How do I limit audio and video kbps - combined?

How do I limit audio and video kbps - combined?

by Don Wellman

on Mar 13, 2013 at 3:59:20 pm

I've been asked to limit my video (640x360) to less than 1000 kbps - audio and video COMBINED.

While I found the setting to limit video in Compressor. I've exported twice - first limiting to 999, and then to 800. Both files exceeded my target. Is this just a question of trial-and-error until I hit the magical number, or is there a Compressor setting to limit Audio and Video combined?

Don Wellman

Re: How do I limit audio and video kbps - combined?

by Jean-Christophe Boulay

on Mar 13, 2013 at 4:15:14 pm

Hi Don,

You just need to go set your audio bitrate, subtract that number from 1000kbps and you get the video bitrate you can run while keeping the combined throughput under 1000kbps.

You'll probably want to use AAC compression on the audio if that fits into your specs. It's impossible to hit that bitrate without compressing the audio anyways, as 24-bit/48kHz stereo PCM is more than 2000kbps.

IHTH

JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com

Re: How do I limit audio and video kbps - combined?

by Don Wellman

on Mar 13, 2013 at 8:05:02 pm

Thanks... I had been hoping to do it without math (and in the process, create a custom conversion in Compressor that would work with every video for this client). I guess I'll have to earn my money the old-fashioned way - with math, rather than a check-box.

Don Wellman

Re: How do I limit audio and video kbps - combined?

by Dave LaRonde

on Mar 13, 2013 at 4:19:41 pm

If you have to make a REALLY small file -- and it sounds like you do -- you can also cut the current frame rate in half.

You also haven't said which codecs you've tried unsuccessfully: it could make a difference.

Dave LaRonde
Former Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA