[Mp4-tech] Re: [audio] best coder for 64kbit/s

[Ralph Sperschneider]

Dear Noor,
Noor Othman wrote:
> Hi,
> 
>    Can anyone help me to understand, what is the best coder at 64kbit/s 
> and above?

Do you mean 64kbit/s/channel?
> And did I get it right that TwinVQ is only operates at bit 
> rates between 6-16 kbit/s?

You are right with respect to what is permitted in the MPEG Audio standard.
> But I have tried for higher bitrate it gives 
> better output.

TwinVQ generally operates also for higher bitrats and as you found the quality 
still increases with the number of bits spend. However, above 16 kbit/s it is 
recommended to use AAC since it provides better quality at those bitrates than 
TwinVQ. TwinVQ uses a vector quantizer for the redundancy reduction, but AAC 
uses Huffman coding. Huffman coding is lossless, while the vector quantizer is not.
Best regards,
Ralph
-- 
Dipl.-Ing. Ralph Sperschneider  | Phone: +49 9131 776 344
Fraunhofer IIS                  | Fax:   +49 9131 776 398
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