Frameserving

Acknowledgements

Many thanks goes to the members of the Magix User Forums, in particular, Richard, alias "rfmmars" on the MEP forum, who first published the Virtual Dub Frameserving solution here. All I have really done is collated the procedure into a couple of pages.

What's the problem?

First up, with recent versions of MEP ie MEP 14 and later, there is no problem!

Movie Edit Pro, up to and including version 2004, will not keep audio in sync on import of MEPGs/VOBs that are larger than about 2gb. The error is non-linear and cannot be fixed on the timeline. Additionally, MEP cannot import MPEG/VOB or AVI files (DV-AVI files are OK!) larger than about 4gb: the file breaks apart and only small pieces end up on the timeline.

Quoted from Magix: "Both versions have problems importing large avi files. Let me explain.... Usually we use the "Video for Windows" device for importing AVI files. But this device has a limitation of 2/4 GB. Therefore it's better to deactivate the VfW AVI import and use the Direct Show device. In MEP2004 you can press the "y" button, click to "Import-Format" and then deactivate the "Internal AVI Import". Generally it's a good idea to deactivate the "Internal AVI Import" and the "Internal DV AVI Import" if you have problems with this kind of file.

Example
rfmmars sent me a large avi file encoded with the Huff codec. This file will load into MEP 2004 with all audio 6 minutes of video followed by 3 minutes of black frames. If I close the program and open it again and use the above process the file will import fully."

This problem is evidenced by out-of-sync audio and files which don't load completely.

MEP 2005 has a correctly-functioning MPEG import module which has overcome the MPEG import problem, but apparently still cannot import large AVIs without some user intervention.

Options

If you want to import large AVI files (not MPEG) into MEP2004 and 2005 successfully, you have some options.

If you want to import large MPEGs or VOBs into MEP 2004, you have some options:

Import of Multiple VOBs

It has been found that MEP 10 has trouble with the standard naming convention used by DVD images ie VTS_01_1.VOB, VTS_01_2.VOB on so on. To get around this, rename the files to remove the "_01_1, 2, 3". For example, rename to VTS1.VOB, VTS2.VOB and so on. Then they should import properly.

Import of AC 3-based VOBs

How do I know whether I have an AC-3 based VOB? Use GSpot to analyse your VOB. The audio section will tell you.

To successfully import VOBs (I'm now not so sure about this: May05) with AC-3 audio into MEP 10 (I can't verify this with MEP 2005 or 4), you'll have to have an AC-3 decoder on your machine. Try this one by FCC Handler.

When you drag one of these VOBs onto the timeline, the import takes many minutes (about 20), with no apparent activity by MEP. But the drive which holds the VOBs will be working flat-out. Eventually, the progress bar at the top of the MEP window will spring in to life and display the time remaining. Be patient!

On second thoughts, It's just as easy to frameserve them in, regardless of your version of MEP.

What is Frameserving?

Frameserving means "serving" the original video (MPEG files and other .AVI formats) frame by frame to MEP without converting it into a format that MEP understands first. This technique "tricks" the receiving program (in this case MEP) into thinking that it has imported a 10gb file that it knows, but in fact the frames it is calling on are still in the original format (quite possibly a format that MEP refuses to import). Using this process, MEP (or you) doesn't have to convert the video file into it's own format (and in so doing mess up the audio sync): it simply uses the frames being served to it as though they were already converted. This technique overcomes all the above problems. It is also used extensively by advanced video editing people to preprocess the original video material (such as old film stock or VHS tape) before it arrives in MEP for editing. This is done using AviSynth and VirtualDub.

The audio component of the MPEG/AVI file is saved separately by you, and then added to the MEP timeline by you (only once). So the video comes in via frameserving and the audio is extracted (demuxed) and imported. The two are then lined up, grouped if necessary, and you have perfect audio sync to edit.

Frameserving Options

We have a couple of options for frameserving to MEP:

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