I wish to test VP9 as I understand it is now optional on Chrome 48.
What I have read so far, while inconsistent, seems to imply:
- no flag is needed anymore
- default is to VP8
- to prefer VP9 over VP8, the video codec list in the SDP sent with offer must be reordered to position VP9 as the first entry in the m record
If this is correct can someone please advise how to edit and then read to verify the SDP to achieve this reordering (i.e. VP9 first in the list)?
After some reading and experimentation I was able to edit the SDP video codec preferred list by reordering the m= video entry from a list that begins "100 101" to "101 100" using javascript replace - sdp.replace(/SAVPF 100 101/g, "SAVPF 101 100"); - I then verified that VP9 was active with webrtc internals and also that the visual results were good - the only downside is that cpu utilization increases about 30% so make sure you have the headroom to avoid heat buildup