No Audio (Green Screen) in Previewed Video

[n1koolkat]

Please bear with me as i'm fairly new to Ulead's Media Pro 7. I had previously used Video Studio 7 and thought that the Media Pro version would be similar. I opted for MP7 after trying out Sony Vegas and getting nowhere with it, so here goes.

I made the mistake of volunteering to compose a film mark for a company presentaion marking 50 years of the business coming into existence. The short film uses clips from various movies to relay significant moments in the companies history. Most of the clips are encoded in DivX and Xvid format (one or 2 mpgs) with MP3 or WAV audit formats (no ac3's). They are of various resolutions and frame rates, however that is a seperate issue.

For some reason, when importing a video clip to the timeline, the preview no longer plays back the associated audio clip even though the source file plays back correctly. I initially thought this might be as a result of a codec conflict and uninstalled and then reinstalled the MP3 codec however the problem still persists. If i extract the audio part of the clip and import it seperately the video works fine however this is a very time consuming work around. Does anyone have any suggestions.

... and one other thing, some of the clips tend to play back with a green screen when previewed before slowly correcting themselves after a couple of seconds. These are not xvid encoded video's. I've tried uncompressing them and they can then be previewed correctly however decompressing the flips more than increases the size by 500%. Can anyone suggest a resolution for this. Thanks.

[guns1inger]

You won't like what I'm going to say, but it has to be said. Using heavily compressed source, especially Divx/Xvid clips, is just about the worst thing you can do from an editing point of view. Not only is the quality questionable if they have to be resized, but many editing programs do not work well with them. Divx/Xvid, like mpeg, is temporal in nature. That means that while some frames contain all the data required, most rely on previous and subsequent frames to get a whole image. This makes editing very difficult. Add to this the fact that they wre probably downloaded and contain errors, and you have a pig's breakfast to work with. MP3s encoded with a variable bitrate are also a problem for editing software, and generally lead to either crashes or sync problems.

If these are the only source you have to work with, then bite the bullet and render them to uncompressed or at least lossless video with seperate uncompressed audio tracks. At least them you might a chance of pulling all this together.

You have set yourself enough of a task simply editing a video to do justice to your company. It will reflect as much on you as the company when it's shown. Trying to work with sub-standard source material is already distracting you from the task at hand. Remove the technical hurdles so you can concentrate on the art. Shortcuts will only come back to bite you on the arse.

[n1koolkat]

Thanks for the quick response guns1inger. I was hoping that that would be the last resort, however admittedly it did appear clearer when it was uncompressed. As a side note, will the fact that the clips are of different resolutions and frame rates be a major problem particularly as i will probably have to compress the final result in order to fit it on a CD?

[guns1inger]

Resolution wont be a problem, other than fluctuating quality caused by different levels of resizing required.

Different frame rates are more likely to cause problems. I'd try it with a just a couple of clips and see what happens before you get to far down the track.