Audio Sync problem in Virtualdub, not audio correction

[JR@ASU]

First off i have been looking through the forum of days but have not found the exact thing i am looking for.

I record 1 hour long TV shows using my WinFAST VPR . Then i encode and try to cut out the commercials using Virtualdub-MPEG2. I usually encode to DIVX and the AVI shrinks to about 400Mb which is good. The problem is when I cut out video (i got the method from another post on this forum) using the slide rulers , then delete, the audio for the video stays the same. So when i replay back the video it will be cut but the audio still remains with the commercials. I dont need audio correction ( i saw that on another post) i need to cut out parts of the audio completely. I dont want to download another program because It would make my life easier to just use one program, Virtualdub-MPEG2 which seems pretty good to me. So any suggestions would be helpful.

Also, do you know of another FREE PVR that can record scheduled stuff and will save it automatically in whatever format you want and also cut out commercials???? Does such a miracle product exist?

[FulciLives]

It is unclear from your post what video and audio format you are doing your capture in.

- John "FulciLives" Coleman

[teegee420]

I dont want to download another program because It would make my life easier to just use one program, Virtualdub-MPEG2 which seems pretty good to me.

I convert tv shows that I captured as mpeg-2 to Divx all the time and I experienced the same audio sync problems at first. Unfortunately the only solution I found was to use another program to edit out the commercials and create a new mpeg. The program is Womble MPEG2 VCR and the good thing is that it won't re-encode when creating the finished mpeg. This program can cut mpeg-2 better than Virtualdub MPEG2 ever could and without sync problems.

Also, do you know of another FREE PVR that can record scheduled stuff and will save it automatically in whatever format you want and also cut out commercials???? Does such a miracle product exist?

As much as I wish it did, such a program does not exist.

[Firk99]

I alse record TV in MPEG2 (the audio is MP3) and use VDUBMPEG2 to cut out commercials. I never had the problems you describe. Can you post the details how you work ?

[JR@ASU]

Sorry if i was not that clear. I was capturing from the TV in MPEG2 format and the audio codec was MPEG 1 Audio Layer-II . This was the default that came with my capture card, WinFast 2000 PVR. It has options to record using different codecs but for some reason when i change the video codec to XVid or DivX and use MP3 at 128kbps ,44KHz , stereo it wont work. So i have to capture using the default settings it came with.

What i do using Virtualdub to cut out pieces of avi is first load, the i use the slide ruler at the bottom and use the start frame tool and then go to the end frame tool and put it where i want to cut it. So the two rulers will black out a little portion. Then i press delete and that portion of the avi (or frames) is cut out. I saw it posted on another post hear on the forum. But again, the sound does not get cut out, only the video.

So Firk99 can you please explain to me how you do it?

[FulciLives]

Sorry if i was not that clear. I was capturing from the TV in MPEG2 format and the audio codec was MPEG 1 Audio Layer-II . This was the default that came with my capture card, WinFast 2000 PVR. It has options to record using different codecs but for some reason when i change the video codec to XVid or DivX and use MP3 at 128kbps ,44KHz , stereo it wont work. So i have to capture using the default settings it came with.

What i do using Virtualdub to cut out pieces of avi is first load, the i use the slide ruler at the bottom and use the start frame tool and then go to the end frame tool and put it where i want to cut it. So the two rulers will black out a little portion. Then i press delete and that portion of the avi (or frames) is cut out. I saw it posted on another post hear on the forum. But again, the sound does not get cut out, only the video.

So Firk99 can you please explain to me how you do it?

Well for MPEG-2 cutting you can use Womble MPEG2-VCR but another solution which is actually a bit cheaper is TMPGEnc DVD Author ... not only is it a DVD authoring program but it will allow you to cut MPEG-2 including the audio be it MP2, WAV or AC-3

You can use TMPGEnc DVD Author for something like 30 days before it will lock up on you and require you to register (aka buy) it.

However I did notice that you said you like to convert your captures to DivX format. For this I suggest VirtualDubMod and AviSynth scripting. You load the captured MPEG file into VirtualDubMod ... do your editing ... then to go the built-in script editor ... do a IMPORT TRIMS AS FRAMESET ... this gives you your trims in AviSynth form. Plug them in a script and load your file that way.

- John "FulciLives" Coleman


- John "FulciLives" Coleman

[JR@ASU]

FulciLives,
Thanks for the help. I'm gonna try your suggestion. Know i know that VirtualDubMod is a combination of the other VDub stuff so I should be ok with that but your last bit of instructions could you please elaborate?
1) Load the file into VirtualDubMoc
2)Do my editing (cutting out commericals?) By the method I described
earlier will that work correctly now?
3)Do a Import Trims as Frameset? This is where i get lost ...exactly where is it and what is it doing?

Also, do you know of any capturing software that will automatically cut out commercials for you or am i just dreaming?

[FulciLives]

FulciLives,
Thanks for the help. I'm gonna try your suggestion. Know i know that VirtualDubMod is a combination of the other VDub stuff so I should be ok with that but your last bit of instructions could you please elaborate?
1) Load the file into VirtualDubMoc
2)Do my editing (cutting out commericals?) By the method I described
earlier will that work correctly now?
3)Do a Import Trims as Frameset? This is where i get lost ...exactly where is it and what is it doing?

Also, do you know of any capturing software that will automatically cut out commercials for you or am i just dreaming?

The more I think about your problem the more I don't understand why you are having that problem.

So maybe we need to take a closer look at this.

So you capture in MPEG-2 with your capture card using MP2 audio and I assume you get a single MPEG file in the end.

You load that MPEG file into VirtualDub (any version that supports MPEG-2 should be fine here) and edit it.

Now this is MPEG-2 so you do realize that you can only edit on KEYFRAMES or in the case of MPEG-2 "I" frames (at least I think "I" frames are the KEYFRAMES with MPEG-2).

So one make sure you only edit on keyframes ... not just "any" frame.

That could be the problem there.

Secondly when you are done editing what do you do at that point? Do you try to save the file to a new format (aka DivX) right away or do you try and do something/anything else?

I'm sure if you give more info on the exact steps you are doing that we can figure out what the problem is.

In the meantime try upgrading to the newest version of VirtualDubMod

- John "FulciLives" Coleman

[JR@ASU]

Ok I think that is maybe where my problem is. I am a newb to all of this so i dont understand the difference between key frames and I frames. I attached a picture to show exactly what i do to cut out the commericals.

After i am done editing all i do is go to SAVE AS AVI. Since i already put my compression for DivX and MP3 for my audio, it saves it in that format. So i dont do anything at all to the audio, mainly because i dont know how.

I also just downloaded the newest version of VirtualDubMod too- thanks, JR

[FulciLives]

OK here is a picture from VirtualDubMod with a MPEG-2 file loaded:



Notice the box I put around the two buttons that look like KEYS

If you use these you will go from I FRAME to I FRAME since I FRAMES are the KEYFRAMES in MPEG-2 files.

Not every frame is an I FRAME or KEYFRAME. There are only so many out of "X" number of frames. I looked at the very start of my SIMPSONS MPEG-2 file and found that FRAME 0 was a KEYFRAME with the next KEYFRAMES being frames 15, 25, 33, 48, 63, 78, etc.

So again you can ONLY place a CUT on a KEYFRAME and with MPEG-2 files the KEYFRAME is the I FRAME

Also notice the BIG RED ARROW points to where VirtualDubMod tells you what kind of frame you are on. I know it is hard to see (I had to reduce my original image down to 75% original size and use heavy JPG compression to make it fit within the file limit of our beloved forum here) but if you look you can see this ---> The letter "I" in parenthasis

Now ...

In MPEG-2 you also have B and P frames.

So as long as you make your edit points on KEYFRAME aka I FRAMES you should be A-OK

Also when you load the file ... make sure you do your edits FIRST then go ahead and set your compression for the VIDEO and AUDIO ... not sure if this really makes a difference but that is how I've always done it.

So give this a try and let us know how it works for you

- John "FulciLives" Coleman

[JR@ASU]

Cool, i did what u said with the I frames, and i editted. Now usually what i do for the compression is

-Video-
Video --> Fast Recompress
Video --> Compression --> DivX

-Audio-
Audio --> Full Processing
Audio --> Compression --> MP3

Then File --> Save AVI

But in VirtualDubMod there is no menu for Audio So what do i do, there is a menu for Audio in VirtualDub-MPEG2 so what do you do at this point Thanks, JR

[FulciLives]

Sorry I forgot that the new VirtualDubMod has a different interface ... it is even new to me as I was using an older version up to just a few days ago.

Anyways here is how you get to the audio.

At the top click on STREAMS and under that click on STREAM LIST

The following dialog window pops up:



If you double click on the grey area it is the same as clicking NO AUDIO in the old version. It will put a checkermark type pattern all over the grey area. So we don't want that.

Instead RIGHT CLICK on the grey area and a menu comes up as in this next picture:



This menu look familiar?

Once you are done setting your compression etc. simply click on OK which is at the rop right.

Then you are done with the audio part. The video part has the same interface. When you are ready to save it is under FILE as SAVE AS (F7)

I tested it ... it worked for me. The converted AVI (I used Xvid and MP3 audio) was in good shape

Hope this helps ... again let us know how it works for you

- John "FulciLives" Coleman

[JR@ASU]

ok i did exactly as we said, and everything worked fine up to a point. I used an hour long show i captured w/ my card. First I edited out the commercials using only the I frames that we discussed.

Then i used the settings:
Video-
Video --> Fast Recompress
Video --> Compression --> DivX
-Audio-
Audio --> Full Processing
Audio --> Compression --> MP3
Then File --> Save As

The lenght of the show was now only 41 min long. It worked up until around the 33rd min. Then the audio lags behind by around .5 second.

Does this happen when you do more than an hour long editing ? Is the editing only good for up to 30 min?

I am going to try to do it again, in case i messed something up. I will post back what happenend on my second try.

But for at least 32 min. it worked great

[FulciLives]

ok i did exactly as we said, and everything worked fine up to a point. I used an hour long show i captured w/ my card. First I edited out the commercials using only the I frames that we discussed.

Then i used the settings:
Video-
Video --> Fast Recompress
Video --> Compression --> DivX
-Audio-
Audio --> Full Processing
Audio --> Compression --> MP3
Then File --> Save As

The lenght of the show was now only 41 min long. It worked up until around the 33rd min. Then the audio lags behind by around .5 second.

Does this happen when you do more than an hour long editing ? Is the editing only good for up to 30 min?

I am going to try to do it again, in case i messed something up. I will post back what happenend on my second try.

But for at least 32 min. it worked great

Sorry to hear you are having so many issues ...

The only other thing I can think of is to try this ... do the audio seperately. Do your editing then go to the audio menu thing (under streams) then try full processing but instead go to a 48k 16-bit stereo PCM WAV file.

Now double click on the audio stream so it get's that cross hatched look which means NO AUDIO then click OK and do your video compression set up and do FILE ... SAVE AS

Now you have a video only (with no audio) DivX AVI file along with a seperate 48k 16-bit stereo PCM WAV file.

Now hopefully your audio file matches the video file.

At this point convert the seperate PCM WAV to MP3 using another tool such as BeSweet.

You can now MUX the two together ... I usually use AVI-Mux (or maybe it is called AVIMux I'm not sure) for this step.

If the audio is still off then me thinks there is a problem with the MPEG-2 files that your capture card and software are making.

I can't think of any other reason why you might be having trouble.

If anyone else has any thoughts now would be the time to express them because I'm at my wits end here sorry!

- John "FulciLives" Coleman

[JR@ASU]

Ok, i did like u suggested and maybe it was the original source (even though it seems fine when i run it) and i tried a different MPG2 file and it worked fine.

So maybe it was just that one that was not working correctly i guess.

But now i have to mess around with it because i'm wondering if i run a bunch of them in batch mode is it ok that i edit them first then save them to the batch mode or will batch mode just simply do the conversions of MPG2 to DivX and the same for audio?

I would like to edit out all the commercials for a whole bunch i have then run them on batch mode when i go to sleep because they take around 80 min. each to compress and edit.

BTW, do you do anything else before you do SAVE AS ? Just wondering if you can sharpen the image or something because it just seems a little grainy at times. Thanks for all your help Fulci

[FulciLives]

Ok, i did like u suggested and maybe it was the original source (even though it seems fine when i run it) and i tried a different MPG2 file and it worked fine.

So maybe it was just that one that was not working correctly i guess.

But now i have to mess around with it because i'm wondering if i run a bunch of them in batch mode is it ok that i edit them first then save them to the batch mode or will batch mode just simply do the conversions of MPG2 to DivX and the same for audio?

I would like to edit out all the commercials for a whole bunch i have then run them on batch mode when i go to sleep because they take around 80 min. each to compress and edit.

BTW, do you do anything else before you do SAVE AS ? Just wondering if you can sharpen the image or something because it just seems a little grainy at times. Thanks for all your help Fulci

Can't say I've ever used batch mode other than to do 2-pass DivX/Xvid on a single file.

As for filters yes you can do that. There are all kinds of filters for VirtualDub. You can use those. But note the filters will not work unless you have VIDEO set to FULL PROCESSING and doing that will increase encoding time.

- John "FulciLives" Coleman