RTP profile: unscaled TS shall always be encoded with W-LSB in UO* packets
Affects | Status | Importance | Assigned to | Milestone | ||
---|---|---|---|---|---|---|
rohc | Status tracked in Rohc-main | |||||
Rohc-1.5.x |
Won't Fix
|
Medium
|
Didier Barvaux | |||
Rohc-1.6.x |
Won't Fix
|
Medium
|
Didier Barvaux | |||
Rohc-main |
Fix Released
|
Medium
|
Didier Barvaux |
Bug Description
According to RFC 4815, §4.1 (https:/
RTP Timestamp (TS) values are always encoded using W-LSB encoding,
both when sent scaled and unscaled. When no TS bits are transmitted
in a compressed packet, TS is always scaled. If a compressed packet
carries an Extension 3 and field(Tsc)=0, the compressed packet must
thus always carry unscaled TS bits. For TS values sent in Extension
3, W-LSB encoded values are sent using the self-describing variable-
length format (RFC 3095-Section 4.5.6), and this applies to both
scaled and unscaled values.
The TS bits in UO* packets shall always be transmitted encoded with W-LSB. W-LSB encoding shall be used if TS is scaled or unscaled.
As of 1.6.0, the ROHC library does use W-LSB for scaled TS but not for unscaled TS. This is not RFC compliant.
Thanks to Fabrice Bellard for reporting the problem.
Branch 1.5.x is affected.