AVI vs MPEG-2 Capture and Syncing

[DVD Maniac]

OK Folks I realise this is a much debated topic but I have lost my patience with trying to get video+audio to sync properly on my VHS captures so I am turning to this community to see if there are any definitive answers.

After playing around awhile with a cheapie capture card (with no end of sync problems) I have splashed out on an All In Wonder 9800 with all the promise of problem free capturing - yer right.

Reading all the various posts on this and other forums, the recommended process for "quality" VHS > DVD conversion is as follows.

1. Use a Good quality VHS player in conjunction with a Time Base Corrector to play the source. I am using a good quality Pamasonic VHS with a DataVideo TBC-1000.

2. Capture the source on a good quality card (All In Wonder cards get good reviews - hence my purchase).

3. Capture in AVI first if you are going to do some cleanup of the source. This is what I am doing

4. Use VirtualDub and a good VHS filter. I have managed one conversion with the Flaxen filter OK

5. Convert the cleaned up AVI > MPEG 2 using suitable encoder. I have CCE so no probs there.

With one execption, I am consistently getting Audio out of sync with my AVI captures. Usually it starts synced but drifts througout and eventually has the audio ahead of the video by some 500ms over a 90 minute capture. I have tried ALL the various capture programs (ie the ATI SW, VirtualDub, VirtualVCR etc) and the same problem every time. The ATI MMC capture reports zero dropped frames so that can't be the problem. This is gettting VERY tedious and annoying

Now, when I try and capture straight to MPEG-2 - all is well. But of course I can no longer use that funky Flaxen filter so my end result is a synced up but awful quality video.

Please can you experts out there help me in my VHS capture nightmare!

[Mac Sidewinder]

You said that you have tried vdub, but have you tried vdubsync? I use it all the time for caps from vhs and from tivo with no sync problems. Over a two hour movie I usually get 2 dropped frames (but that is vdubsync keeping the video and audio in sync).

Mac

[bb]

I assume you get the audio from a separate sound card. Because of the different clocks there can be synching issues, but e.g. VirtualDubSynch should solve this problem. Even plain VirtualDub should do the job, if you select the proper audio option (which should be set by default, if I remember correctly).

You can avoid the audio synch problem which is caused by different clocks, if you use a card having a tuner with audio output, e.g. my Philips 7134 card.

bb

[DVD Maniac]

Thanks for the pointers on this. Doom9 download section does not appear to have "VirtualDubSynch" or "vdubsync". Also tries Digital Digest site - no reference there. Where can I download this program from?

[iradic]

http://www-user.rhrk.uni-kl.de/~dittrich/sync/

[rfmmars]

I use a VDF to WDM wrapper with ALL of my ATI AIW cards. Am I to understand that you can't use VD to do filtering? Get Virtualdubmod ac-3 version 1.5.4 or 1.5.10 It takes mpeg2 files, and outputs mpeg2 with the YMPEG plugin.

If you can't find this wrapper, e-mail me at rfmmars@cox.net and I will attach.

richard
photorecall.net

[Karl Beem]

The audio synch of my avi captures were always iffy until I started using AVI_IO. Now they never get out of synch. Never.

[hartford]

This is what I do to get captures to sync:

I set my capture card to make the Audio the Master channel.

Then I run the video through AviSynth with these parameters (NTSC):

AVISource("d:\clip.avi").ConvertToYUY2(interlaced=true).AssumeFPS(29.970,True)

This makes the video timing exact and keeps the audio synced to the
video. Unfortunately, the audio is often resampled out of spec. So...

I load the AVI file into VirtualDub and save the WAV. The wave
is most likely not to spec (check VDub "file information").

I then run the WAV through BeSweet and select SSRC, set the sampling
rate, set 2-pass, set Normalize, then press "Convert WAV." Resulting
file is a "-New" with the same length as the video with the correct
sample rate.

I've done 2 hour movies with perfect sync with this method.

[DVD Maniac]

Thanks for these tips all of you. I have now tried vdunsync with much better results. Once I have done two or three captures like this I think I have this problem sorted.


@bb

I use a VDF to WDM wrapper with ALL of my ATI AIW cards. Am I to understand that you can't use VD to do filtering? Get Virtualdubmod ac-3 version 1.5.4 or 1.5.10 It takes mpeg2 files, and outputs mpeg2 with the YMPEG plugin.

I played around with the Mpeg version of VD but with my old capture process. Although my MPEG captures never suffered from sync problems, when I tried to use this version of VD with the YMPEG plug-in with the VHS filters it always crashed partway through the process.

Question - If you want to run your VHS captures through the these cool VHS filter programs what is the best process?

Options appear to be -

Approach 1
1. Capture to AVI
2. Fllter with standard VD + filter (eg Flaxen) to a new AVI
3. Encode your filtered AVI to MPEG

Approach 2
1. Capture to MPEG
2. Filter with the MPEG version of VD + YMPEG + Flaxen to new MPEG

Like I mentioned before, many posts seem to indicate that Approach 1 is best - but why? Is there a quality difference? When you consider that a 90 minute AVI compressed capture can be anything up to 45GB its a very expensive way of doing things in terms of disc space and AVI always seems to be more exposed to these annoying sync issues that MPEG does.

[bb]

You didn't quote me, did you?

Why you should capture to AVI formats like Huffyuv or MJPEG instead of MPEG:

- Noise is problematic for MPEG compression, thus you should get rid of it before encoding to MPEG formats, especially if you target low bitrates. Here Huffyuv performs better than MJPEG in terms of quality.

- Huffyuv / MJPEG allows for frame accurate cuts.

- You'll never get back what you lost during a direct MPEG-2 capture.

- Direct MPEG-2 captures typically use lower quality settings than what you would use in a secondary conversion. The reason is performance.

You are lucky if you don't have synch issues with MPEG captures by the way. You'll find many posts where users are in big trouble to keep their MPEG captures in synch.

bb

[rfmmars]

For me all I have done is MPEG2 captures, never a audio sync issue, never and no dropped frames. I start with 12,000 bps 29.97 fps 720x480 interlaced. I use only ATI WIW cards.

There are alot of junk capture cards out there which do not have hardware encoders. You can not use these as a comparasion for the Mpeg2 format. If you are going to do no additional editing requiring recompression, then the video is about the same as DV.avi.

For me HUFF is not an option because of the hugh file space. I operate a telecine service which means hundreds of files at one time. Even with 600 gig of HDs on each workstation, with huff I would be out of space, out of busniess in no time.

This new codec by LEADTOOLS looks like a solution. Super fast on the time line, many levels of quality versus file space. So if I need to process, I use it. For noisy low brightness clips, I captures with it.

This MJPEG has a softer look after recompression compared to MPEG2. The total cost is $9.95 US. Download a demo and try it out.

If you are a hobbiest doing video for yourself, then do HUFF all the way.

When time is inportant doing editing, Huff is not acceptable, nor is Xvid or Divx. I want to be able to move through a two hour timeline with my mouse with no delay of seeing the correct for that time point, and thats only possible with Mpeg2,DV.avi, and Mjpeg by Leadtools.

richard

[sh03z]

rfmmars, I think I'm going to go with you =D