Re: Reusing a transceiver to send a new track with different encodings (WANNA DIE)

I am not reusing transceivers for sending and creating new ones instead 
for the exact reasons you are mentioning, but could we use 
transceiver.stop() in this case and add a new transciver instead (that 
would reuse the mid, right?)?

(Note: Last time I checked, stop was not implemented in chrome, so not 
sure how it behaves at all).

Best regards
Sergio


On 28/01/2019 17:29, Iñaki Baz Castillo wrote:
> Hi,
>
> It seems that reusing a transceiver is a pain. Use case:
>
> 1) Create a transceiver for sending video.
>
> 2) Pass 3 encodings in the `addTransceiver()` call or later in
> `transceiver.sender.setParameters()`.
>
> 3) Later "stop" the sender by stopping the track and calling
> transceiver.sender.replaceTrack(null) and transceiver.direction =
> "inactive".
>
> 4) Reuse the transceiver to send a new video, now without simulcast.
> Do it via transceiver.sender.replaceTrack(newTrack),
> transceiver.direction = "sendonly" and
> transceiver.sender.setParameters(newEncodings), where `newEncodings`
> is an array with just one encoding (no simulcast desired).
>
> According to the spec [*] this is not valid:
>
> [*] https://www.w3.org/TR/webrtc/#dom-rtcrtpsender-setparameters
>
>> 6.3 Let N be the number of RTCRtpEncodingParameters stored in sender's internal
>>        [[SendEncodings]] slot.
>>        If any of the following conditions are met, return a promise rejected with a newly
>>        createdInvalidModificationError:
>>
>> 6.4 encodings.length is different from N.  <==== THIS
>
> So reusing a transceiver is just a pain because having to reuse
> previous encodings is not friendly at all.
>
> Yes, of course, I could initially set 20 encodings and set
> active=false in most of them, so later I can switch them on/off
> individually to get the "desired" behavior. No. This is a pint.
>
>
> Can we please move to WebRTC 2.0 and get rid of SDP semantics and
> artificial limitations due to the nature of SDP?
>
>

Received on Monday, 28 January 2019 17:41:55 UTC