Building Audio Proxy

Yep wrote on 8/19/2014, 8:32 AM

I am using Vegas Pro 13. My PC has reasonable specs - i7 3.5GHz, 8 GB ram, Nvidia GeForce GTX 560 Ti video card, and OS is Win 7 64bit.

I am working on a project in which the raw footage is wmv. Everything was going smoothly until I experienced a crash while rendering a small loop section in the middle of the project.

When I re-opened the project, Vegas started building Audio Proxy files. I started trying to work on the project while this was going on but Vegas crashed again. Opening it again I tried to cancel the audio proxy building operations so that I could continue working. Shortly after that it crashed again. I then decided to just wait until it had built the audio proxy files. That was more than 90 minutes ago and progress bar is indicating 90% (4 of 12)!!! At that rate it will take several hours to complete. I can't find any relvant information searching Vegas Help, and I tried doing a search here but it didn't turn up anything. So I have a few questions.

a. Why does Vegas need to build audio proxy files?
b. When does Vegas build audio proxy files - I've noticed it doing this before at odd times but haven't figured out what triggers the operation. (up until now it hasn't been a problem).
c. Why does it take so long - at the rate this is going it will take many times longer to build the proxy files than it would to complete a full render of the project?
d. Are there any workarounds?

P.S.

Some information about the project that may be of some assistance.

The original footage is 2 hours 45 minutes long. The final project length has been edited down to just over 40 minutes. The same Video FX (color curves and color corrector) have been applied to all events on the time line. I am using some imported mp3 files on a second audio track and sections of the original audio track have been muted with the audio envelope. Slow motion and reverse has been applied to some short events on the timeline

Comments

Former user wrote on 8/19/2014, 8:36 AM

This thread might help.

http://www.sonycreativesoftware.com/Forums/ShowMessage.asp?Forum=4&MessageID=828563

Yep wrote on 8/20/2014, 7:54 AM

Thanks Dave - interesting thread.

I've done a lot of searching on this subject over the last day, and have also discovered what I believe is causing the problem - for me at least.

First, it seems to be a pretty common problem from what I can find using google. One recurring theme seems to be the lack of compatability of wmv files with Vegas.

Second, none of the discussions I read on the subject seemed to have a reasonably easy workaround. Rencoding the original footage to a more Vegas friendly codec seems to be the best option I can find at the moment.

I've finally been able to identify what was triggering Vegas into building audio proxy files. I imported a small wmv clip and copied it multiple times across the timeline. I then started applying different effects to each clip one at at time to see what would happen. I tried a range of effects from Video FX - pan/crop, color, blurs etc., as well as time line effects like volume envelope, slow motion reverse etc.

As soon as I applied reverse to a clip - Vegas started building an audio proxy file. I then applied reverse to the next clip and the progress bar bottom left changed to indicate "10% (1 of 2), and then 11% (1 of 3) when I applied reverse to a third clip. I also tried deleting the audio track from the wmv clips before applying reverse, but again Vegas still started building the audio proxy files.

I tried the same experiment with a number of random avi and mp4 formats - but Vegas didn't start building audio proxy files for them when reverse was applied.

While not an exhaustive study - it seems pretty conclusive that reverse and wmv do not work well together in Vegas.

While I now know what to avoid, I'm still interested in finding out what is going on from a technical point of view. In particular I'd like to know why the building of these audio proxy files takes so long - as I said previously - many times longer than a complete render of the entire project. So please feel free to add any information or comments you might have.