Rendering to .wmv slow with pauses

engineeringnerd wrote on 12/5/2007, 5:24 PM

When I render from .m2t source to 8 Mbps .wmv output , the rendering flies for 29 frames, then pauses for 6 - 8 seconds, then flies for 30 frames, pauses 6 - 8 seconds..... at about 8 seconds rendering per 1 second of content ( 8x ). If I render to .avi, .mov, or mpeg2, I cruise along at about 2x or better. I like to use .wmv for sharing projects at work on our server. I've rendered on both VMS7 & VMS8 using two different, honking computers (3.2GHz dual & 2.8 GHz dual, both with 4GB RAM and good video cards, trying XP(32), XP(64), Vista(32), and Vista (64) with very similar results).

Anyone know a secret to loose the pause when converting to .wmv?

Comments

Eugenia wrote on 12/5/2007, 5:43 PM

This is not pausing, it's just buffering and release. It's just how the encoder works, it is not slower than it should be. It's just how it works.

engineeringnerd wrote on 12/5/2007, 6:19 PM

Thanks for the reply. So the .wmv encoder is 1/4th as efficient than .mov and mpeg2 encoders?

Eugenia wrote on 12/5/2007, 6:30 PM

It's true that the WMV encoder that Sony licensed is slow, but this does not mean that the "frames fly by" thing you are seeing is a weakness. It's just that it renders the frames off Vegas (so Vegas does not count the frames exactly when they are rendered) and when the batch is done, it tells Vegas "ok, frames 120 to 150 are done, fetch me the next frames", and so then Vegas adjusts the frames rendered so far by "flying them by". This behavior is NOT an indication that the encoder is slower, it's just that it has a different internal workflow.

As for WMV encoding being slower overall, well, you have to also consider that WMV is mpeg4-based and mpeg4 requires more CPU power than mpeg2. You can have the same quality as mpeg2 in a smaller filesize.

It is definitely not 1/4 the speed of mpeg2 btw. Maybe about 30% slower, but not 300%.