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Thread: Virtual Dub Question

  1. #1
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    I'm trying to delay the audio of a movie, and can't seem to do it properly.
    First, it was coming out as 50 gigs.
    THen I went to compression and selected XVID, and it came out as 450megs instead of 600 megs.
    What am I doing wrong?

  2. Software & Hardware   -   #2
    Since your only trying to work with the audio don't do anything with the video, thats best anyway since it will not get reencoded and you will not loose any quality. To do that, always choose Direct Stream instead of Full processing and the video will just get copied not encoded. The reason you got a 50gig file was the default setting for Video Full Processing is avi no compression. Then when you selected xvid the default settings in there must have had half the bitrate of the original video so you got half the size (450mb).

    I like to use GSpot Codec Appliance to view the particulars of my avi's so I can see what the original bitrates are for the audio and video so I can match them later on to keep the file size similar. V Dub has a file info section under the FILE tab but I seldom remember to look there before I have already changed and loaded a new file.

    A word to the wise, V Dub does not like VBR audio and alot of times VBR audio will go out of sync during conversion. I like to change all my avi's as I get them to CBR audio for later compatibility reasons. To do so with the least amount of effort (as long as the vbr audio is in sync) I put the video in Direct Stream and audio in Full Processing (default is PCM no compression and thats what I want) and then save the file as a new name (usually I just add "pcm" before the .avi. Then I reload the larger PCM wav video and again with video in Direct Stream this time I set the audio to full process and select mp3 or ac3 with the same bitrate or close to the original file. Test it and if its good I delete the others. Ac3 has a tendency to be softer than wav or mp3 so if I use that (I normally do) I always set the volume (under the audio section) to 246% boost, then it will match the original file.

    If you google "Aud-x" go to their site, you will find on their download page their ac3 codec and a special Virtual Dub Mod Aud-x Enabled. Its a special version of V Dub that has ac3 support for the aud-x codec, built in. The mod version of V Dub is similar to the regular but its audio section is called Streams and can have multiple audio files in there. So to edit the audio in the mod version you have to right click the file to bring up its menu. The mod version will also load some obcure files like MKV and OGM files used mostly in the anime scene as well as VOB files right off a dvd disk.

    For audio syncing the interleaving section will operate with both the audio and video sections in Direct Stream mode so neither gets reencoded. in the delay audio by window you enter the amount of seconds you think the audio is off by where 1000 = 1 sec. 250 would be 1/4sec and using a -250 would be 1/4 sec the other way. So if you think its off by 2 1/2 sec enter 2500 and save the file, if its worse go back and add the - sign -2500 and zoom in on the proper timing. Its actually easier to extract the audio, save a copy of the video only by disabling the audio then open the video only file and import the audio you demuxed or saved wav. Now with separate audio and video in v dub you can set the interleaving and watch the video to see the results without having to save the file first. its alittle more work but much easier to zoom in on a difficult sync.
    Last edited by Appzalien; 04-13-2008 at 10:39 PM.

  3. Software & Hardware   -   #3
    KiNdZiUs's Avatar BT God BT Rep: +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100BT Rep +100
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    one more tip for the future: www.videohelp.com you will find tons of tutorials how to do this or that with video files. AWESOME site !

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