W3C home > Mailing lists > Public > public-webrtc@w3.org > June 2013

Re: How to know if a given track or media stream is being transmitted

From: José Luis Millán <jmillan@aliax.net>
Date: Mon, 17 Jun 2013 16:33:14 +0200
Message-ID: <CABw3bnN1bp6Aoi3SGfZsv0R0Kf1DXSikWQ5zipew6Bj83Yy2Ng@mail.gmail.com>
To: Adam Bergkvist <adam.bergkvist@ericsson.com>
Cc: Iñaki Baz Castillo <ibc@aliax.net>, "public-webrtc@w3.org" <public-webrtc@w3.org>
Hi Adam,

Yes, that is the way to do without having specific API method. We where
asking for a built-in mechanism though.

Regards


2013/6/17 Adam Bergkvist <adam.bergkvist@ericsson.com>

> I agree it's a bit of a confusing situation when you have streams in your
> local stream set, which usually means that they are being sent or about to
> be sent, but not all tracks in these streams have been negotiated.
>
> My first thought is that it's most likely possible to find out what's
> being sent via the stats API. I'm not sure that should be the final answer
> to your question though.
>
> /Adam
>
>
>
> On 2013-06-14 21:07, Iñaki Baz Castillo wrote:
>
>> This is the typicall scenario in which a peer wants to add video to a
>> only-audio session, and also wants to know whether it is in fact
>> sending its local video to the peer, and whether the remote peer is
>> receiving it or not.
>>
>> For example, all the people expect that, when using Skype, if we see
>> our own local video that means that we are sending it to the remote
>> peer. Otherwise the application hides our local video and switches off
>> the webcam.
>>
>> Due to SDP extra-flexibility there are multiple ways to indicate that
>> video is not being received:
>>
>> - The peer answers an SDP with m=video line with port 0.
>> - The peer answers an SDP with m=video line active but a=recvonly.
>> - May be another way due to the addition of "track" concept.
>>
>> Is there a reliable API for detecting all those cases?
>>
>> Thanks a lot.
>>
>> 2013/6/14 José Luis Millán <jmillan@aliax.net>:
>>
>>> Hi,
>>>
>>> I wonder if the following scenarios are considered in the WebRTC API.
>>>
>>> Alice and Bob have a peerConnection each. Both have a mediaStream loaded
>>> in
>>> their peerConnection. The mediaStream in Alice's peerConnection has one
>>> audio track and zero video tracks, Bob's has one audio and one video
>>> track.
>>>
>>> Alice sends a SDP offer to Bob. She wants to establish an audio media
>>> session. Bob receives the offer and answers Alice. Both SDPs have an
>>> audio
>>> only media description.
>>>
>>> After a while Bob decides to share his video with Alice. He looks at his
>>> peerConnection and he notices he actually has a video track, but he
>>> doesn't
>>> know whether he is already sending that video to Alice or not.
>>>
>>> How does Bob know if he is sending his video to Alice by looking at his
>>> peerConnection?
>>>
>>> Another scenario is the one where Carol offers Alice a SDP offer
>>> containing
>>> audio and video media description and Alice only accepts the audio, she
>>> is
>>> not willing to receive any video from Carol.
>>>
>>> How does Carol know she is not sharing her video?
>>>
>>> Same for entire mediaStreams in a peerConnection.
>>>
>>> I can't figure out how to achieve it. Have this been considered?
>>>
>>> Regards,
>>>
>>> --
>>> José Luis Millán
>>>
>>
>>
>>
>>
>


-- 
José Luis Millán
Received on Monday, 17 June 2013 14:33:43 UTC

This archive was generated by hypermail 2.3.1 : Monday, 23 October 2017 15:19:33 UTC