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AVI Glitching in preview AND final render
I had an FLV that I downloaded off of a website that I wanted to edit in Sony Vegas, so I converted it to an AVI, using MP4 compression on TMPGEnc 4 XPress.
It plays fine both in Windows Media Player, and VLC, but when I edit it in sony vegas, it won’t work very well. It’s fine when there’s not much panning/action, but when there’s zooming and action on the screen there’s huge glitches/artifacts, and streaking, and the color goes off!
Is it because I used MP4 compression with an AVI, which in turn confuses sony vegas? WMP doesn’t have a problem with that! If instead of AVI I convert the FLV to an MPEG2/4 file (not in AVI container, in MPEG container), will that fix this?
View an example of what is happening at: https://www.youtube.com/watch?v=777DudxiGs4
It occurs most prominently at 0:20-0:25 in that video – it gets worse later on (I picked a bad example, but you can still see what I mean if you watch it). It also looks more terrible on the original file on my computer, and actually doesn’t look THAT bad on youtube, but please watch and see the problem I’m having.
Understand that AVI (when played in VLC) looks fine, but when previewing or rendering in Vegas, it looks like the youtube video linked above :S.
Please let me know! I’d like to get this project done!
Thanks tons,
Connor
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3 Replies
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Is it because I used MP4 compression with an AVI, which in turn confuses sony vegas?
Yes, and not only that but MP4 is a horrible editing format in general. Convert the FLV file to Huffyuv, Lagarith, or MJPEG and you will have a better time editing it.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thanks tons!
I downloaded Huffyuv, and then got TMPGEnc to encode the flv to that, and it works fine now!
Why is MP4 such a bad editing format? What difference do these formats make to one another (basically, what makes a good editing format)?
Connor
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Why is MP4 such a bad editing format? What difference do these formats make to one another (basically, what makes a good editing format)?
That’s a great question and one that every editor should understand. There are two major ways that codecs compress video. One is to compress each frame as if it were a single image. This is called Intraframe compression because each frame is a whole image. Codecs like DV, MJPEG, Huffyuv, & Lagarith use intraframe compression. This creates smaller files than if the video were uncompressed, but they are still not small enough for DVD or internet delivery.
The second is a very cleaver way to increase compression and decrease the file size dramatically by NOT storing each frame but rather, only store the delta changes from each frame. This is called Interframe compression because each frame depends on some number of previous frames to be complete. Now obviously you can’t store deltas forever so the frames are processed as a Group Of Pictures or GOP. HDV, AVCHD, MPEG4, use a 15 frame GOP. This means for each 15 frames, one is a full frame (called I-Frame) and the other 14 are delta and predictive frames (called B & P-Frames).
The reason codecs like MP4 are so hard to edit is because in order to reconstruct any given frame, you must find the previous I-Frame and process all the B & P-Frames in between. Worst case scenario you may have to process up to 14 previous frames just to make one frame!!! This makes 14 times more work for your NLE and is why you always want to edit with an intraframe codec for speed and deliver with an interframe codec for small file size.
Hope that explains it.
~jr
http://www.johnrofrano.com
http://www.vasst.com
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