Sdp described in webrtc of:
By adding an extension rtp information in advance to complete the mobile phone side of the rotating video description.
Described as follows:
https://mailarchive.ietf.org/arch/msg/rtcweb/NsBchthmGD4aWy7K74r_1xCK-SI
https://tools.ietf.org/html/rfc5285
3gpp document path is as follows:
https://www.etsi.org/deliver/etsi_ts/126100_126199/126114/12.09.00_60/ts_126114v120900p.pdf
Rtp rotation about extension headers are as follows:
