video/audio sync problem

[loopyloops]

The last couple of mpeg2s made with Beyond TV have video/audio sync issues - the audio is is ahead of the video, and the problem seems to get worse as the show plays. Also, I use videoredo to take out commercials and the edited mpeg2 seems worse than the unedited one. Thoghts?

[loopyloops]

bump

[Krispy Kritter]

sounds like a problem with the recordings. I'm not familiar with that software. Computer possibly isn't fast enough to keep up with the quality settings you are using. Try some sample recordings at different resolutions/quality settings and see if the audio is still out of sync.

[firebirdude]

Just had a similar problem. Different software, but same problem.
https://www.videohelp.com/forum/viewtopic.php?t=251368
I found out it doesn't happen with ALL of my video files. And I stumbled onto something while loading a file into VirtualDub. It gave me an error stating that the audio was VBR and it would change it to CBR, but this may cause out of sync.......... or something like that. And that error only comes up on certain movies I have. So I think that may be the problem. CBR vs. VBR.....or VBR vs. CBR. Just a guess.

[loopyloops]

sounds like a problem with the recordings. I'm not familiar with that software. Computer possibly isn't fast enough to keep up with the quality settings you are using. Try some sample recordings at different resolutions/quality settings and see if the audio is still out of sync.

How fast does you comp. need to be to work with quality settings? And why was my comp. fast enough a few days ago? Look, my comp. has some legacy parts - xp3000+, 5950 ultra video card, audigy 2 - non zs, but it's also got 2 raptors in raid-o, a gb of xms memory...

[rkr1958]

The last couple of mpeg2s made with Beyond TV have video/audio sync issues - the audio is is ahead of the video, and the problem seems to get worse as the show plays. Also, I use videoredo to take out commercials and the edited mpeg2 seems worse than the unedited one. Thoghts?

Below is a link to a thread in which I discuss the method I use to re-sync audio and video. Good Luck.
https://www.videohelp.com/forum/viewtopic.php?t=251014&highlight=

[loopyloops]

The last couple of mpeg2s made with Beyond TV have video/audio sync issues - the audio is is ahead of the video, and the problem seems to get worse as the show plays. Also, I use videoredo to take out commercials and the edited mpeg2 seems worse than the unedited one. Thoghts?

Below is a link to a thread in which I discuss the method I use to re-sync audio and video. Good Luck.
https://www.videohelp.com/forum/viewtopic.php?t=251014&highlight=

Thanks - will check it out right away

[loopyloops]

The last couple of mpeg2s made with Beyond TV have video/audio sync issues - the audio is is ahead of the video, and the problem seems to get worse as the show plays. Also, I use videoredo to take out commercials and the edited mpeg2 seems worse than the unedited one. Thoghts?

Below is a link to a thread in which I discuss the method I use to re-sync audio and video. Good Luck.
https://www.videohelp.com/forum/viewtopic.php?t=251014&highlight=

I'd have to do what you suggest each time I want a usable mpeg2, no? I'd love to fix the problem - wonder how it got messed up?

[rkr1958]

Well ... sometimes the problem is with the audio capture rate. For example, I've set the audio capture rate to 48000 Hz in VirtualVCR. The actual rate turned out to be 47993 Hz due to some error I don't know. However, a player thinks that the rate is 48000 Hz and will play it at that rate. The result of this is that after an hour the audio will be ahead of the video by over 0.5-seconds.

To see it another way, at 48000 Hz and after an hour the audio will have played 48000 Hz * 3600-seconds = 172800000 samples. But since the actual capture rate was 47993 Hz, the audio should have only played 172774800 samples. Thus, the audio is 172800000-172774800 = 25200 samples, or 25200/47993 = 0.525-seconds, ahead of where it should be.

If you're having a similar problem ... there may be not easy fix to correcting this error at capture ... however, the timewrap function in Goldwave will correct the error after capture ... good luck.

[loopyloops]

Well ... sometimes the problem is with the audio capture rate. For example, I've set the audio capture rate to 48000 Hz in VirtualVCR. The actual rate turned out to be 47993 Hz due to some error I don't know. However, a player thinks that the rate is 48000 Hz and will play it at that rate. The result of this is that after an hour the audio will be ahead of the video by over 0.5-seconds.

To see it another way, at 48000 Hz and after an hour the audio will have played 48000 Hz * 3600-seconds = 172800000 samples. But since the actual capture rate was 47993 Hz, the audio should have only played 172774800 samples. Thus, the audio is 172800000-172774800 = 25200 samples, or 25200/47993 = 0.525-seconds, ahead of where it should be.

If you're having a similar problem ... there may be not easy fix to correcting this error at capture ... however, the timewrap function in Goldwave will correct the error after capture ... good luck.

Thanks! Does this tell us anything?:

[1/11/2005 21:50:07] Setting MPEG-2 constant video bitrate to: 4000000
[1/11/2005 21:50:07] Setting MPEG-2 audio sampling rate to: 48000 Hz
[1/11/2005 21:50:07] Setting MPEG-2 audio bitrate to: 224000
[1/11/2005 21:50:07] Setting MPEG-2 stream type to MPEG2 DVD Stream

[rkr1958]

Thanks! Does this tell us anything?:
[1/11/2005 21:50:07] Setting MPEG-2 constant video bitrate to: 4000000
[1/11/2005 21:50:07] Setting MPEG-2 audio sampling rate to: 48000 Hz
[1/11/2005 21:50:07] Setting MPEG-2 audio bitrate to: 224000
[1/11/2005 21:50:07] Setting MPEG-2 stream type to MPEG2 DVD Stream

Its not the setting values that you need but the actual audio sampling rate. For example, VirtualVCR produces a capture log that give the actual audio rate, which is slightly off fro the setting.

[loopyloops]

Ok, the mpegs I'm recording with BTV are pulsating, i.e. 3 secs or so fine then a very brief pause with total regularity - now using an aiw, btw. Thoughts?

Also, it's like this in any player or burned to DVD...This is especially niticable when zooming or panning is going on....

[funkguy4]

Ok, the mpegs I'm recording with BTV are pulsating, i.e. 3 secs or so fine then a very brief pause with total regularity - now using an aiw, btw. Thoughts?

Also, it's like this in any player or burned to DVD...This is especially niticable when zooming or panning is going on....

soudns like there's an I/O bottleneck somewhere or ther's not enough buffering to memory. try also capturing raw as encoding to MPEG2 while reeciving a stream is VERRRY I/O intensive.

[loopyloops]

Ok, the mpegs I'm recording with BTV are pulsating, i.e. 3 secs or so fine then a very brief pause with total regularity - now using an aiw, btw. Thoughts?

Also, it's like this in any player or burned to DVD...This is especially niticable when zooming or panning is going on....

soudns like there's an I/O bottleneck somewhere or ther's not enough buffering to memory. try also capturing raw as encoding to MPEG2 while reeciving a stream is VERRRY I/O intensive.

Thanks - I have no choice how I capture - only compression degrees of mpeg2. Just tested the ati pvr software and it doesn't do it with that - so it must be a btv problem - what, I wonder?

[loopyloops]

bump

You are in breach of the forum rules and are being issued with a formal warning. PLEASE wait a few days before you bump.
/ Moderator Baldrick

[loopyloops]

bump

Turns out it's the new BTV encoder and Athlon Procs.

[loopyloops]

bump

Turns out it's the new BTV encoder and Athlon Procs.

Sorry 'bout that!