AMR Compound Payload

The compound payload consists of one payload header, the table of contents and one or more speech frames

These elements SHALL be put together to form a payload with either simple or robust sorting. If the bandwidth efficient operation is used, simple sorting MUST be used.

Definitions for describing the compound payload:

b(m)    - bit m of the compound payload, octet aligned
o(n,m)  - bit m of octet n in the octet description of the compound
             payload, bit 0 is MSB
t(n,m)  - bit m in the table of contents entry for speech frame n
p(n,m)  - bit m in the CRC for speech frame n
f(n,m)  - bit m in speech frame n
F(n)    - number of bits in speech frame n, defined by FT
h(m)    - bit m of payload header
C(n)    - number of CRC bits for speech frame n, 0 or 8 bits
P(n)    - number of padding bits for speech frame n
N       - number of payload frames in the payload
S       - number of unused bits

Payload frames f(n,m) are ordered in consecutive order, where frame n is preceding frame n+1. Within one payload with multiple speech frames the sequence of speech frames MUST contain all speech frames in the sequence. If interleaving is used  the interleaving rules defined in section 2.2 applies for which frames that are contained in the payload. If speech data is missing for one or more frames in the sequence of frames in the payload, due to e.g. DTX, send the NO_DATA frame type in the ToC for these frames. This does not mean that all frames must be sent, only that the sequence of frames in one payload MUST indicate missing frames. Payloads containing only NO_DATA frames SHOULD NOT be transmitted.

The compound payload, b, is mapped into octets, o, where bit 0 is MSB.

references
https://www.ietf.org/proceedings/51/I-D/draft-ietf-avt-rtp-amr-10.txt