Recordings always have studder

[feilh]

I have been using GBPVR for sometime, and the recording did occasional have studder. Recently I have been trying to migrate to NPVR version 2.4.3. The recording have very frequent studder sometimes a recording goes for awhile without studder and then it studders a lot for the remainder of the recording. I have sometimes watched my TV while doing a test recording. The TV is is getting the same signal through a splitter, and I do not see studder while watching TV but then I see studder in the recording. I have tried flipping the cable between the TV and the tuner card and it made no difference.

I have tried doing recordings on two devices a HVR-2250 and a AverMedia Volar Max both in QAM mode. They both produced similar results. I have tried turning off my antivirus (Avast) and it made no difference. I feel very strongly that the studder is in the recordings and not the playback rendering, because the playback shows the studder at the same place if I rewind. I also see the studder in the same if I view with windows media player.

I am running Vista 32 HP bit, on a 780G HD motherboard with a AMD Athlon X2 4850e. Not the newest machine its about 4 years old. One thing I have noticed with NPVR is my machine seems less responsive when recordings are on-going than with GBPVR. My CPU runs a little higher with NPVR (10%), but memory consumption isn't noticeably different.

Anyone have any idea how to begin to diagnose and remedy?

Howard

[feilh]

Is it possible my Western Digital Green Drive is not consistently fast enough for NPVR TS recordings? I notice that NVPR recording really impact my computers performance much more then by GBVPR recordings using an ATI mpeg2 MUX. I wouldn't think there would be much difference in the I/O requirements, but the computer is notably slower with the NPVR recordings. Could buffer overflows due to hard disk I/O be causing the stutter?

Howard

[sub]

Your drive should easily be fast enough for a single recording. Maybe check the drive isn't super fragmented though.

Are you sure it's not just a playback issue? Have you tried playing the recording in another player like VLC? or even taking the recording to another PC and playing it there.

When it comes to recordings from digital recordings, it's just a dump of the broadcasters original stream, and very little that can go wrong. There shouldn't be any way the recording itself has a problem unless you've got signal issues and it's dropping packets.

[imilne]

If you can upload a small sample recording somewhere, then others can test it for you and see if it stutters for them too. If it does, then it was probably a poor signal in the first place. If it doesn't, then it's some other issue with your setup causing it to happen.

Iain

[Reddwarf]

You could also try omitting the splitter for a test recording, many capturecards have less sensitivity than TV's and require a much stronger signal for stutter free reception.

[bgowland]

I agree with Reddwarf although not just in the sense that capture cards might have less sensitivity.

A TV will be using hardware decoder chips which will have error compensation capabilities. NextPVR basically grabs the stream and writes it to disk 'verbatim'. If there's a glitch in the stream (causing a timing problem) it will stay there and rear its ugly head in the same place every time the stream is replayed through software.

[feilh]

I have tried omitting the splitter. Its a QAM signal and my Hauppauge card's signal monitor says the SNR is 30db. I'm convinced its in the recordings because its always in the same place regardless of what software I use to replay it. Yes. The Hauppauge signal monitor card also shows errors on the line. I have also tried mounting an antenna and getting OTA signals. Again, I had strong SNR, but there were still errors on the line, and I got similar results. The issue is more pronounced on some channels more so than others. On some channels even though the SNR is good, I get almost constant stutter.

Is it possible the ATI MUX I'm using in GBPVR handles the errors better then the TS mux of NPVR? It appears to be the case. Is there any tuner card that has better error compensation capabilities? I have been recording with my Hauppauge for 3 years now using GBPVR, and I have never really been satisfied with recordings. Many recording cut off when there are errors on the line. The NPVR TS MUX never cuts off, but the stutter makes the recordings unwatchable.

[Reddwarf]

I have tried omitting the splitter. Its a QAM signal and my Hauppauge card's signal monitor says the SNR is 30db. I'm convinced its in the recordings because its always in the same place regardless of what software I use to replay it. Yes. The Hauppauge signal monitor card also shows errors on the line. I have also tried mounting an antenna and getting OTA signals. Again, I had strong SNR, but there were still errors on the line, and I got similar results. The issue is more pronounced on some channels more so than others. On some channels even though the SNR is good, I get almost constant stutter.

Is it possible the ATI MUX I'm using in GBPVR handles the errors better then the TS mux of NPVR? It appears to be the case. Is there any tuner card that has better error compensation capabilities? I have been recording with my Hauppauge for 3 years now using GBPVR, and I have never really been satisfied with recordings. Many recording cut off when there are errors on the line. The NPVR TS MUX never cuts off, but the stutter makes the recordings unwatchable.

I have found that the Cinergy C cards have better sensitivity than most others, I have not compared to Hauppauge thou. There is a couple of things you can try, in case the stuttering is not caused by signal strength/quality you can try to boost the priority of Nrecord. There is a setting in Config.xml named UseHigherPriority in the recording section, if you set it to true and restart the recording sercive it will run Nrecord at a higher priority.

You can also try to fix errors in the recordings with TSDoctor (http://www.cypheros.com), there is a free trial version. I use it in PostProcessing.bat because I have some noise in my signal.

[johnsonx42]

that link points to a search squatting site... perhaps you meant: http://www.cypheros.de/tsdoctor_e.html

[Reddwarf]

that link points to a search squatting site... perhaps you meant: http://www.cypheros.de/tsdoctor_e.html

Correct, my memory slips me :o