256 or 128 Kbps sound?

[andyfranks]

Hi,

I'm outputting DV-AVI files filmed on a Sony A1 in DV CAM as MPEG-4 videos for upload to Vimeo.

The projects and source files are:

PAL (25 fps)
Microsoft AVI files
24 bits, 720 x 576, 16:9, 25 fps
Lower Field First
Matrox DV/DVCAM -- type 2
PCM, 48.000 kHz, 16 Bit, Stereo

I have been outputting to upload the files to Vimeo as:
MPEG-4 Files
24 bits, 1280 x 720, 25 fps
Frame-based
H.264 Main Profile Video: 5000 Kbps
44100 Hz, 16 Bit, Stereo
MPEG AAC Audio: 128 Kbps

My question is if there's any benefit or drawback to outputting at 256 Kbps sound instead of 128? The file sizes are pretty similar (I guess the extra sound quality takes a bit of the picture kbps instead?) but I can't notice a difference with either image or sound quality.

I'm using Video Studio Pro X5.

Any thoughts welcome, many thanks as ever Andy F

[pvreditor]

It may depend on the type of content in your videos. If it's a presenter speaking at a podium, then a lower bit rate for audio is fine. If you have music or complex sound that you want to render as naturally as possible, then I recommend the higher bit rate for the audio. It's possibly hard to tell without test equipment, but the 256 kbps audio should be better. What it comes down to is how important maintaining audio quality is to you -- if your content works best with higher quality audio, go for that. The audio improvement between 128 and 256 kbps is MUCH greater to the audio than the slightly reduced video bandwidth is to the video. But again... if it is just talking heads, the lower bit rate is fine.

Bob Kovacs
http://www.bobkovacs.com

[andyfranks]

Many thanks, much appreciated.