Hi, I just downloaded Intel IPP library for mac os. There are some ipp sample codes. I built the sample application, usc_speech_codec application and ran it. I'm interested in the decoding. I tried to decode GSM 6.10 wave format to PCM. I have a GSM 6.10 wave file(8kgsm.wav) that i downloaded from the web elsewhere. when I tried to run the decoding process:
it complainted that the input file format unknow, "FAIL:Unknown decode format."
However, if I ran the encoder first(using the same usc_speech_codec app), PCM -> GSM 6.10(examplegsm.wav), then decoder GSM 6.10 -> PCM, the decoder will run successful. Why?
When I took the further look, the formatTag embedded inside the header between 8kgsm.wav & examplegsm.wav is different.
formatTag(compression code) value for 8kgsm.wav is 0x0031
formatTag value for examplegsm.wav is 0x7298
Aren't the compression code value standard?
The following is a list of the common compression codes used today(from http://www.sonicspot.com/guide/wavefiles.html#fmt).
|2 (0x0002)||Microsoft ADPCM|
|6 (0x0006)||ITU G.711 a-law|
|7 (0x0007)||ITU G.711 -law|
|17 (0x0011)||IMA ADPCM|
|20 (0x0016)||ITU G.723 ADPCM (Yamaha)|
|49 (0x0031)||GSM 6.10|
|64 (0x0040)||ITU G.721 ADPCM|
How come IPP using different compression code values than standard? e.g. 0x7298 vs 0x0031 for GSM 6.10
Therefore it seems like the sample application, usc_speech_codec, can only decodes the files that were encoded first by itself.