Quantcast Audio Sync Errors - in Trouble Again it Seems - digitalFAQ.com Forums [Archives]
  #1  
10-14-2003, 07:09 AM
Drisanna Drisanna is offline
Free Member
 
Join Date: Sep 2003
Location: Maryland
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Using Black Prince's wonderful guide, I attempted my first DivX to KVCD conversion today. Because the file is relatively short and I wasn't worried about file size, I used MPEG-2 so I could burn it as an SVCD. However, the audio is slightly out of synch. I went back and re-muxed it, with no difference.

Can somebody help me here? I used Virtual Dub to decompress the wav file and converted the WAV to MP2 using Headac3he, re-sampling the file to 44.1 kHz, TMPGEnc to encode the video, and bbMPEG to mux the two.

Thanks in advance for your help.
__________________
Dris
Reading comprehension > me
Reply With Quote
Someday, 12:01 PM
admin's Avatar
Site Staff / Ad Manager
 
Join Date: Dec 2002
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
  #2  
10-14-2003, 07:23 AM
Dialhot Dialhot is offline
Free Member
 
Join Date: May 2003
Posts: 10,463
Thanks: 0
Thanked 0 Times in 0 Posts
You're avi is probably not in a regular framerate (23.97, 25 or 29.97 fps) so the sound goes out of synch.

Encode directly video and audio with tmpgenc, it will give you a perfect mpeg.
Reply With Quote
  #3  
10-14-2003, 07:55 AM
Drisanna Drisanna is offline
Free Member
 
Join Date: Sep 2003
Location: Maryland
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Okay hon, thanks so much for the help. I'll give that a shot.

Hugs,
__________________
Dris
Reading comprehension > me
Reply With Quote
  #4  
10-14-2003, 01:13 PM
Drisanna Drisanna is offline
Free Member
 
Join Date: Sep 2003
Location: Maryland
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Okay, .avi was at 23.97 but decided to try it anyway. Unfortunately, it didn't work. Other suggestions?
__________________
Dris
Reading comprehension > me
Reply With Quote
  #5  
10-14-2003, 01:30 PM
Dialhot Dialhot is offline
Free Member
 
Join Date: May 2003
Posts: 10,463
Thanks: 0
Thanked 0 Times in 0 Posts
What kind of synch problem it is : a constant one, all along the movie or a sliding one ?

Are you sure the source isn't unsynch itself ?
Reply With Quote
  #6  
10-14-2003, 04:27 PM
Drisanna Drisanna is offline
Free Member
 
Join Date: Sep 2003
Location: Maryland
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Okay, I checked the original .avi, and it is in synch. The out-of-synch problem is constant, all along the movie. What I've done to correct it is to add a delay into HeadAC3che when encoding the audio. This has been rather a hit and miss thing, however. I finally, after several attempts, settled on a delay of +200 ms.

However, I'd like to know if I can tell when this extra step is going to be necessary from any of the information given by VirtualDub, and if so, how much of delay will be necessary. Hit and miss for synching the audio doesn't tickle my fancy particularly.
__________________
Dris
Reading comprehension > me
Reply With Quote
  #7  
10-14-2003, 04:41 PM
Edlund Edlund is offline
Free Member
 
Join Date: Jul 2003
Location: Pazardjik, Bulgaria
Posts: 147
Thanks: 0
Thanked 0 Times in 0 Posts
The program avi2wav claims to separate the audio exactly as it is in the source, I have never had any problems with it (with VDub neither You could try avi2wav or you could try a newer version of VirtualDub.
Reply With Quote
  #8  
10-14-2003, 04:54 PM
Drisanna Drisanna is offline
Free Member
 
Join Date: Sep 2003
Location: Maryland
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
I'll try it if the problem persists. I've never had a problem with VirtualDub either (until now).
__________________
Dris
Reading comprehension > me
Reply With Quote
  #9  
10-21-2003, 02:15 AM
Markymoo Markymoo is offline
Free Member
 
Join Date: Aug 2003
Posts: 43
Thanks: 0
Thanked 0 Times in 0 Posts
To fix constant audio sync problem do this : download http://www.goldwave.com/release.html

Load Goldwave then Select File->Open to open your video source (Goldwave will ONLY open the audio)

Select Effects->Time Warp

Change %

If NTSC(23,976fps) to PAL(25fps) select 104.27%
If PAL(25fps) to NTSC(23,976) select 95.9%

you can use these % will all film conversions.

Hit OK, your audio should now be either a bit shorter or longer depending what conversion you made.

Select File->Save as

Select File Type, WAV

Select PCM 16 bit stereo

Load this new wav into headache3 and convert as normal.

Remux again.

This will solve constant sync problems throughout the film.
Reply With Quote
  #10  
10-21-2003, 02:36 AM
Markymoo Markymoo is offline
Free Member
 
Join Date: Aug 2003
Posts: 43
Thanks: 0
Thanked 0 Times in 0 Posts
You can use this alternative method:-

Download Beseet and BeSweetGui http://dspguru.notrace.dk/

Load your extracted sound wave from VirtualDub into BeseetGui and then check FRC Presets (on the left) and select the NTSC2PAL (23.976 to 25.000) from the list and covert to mp2.
Reply With Quote
  #11  
10-21-2003, 03:17 AM
Dialhot Dialhot is offline
Free Member
 
Join Date: May 2003
Posts: 10,463
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Markymoo
You can use this alternative method
That is a way far better method than the other one.

My 2 cents.
Reply With Quote
  #12  
11-06-2003, 06:23 AM
Paulus Paulus is offline
Free Member
 
Join Date: Jun 2003
Location: Ottersum, The Netherlands
Posts: 199
Thanks: 0
Thanked 0 Times in 0 Posts
I think this can also help me with my problem......

I have an .avi with a non standard frame rate (23.979 I believe).

As I use DVD2SVCD this framerate is not supported and is automatically adjusted by DVD2SVCD (adjusted to 23.976 I think).

The problem is that the framerate of the audio is not adjusted because the audio graduately gets out of synch in the resulting KVCD. So I need to adjust the audio of the 23.979 avi to 23.976 manually.

Maybe I can use the "GoldWave" method for this (or better: SoundForge or CoolEdit which I used for my Audio Vinyl conversion projects in the past ).

Any additional info is welcome however...........
Reply With Quote
  #13  
11-07-2003, 06:52 AM
incredible incredible is offline
Free Member
 
Join Date: May 2003
Location: Germany
Posts: 3,189
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to incredible
Im not that in DVD2SVCD but generally you can fix your nonstandard FPS(23.979) including synced audio by the following:
(As I know its possible to modify the AVS commands within DVD2SVCD so Dialhot maybe can explain you how to integrate it correctly)

Method 1:
Totally in Avisynth.

AssumeFPS(23.976, true)
ResampleAudio(44100)

Method 2:
I did several tests with AVS's Resampling engine and it was ok but not HQ!.
So in case of a wanted high quality I would recommend to use only:

AssumeFPS(23.976, true)

After encoding you open the AVS with the "AssumeFPS(23.976, true)" line in Vdub (watch out for the audio codec of your source !!) and "safe as WAV". Open the Wav in HeadAC3he and use "Convert Samplerate to 44.100!! And encode as mp2.
This will give you a higher quality.

Explanation:
What does "AssumeFPS(23.976, true)"???
The AssumeFPS() Command adjusts the playback speed of your video stream WITHOUT adding or removing frames. And to keep the audio still in sync we use the value "true" within the command which pitches also the "speed" of the audio by modifying the Samplerate of the Audio-component of your AVI. That means therefore the Sampligrate is no longer standard 44.1 khz!!! Maybe 44.098 or 44.105. So the Samplingrate of your audio has to be re-sampled to 44.1khz and there do exist several ways:

1. Doing it in Avisynth by adding "ResampleAudio(44100)" which is ok, but as I said not in HQ!
2. Or without adding "ResampleAudio(44100)" and using HeadAC3he's or Besweet's resampling Engine which got IMHO a better quality. And this will be done by extracting the Audio as WAV before using Vdub, as explained above. This is in my opinion is the right way cause anyway you have to encode your audio in mp2 using for example the Audio converting Apps. as mentioned above.
Reply With Quote
  #14  
11-09-2003, 05:22 AM
Paulus Paulus is offline
Free Member
 
Join Date: Jun 2003
Location: Ottersum, The Netherlands
Posts: 199
Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for the extensive repy incredible....

I think I'm going for the HeadAC3he option.

Were should I place the "Assume FPS" line in my script ? Just after the source line ?.
Reply With Quote
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Recording Video: Dropped Frames and Audio sync errors! the viking Video Capturing / Recording 19 01-06-2005 10:42 AM
BBMpeg: errors muxing mp2 audio with m1v movie Clessy Video Encoding and Conversion 0 01-20-2004 10:33 PM
TMPGenc errors and Avisynth plugin errors? mbbrinker Video Encoding and Conversion 13 12-10-2003 05:03 AM
KVCD: converting 23fps to 29.976fps causes audio sync errors? pixeldotz Video Encoding and Conversion 2 05-18-2003 09:54 AM
TMPGEnc produces errors on Audio VBR Conversion? Jellygoose Video Encoding and Conversion 29 02-11-2003 03:48 AM

Thread Tools



 
All times are GMT -5. The time now is 08:22 AM  —  vBulletin © Jelsoft Enterprises Ltd