A/V Sync Problem With MainConcept Plug-In

mdailor wrote on 1/18/2002, 8:25 PM
I am using VF 2.0 with the MainConcept plug-in to produce a VCD. I captured to a 400x240 29.97fps AVI file, which plays fine in both Windows Media Player and VideoFactory. However, when I render to a VCD-compliant file (MPEG-1, 352x240 @ 29.97fps), the audio and video in the resulting file are out of sync by .25 seconds or so. This is definitely a result of the encoding process, since the AVI file plays fine in VideoFactory. Any ideas, anyone? Thanks in advance.

Mike

Comments

MCTech wrote on 1/18/2002, 11:31 PM
That's not typical. We'll do some testing with our own source material at the settings you indicated to see if it's a general situation.

Can you tell me how you captured the material?

MainConcept Tech Support
mdailor wrote on 1/19/2002, 1:43 PM
Hi, thanks for the reply. The AVI file was captured from an ATI TV Wonder card via the ATI Multimedia Center "TV" application with most recent drivers and application installed. The capture and encoding are both being done on a Compaq Presario 7470 with an AMD K6 550Mhz processor and 184 MB RAM.

After some further tinkering, I have found that if I render to an AVI file instead of an MPEG, the audio is *still* slightly out of sync with the video, so it appears that this is a problem with VideoFactory rather than with the MainConcept plug-in. Although if you could solve it for me anyway that would be bitchin'. :^)

Mike
pelvis wrote on 1/20/2002, 9:30 PM
Please confirm how you have determined this is a VF problem (as opposed to a capture card problem or a playback problem, or other). Can you play the files back in sync anywhere? If you can help narrow down the variables we can likely get you straightened out...
mdailor wrote on 1/21/2002, 10:08 AM
The short answer is: after capturing the video, I can play it back in Windows Media Player and VideoFactory (both 1.0 and 2.0) and it plays just fine. After rendering the video, it plays out of sync in all three applications. The long answer is: I am taking the following steps:

1. Capture a 30-second AVI file, 400x240 @ 29.97fps, using ATI TV Wonder TV application. The resulting file is 192,000KB in size.

2. Play the file back in Windows Media Player 7.01; plays in sync.

3. Start VideoFactory 2.0.

4. Add the AVI file to the media pool, then drag it to the Video and Audio timelines.

5. Press "Play", video and audio play in sync.

6. Select "Project Properties..." menu item.

7. In the "Project Properties" dialog, select "NTSC Video CD (352x240, 29.970 fps)" from the "Template" pulldown menu.

8. Click "OK".

9. Select "Make Movie..." menu item.

10. in the "Select Destination" dialog, select "Write your movie to file on your disk".

11. Click "Next >".

12. In the "Render Settings" dialog, select "Video for Windows(*.avi)" from the "Format" pulldown menu, select "Default template (uncompressed)" from the "Template" pulldown. "Description" now reads "Render 352x240x32, 29.97 fps video with 44,100 Hz, 16-bit, Stereo audio". The "Render loop region only" checkbox is disabled, the "Stretch video to fill output frame" checkbox is cleared, the "Fast video resizing" checkbox is checked.

13. Click "Next >".

14. 1 minute, 28 seconds later, the resulting AVI file has been rendered and the "Completed" dialog appears. The output file is 334,000KB in size, almost twice the size of the input file even though it's been rendered at a smaller frame size.

15. In the "Completed" dialog, click "Play File".

16. The rendered AVI file plays back in Windows Media Player 7.01, audio and video out of sync.

17. Load the rendered AVI file into VideoFactory and press "Play", file plays with audio and video out of sync.

Since the file plays in sync before being rendered, and plays out of sync after being rendered, with no editing of any kind in between, I conclude that it is VideoFactory that is causing the problem. What's your take?

Mike



Former user wrote on 1/21/2002, 10:27 AM
I don't know if this makes a difference but, the PROJECT PROPERTIES should match the footage. In this case you captured analog at 400 x 240, but you have set the PROJECT PROPERTIES to DV at 352 x 240. DV audio is either 32 or 48k, so it might be trying to conver to the audio to 44.1k for output, even though the audio is not DV standard. Then you are telling it to convert to DV 352 x 240. This could be causing some confusion. Just a guess.

Dave T2
mdailor wrote on 1/21/2002, 6:01 PM
Tried that, still no go. Thanks for the advice, though.
SonyEPM wrote on 1/22/2002, 8:42 AM
Your captured clips were compressed by the capture card, but your rendered clips are not compressed.

Try this- toss a captured clip on the timeline, right click on the event> media properties> ...and here you will see a listing for the "Format". This is the compression option you should use when rendering.

If all the render settings, including compression, match the captured clip's properties exactly, you should have the same performance with the rendered clips as you do with the freshly captured clips.