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| Abrazo |
| Posted: Jun 14 2013, 06:14 AM |
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When converting DVD VOB-video (recorded from TV) to AVI on the hand of VirtualDub in combination with fccHandlers MPEG-2 (v4.5) and AC-3 (v1.9) vdplugins, I sometimes have to use the Audio > Interleaving > Audio skew correction > Delay audio track by x number of milliseconds.
When cutting/deleting some parts of the imported VOB-video, it seems that the audio skew correction is only applied to the first part of the video that has been retained and not to the following parts. Actually I do resolve the problem by saving the several parts each to a separate AVI, and after that, I join the different AVI's to one AVI. This works, but it is time consuming...
I do not know if this problem can be resolved, and wether it should be done via VirtualDub or via the MPEG-2 and/or AC-3 inputdriver plugin ?
N.B.: The problem is already there in VirtualDub v1.9.11 and still there in v1.10.4-test10.
It is not reproducable with AVI files, only (at my knowledge) with VOB/MPEG-2 files. |
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| Jam One |
| Posted: Jun 16 2013, 04:25 PM |
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Please check your MPEG2 and your AC3 decoders.
Since input drivers do not decode video, they "unpack the box" (container), some decoder is to be used. The latter can be ffdshow, MainConcept, ffMPEG, InterVideo, Matrox, Ulead/Corel, Pinnacle/Avid, Solveig/Elecard, Morgan, LEAD Multimedia... and what not.
I would suggest you checking the option that the current default decoders for MPEG2 video and AC3 audio in your system are "guilty" of ignoring the skew. |
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| Abrazo |
| Posted: Jun 16 2013, 06:56 PM |
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Jam One, thanks for your answer.
I do not know immediatly how to verify, but I was almost convinced that these two particular plugins do not use external decoders for reading/opening VOB/MPEG-2 files.
Concerning audio: When removing fcchandler's AC3ACM.acm (v2.2) audio-codec, I get indeed an error "No audio decompressor could be found".
Concerning video: I do not know where the MPEG-2 decoder should come from. Disabling it in ffdshow does not make a difference.
When further testing I must admit that the problem is not always there, but sometimes it is, and most remarkable when playing the resulting AVI. It also looks that when trying to open a particular VOB-file (that makes a problem) with the FFMpeg inputdriver in VirtualDub, I am not able to navigate through the whole file, it stops at a certain point. Other files have no problem from the start untill the end. It makes me think of an error somewhere in the stream of the VOB-file.
So, I guess, I was wrong in making my conclusions.
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| DarrellS |
| Posted: Jun 20 2013, 03:39 AM |
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The problem with copying DVDs as separate VOBs is that the audio and video rarely line up but depend on parts of the DVD structure to tell the audio and video when to start. DVDs that my friend used to copy TV recordings with his DVD recorder seemed to all be terribly out of sync and would take me all day to fix. I had to do like you said, fix the first part and save as AVI. Delete that section and fix the next section and save as AVI and delete that section until I had the DVD finished and then join the AVIs. If I tried to save too big of a section it would go out of sync. I don't know if this was a fault of the DVD recorder or the broadcaster (or both) to make it discouraging for most people to try and copy satellite or cable broadcasts. After doing this for about a year, he finally broke down and bought Videoredo which not only fixed the sync issues but allowed him to cut out all the commercials and save to MPEG2 without having to re-encode.
The Best option when copying a commercial DVD is to save as one complete VOB or with DVDFAB, MPEG2 passthrough with no splitting.
Using DGIndex to create an AVS file to load in Virtualdub to minimize out of sync files or using the payware VideoRedo in Quicksync mode to guarantee MPEG files that are in sync. Most editors don't seem to have a function to automatically fix audio sync.
The exception is music DVDs or episode DVDs where each song or episode should be ripped in it's own VOB where the audio and video should match up. |
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| Abrazo |
| Posted: Jun 20 2013, 06:31 PM |
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DarrellS, thanks for the extra information and confirming the audio synchronization problems with recorded DVD-VOB files.
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