Render runs video twice

danesk wrote on 7/27/2009, 9:16 AM

Based on a previous thread here, I made sure Loop Playback is OFF, but when I render in VMS Plat 8, the render process constantly starts to runand render the video a second time (first pass uses approx. 50% of total time, according to dialog box - one hr plus video).

Do I need to remove the Loop region entirely? It encompassed entire video. Cannot find procedure to do so. And not sure how the Loop region got there initially!

Or is some other issue causing the double play?

BTW, am following precisely Eugenia's excellent tutorial for rendering to Vimeo.

Obviously a newbie issue - thanks for your patience and for any and all help.

Dan

Comments

Chienworks wrote on 7/27/2009, 11:14 AM

Does the output file contain the video twice or only once? I suspect only once. You most likely are selecting a 2-pass encoding when you render, and this is a good thing. It allows the encoder to see which areas of the video need more attention and more data to encode with higher quality while finding which areas need less data without losing quality. It will create a better looking output than a single pass encode will.

What file type and codec are you rendering to?

danesk wrote on 7/27/2009, 11:23 AM

Thanks for the prompt response!

The output file contains just one instance. Perhaps I have selected a 2-pass encoding...didn't even know that was possible. ;-) Will need to find that in the Vegas Platinum 8 Preferences or Options.

Am rendering to wmv 9, 1280-720, but with bitrate reduced to 3M (max 3.5) to restrict file size to under 1 GB Vimeo limit.

Will keep experimenting...

gogiants wrote on 7/27/2009, 11:49 AM

I've used the same template for Vimeo (from the same person, agreed, very useful!). It is two pass encoding, hence why you see it run through the video twice in the preview window during encoding.

The drawback to this is, of course, the time to encode. You might experiment with other codecs/configurations and decide if the improvement in quality is noticeable to you and worth the extra render time.

danesk wrote on 7/27/2009, 12:02 PM

OK, now I understand a bit more...thanks for the help!

Once I get my newbie questions behind me, this will actually be fun.

Thanks to all for the great help so far...nice to find such an active, knowledgeable community.

Dan

mike_in_ky wrote on 7/29/2009, 12:11 PM

I'd like to know more about 2-pass encoding. Can you tell me where I would find that in rendering? Does Eugenia have a 'rant' on that subject?

mike_in_nc

Chienworks wrote on 7/29/2009, 3:24 PM

It's not very obvious in the WMV settings. Click the Custom button and go to the video tab. There are several choices under Mode:

I'm not sure what the point of the 2-pass CBR mode is, since two pass is used to pick the appropriate variable bit rates and "CBR" means constant bitrate so it seems rather pointless.

I almost always use Bit Rate VBR (Peak), which gives a rather nice two-pass encode, even though it doesn't say that.

Note, on this same screen i also set the frame rate to match the source video. I'm in NTSC-land so most of my video is 29.97fps. Rendering to 30 causes Vegas to resample and this can soften the image substantially. Matching the frame rate prevents this from happening.

mike_in_ky wrote on 7/29/2009, 8:31 PM

Thanks, Chienworks. I'll take a look at that option and see if it helps any of my videos to improve.

mike_in_nc