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Topic: meaningful sampling rates for HE-AAC (Read 3117 times) previous topic - next topic
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meaningful sampling rates for HE-AAC

Hi. I would like to ask what input and output sampling rates are supported by HE-AAC and which of them are "meaningful"?

I did a search but could only find the sampling rates supported by AAC:  8 to 96 kHz
Concerning HE-AAC I only found the specs of one particular codec (Fraunhofer HE-AAC: 24 to 96 kHz  http://www.iis.fraunhofer.de/EN/bf/amm/products/heaac.jsp ) but nothing in general.


However, the developer of the program "MediaCoder" gave different numbers in a forum posting:

Quote
HE-AAC format is designed to be only compatible with sample rate > 32khz.
Actually it is meaningless and no benefit to use HE-AAC for audio with sample rate < 32khz. Just use LC-AAC.


Do you agree with this, or what's your take?

My guess would be that it is "meaningless" due to SBR's frequency range. But why does the encoder not automatically choose LC-AAC for too low sampling rates (logically similar - albeit technically unrelated - to mp3 encoders automatically chosing a lower sampling rate for low bitrates) ?

thank you.
 

meaningful sampling rates for HE-AAC

Reply #1 –
HE-AAC supporting sampling frequencies depends on the supported levels,aac spec contains the details of
supporting SFs for each level.

rgds
mk