Audio envelopes differences... ADTS, CAF, ...

Question

Hello,

I would like to know differences between these different audio envelopes. and when to use one instead another one.

Sorry if my question seems stupid...

Thanks for your help.

Thierry

Answer 1

Not a stupid question at all. ADTS is a container (file format) for AAC (data format) encoded audio. CAF on the other hand is a container developed by apple for a number of different audio data formats. You can find a list of formats supported by this container here.

As for which one to use and when..

I'm not sure how familiar you are with audio formats but as mentioned above, there are two concepts to consider:

1. How will I encode the audio?
2. What file format will I package it up with?

The answer to the first question will mostly be determined by the final audio quality you are seeking, and what size you want the final data to be.

The answer to the second question also depends on the answer to the first question and other considerations such as what other data would I like to include with the audio (video, text, GPS coordinates, etc.).

For both questions, you will also need to consider compatibility with the hardware and software you want to use to play the audio back.

Answer 2

I agree with capar and vote him up, however I would like to point out the problem of lexicon in this question... (terminology being a very important factor). an audio envelope is something very different from an audio file format (regardless of whether the format is a wrapper or not).

to quote from Barry Truax's Handbook for Acoustic Ecology:

The envelope of a sounds is its macro-level amplitude behaviour in time, whereas its micro-level pattern of SOUND PRESSURE variation is its WAVEFORM.

ENVELOPE

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