Audio / Sync Glitch with PV256

[Xleon]

I'm not sure if this is SageRecorder or even if it's version specific as it doesn't happen very often but...

You'll be watching something recorder (or time shifting) and you'll
notice the sync has gone out by around 5 seconds. Then, over the next 30 seconds, the audio pops slightly but the sync gradually comes back and after around 30 seconds, is 100% locked correctly again!

It's actually recorded like that, not playback. I was wondering if it could be where the PC pages occasionally. I had considered disabling VM as it has more than enough and I've successfully done this with other PCs in the past.



Weird thing with the Xcard (I think it's Sigmas installer) but when you update the Xcard drivers, the card no longer appears in the Sage decoder list. BUT, if you select Default, it uses the Xcard!

[Xleon]

I've tested this problem with all versions of SageRecorder and it exists in all of them.

The actual sync problem is recorded in to the file. The audio will suddenly be out of sync for no reason. You can then hear the audio clipping words and sections of audio as it attempts to 'catch up' with the video.

Still not sure if it is Sage or the PC. Does Sage know if it's gone out of sync and try to correct the fault by cutting small pieces of audio out in blocks? I know you have spent a lot of time on the Muxer / Demuxer for the AV. Is this simply it's attempt to fix an error it has detected?

[Narflex]

It could be...that is what it does to fix it. We've got many Provideo users who've been going for about 3 months with no sync loss from what I know.

Thanks,
Jeff

[Xleon]

It happens so rarely it's hard to catch it. It's just annoying when it does. You notice it as it takes around 60 seconds to become fully locked again and there's no indication when it suddenly happens. It doesn't go out of sync slowly, it's just suddenly 3-4 seconds out in a split second.

It's just one of those niggles it would be nice to iron out

I'm currently running my HTPC with no virtual memory at all as I think it might be the fact that Windows pages out every so often and it might be making the audio encoder loose sync for a split second. It's been running fine so far without virtual memory. My MP3 player has never had virtual memory in the 18 months since I built it with no detrimental effects.

[Xleon]

The above test failed as Win2K decides to open up it's own virtual memory even if you tell it not to use any!

At the very least, is it possible to get Sage Recorder to make bigger 'cuts' if it notices the audio is that far (upto 10 seconds on severe occasions) out of sync with the video. As it stands, it takes 60 seconds to gradually come back in to full lock.

I know it doesn't get to the cause of it (I'm still working on that) but it would help the problem when it does go wrong.

[Narflex]

High CPU/bus usage, channel changing, and interruptions in the source signal are what will cause the PV256 to temporarily lose sync if that helps at all.

[Xleon]

The CPU according to TaskManager is only around 20% when recording so it shouldn't be that.

I'm not changing channel and the composite runs straight from the back of the satellite box to the input of the PV256 so I'm stumped as to why this happens as there is no problems with the video at all. No stutters or blocks etc.

I think I'll try to find a freeware CPU / Memory usage logger and let it run alongside SageRecorder to see if Sage 'peaks' sometimes during recording.

[ku71]

start, programs, administrative tools, performance
f1
performance logs and alerts, how to, create and configure counter logs

follow on screen instructions. record memory, process, processor, physical disk and system objects.

avg disk queue should be below five. CPU spikes to 100% are OK, if system>processor queue length goes up your system is suffering

(this is on XP. 2000 may differ slightly)

[Xleon]

Cheers for the info, I'll give that a try !!

[Xleon]

It's been a while since my last reply as I've been busy and also trying to investigate the problem.

It seems like I might have _finally_ fixed it

Up until now, I've been running the audio at either 128Kbps or 192Kbps. The other day, I put the audio on it's maximum setting in Sage of 384Kbps and it's not gone out of sync since.

Weird fix, but as long as it fixes the problem, I don't care.

[newtbert]

Sounds similar to my problem, not sure yet.

About above performance monitor thing, great advice! I never noticed the logger option before. But I suggest also looking at DPC time too, which i guess is disk access. Theres a possibility that file fragmenting may cause the recorder to drop frames when making the recording, if your disk is too fragmented, which causes an audio glitch on playback. And apparently the computer players can compensate for the resulting synch error, which is the distortion your hearing.

But if you burn the recording to a true DVD, playing on a real dvd player will NOT catch-up, resulting in an audio-visual synchronization error (which is much worse than the intermittent audio glitch).

This problem is related to the overall bit rate your using. So my 2.5 Mbps recordings never have the problem, but anything over 4 Mbps does. When the disk is fragmented. Did you use a lower video bitrate on your higher speed audio recordings? Or recently reformat your disk perchance?

Anyway thats my current working hypothesis, fwiw.

[Xleon]

I keep the disk unfragmented and I use 64K blocks which helps a lot. I've been testing the system and I still get the sync issues, but not as often and they bounce back in to sync much quicker now.

It's on the recording, so if I play the file on another PC with Zoom player across the network, the audio still goes out of sync, but locks again. It's always the same, suddenly, the audio is 4 to 5 seconds behind the video.

I just put a faster CPU in the machine which has made no difference at all, so I'm going to replace the SB Live! with another sound card temporarily to see if it's a problem with that card keeping time with it's crystals or drivers.

I don't like to use anything below 4Mbs or the quality drops and also, I have to add an audio delay in the setup menu for some reason as the audio starts too early. This means I can't watch the stream on another PC as the audio delay on SageRecorder only fixes the skew on playback, it doesn't fix it on record and I don't think that's going to be fixed.

The drive is a fast one, the input signal is very solid, the CPU doesn't seem to be maxing out at all anywhere. I'm not running other programs either. One thing I've not tried is moving the card to another PCI slot which might make a difference.

[newtbert]

Oh no, next questions get more expensive and painfull:

1. Is your an AMD or Intel system?

2. What operating system are you using?

Hopefully its the notorious SB Live?

arge

[Xleon]

Yep, it's the notorious SB Live running the latest unified driver pack, which was a nightmare to install as it kept crashing my machine. I have a replacement card to try to get the SB Live out of the equation.

The Machine is a:

450 Mhz Pentium III (now at 550Mhz)
MSI 6139 Motherboard
192 Mb RAM
128 GB HDD
DVD ROM
GeForce2-MX with TV in / Video Out
ProVideo 256T
Sigma Designs XCard
SB Live! Value
Realtek 8139 Ethernet
Windows 2000 Professional with SP4

[Xleon]

I don't want to speak too soon, BUT, after many weeks of trying to hunt down the cause of my sync glitches, I _think_ I've finally nailed it down to the SB Live! card.

I went to my local shop and bought the cheapest sound card I could find for testing and it's been rock solid for over 5 hours worth of recordings so far.

Fingers Crossed

[Xleon]

I DID speak too soon. After 5 hours of recordings, it went wrong for a minute again. I'm fast running out of ideas.

I'll try moving the cards around to see if putting them in a different order in the PCI slots makes a difference.

I might then have to resort to taking it all apart and trying another motherboard in case there is some strange problem with the PCI bus timing.

[newtbert]

I'm still trying to find it too, so resorted to complete system re-install! And the result is:

pretty much the same thing. DVD over 4 MB/S and an hour or so has noticable audio synch problems.

Well, guess I'll not upgrade the sblive software. With original versions of all drivers its mostly like before. So I backed-up and upgraded Hauppauge software (I have PVR-350). All test so far at 5 MB/S have FAILED! One had corrupted file, other stopped recording after about 18-minutes.

Oh well, can always restore backup that mostly works...

Highly reccomend re-installing windows if your changing parts. Since doing that I found out a couple things:

1. Old ATI Wonder drivers did not completely uninstall and were messing up the system. More works now than before. But the DVD stuff still has the same glitch.

2. There was much chaos from multiple decoder codec's installed, especially from demo software I tried.

3. System boot and shutdown much faster now.

And learned some potentially bad news:

1. May be a problem with VIA chipset, used on most AMD systems. Hauppauge has link to VIA synch problem patch, but the link is dead. They also link a VIA 4in1 driver thats newer than what my motherboard's manufacturer recommends.

2. Ulead's patch for dvd movie factory 2 is for Penium hyperthreading. Havent tried it on my AMD since re-install but kinda remember that it fixes some annoying buggs.

3. Videophile friend had no end of synch problems with his AMD so he dumped it for an intel board and has been good ever since.

4. But I HATE Intel and they have a whole new batch of proprietary crap to shove down our throats.

So, lets hope the new released version of Sage Recorder fixes everything!!!

Good Luck!

[Xleon]

My motherboard is an old Intel PIII Slot 1 so should be rock-solid. I've tried my old VIA/AMD combo and is does nothing but crash.

Swapping the positions of the cards has not helped one single bit.
Mine is very irratic. I could have an hour show which goes out of sync every 8 minutes, then other times, I can record a 4 hour block with no errors.

This leaves only a few things left. Either, trying a new motherboard or trying to re-route the input.

I'm beginning to wonder how stable the output from my satellite decoder is and whether that is causing the sync problems. The thing that is troubling me is that the VIDEO is completely unaffected, not a frame out of place. It's only the AUDIO which is the problem, which on mine, is encoded by the soundcard so how do the two time-stamps get separated?

[newtbert]

Ew thats pushing the slowness limit isn't it? What speed CPU (400 MHz?) drives and interface (ATA 66?) and memory (512 MB of PC 100?) does it have? I'de expect some kind of dropped frames, maybe audio? If so, the problem should be reduced when you record at a slower speed? You can get a much better box for $500 if you got it to invest... did you get new sound card?

I got the Hauppauge for its on-board audio in an attempt to avoid the problem, too bad that didint work out too well either. At least my problem doesent appear when playing through sagerecorder, it only happens when I try to edit and make a dvd.

[Xleon]

Currently it has:

Intel Slot 1 MB with ATA 33
256MB SDRAM
550Mhz PIII CPU (733Mhz downclocked as my MB maxed out!)
SB Live! Value (or another CMM Soundcard)
128G Maxtor HDD
DVD Drive
ASUS Geforce 2MX (the weak video link! - due for upgrade soon)
Provideo PV256T
Realmagic Xcard
RealTek Ethernet card

I'm trying to build it cheaply (I was given the PC), hence not using something faster. It also uses less electric than a 2Ghz and is quiter to cool.

The ProVideo docs say a 450Mhz is minimum as it's only encoding audio after all. When recording, Taskmanager says CPU usage is around 20 to 30%