MP3 to MP2 or AC3 sample rates

[monzie]

Just a simple question:

Whats the ratio of encoding rates going from (an avi with mp3 audio) mp3 to MP2 or 2 chanel AC3 is it 1:1 or higher (when making audio for DVD's)?

For example: if an avi has an mp3 audio track at (say) 128 whats the conversion rate to MP2 or AC3...and what about VBR mp3's?

This must be a common question but I cant seem to find the correct answer........yeh I know its basic and something everyone should know..........so can someone tell me?

Will resampling at a higher (than needed) bitrate create noise...or just lose space for the video?

What about sample rates that are originally 44.1khz re-sampled to 48khz?

As i said earlier this MUST be dead basic stuff (coz we all need to know) so can anyone help?

[jimmalenko]

Just a simple question:

...more like 5 questions...

Anyway...

Let me first say that the easiest way is to choose a bitrate that you are happy with and just convert it to that all the time. At times it will be overkill but I did say easiest.

This must be a common question but I cant seem to find the correct answer........yeh I know its basic and something everyone should know..........so can someone tell me?

Can't say that I've seen it too often - I think those that don't know stick to whatever their template or default settings are and those that do know probably have certain "criteria" for when they will use 224 MP2 448 AC3 or 1536 PCM. As the most general of all general rules, for best efficiency, use the same as your source.

Whats the ratio of encoding rates going from (an avi with mp3 audio) mp3 to MP2 or 2 chanel AC3 is it 1:1 or higher (when making audio for DVD's)?

1:1. Going higher does not offer any blindingly different advantages short of filters/enhancements. You ain't gonna improve the source at all without these.

For example: if an avi has an mp3 audio track at (say) 128 whats the conversion rate to MP2 or AC3...and what about VBR mp3's?

VBR audio still has an average bitrate. You could use this, or slightly higher than this, or just use your "blanket" bitrate you chose earlier.

Will resampling at a higher (than needed) bitrate create noise...or just lose space for the video?

Don't know about noise but it will give you less space for the video.

What about sample rates that are originally 44.1khz re-sampled to 48khz?

You must resample to 48Khz if you wish to be DVD compliant. In terms of what bitrate to use, just use same as source.