Out of sync Audio; Video Compression?

[Thortok2000]

I am attempting to record directly from my Nintendo 64, and then e-mailing a video file to an online friend so she can watch it.

So, file size is a consideration. I'll be recording several hours of video (I'm going to play the entire game from start to finish), although I'm going to break it up into segments if I have to, no problem. But the image quality can't be so horrible that she can't see anything anymore.

I have a 7131 card from Kworld, that comes with a program PVR Plus. I've recorded the first few minutes of the game and noticed the audio is out of sync. The video is about 2-3 seconds before the audio, consistently throughout the entire file I think. I've been flying by the seat of my pants, just trying settings until something works, and this is the best I've come up with, but the out of sync audio has bested me, I don't know how to fix it.

This is my first time attempting to do anything like this. Right now I'm recording in mpeg2, at a 2000 bit rate, 30 fps, 640x480, and 'fastest' capture quality. So far this is the lowest filesize I can get, unless I set the bit rater lower, and if I do, image quality is too bad. I assume that since the N64 plays at 640x480 resolution, that's the resolution I should use, same with fps. Capture input is YUY2. Audio format is PCM, 44100 Hertz, 16 Bits, 2 Channels. Video system is set to NTSC-M, for both composite and S-Video. I only know what about half that stuff means.

I've tried to record in Mpeg4, but it won't let me. There's a second option for which mpeg4 codec to use. Options are Microsoft v1, v2, v3, and divx. Only the Divx one works.

I have no real idea what I'm doing. Is it possible to record in one format and then compress it using some external program?

Complete newbie here. Go easy. ^_^

[Thortok2000]

Okay, I just recorded another file, and the audio lag is not consistent throughout the entire file.

After about 5 minutes, it gets a .75 second lag. So after 10 minutes, that's 1.5 seconds, after 15 minutes, 2.25 seconds, etc. That's with the audio coming that amount of time after the video.

It might be more like .60 seconds per five minutes, I'm just guesstimating. Anyway, the audio lag gets worse as time goes on.

[redwudz]

This could be a little complicated. If your sync error stays the same throughout the video, then you just need to apply a offset to correct it. If it increases during the video, then it gets harder. Generally, when the offset increases, the video and audio are different lengths. In that case, you would need to adjust the running time of one or the other.

Try this: Drop your video file into VirtualDub Mod. Check the video and audio lengths.

If you must use MPEG, MPEG-1 is probably a better option. The bitrate can be lower, down to 1150KBps and still have reasonable quality. MPEG-2 won't work at those bitrates as it will look bad. Another similar option is 1/2 D1, basically one half the regular DVD format.

Or capture at D1 and re-encode to Xvid or a similar AVI type format. That may give you enough quality and still have a smaller filesize.That would be similar to what you are asking about re-encoding to a smaller format.

But this is a lot to absorb in one sitting. You might want to read a few of our guides and see what capabilities your hardware has.

And welcome to our forums.

[Thortok2000]

My recording format options (using PVR Plus) are:

MPEG 1
MPEG 2
MPEG 4
AVI
VCD (NTSC)
VCD (PAL)
DVD (NTSC)
DVD (PAL)
SVCD (NTSC)
SVCD (PAL)

I haven't tried MPEG1 as I assumed it would be 'lesser version' of mpeg... I'll give it a shot. I didn't use AVI because the filesize was enormous, and same with the only version of MPEG4 I could get working. For the others, I just assumed that it would be impossible for her to open on her end, since I figured those options for were later burning to a DVD or VCD that would be read by a DVD player, not a computer.

I realize I'm doing a lot of assuming. -.- But that's why I came here for help.

I'll check out that program and get back to ya. Thanks for the help and welcome!

[Thortok2000]

Okay, just browsing around trying to figure out how VDM works, I selected 'report' and was told this:

---== Video stream ==---
Source : [Input MPEG file]
Description : MPEG video stream
Length : 00:22:11.433

---== Other stream ==---
Source : [Input MPEG file]
Description : MPEG audio stream (MPEG)
Length : 00:22:10.991

Which I assume means that at the end of a 22 minute file, it's a little under than half a second off. Guess my estimates were wrong. =P

So....now what? Is it fixable, or do I have to re-record, or what?

Can I actually record using VDM instead of PVR Plus? Is there other recording software I could use? Totally new to this.

[Thortok2000]

Okay, I'm still having this problem. The audio/video sync gets worse and worse, especially as time goes on.

I'm recording the game in 20-30 minute long segments and at the end, it's off by a couple seconds, very noticeable.

A fix for this (and a way of compressing the file) is still desired...I still don't know how to fix it. Please help?

[neoplasticity]

Im having the EXACT same problem with an ATI AIW Radeon 7500. Im encoding using VDUB and Lagarith for video and MP3 32kbps for audio and the audio lags behind the video farther and farther as the movie goes on. At the end of the 90 minute movie, the audio lags by like 15 seconds. its ridiculous. I read on the vdub website that it has something to do with the timing of the system clock vs the timing of the sound card. and I tried every sync option in vdub and none of them fix it.

If anyone has a clue how to fix this, that would be awesome.

Thanks

[me-eyes]

From what I gather the issue of audio being out of sync with the video when captured via a USB or PCI device is quite common. Latencies within these two will cause the asynchrony.

You're best bet might be to either record in quite short segments (say a couple of minutes) so any asynchrony is not as noticeable - however it'll be a tortuously long process for you! Other option is to purchase something like a Canopus ADVC100 which 'time locks' the video and audio tracks - but you'll need a firewire connection to to get it on your PC.

I suppose you could try updating your drivers/software (assuming you haven't already) but bottom line is most of the cheaper capture devices are really only good for capturing a few minutes worth of clips at a time.

[Thortok2000]

My issue was resolved by using a soundcard instead of not using a soundcard. After updating drivers and rebooting a few times, the problem eventually repaired itself, I don't really know how. After I stopped trying to fix it, it started working. =P But it was most probably the new soundcard that did it.