RTP profile: RTP header with extension flag set not correctly handled

[Didier Barvaux]

On trunk, there is a problem if the first packet of one RTP stream has its extension flag set. The packet is then compressed as IR packet with a dynamic chain but no TS_STRIDE (not possible on first packet of a stream). In this case, RX is set to TSS and that's wrong. The X bit is so not transmitted.

[Didier Barvaux (didier-barvaux)]

Confirmed on trunk.

[Didier Barvaux (didier-barvaux)]

Confirmed on branch 1.4.x.

[Didier Barvaux (didier-barvaux)]

Confirmed on branch 1.3.x.

[Didier Barvaux (didier-barvaux)]

Non-regression test added for the bug. It fails for the moment.

See http://bazaar.launchpad.net/~didier-barvaux/rohc/main/revision/715

[Didier Barvaux (didier-barvaux)]

Fixed on main branch. See http://bazaar.launchpad.net/~didier-barvaux/rohc/main/revision/716 for details.

The first packets of a new stream must transmit the value of the RTP eXtension (X) bit. The field is considered as STATIC, so it should not change often but it must be transmitted at least on first packets. On those packets, the RX bit shall be set to 1 even if the TSS field (for TS_STRIDE) is set to 0. Upon field change, the compressor shall go back to FO state because the RTP eXtension bit is a STATIC field. It then can use either one IR, IR-DYN or UO-1-ID with extension 3, or any UOR-2* with extension 3.

Always transmitting the RTP eXtension (X) bit in the first packets of a stream makes change the reference captures of all the non-regression tests.

[Didier Barvaux (didier-barvaux)]

Bug won't be fixed on branch 1.5.x: too invasive and compatibility between 1.5.x releases would be broken.
See http://bazaar.launchpad.net/~didier-barvaux/rohc/1.5.x/revision/564

[Didier Barvaux (didier-barvaux)]

Bug won't be fixed on branch 1.4.x: too invasive and compatibility between 1.4.x releases would be broken.
See http://bazaar.launchpad.net/~didier-barvaux/rohc/1.4.x/revision/365

[Didier Barvaux (didier-barvaux)]

Bug won't be fixed on branch 1.3.x: too invasive and compatibility between 1.3.x releases would be broken.
See http://bazaar.launchpad.net/~didier-barvaux/rohc/1.3.x/revision/214