C64x+ EVRC-A Endianness

Chris Johnson1

Hello,

I am using the TI EVRC-A algorithms and noticed that in the demo C code that comes with the download showing how to use the codec the bytes are swapped in the output of the encoder and in the input of the decoder.

Is this byte-swap something that is standard for EVRC-A and for whatever reason isn't handled by the process() call or is this something added specifically for testing with the TI demo code and not inter-operable with the standard EVRC implementation that a call endpoint would be using?

Chris

over 11 years ago

0 Venkateswara Rao R over 11 years ago

Intellectual 890 points

Hi Chris,

TI EVRC-A is complaint with the standard reference and it follows the bit-stream as per RFC 3558 and is inter-operable with standard reference implementation.

However, to verify the complaince with the 3GPP provided standard test vectors, we have to swap the reference as the way the standard test vectors are provided (written as short values in little-endian mode) and the way they are accessed in the Demo code (read as char values) are different.

-Venkat

0 Chris Johnson1 over 11 years ago in reply to Venkateswara Rao R

Expert 1715 points

Thanks, Venkat.

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C64x+ EVRC-A Endianness