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Beginner
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Using GSM-FR decode/endocde with MS WAV 65 byte double frames

I'm using the USC library with IPP 5.2, implementing code to decode a WAV file GSM-FR codec file to PCM-16, and also to encode PCM-16 to GSM-FR and store in an MS WAV file. The Decode function works if passed 33 byte GSM-FR packed frames, but will not handle the 65 byte packed double frames which MS uses. Similar problem when encoding -- I tried simply packing together the two 32.5 byte encoded frames into a 65 byte frame, but it is not that simple. Does anyone have experience using the library with the MS 65 byte format?
Thanksin advance,
Frank
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Do you have a chance to check this with the latest IPP 6.0 release?

Vladimir
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Beginner
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Do you have a chance to check this with the latest IPP 6.0 release?

Vladimir
No, we don't have IPP 6.0 here. Do you know if GSM-FR support for MS WAV format has been added in the 6.0 release?
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New Contributor II
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Quoting - fviggian
I'm using the USC library with IPP 5.2, implementing code to decode a WAV file GSM-FR codec file to PCM-16, and also to encode PCM-16 to GSM-FR and store in an MS WAV file. The Decode function works if passed 33 byte GSM-FR packed frames, but will not handle the 65 byte packed double frames which MS uses. Similar problem when encoding -- I tried simply packing together the two 32.5 byte encoded frames into a 65 byte frame, but it is not that simple. Does anyone have experience using the library with the MS 65 byte format?
Thanksin advance,
Frank

Hi Frank

IPP does not support Microsoft propriatary GSMWAVformat (MSGSM), instead IPP support GSM RTP format (see RFC3551).Each frame in RTPGSM format has 4 leadingextra bits which are not used for decompression, so can be be omitted.These bits must beremoved by left-shift of all bits while packing two RTP GSM frames intoMSGSM 65-bytes double frame and vice versa.

Best regards, Vyacheslav, IPP, speech codecs.
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