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lonelysurfer lonelysurfer at web.deAMR codec is said to have a 1 byte header. AMR run at various bitrate 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.2 or 12.2 kbit/s and each bitrate provide different sized output blocks of 95, 103, 118, 134, 148, 159, 204, and 244 bits. In the 1 byte header it's written which is the encoding bitrate of the specific AMR 20ms encoded audio sample. In particular the top 4 bits tell the bitrate (CMR) while the lower bits are reserved and not used (all 0 or all 1). *CMR* * MODE* *FRAME SIZE( in bytes )* 0 AMR 4.75 13 1 AMR 5.15 14 2 AMR 5.9 16 3 AMR 6.7 18 4 AMR 7.4 20 5 AMR 7.95 21 6 AMR 10.2 27 7 AMR 12.2 32 AMR Reference: http://wiki.forum.nokia.com/index.php/AMR_format http://wiki.forum.nokia.com/index.php/AMR_format http://en.wikipedia.org/wiki/Adaptive_Multi-Rate_audio_codec http://en.wikipedia.org/wiki/Adaptive_Multi-Rate_audio_codec -- View this message in context: http://baseband-devel.722152.n3.nabble.com/my-patch-for-decode-using-burst-id-tp4025076p4025082.html Sent from the baseband-devel mailing list archive at Nabble.com.