2.2.10.1 SDES PRIV extension for media quality
The SDES private extension for media quality follows SDES PRIV, as specified in [RFC3550] section 6.5.8. The format for media quality SDES PRIV extension is as follows. <20>
§ Prefix string MUST be "MS-EVT", and MUST NOT be null terminated.
§ Value string MUST NOT be null terminated, and MUST follow the following format:
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"v=V m=R…RMMMMMMMM q=R…RQQQQQQQQ"
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V: Version of the extension MUST be 1 (v=1).
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R: Reserved bits MUST be ignored by the receiver; might be added in future releases.
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MMMMMMMM: Bitmask, represented in 8-digit lower case Hexadecimal, indicating which media qualities are known. Each bit can be either zero (0) for unknown or 1 for known.
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The following table shows the component values for the m bitmask.
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|
Bitmask |
Description |
|---|---|
|
0x1 |
Send network quality. |
|
0x2 |
Receive network quality. |
|
0x4 |
Network latency. |
|
0x8 |
Network bandwidth. |
|
0x80 |
Received video rate matching. |
|
0x70 |
Reserved for future use. |
|
0x100 |
Audio capture device is not functioning. |
|
0x200 |
Audio render device is not functioning. |
|
0x400 |
Audio render glitch. |
|
0x800 |
Low signal to noise ratio on device. |
|
0x1000 |
Low speech level on device. |
|
0x2000 |
Microphone clipping. |
|
0x4000 |
Echo. |
|
0x8000 |
Near echo to echo ratio. |
|
0x10000 |
Device is in half duplex mode. |
|
0x20000 |
Multiple audio endpoints. |
|
0x40000 |
Device howling detected. |
|
0xF8000 |
Reserved for future use. |
|
0x100000 |
Low CPU cycles available. |
|
0xFE0000 |
Reserved for future use. |
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When a bit mask from the previous table that is listed as reserved is applied to m bits, the resulting value MUST be zero (0).
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QQQQQQQQ: Bitmask, represented in 8-digit lower case Hexadecimal, indicating which media quality is good (0) and which media quality is bad (1). If the m bitmask is unknown (0), Q bitmask SHOULD be set to zero (0) and MUST be ignored by the receiver.
Additional fields, separated by a space and indicated by the same name=value syntax, might be added in future releases. These additional fields SHOULD be ignored.
Additional digits (R) in the m and q fields might be added in future releases. However, the least significant 8 digits MUST follow the preceding definition for the m and q bitmask. Any additional digits SHOULD be ignored.