Digigram PYKO-out - 11 Appendix D: Rtp Format

PYKO-out: Professional IP audio endpoint
11. APPENDIX D: RTP FORMAT
An audio stream encoder must respect the size and the payload type described underneath.
RTP frame size
The maximum payload size in bytes for the encoder can be calculated from the formula:
Min(1300, 20.chans  .Bps  .samplerate  /1000)
where chans  is the number of channels, Bps  is the number of bytes per sample and samplerate  is the
sampling rate in Hertz;
The maximum payload size for MP3 is 1400 bytes.
RTP payload types
The following table shows the defined RTP payload types that the encoder must respect.
RTP
payload
type
Audio Format
0
μ-Law, 8bit, mono, 8kHz
8
A-Law, 8bit, mono, 8kHz
10
PCM 16bit, MSB first, signed, 44.1 kHz stereo, left channel
first
11
PCM 16bit, MSB first, signed, 44.1 kHz mono
14
MPEG audio
96
PCM, 16bit, MSB first, signed, 8 kHz mono
99
PCM, 16bit, MSB first, signed, 24 kHz mono
102
PCM, 16bit, MSB first, signed, 32 kHz mono reserved
103
PCM 16bit, MSB first, signed, 48 kHz stereo, left channel
first
111
PCM, 16bit, MSB first, signed, 12 kHz mono
127
Other formats*
Payload types 0, 8, 10, 11 and 14 are defined by the RTP standard.
Digigram defines assignment for payload types 96 to 127 (dynamic payload types) in the above tables.
* For a PCM 24 bits stream coming from a PYKO-in, and from firmware version v020, payload is 113
instead of 127.
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