MX 64mb
40gig hardrive (have 12gig free)

Not sure why, but when I watch the TV on my PC it is noticeabley slower, and after a few minutes it's clear that it is "lagging" behind my actual TV ;/

I'm not too bothered about it being "a little bit slower" but it's the "glitches" I really do need to try and remove as they are UGLY as hell :(

Could you reccomend some other drivers to download? Maybe that could help, but I don't really know which ones are good or not :/

BTW I played aroundwith the GOP settings in WinTV2000 and its was set to 15, but there was another option of 6, so I tried that and it made no difference at all. I have read the Hauppauge help files & site but with no luck.

Anybody elese experiece the same problems or able to help me get smooth captures?

Hope so, many thanks

Az

[UkF1]

BTW the audio seems to be in sync, it doesn't go out of sync, even when recording.

I have a Creative Soundblaster PCI (WDM), whatever that is. So it might be worth downloading some drivers for that card, but I'm not sure how to do that. :( If you can give me a link to the drivers I need i'll try and install them. :)

Much thanks

[Joe_Bloggs]

Sorry to be away for so long. I had to mod my Lan Li case as my processor and motherboard were overheating. This is totally due to overclocking and 30 degree ambient tempertures. I found a plastic thermos flask top in the park,hacked it to make a truncated conical inlet above my processor fan. Well It got me 3 degrees C cooler and could be used as a paper shredder in an emergency. I also lapped by northbrige heat sink but the taste was unpleasant so I used a fine abrasive paper and Artic silver III compound . Blogg Blogg Blogg.

Dear UKF1,
It appears from your slightly contradictory post that the recording
apsect of your mpeg encoding card works ok.
The problem as I understand it is with the simultaneous recording to hard disk and playback of video and audio. Either audio gets out of sync or the video gets out of sync with the audio. There is certainly less work to do for the audio than for the video. As far as I can tell the newly created mpeg stream is read by a WinDVD filter as if you were viewing a DVD source. The latest drivers are alleged to get on better with existing DVD playback programs. They are about a week old so they must be good!

Here are some useful links:-

Latest driver
http://www.hauppauge.com/html/sw_pvr_250.htm#beta
A very useful site and forum can be found here.
http://www.shspvr.com/

PS why did you buy a Hardware mpeg encoder for analogue TV
signals? Digital TV broadcasts Mpeg direct to your computer so no
encoding to mpeg is required. Plus you get more channels and it costs
no more than analogue to receive. More often than not, it is
not interlaced so it looks fantastic.

I can understand it if you wish to transcode a video collection to DVD
or are in a poor digital TV reception area or have been sold a
misleadingly advertised product.

Keep plugging away and remember buying a Hauppauge product is
an educational experience with additional frustrating elements.
Once you have mastered what the problem it is then you will wonder
why didn't I do this in the first place.
Joe.

PS what operating system are you using and what if any service pack
have you a patched to it?

[UkF1]

I did have a WinTV Nova-t PCI digital card but I am in a terrible digital signal area, and i'm not meant to be able to pick up hardly anything. I could get BBC1 and BBC2 and a handful of other crappy free channels, but the 2 I wanted most - ITV and Channel 4 I couldnt get so that card was no good to me.

The quality of my videos is more than good enough, it's just when watching TV through my PC it lags behind and get further behind my actual TV. Maybe my PC just isn't fast enough. ;-/ Should be though.

The glitching is sometimes quite annoying though, as it ends up glitching at the bit I want to record :(

BTW when I mean watching TV on PC I mean just watching, not recording as well. Thats when you can see it being slower that normal TV. It's only noticeable after a few minutes when it's clear my TV is faster.

Damn cards.

[Joe_Bloggs]

@UKF1
The second link I mentioned is a good read and I think they have
alternative drivers as well as originals and lots of tips and pvr software utilities for your card. I can now understand your irritation as sync problems drive me mad. I have two nova-pci.

Hauppauge products start of with lots of driver and application
issues that drive customers mad. They really ought to do more
testing or use volunteers prior to the release of their stuff.

I am fortunate in having a transmitter within line of sight. In fact it is an eyesore. It is times like these that you need friends who
could loan you a more up to date sound card and eliminate this
aspect as a problem, without wasting money.
Creative recommend that you pull out your sound card and jot down numbers to determine the appropriate driver so browse their site prior to this action.

The powers that be, say that the transmitter frequencies used by analogue TV will be pulled eventually. My question to you is, why is your reception poor and what are you going to do about it? I recommend joining the forum at:-
http://www.digitalspy.co.uk

Even though you are not a digital user you can get tips and advice from people in your location using terrestrial,cable,or satellite TV.

Do not despair, there is always hope!
Joe.