- From: Cullen Jennings (fluffy) <fluffy@cisco.com>
- Date: Sat, 17 Nov 2012 17:44:33 +0000
- To: Göran Eriksson AP <goran.ap.eriksson@ericsson.com>, "DAN DRUTA" <dd5826@att.com>, "Subha Dhesikan (sdhesika)" <sdhesika@cisco.com>
- CC: Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
Thanks Göran,
That jogs my memory and is exactly what the action item should be.
The draft-ietf-rtcweb-qos-00 has the note in it
[Editor's Note: the application type is currently inconsistent with
similar applications defined in [6]. Further
discussion is likely needed to resolve this.]
and that is the only point in that draft that refers to reference [6]. That reference, and for that matter, that note, should be removed from draft-ietf-rtcweb-qos-00
I'll work with Dan and Subha to try and get that sorted out.
Could we update the action item to say
Remove the normative reference to draft-ietf-mmusic-traffic-class-for-sdp from draft-ietf-rtcweb-qos
And, if he is willing, Dan might be a better owner for this than me.
Cullen
On Nov 17, 2012, at 2:38 AM, Göran Eriksson AP <goran.ap.eriksson@ericsson.com>
wrote:
>
>
> Sent from my iPad
>
> On 16 nov 2012, at 23:30, "Cullen Jennings (fluffy)" <fluffy@cisco.com> wrote:
>
>>
>> I've read the minutes that say
>>
>> goran: cullen's draft refers to other drafts
>>
>> cullen: we will remove that reference.
>>
>> and tried to figure out which refernce was being discussed. Does someone remember? I'm sure that I was not suggesting removing a reference to the qos draft.
>
> As part of the discussion, we also touched on the relevance of "Polk, The session description protocol traffic class attribute.." draft that is listed in the reference list of draft-IETF-RTCWEB-qos.00.
>
> This was in the context of whether this will be part of the JSEP o/a or not and if it is in JSEP, what security considerations that would mean (the "trusted SDP" question, :-)!).
>
> We did not dive into this in any detail, but people were leaning towards other solutions including HTTP interface from the browser UA. It was in this discussion it was mentioned removing the reference to Polk's [traffic class attribute] draft from the reference.
>
> Now, the notes does not capture that perhaps (unsurprisingly since the discussion was brief but intense, :-)) but personally I am not sure dropping it is needed- the webRTC qos draft could also be complemented with information proposing how DSCP values are set using JSEP, some HTTP interface from browser UA or XYZ method and with this as backdrop, the relevance of the traffic class attribute draft is clearer.
>
> That is how I remembers the discussion- hope it helps, :-)!
>
> Regards
> Göran
>
>
>
>
>
>>
>>
>> On Nov 15, 2012, at 7:18 AM, Stefan Hakansson LK <stefan.lk.hakansson@ericsson.com> wrote:
>>
>>> Dom,
>>>
>>> thanks!
>>>
>>> I have only one comment:
>>>
>>> * I think "[NEW] ACTION: Cullen to update draft to remove reference." should not be here, from the context of the discussion I interpret that it is an IETF document that should be updated.
>>>
>>> Stefan
>>>
>>> On 11/15/2012 11:37 AM, Dominique Hazael-Massieux wrote:
>>>> Hi,
>>>>
>>>> I've just finished compiling and cleaning up the draft minutes of our
>>>> F2F meeting two weeks ago at TPAC:
>>>> http://www.w3.org/2012/10/29-webrtc-minutes.html
>>>> http://www.w3.org/2012/10/30-webrtc-minutes.html
>>>>
>>>> The minutes of the Media Capture Task Force meeting on the afternoon of
>>>> October 30th will be send separately to the media capture task force
>>>> mailing list.
>>>>
>>>> Please send corrections as needed; text-only copy of the minutes
>>>> embedded below.
>>>>
>>>> Dom
>>>>
>>>> Web Real-Time Communications Working Group F2F
>>>>
>>>> 29 Oct 2012
>>>>
>>>> See also: [2]IRC log
>>>>
>>>> [2] http://www.w3.org/2012/10/29-webrtc-irc
>>>>
>>>> Attendees
>>>>
>>>> Present
>>>> andy_hutton, adambe, hta, stefanh, derf, burn,
>>>> dan_druta, richt, anant, dom, juberti, jim, matthew,
>>>> ekr, fluffy, Magnus
>>>>
>>>> Regrets
>>>> Chair
>>>> Harald, Stefan
>>>>
>>>> Scribe
>>>> adambe, markus, JimB, martin
>>>>
>>>> Contents
>>>>
>>>> * [3]Topics
>>>> 1. [4]API functionalities missing in PeerConnection API
>>>> 2. [5]SDP handling
>>>> 3. [6]Implementation status
>>>> 4. [7]General error handling principles
>>>> 5. [8]Call flows Walk-through
>>>> 6. [9]State machines
>>>> * [10]Summary of Action Items
>>>> __________________________________________________________
>>>>
>>>> <inserted> scribenick: adambe
>>>>
>>>> hta: the best use of face-to-face time is to be specific
>>>> ...: people pay more attention campared to mailing lists
>>>> ... we've tried to make the agenda specific
>>>> ... we might go with presenters proposal
>>>> ... there also be discussions
>>>> ... we should record off-topic topics and move them to the AOB
>>>> session
>>>>
>>>> stefanh: fist session is about API functionality we haven't
>>>> addressed yet
>>>> ... this might be the least concrete item on the agenda
>>>> ... what de we need to do now and what can we postpone
>>>>
>>>> API functionalities missing in PeerConnection API
>>>>
>>>> [11]Stefan's slides
>>>>
>>>> [11] http://www.w3.org/2011/04/webrtc/wiki/images/1/1e/MoreAPIs.pdf
>>>>
>>>> stefanh: API topics
>>>> ... width, hegiht sent over a PeerConnection
>>>> ... priority
>>>> ... is media flowing?
>>>> ... how much bandwith is used
>>>> ... how much can be used
>>>> ... how to reject media streams
>>>> ... echo control
>>>> ... one thing missing on the slides
>>>> ... should we support security descriptions
>>>>
>>>> (a use case is presented)
>>>>
>>>> scribe: one peer sends video with two different resolutions to
>>>> two other peers
>>>> ... are people ok with this?
>>>>
>>>> fluffy: we should support this
>>>>
>>>> burn: you're showing the entrence and the consumer side
>>>>
>>>> stefanh: yes
>>>>
>>>> hta: there are multiple ways to achive this reuslt
>>>> ... first question is.. do we need to support this?
>>>> ... the answer is yes
>>>> ... then how should we solve it
>>>>
>>>> stefanh: this is the most difficult slide in my deck
>>>> ... application knows about the receiving side
>>>> ... or the receiving side could tell the sender
>>>> ... third possibilty is that the app isn't involved
>>>>
>>>> matthew: even if the receiver is involved the sender needs to
>>>> be involved
>>>>
>>>> justin: there needs to be some higher limit
>>>>
>>>> matthew: there might be a lot of contstraints
>>>>
>>>> fluffy: this is one of the reasons we need constraints
>>>>
>>>> stefanh: we shouldn't modify the sdp unless we have very good
>>>> reasons
>>>>
>>>> hta: we currently don't use a speakers queue
>>>>
>>>> ekr: what do we expect to happen if the receiver asks for a
>>>> different aspect ratio
>>>> ... should the PeerConnection rescale
>>>> ... ?
>>>>
>>>> justin: the sender might need to chose the closest thing
>>>>
>>>> hta: we want people to separate the case where you really
>>>> require something compared to the case where you really can't
>>>> live without something
>>>>
>>>> <matthew> side comment: generally we either need to fully
>>>> specify the SDP the is used to negotiate things like this OR we
>>>> need contraints. unfortunately when there's contraints, we
>>>> *also* need to fully specify the SDP that flows between them...
>>>> unless we choose to have it *only* be an API issue ("direct
>>>> manipulation" vs. "constraint setting")
>>>>
>>>> stefan: is the sending app or sending PeerConnection informe
>>>>
>>>> justin: information about the consumer dimensions could be sent
>>>> as a session description
>>>>
>>>> fluffy: the connection to the video tag is interesting
>>>> ... would it be reasonable to adjust the send size to the
>>>> consumer size?
>>>> ... this was a driver for renegotiation callback
>>>>
>>>> martin: you don't have the consumer in the initial negotiation
>>>>
>>>> fluffy: it's not always true
>>>>
>>>> derf: css also impacts this
>>>>
>>>> fluffy: a video tag might be specified with a size or not
>>>>
>>>> stefanh: there could be several video tags that wants to affect
>>>> the sender side
>>>>
>>>> hta: there's a ultimate fallback video size
>>>>
>>>> burn: smart browsers might behave differently
>>>>
>>>> matthew: smart browser decisions must be overidden if the
>>>> developer wants to do something else
>>>>
>>>> burn: if we have an API then the browser must take input from
>>>> the API into account... otherwise the browser can do its magic
>>>>
>>>> stefanh: what is the conclusion?
>>>> ... the receiving side can influence, but we also need an API
>>>> to let the developer tweak
>>>>
>>>> ekr: do we want information from the receiver to bubble back
>>>> all the way to the camera on the sender side?
>>>>
>>>> burn: a browser can use any valid value in a contraint range
>>>>
>>>> matthew: if several consumers (local, remote).. who wins?
>>>>
>>>> ekr: some constrains are enforced when set and some constrains
>>>> seems to be enforced continiously
>>>>
>>>> burn: we might need a constraints that says "do not change
>>>> video size"
>>>>
>>>> stefanh: recap on proposed conclusion
>>>> ... receiving side as driver with an API for the app to
>>>> influence
>>>>
>>>> matthew: there's two ways to implement this
>>>>
>>>> fluffy: we don't know if we'll use RTCP or SDP to negotiate
>>>> video size
>>>>
>>>> matthew: even if we go with RTCP we need an API to influence
>>>> how the browser should behave
>>>>
>>>> stefanh: let's move on
>>>> ... next slide
>>>> ... if the receiver detaches a stream from the consumer.. what
>>>> should happen,
>>>> ... ?
>>>>
>>>> ekr: what if sender offers something that the receiver doesn't
>>>> want?
>>>>
>>>> stefanh: we'll get to that in a later slide
>>>>
>>>> fluffy: we have two operations.. mute (undetectable from the
>>>> sender side) and to say "don't send me packets"
>>>>
>>>> justin: how do you say that I only want a subset of the offered
>>>> set of streams
>>>> ... we don't have a good way to express that today
>>>>
>>>> stefanh: next slide
>>>> ... requeseting a certain bandwith
>>>> ... there's an IETF draft talking about this
>>>>
>>>> DanD: I propose a priority param to addStream()
>>>> ... we can discuss how the priority information should be
>>>> handeled but we should decide on a mechanism to specify the
>>>> intent
>>>>
>>>> stefanh: addStream() is only called once per stream, it's a
>>>> problem
>>>>
>>>> DanD: we're the right group to specify the priority intent
>>>>
>>>> burn: intent means it might not happen
>>>>
>>>> <martin> hmm...s/constraint/pref/g ?
>>>>
>>>> <ekr> ?
>>>>
>>>> <martin> that works too
>>>>
>>>> <matthew> there's a difference between "preferences" and
>>>> "absolute limits"
>>>>
>>>> <matthew> i "prefer" 720P, but there's no way i ever want >2560
>>>> horizontal pixels
>>>>
>>>> <burn> no, constraint != intent
>>>>
>>>> DanD: at least the browser sholud be able to say that I marked
>>>> you packets in a certain way
>>>>
>>>> <burn> intent == hint, discussions about hints lead to a
>>>> decision to support both mandatory and optional constraints
>>>>
>>>> <matthew> if you just go with direct manipulation then the API
>>>> only has "settings", and the difference between "constraint"
>>>> and "preference" is JS code
>>>>
>>>> <matthew> but the moment you let the two ends talk to each
>>>> other via possibly-unmodified SDP blobs then you need places on
>>>> the monster where it can be poked with a stick
>>>>
>>>> Göran: we should describe this case in more detail
>>>>
>>>> scribe: can the network trust the diff-serv code points set by
>>>> the app
>>>>
>>>> fluffy: in some environment you can't
>>>> ... they might provide information
>>>> ... but a separate request is needed to verify
>>>>
>>>> Göran: we need more discussion around use cases
>>>>
>>>> fluffy: I think this should be a topic for the AoB section
>>>>
>>>> (people agree)
>>>>
>>>> hta: new topic - Security for Qos flow labels
>>>>
>>>> ekr: there might be two API surfaces needed: tie constraints to
>>>> media flow, (missed the other one)
>>>>
>>>> DanD: I wan't a request that should be handeled by the trusted
>>>> environment
>>>>
>>>> matthew: even if diff-serv cps isn't supported a system may
>>>> enforce priority anyhow (we need to support this case as well)
>>>>
>>>> hta: new topic for AoB - Control of the DSCP interface
>>>>
>>>> stefanh: next slide
>>>> ... other side of the same coin
>>>> ... feedback on bw..
>>>>
>>>> martin: I thin we need generic feedback on constraints set
>>>> ... there might be existing mechanisms
>>>> ... for others we might need to add something
>>>>
>>>> matthew: e.g., if video has highter priority over slides, the
>>>> app might want to know if the slides can't be sent at all
>>>>
>>>> stefanh: next slide
>>>> ... sender side pause/resume
>>>> ... we currently have enable/disable on MediaStreamTrack
>>>> ... every consumer is affected
>>>> ... we could have enabel/disable on PeerConnection
>>>>
>>>> burn: we don't need that since you could clone media streams
>>>>
>>>> hta: we implemented enable and disable as affecting the
>>>> associasion between a stream and track
>>>>
>>>> stefanh: next topic, AGC
>>>>
>>>> fluffy: the text on the slides looks good to me
>>>>
>>>> <martin> conclusion here was that we don't need to prioritize
>>>> the agc/noise settings, it's not a preference, it's a setting
>>>>
>>>> <martin> it might also be necessary to change this on the fly
>>>>
>>>> burn: what happens if you turn AGC on and it's not available
>>>>
>>>> fluffy: it should be a on/off setting
>>>>
>>>> derf: I hope there's a way to enumerate settings
>>>>
>>>> <martin> we need a way to enumerate settings, for sure
>>>>
>>>> fluffy: we should require that
>>>>
>>>> <martin> agc/noise is a property of a track
>>>>
>>>> hta: AGC should be on track level
>>>>
>>>> stefanh: next topic
>>>> ... rejecting streams
>>>>
>>>> martin: we need to know if multiple streams are offered
>>>> ... we need basic methods on the session description
>>>>
>>>> derf: example: you offer me 10k streams.. how do I reject
>>>>
>>>> DanD: it's not only if your device can do something.. there's
>>>> also a question if your service can support this
>>>>
>>>> martin: we need to know what you get before you can say what
>>>> you want to accept
>>>>
>>>> hta: if we have a mechanisms for the receiver to turn off a
>>>> stream at any point.. would it be sufficient to turn it off
>>>> rather than not accepting it?
>>>>
>>>> matthew: it might be a resource question
>>>>
>>>> ekr: I interpret it as: you set the remote description and you
>>>> see what streams are offered
>>>>
>>>> stefanh: is the sending app informed about a rejected streams
>>>> ... ?
>>>>
>>>> hta: if the use case for rejecting streams is to save resources
>>>> then the sender needs to know
>>>>
>>>> matthew: it's important how quickly can this be done
>>>>
>>>> fluffy: can someone send a proposal to the list?
>>>>
>>>> (I missed to scribe a lot of stuff while I was talking)
>>>>
>>>> stefanh: next thing - AEC
>>>>
>>>> fluffy: one param you need is what's going to the speakers
>>>>
>>>> <martin> new issue that is related to this, and one that I will
>>>> bring up later when we talk about this: SDP describes RTP
>>>> sessions. The one m= section can have multiple tracks. How do
>>>> we learn of these other than just waiting for arrival of
>>>> packets on one of those?
>>>>
>>>> <hta> adambe said: I sent a proposal to the list with inbound
>>>> and outbound streams as different objects, which might make
>>>> this discussion easier; missed having feedback on that.
>>>>
>>>> <matthew> another issue that's related to the last slide and
>>>> not yet decided (and different in different implementations) is
>>>> what to offer/send before user consent on a sending device
>>>> occurs. one approach is to say "recvonly" and change to
>>>> "sendrecv" when the consent happens, the other is to say
>>>> "sendrecv" and send muted audio + black video until consent is
>>>> received. recvonly->sendrecv takes the extra round trip to
>>>> enable.
>>>>
>>>> (scribe is missing a lot of stuff here)
>>>>
>>>> burn: why do we need API for this?
>>>>
>>>> fluffy: you might want to turn it off
>>>>
>>>> burn: could this be a browser control?
>>>>
>>>> someone: music is a use case where you wan't to turn EC off
>>>>
>>>> matthew: broadcast is also a use case where you want to turn
>>>> AEC off
>>>>
>>>> martin: if the browser and user wants differents things, the
>>>> user setting should win
>>>>
>>>> stefanh: final slide - SDES
>>>> ... wait until RTCWeb has discussed this
>>>>
>>>> ekr: yes
>>>>
>>>> stefanh: that was easy
>>>> ... summary slide
>>>>
>>>> martin: you could get two different tracks - one with AEC and
>>>> one without
>>>>
>>>> hta: new AoB (MC TF) to topic - Multiple open of camera/mic?
>>>>
>>>> martin: AGC, NR should be fairly simple
>>>>
>>>> burn: rather than doing this right now we should sumarize what
>>>> we have decided the last hour and update the summary
>>>>
>>>> hta: there are things that needs to be discussed and some that
>>>> just can be edited in
>>>>
>>>> Acoustic Echo Cancellation
>>>>
>>>> stefanh: we're 15 minutes before schedule
>>>>
>>>> <markus> coffee break
>>>>
>>>> <hta> anyone remote actually here?
>>>>
>>>> SDP handling
>>>>
>>>> [12]Cullen's slides on SDP handling
>>>>
>>>> [12]
>>>> http://www.w3.org/2011/04/webrtc/wiki/images/2/2d/RTCWeb-SDP-API_v6.pdf
>>>>
>>>> <markus> getting started, markus is the scribe
>>>>
>>>> <markus> fluffy showing slides
>>>>
>>>> issues: what SDP do createOffer and createAnswer create and how
>>>> they can be manipulated before passing them back to the browser
>>>>
>>>> matthew:some changes are ok from SDP syntax perspective but not
>>>> for the browser to act upon
>>>>
>>>> goals: clear definition of SDP and error handling rules
>>>>
>>>> how are new ICE candidates added to the set SDP
>>>>
>>>> Matthew: when I ask which SDP is in use is it the one I have
>>>> set or can it be something slightly different?
>>>>
>>>> constraints: can be used to enable common use cases, but do not
>>>> solve what can be changed
>>>>
>>>> burn:constraints can affect what SDP gets generated in the
>>>> first place so it does not need to be modified anymore
>>>>
>>>> fluffy: the place to define SDP use is in the JSEP draft -
>>>> latest draft has a start
>>>>
>>>> <AndyHutton> remote audio not working
>>>>
>>>> matthew:state transitions need to be taken into account, can't
>>>> call everything multiple times
>>>>
>>>> <matthew> specifically, setRemoteDescription("answer") is
>>>> restricted to only-call-once even though we are saying that
>>>> enforcement of these transitions is up to the JS
>>>>
>>>> what can be changed between create* and setLocal/Remote
>>>>
>>>> use cases: remove codec, change bw limit etc.
>>>>
>>>> justin: enable/disable bundle is one case
>>>>
>>>> adam:rejecting audio, getting video - is that with munging SDP?
>>>>
>>>> fluffy:no, if we have explicit API then don't use SDP mungling
>>>>
>>>> matthew:have a detailed set of cases
>>>>
>>>> fluffy:grouping of cases:
>>>>
>>>> fluffy:don't do RTCP mux via settings, not SDP
>>>>
>>>> matthew:ptime for codecs
>>>>
>>>> matthew:want to fix it
>>>>
>>>> matthew:will take my cases to the list
>>>>
>>>> [several people agree most things being discussed should be
>>>> done via other mechanisms than changing SDP]
>>>>
>>>> burn: nervous about limiting too much what in SDP can be
>>>> modified
>>>>
>>>> fluffy:changing SDP on the way between browsers can be done
>>>> flexibly, changing between create* and set* in the same browser
>>>> more limited
>>>>
>>>> justin:don't understand why there is big difference between
>>>> different manipulation "loops"
>>>>
>>>> fluffy:positive list of what can be changed is needed, not the
>>>> list of what can't be
>>>>
>>>> provide a list of changeable things that is *guaranteed* to
>>>> work
>>>>
>>>> matthew: errors need to be specific on what is wrong
>>>>
>>>> [argument over what the current spec (JSEP?) says...]
>>>>
>>>> burn: many kinds of modifications will be needed before sending
>>>> SDP out
>>>>
>>>> burn:what you send out does not match with what you set with
>>>> setLocal?
>>>>
>>>> <ekr> who was speaking?
>>>>
>>>> matthew:jsep-02 has fixed the ice password issue
>>>>
>>>> fluffy:need to have the use cases that motivate changes
>>>>
>>>> justin:needs coming up in the future anyway...
>>>>
>>>> how much and what state does createOffer create? devices with
>>>> HW codecs?
>>>>
>>>> <matthew> jsep-02 fixed the "createOffer is optional" language,
>>>> though whether or not createOffer creates state is true or not
>>>> is questionable
>>>>
>>>> <ekr> matthew: though, there's clearly an implication of that
>>>> b/c of the validity window of the offer.
>>>>
>>>> <ekr> i.e. during the callback.
>>>>
>>>> <matthew> indeed
>>>>
>>>> martin:set down the list of things that MUST be possible to
>>>> change
>>>>
>>>> burn:is everything else MUST reject?
>>>>
>>>> people have different interpretations...
>>>>
>>>> explicit list of things that MUST be changeable, explicit list
>>>> of things that MUST not be changed and what falls in between
>>>> the browser need to explicitly error report if it won't support
>>>> it
>>>>
>>>> <martin> there is a list of things that we MUST be able to
>>>> change; there is a list of things that MUST NOT be able to
>>>> change, which trigger an error; everything else the browser
>>>> MUST either accept or reject with an error
>>>>
>>>> <matthew> silent failure is incompatible with the assert on the
>>>> 2nd slide. either the browser fires an error (invalidating the
>>>> assert) or it is lying to you in order to make that assert.
>>>>
>>>> [the above three comments (markus, martin, matthew) try to
>>>> record the consensus in the meeting]
>>>>
>>>> AndyHutton: Configuration/settings? how do they relate to the
>>>> MUST, MUST NOT, ...
>>>>
>>>> fluffy:start with the list of use cases to get the
>>>> MUST-be-changeable list
>>>>
>>>> matthew:listing MUST-items...
>>>>
>>>> [cullen taking notes...]
>>>>
>>>> adam: we will have APIs for some of these things anyway
>>>>
>>>> fluffy:if we have an API to control what createO/A gives, is
>>>> that not enough, do we still need to change SDP for those
>>>> "features"
>>>>
>>>> justin, matthew: there may be cases where SDP change is still
>>>> needed
>>>>
>>>> fluffy: use cases are still not clear
>>>>
>>>> burn:do not worry about MUST-list anymore because anything on
>>>> the MUST NOT list can still work...
>>>>
>>>> still sensing consensus on having three lists: 1. MUST be
>>>> changeable, 2. MUST NOT be changeable, 3. (default) Browser
>>>> MUST give an error if it does not support it
>>>>
>>>> fluffy:next issue
>>>>
>>>> when can two different video flows use the same m-line
>>>>
>>>> Proposal: all codec parameters are the same, "content-label" is
>>>> the same, are in same MediaStream
>>>>
>>>> (hta, fluffy, martin debate the details)
>>>>
>>>> next: How does createOffer know to offer receiveOnly flow?
>>>>
>>>> want to receive video but don't have video camera
>>>>
>>>> justin has a proposal, mind to write it down here?
>>>>
>>>> matthew: can you put "send" in SDP before getting user consent?
>>>>
>>>> or do you first have to use receiveOnly and add sendReceive on
>>>> a separate O/A
>>>>
>>>> ekr: how do we correlate multiple offered video m-lines to the
>>>> multiple video streams the answerer has
>>>>
>>>> next topic: how does createOffer decide to offer a data
>>>> channel?
>>>>
>>>> should OfferToExchangeData constraint be added?
>>>>
>>>> matthew: data is a great idea, but SCTP is horrible.
>>>>
>>>> fluffy:take this to the IETF
>>>>
>>>> tim:SCTP was decided in Feb
>>>>
>>>> <ekr> matthew: how do you really feel about SCTP?
>>>>
>>>> DanD:data is easy within a single app, but trapezoid between
>>>> two apps is more difficult
>>>>
>>>> martin:issues could come also if the other device running the
>>>> "same" app has constraints
>>>>
>>>> consensus: don't add this constraint
>>>>
>>>> next: DTMF
>>>>
>>>> will be discussed tomorrow with a proposal
>>>>
>>>> next: How long is SDP from createOffer/Answer valid?
>>>>
>>>> matthew:90 seconds would be an ultimate timeout
>>>>
>>>> use case: the SDP is sent to the server for modification
>>>>
>>>> should it be valid beyond the duration of the callback function
>>>>
>>>> ice candidates etc. time out in matter of 10s of seconds
>>>>
>>>> hta: time-to-live for the session description?
>>>>
>>>> matthew:can createOffer be called again after getting the
>>>> modified SDP back from the server?
>>>>
>>>> matthew:proposes that createAnswer is valid only for the
>>>> duration of callback and no longer
>>>>
>>>> consensus: it must be valid at least for the duration of the
>>>> callback function
>>>>
>>>> ACTION: ekr to take follow-up to the list
>>>>
>>>> slides about rollback and error handling left for now
>>>>
>>>> (now lunch break until 1:30)
>>>>
>>>> Implementation status
>>>>
>>>> <fluffy> Cullen is scribing
>>>>
>>>> HTA is presenting what chrome is doing
>>>>
>>>> TURN and opus are scheduled to be in M24 all going well
>>>>
>>>> DTMF is waiting on this group
>>>>
>>>> Anant has a demo of firefox
>>>>
>>>> THe demo allows login, gives a list of users, then you can call
>>>> one of the other users
>>>>
>>>> Have getusermedia, have peerConnection,
>>>>
>>>> expectation to not have behind a flag in firefox 19
>>>>
>>>> currently in firefox 18 in nightly builds behind a flag
>>>>
>>>> have a fairly complete version of the DataChannel
>>>>
>>>> showed cool file sharing with drag and drop using DataChannel
>>>>
>>>> THey have DTLS-SRTP
>>>>
>>>> ICE but no TURN
>>>>
>>>> prototype of Identity working
>>>>
>>>> Doing desktop first, then working on mobile
>>>>
>>>> VP8, opus, and G.711 as codecs
>>>>
>>>> HTA: There was a test web even 2 days ago
>>>>
>>>> dom: The idea of these is to get lots people to develop and
>>>> contribute test cases
>>>>
>>>> . presentation of theory of testing
>>>>
>>>> . Event led to 404 test cases
>>>>
>>>> General error handling principles
>>>>
>>>> ScribeNick: JimBarnett
>>>>
>>>> [13]Anant's slides on error handling
>>>>
>>>> [13]
>>>> http://www.w3.org/2011/04/webrtc/wiki/images/d/d1/TPAC_2012_WebRTC_error.pdf
>>>>
>>>> Anant: exceptions vs error callbacks. exceptions when you can
>>>> detect error without blocking the main thread. Covers only very
>>>> simple errors. In all other cases, error callback. So as
>>>> policy, favor error callbacks because they don't block the main
>>>> thread.
>>>>
>>>> Cullen: so lots of functions will do both?
>>>>
>>>> Anant: yes
>>>>
>>>> EKR: there's no way to get around exceptions occasionally.
>>>>
>>>> Tim: what do you do if you pass in something that is not a
>>>> function as the error callback?
>>>>
>>>> Cullen: there are things that you should never see in
>>>> production code, and those that have to be caught at runtime.
>>>> The former are programming errors. We're interested in input
>>>> errors.
>>>>
>>>> Anant: what goes in spec is a list of things that must be
>>>> exceptions and what should be callbacks. This will be the
>>>> result of consensus of browser implementations.
>>>>
>>>> Justin: so programming errors will be exceptions, bad SDP from
>>>> the other side will be an error callback.
>>>>
>>>> Anant: exceptions will be only for development. They shouldn't
>>>> occur in deployments at runtime. In exceptions should include
>>>> name and message, which all platforms support We should
>>>> standardize the names of exceptions, message can be
>>>> platform-specific, thought should be human readable. stack and
>>>> linenumber are useful where available. We will inherit from
>>>> Error object to make SDPErrorObject.
>>>>
>>>> ekr: we should create new attribute for SDP error, rather than
>>>> overloading linenumber.
>>>>
>>>> Anant: yes, having different names helps. We should standardize
>>>> on the ones that need to
>>>> be machine readable. Human-readable ones can be
>>>> platform-specific.
>>>>
>>>> Dom: W3C policy is to re-use existing names as much as
>>>> possible.
>>>>
>>>> Anant: we will use same object for error callback and
>>>> exception. So name and message must be present in object passed
>>>> to error callback. As with exceptions, human-readable
>>>> properties can be platform-specific. For SDP errors may want to
>>>> create a new property. Error callbacks should be mandatory. In
>>>> current spec, they're optional. That makes it easy to make
>>>> sloppy errors. If they're mandatory, at least you get an
>>>> exception if you forget to define the error callback. It should
>>>> never be the case that there's an error and nothing happens.
>>>>
>>>> ... In CreateOffer, exceptions: Invalid_callback,
>>>> invalid_constraints, invalid_state.
>>>>
>>>> Dom: these can be webIDL type mismatch errors. We don't need to
>>>> specify them separately.
>>>>
>>>> Anant: we can move invalid state to a callback (for cases where
>>>> app violates the state machine that we define.) So we won't
>>>> need to define any exceptions for (most?) functions. setLocal
>>>> and setRemote can have invalid_sdp as error in callback. Assume
>>>> that the success callback in set remote isn't called until the
>>>> description has been fully applied.
>>>>
>>>> Cullen: if have setRemote with provisional SDP and then later
>>>> will apply final SDP. Consider the case where are parsing SDP
>>>> and acting on it as you go along. Do you have to roll back? It
>>>> may be hard to do that.
>>>>
>>>> ekr: setRemote shouldn't generate callback until it's complete
>>>> and in correct state.
>>>>
>>>> Justin: we need a separate error to signal case that media
>>>> system is hopelessly busted.
>>>>
>>>> Cullen: we need two kinds of errors. Implementation will know
>>>> whether the situation is
>>>> hopeless or not.
>>>>
>>>> Harald: Invald SDP indicates that you have been able to
>>>> rollback, so it's not fatal.
>>>>
>>>> Cullen: when SDP fails a syntax check and no state has been
>>>> changed, as opposed to case where what you thought was a camera
>>>> turns out to be a mouse.
>>>>
>>>> ekr: there are cases where the error is reversible, but you're
>>>> still screwed.
>>>>
>>>> Harald: let's put Anant's proposal into the spec, and work out
>>>> some of these details later.
>>>>
>>>> Anant: we can leave the decision on which errors are fatal to
>>>> the UA. Further discussions of specific error cases on the
>>>> list.
>>>>
>>>> Dan: are error callbacks mandatory?
>>>>
>>>> Dom: sloppy programmers can always put in a no-op error
>>>> callback. On the other hand, if we make them mandatory, we will
>>>> have to include them in our examples.
>>>>
>>>> RESOLUTION: ERROR CALLBACKS ARE MANDATORY. Anant to update
>>>> spec.
>>>>
>>>> So decided that invalid_state will be a callback no exception
>>>>
>>>> <dom> [14]Error Types defined in DOM 4
>>>>
>>>> [14] http://www.w3.org/TR/dom/#error-types-0
>>>>
>>>> Decided that for SDP, will add a sdpLineNumber
>>>>
>>>> decided all errors callbacks will not be optional
>>>>
>>>> Call flows Walk-through
>>>>
>>>> Justin: when you call setLocal that's when UA starts gathering
>>>> ICE candidates. Get callbacks as each candidate is gathered,
>>>> another when all are gathered. If call createOffer before any
>>>> candidates are gathered, it will have just your local address.
>>>>
>>>> Justin: if you want to do trickle, have to get offer first and
>>>> then gather candidates. So must get getOffer callback before
>>>> all candidates are gathered.
>>>>
>>>> Cullen: what things can cause gathering to begin? What
>>>> indicates how many candidates to gather? How do you know when
>>>> you're done.
>>>>
>>>> Matthew: it has to be a settable parameter whether createOffer
>>>> callback can fire before you have enough candidates to produce
>>>> valid SDP. I don't like to get a success callback when the
>>>> offer is not valid yet.
>>>>
>>>> Cullen: one model is you can decide to wait until SDP is
>>>> complete. Or we can say that you get callback immediately, then
>>>> get another when you have all the candidates.
>>>>
>>>> Harald: must have ICE candidates to be valid.
>>>>
>>>> Cullen: but local address suffices for validity.
>>>>
>>>> Justin: in Jingle can send offer without any candidates and
>>>> it's fine.
>>>>
>>>> ekr: it won't work with SIP.
>>>>
>>>> Adam: we should have matching examples and callflows, including
>>>> trickle.
>>>>
>>>> Stefan: the Chrome implementation seems to work, with and
>>>> without trickle. So it should be our reference.
>>>>
>>>> Justin: we discussed calling createOffer and setLocal early to
>>>> start allocation, and then add streams later
>>>>
>>>> Cullen: we don't have mechanism for declaring dummy streams.
>>>> What if had new method: gather n candidates.
>>>>
>>>> Justin: that's like setLocal with empty m=lines.
>>>>
>>>> Cullen: calling app has pretty good idea of how many candidates
>>>> it will need. At least an upper bound.
>>>>
>>>> ekr: two proposals for pre-allocation: - a direct instruction
>>>> to peerconnection, or some sort of dummy SDP via createOffer
>>>> and setLocal.
>>>>
>>>> Cullen: we have 6 issues to discuss, all at least as big as
>>>> this.
>>>>
>>>> Harald: I'd like to get an overview of all the questions. for
>>>> this issue, we have two questions: how to know when SDP is
>>>> sendable, and how to do pre-allocation.
>>>>
>>>> Matthew: what happens with resource reservation? What happens
>>>> when you do all this gathering and find out that the camera
>>>> isn't available any more?
>>>>
>>>> Cullen: next issue. How does receiving side find out what's in
>>>> the offer, so that it can show the user: Alice is calling and
>>>> she wants audio and video.
>>>>
>>>> Matthew: when you call setRemote, you have no idea how many
>>>> times onaddstream will be called.
>>>>
>>>> Cullen: general model is a callback for each structure, and a
>>>> final callback saying that you won't get any more. questions:
>>>> when do you know that you've gotten all mediastreams? When do
>>>> you know you have all the tracks? When do the callbacks fire
>>>> with respect to the setRemote callback?
>>>>
>>>> ekr: at what point do side effects take effect w.r.t the
>>>> callback? I think it must be before.
>>>>
>>>> Justin: when does peerconnection.remotestreams get populated?
>>>> When you get a stream, the tracks should be filled in already.
>>>>
>>>> Matthew: parse them into the array, and then call
>>>> processingcomplete.
>>>>
>>>> Justin: how about a callback saying the remotestreams value has
>>>> changed? (It would be an array value, so this callback would be
>>>> called only once.)
>>>>
>>>> Adam: it's more convenient to get the new stream in the
>>>> callback, rather than having to parse the array to see what's
>>>> different.
>>>>
>>>> Justin: but it's important to know when the changes are
>>>> complete, rather than getting changes one at a time.
>>>>
>>>> State machines
>>>>
>>>> [15]Justin's slides
>>>>
>>>> [15]
>>>> http://www.w3.org/2011/04/webrtc/wiki/images/f/fa/WebRTC_States_v2.pdf
>>>>
>>>> <inserted> ScribeNick: martin
>>>>
>>>> juberti: [presenting on states]
>>>>
>>>> martin: does back to gathering happen for moving from "relay"
>>>> to "all"?
>>>>
>>>> juberti: you probably already have all the necessary candidates
>>>>
>>>> matthew: is there any way to remove candidates?
>>>>
>>>> juberti: ice restart
>>>>
>>>> ekr: can we have multiple components with one completed and the
>>>> other one with no candidates
>>>>
>>>> juberti: we are in checking until all components have resolved
>>>>
>>>> fluffy: checking encompasses frozen
>>>>
>>>> matthew: restart doesn't affect active flows
>>>>
>>>> juberti: yes
>>>>
>>>> matthew: why not just describe each of the states as they
>>>> relate to the underlying states
>>>>
>>>> fluffy: this is part of what I prepared for the last call on
>>>> this topic and we rejected that
>>>>
>>>> hta: there is no harm in playing audio while video is failing
>>>> and restarting
>>>> ... is there any difference betwen connected and completed?
>>>>
>>>> juberti: middleboxes might require the updated offer that would
>>>> be triggered from the completed transition
>>>>
>>>> martin: is this application driven or not, can the browser add
>>>> new candidates and contine?
>>>>
>>>> juberti: restart is required by RFC 5245
>>>>
>>>> fluffy: the application is going to need to be involved
>>>>
>>>> juberti: if you get a new NIC (e.g. WiFi) you might just
>>>> trickle that
>>>>
>>>> hta: transitions to starting are tied to user actions
>>>>
>>>> martin: how does the new WiFi candidate fit into this?
>>>>
>>>> juberti: that would trigger a transition to connected
>>>>
>>>> fluffy: there is an implication that disconnected might
>>>> transition to failed, in the case where you were connected and
>>>> you disconnect then something failed
>>>>
>>>> juberti: proposes changing name of "starting" to "noo"
>>>>
>>>> <hta> IceConnectState -> IceConnectionState
>>>>
>>>> juberti: remove onicegatheringchange, and provide just
>>>> onicecandidate to fire when the gathering state is changed
>>>>
>>>> derf: propose to rename iceConnectState to iceConnectionState
>>>> or something
>>>>
>>>> * missed the name conclusion
>>>>
>>>> ekr: is this same as the other state machine, just with the
>>>> states merged?
>>>>
>>>> juberti: yes
>>>>
>>>> <hta> martin, name conclusion was to use IceConnectedState
>>>> rather than IceConnectState (I think - my ears are going)
>>>>
>>>> matthew: set...(answer) can't be done twice?
>>>> ... why isn't createOffer and createAnswer shown on the
>>>> diagram?
>>>>
>>>> juberti: once you set...(answer), you may have removed some
>>>> critical state for the offer, which invalidates some of the
>>>> answers
>>>>
>>>> Summary of Action Items
>>>>
>>>> [End of minutes]
>>>>
>>>> ***************************************************************
>>>>
>>>> [1]W3C
>>>>
>>>> [1] http://www.w3.org/
>>>>
>>>> Web Real-Time Communications Working Group Teleconference
>>>>
>>>> 30 Oct 2012
>>>>
>>>> See also: [2]IRC log
>>>>
>>>> [2] http://www.w3.org/2012/10/30-webrtc-irc
>>>>
>>>> Attendees
>>>>
>>>> Present
>>>> andy_hutton, adambe, hta, stefanh, derf, burn,
>>>> dan_druta, richt, anant, dom, juberti, jim, matthew,
>>>> ekr, fluffy, Magnus
>>>>
>>>> Regrets
>>>> Chair
>>>> Harald, Stefan
>>>>
>>>> Scribe
>>>> DanD, Juberti
>>>>
>>>> Contents
>>>>
>>>> * [3]Topics
>>>> 1. [4]Identity
>>>> 2. [5]API for removing streams
>>>> 3. [6]DTMF
>>>> 4. [7]Other business
>>>> 5. [8]What Triggers Candidate Fetching
>>>> 6. [9]When is SDP sendable?
>>>> 7. [10]Security for QoS labels
>>>> * [11]Summary of Action Items
>>>> __________________________________________________________
>>>>
>>>> <trackbot> Date: 30 October 2012
>>>>
>>>> Identity
>>>>
>>>> <dom> ScribeNick: DanD
>>>>
>>>> ekr presenting
>>>> [12]http://www.w3.org/2011/04/webrtc/wiki/images/f/f2/Idp-issue
>>>> s.pdf
>>>>
>>>> [12]
>>>> http://www.w3.org/2011/04/webrtc/wiki/images/f/f2/Idp-issues.pdf
>>>>
>>>> ekr: Three proposals on the list
>>>> ... Proposal 1 - Identity provided by gUM (Thomson)
>>>> ... Proposal 2: Prompt user after call (Ohlsson)
>>>> ... Proposal 3 - Site permissions with identity display (EKR)
>>>> ... Proposals 1 and 2 require the user to explicitly assent to
>>>> identity
>>>>
>>>> fluffy: How does the person answering the call who's calling
>>>> before answering the call?
>>>>
>>>> ekr: Long term consent
>>>>
>>>> Mathew: I like to setup the video selection and enable the
>>>> camera and the identity makes it complicated
>>>> ... easy to be done with proposal 1
>>>> ... We need to make sure the browser does not get into the
>>>> address book without user's consent
>>>>
>>>> hta: I'm not happy with proposal 2
>>>> ... when the green light go on
>>>> ... I have an origin that is not bound to an identity but later
>>>> get's bound
>>>>
>>>> ekr: Proposal 4 is a hybrid of 1 and 3
>>>>
>>>> dom: I don't think we should use a null value for a parameter
>>>> with a different meaning as a parameter not being set
>>>>
>>>> ekr: I'm happy to use a different parameter name for option3
>>>>
>>>> justin: There's a difference between site having access to the
>>>> camera and site recording
>>>>
>>>> dom: We're focusing too much on the green light where mobile
>>>> devices don't have a green light; I want to make sure we don't
>>>> build security on top of hardware indicators that are not
>>>> always available
>>>>
>>>> martin: the idea is to have an indicator in the chrome
>>>>
>>>> justin: there's confusion about what the green light means
>>>>
>>>> fluffy: we are adding to the confusion
>>>>
>>>> ekr: the green light (the indicator) is supposed to be on once
>>>> the camera is accessed
>>>>
>>>> hta: there is a issue when applications via USB can access the
>>>> green light
>>>>
>>>> martin: if it's on can drain battery without sending any data
>>>>
>>>> fluffy: expectation is that when camera goes on light goes on
>>>>
>>>> ekr: going over the proposed rule
>>>>
>>>> dom: I'm a little bit confused. if the indicator is in the
>>>> chrome I won't see it if I switch to a different app (on a
>>>> mobile phone); how does that affect the reliability of granting
>>>> access to a camera to a peer
>>>>
>>>> ekr: we should
>>>>
>>>> Mathew: will we be able to check for long term permissions?
>>>> ... action on ekr to write something up on tainted streams
>>>>
>>>> hta: suggest camera access as a topic for the other issues
>>>> later today
>>>>
>>>> API for removing streams
>>>>
>>>> hta: presenting what "remove" means
>>>>
>>>> fluffy: we should not look at index
>>>>
>>>> hta: either we don't remove the streams and you have a fixed
>>>> index
>>>>
>>>> adam: if we reference it by object even if it's removed from
>>>> the array I can still find it by object reference
>>>>
>>>> dom: this is what DOM is doing
>>>>
>>>> hta: in this proposal I have two methods to access: one by
>>>> returning all and iterate another one by name
>>>>
>>>> fluffy: why are we handing developers indexes when they can get
>>>> them by name
>>>>
>>>> dom: using index is not a bad thing as long as you don't assume
>>>> that what it refers to is immutable
>>>>
>>>> adam: I don't think you want to have the sequence because
>>>> developer can store the sequence and can change later
>>>> ... the msid draft has already a proposal how to name things
>>>>
>>>> hta: we need to decide if we want to get rid of the indexes and
>>>> go with the labels
>>>>
>>>> Mathew: legacy devices might not label
>>>>
>>>> Adam: we should go with ID's for both streams and tracks
>>>>
>>>> hta: we need somebody to write a proposal
>>>>
>>>> <martin> there seemed to be general agreement with Adam's
>>>> suggestion, namely assigning ids to every stream and track and
>>>> having label used only for human-readable text
>>>>
>>>> <dom> ACTION: Adam to update APIs to use mutable arrays of
>>>> streams in peerconnection with ids [recorded in
>>>> [13]http://www.w3.org/2012/10/30-webrtc-minutes.html#action01]
>>>>
>>>> <trackbot> Created ACTION-59 - Update APIs to use mutable
>>>> arrays of streams in peerconnection with ids [on Adam Bergkvist
>>>> - due 2012-11-06].
>>>>
>>>> DTMF
>>>>
>>>> hta: presenting API requirements
>>>>
>>>> hta: proposal to have two new functions on RTCPeerConnection
>>>>
>>>> justin: I like the idea of having the callback with tone and
>>>> duration
>>>>
>>>> Martin: the proposal was to have a track (something that looks
>>>> like a track)
>>>>
>>>> hta: what's the factory for that track?
>>>>
>>>> Martin: you construct it
>>>>
>>>> hta: now you need to the go from the track to the
>>>> peerConnection
>>>>
>>>> Martin: you get the track from getUserMedia, you decorate it
>>>> for DTMF and attach to the peerConnection
>>>> ... on the receiving end it's simple
>>>>
>>>> hta: If I would be to implement where do I reliably place this?
>>>>
>>>> Fluffy: How do you know to negociate for DTMF?
>>>> ... another one is long tones use cases
>>>>
>>>> justin: you can emulate this with the proposal
>>>>
>>>> fluffy: I"m fine with getting rid of the long tones
>>>>
>>>> Stefanh: I like the proposal. I'd like more control on the
>>>> outgoing part
>>>>
>>>> burn: I think you can have the DTMF track be created by the
>>>> peerConnection
>>>>
>>>> justin: I support hta's proposal
>>>>
>>>> hta: I'll modify the proposal to incorporate burn's suggestion
>>>>
>>>> Other business
>>>>
>>>> hta: reviewing the collected items for discussion
>>>>
>>>> What Triggers Candidate Fetching
>>>>
>>>> Mathew: Use case is when a web page displays "call agent" . I
>>>> don't want all the visitors of the page to use my turn servers
>>>>
>>>> ekr: This should not be a problem
>>>>
>>>> hta: I don't understand why the use case is not satisfied
>>>>
>>>> Martin: you want to load the page and show as quickly as
>>>> possible
>>>>
>>>> justin: we have two mechanisms to control the candidates
>>>> gathering
>>>> ... you can do that now
>>>>
>>>> Martin: this brings us to changing constraints on the fly
>>>>
>>>> fluffy: we want to preallocate now were' talking about how to
>>>> do it in the API design
>>>>
>>>> justin: you would know what you need if you call setLocal
>>>>
>>>> fluffy: you can optimistically assume two
>>>>
>>>> Mathew: you got two use cases: the conference model where you
>>>> call in to a conference or the public page. We need to support
>>>> both efficiently
>>>>
>>>> fluffy: can we try to make a proposal
>>>> ... it's less elegant but should work
>>>>
>>>> justin: we can do this using setLocal
>>>>
>>>> fluffy: I have a different proposal. Have a constraint that
>>>> defines the preallocated streams
>>>>
>>>> ekr: it's fine for me
>>>>
>>>> hta: is this sort of creating a pool?
>>>>
>>>> fluffy: yes
>>>>
>>>> <martin> proposal is to add a new constraint
>>>> preallocateCandidates, which takes an integer value that
>>>> defaults to zero. setting this to any other value through the
>>>> constructor or updateIce triggers the filling of a candidate
>>>> set pool of that size. final actions are taken on
>>>> setLocalDescription
>>>>
>>>> hta: decision to go with the proposal to create a pool
>>>>
>>>> <martin> cullen will take an action to follow up on the last
>>>> issue (see my last item starting with "proposal")
>>>>
>>>> When is SDP sendable?
>>>>
>>>> <juberti> Next topic: when is SDP sendable
>>>>
>>>> <juberti> When do we know if we have all streams?
>>>>
>>>> <martin> my proposal for this was that the success callback
>>>> would fire, at which time the array^Wcollection would include
>>>> all the streams
>>>>
>>>> cullen: this doesn't let you know whether a stream was added or
>>>> removed.
>>>>
>>>> matthew: that doesn't work in all cases anyway; imagine calling
>>>> setRemoteDescription twice, the second time before all
>>>> callbacks have been received.
>>>>
>>>> cullen: on all functions that have callbacks, you can't call
>>>> the function again before the callbacks have dispatched.
>>>>
>>>> juberti: this would be setLocal, setRemote, createOffer,
>>>> createAnswer.
>>>>
>>>> ekr: what about getUserMedia?
>>>>
>>>> . should be possible to ask for multiple cameras.
>>>>
>>>> juberti: I have a proposal to handle the getUserMedia case.
>>>>
>>>> adambe: what about onaddtrack events?
>>>>
>>>> adambe: do we need onaddtrack when a stream is added?
>>>>
>>>> cullen: I read the spec, I think it says any time the remote
>>>> side adds a track, you need a callback.
>>>>
>>>> adambe: there's also an onunmute event on tracks too.
>>>>
>>>> adambe: how about only onaddtrack only when a stream is
>>>> updated, as opposed to added/removed?
>>>>
>>>> juberti: I like that proposal.
>>>>
>>>> cullen: I don't.
>>>>
>>>> martin: Let's address the stream callbacks first.
>>>>
>>>> hta: Let's do that.
>>>>
>>>> martin: setLocal, setRemote, createOffer, createAnswer should
>>>> all be non-reentrant.
>>>>
>>>> <fluffy> proposal is that that the createOffer / createAnser,
>>>> setLocal, setRemote, you can not call the same function again
>>>> if the callback from a previous invocation has not returned
>>>>
>>>> martin: during time between setRemote and callback, exceptions
>>>> should occur on any of these 4 APIs.
>>>>
>>>> martin: when you call setRemote, stuff will happen, but the
>>>> browser will return to stable state multiple times.
>>>>
>>>> <fluffy> On set remote, you install all the stuff, then does
>>>> does callback for onaddstream for each stream, then does
>>>> callback with null to on add stream, then it call the success
>>>> callback for set remote
>>>>
>>>> dom: do any other APIs do this?
>>>>
>>>> anant: in XHR, some things are disallowed while it is running.
>>>>
>>>> martin: during state transitions, no other transitions are
>>>> allowed.
>>>>
>>>> anant: you can't call open on the same XHR twice.
>>>>
>>>> stefan: might this introduce a timing problem? some browsers
>>>> are slower than others?
>>>>
>>>> dom: I don't think so
>>>>
>>>> cullen: I would guess that this is an atomic change, and it
>>>> takes some time - I would look at some API that has similar
>>>> needs
>>>>
>>>> dom: maybe IndexedDB
>>>>
>>>> jimbarnett: call should block instead of throwing exception
>>>>
>>>> adambe: if you get onrenegotiationneeded, that could cause a
>>>> problem
>>>>
>>>> cullen: onrenegotiationneeded fires after the success/error
>>>> callback, if needed.
>>>>
>>>> martin: queuing of calls could work OK.
>>>>
>>>> cullen: one lock across all 4 APIs.
>>>>
>>>> <timpanton> The way most UI APIs deal with this is to say that
>>>> those functions can only be called on the 'main' thread
>>>>
>>>> hta: proposal is: when calling one of these APIs - check args,
>>>> throw exception if needed, check lock, do work or queue task if
>>>> needed.
>>>>
>>>> <timpanton> if the callback is also invoked on the same thread,
>>>> this makes the thing queue naturally.
>>>>
>>>> hta: nobody argued for throwing an exception instead of
>>>> queueing.
>>>>
>>>> hta: anant to write up the details here.
>>>>
>>>> <dom> ACTION: Anant to write up queuing mechanism for
>>>> set{Remote,Local}Description, create{Offer,Answer} [recorded in
>>>> [14]http://www.w3.org/2012/10/30-webrtc-minutes.html#action02]
>>>>
>>>> <trackbot> Created ACTION-60 - Write up queuing mechanism for
>>>> set{Remote,Local}Description, create{Offer,Answer} [on Anant
>>>> Narayanan - due 2012-11-06].
>>>>
>>>> <martin> callbacks have to be called on the same thread, there
>>>> is only one thread
>>>>
>>>> juberti: when does onaddstream fire?
>>>>
>>>> <timpanton> So how could you get re-entrancy ?
>>>>
>>>> hta: onaddstream fires after installation is complete, but
>>>> before the success callback has been dispatched.
>>>>
>>>> <martin> re-entrancy applies only in the sense that the actions
>>>> associated with the methods take time and so could
>>>> (conceivably, without these measures) operate in parallel
>>>>
>>>> burn: no add stream for failures, naturally
>>>>
>>>> <martin> the actions occur on browser-internal threads or "in
>>>> the network"
>>>>
>>>> <timpanton> ok. got it.
>>>>
>>>> juberti: when is pc.remoteStreams updated?
>>>>
>>>> adambe: before the first onaddstream callback is fired,
>>>> remoteStreams will be fully up to date with the changes.
>>>>
>>>> derf:<same thing>
>>>>
>>>> cullen: stream names are confusing.
>>>>
>>>> derf: event callbacks need to change to be less confusing.
>>>>
>>>> <dom> ACTION: Timothy to write up proposal for new stream event
>>>> names. [recorded in
>>>> [15]http://www.w3.org/2012/10/30-webrtc-minutes.html#action05]
>>>>
>>>> matthew: if SessionDescription is 3264 SDP, that SDP must
>>>> always be 3264-compliant.
>>>>
>>>> cullen: if you can't do local candidates, we should return an
>>>> error when trying to write SDP.
>>>>
>>>> matthew: will trickle update 3264?
>>>>
>>>> cullen: I think we'll need to.
>>>>
>>>> matthew: if we're doing trickle, we're going to need to update
>>>> something.
>>>>
>>>> matthew: how do we generate workable SDP when trickling?
>>>>
>>>> matthew: Chrome currently generates broken SDP?
>>>>
>>>> matthew: How do I get valid SDP in the non-trickle case?
>>>>
>>>> cullen: wait for ICE complete callback, then SDP will be fully
>>>> filled-in.
>>>>
>>>> matthew: but what about the initial setLocal? That SDP isn't
>>>> fully valid.
>>>>
>>>> juberti: That is just a subset of the trickle case.
>>>>
>>>> matthew: But the SDP still isn't valid.
>>>>
>>>> juberti: We are going to solve this with the trickle ICE I-D.
>>>>
>>>> . and then the rest of the stuff should fall into place. You
>>>> can call setLocal with an initial "no candidates" SDP, and then
>>>> gathering commences.
>>>>
>>>> hta: we'll refer this to the IETF rtcweb WG to figure this out,
>>>> and then we can resume this discussion.
>>>>
>>>> Security for QoS labels
>>>>
>>>> matthew: Want to see API where packet priorities can be set.
>>>>
>>>> hta: culler's proposal does this - gives 3 levels of
>>>> priorities.
>>>>
>>>> cullen: API that provides 3, 4, etc levels
>>>>
>>>> matthew: I don't know which one is more important.
>>>>
>>>> matthew: data could be above or below media (gaming, higher,
>>>> file transfer, lower)
>>>>
>>>> dand: where would this priority be set from an API perspective
>>>>
>>>> stefan: on a track or datachannel.
>>>>
>>>> <dom> there was a (currently abandonned) proposal for
>>>> setPriority on XHR that also had 4 levels FWIW
>>>> [16]http://ajaxian.com/archives/xmlhttprequest-priority-proposa
>>>> l
>>>>
>>>> [16] http://ajaxian.com/archives/xmlhttprequest-priority-proposal
>>>>
>>>> matthew: someone needs to write up a proposal for where these
>>>> things go.
>>>>
>>>> hta: set at initialization, or during the call?
>>>>
>>>> matthew: I think it could be initialization.
>>>>
>>>> dand: once we get this request, we need a confirmation from the
>>>> browser that it tried to accomplish this.
>>>>
>>>> martin: why?
>>>>
>>>> dand: this request can be fulfilled by going to a policy
>>>> server.
>>>>
>>>> matthew: I don't care about marking, I just care about the
>>>> congestion control prioritization
>>>>
>>>> matthew: not all packets will be labeled the same way
>>>>
>>>> matthew: either for different streams, or different packets in
>>>> the same stram
>>>>
>>>> hta: need to set priority levels, and have it per track, and
>>>> have 3 or 4 levels.
>>>>
>>>> hta: this will set congestion control/queuing in the browser,
>>>> and setting of QoS is something for further study
>>>>
>>>> matthew: cullen has already written a draft
>>>>
>>>> goran: cullen's draft refers to other drafts
>>>>
>>>> cullen: we will remove that reference.
>>>>
>>>> cullen: we don't want JS to set the diffserv code points, but
>>>> we do want it to be able to discover them.
>>>>
>>>> hta: want mapping from track to 6-tuple?
>>>>
>>>> <juberti> ACTION: Cullen to update draft to remove reference.
>>>> [recorded in
>>>> [17]http://www.w3.org/2012/10/30-webrtc-minutes.html#action06]
>>>>
>>>> <trackbot> Created ACTION-61 - Update draft to remove
>>>> reference. [on Cullen Jennings - due 2012-11-06].
>>>>
>>>> Action. stefanh to propose priority API.
>>>>
>>>> <juberti> ACTION: stefanh to propose priority API. [recorded in
>>>> [18]http://www.w3.org/2012/10/30-webrtc-minutes.html#action07]
>>>>
>>>> <trackbot> Created ACTION-62
>>>>
>>>> Adjourning for lunch.
>>>>
>>>> Summary of Action Items
>>>>
>>>> [NEW] ACTION: Adam to update APIs to use mutable arrays of
>>>> streams in peerconnection with ids [recorded in
>>>> [19]http://www.w3.org/2012/10/30-webrtc-minutes.html#action01]
>>>> [NEW] ACTION: Anant to write up queuing mechanism for
>>>> set{Remote,Local}Description, create{Offer,Answer} [recorded in
>>>> [20]http://www.w3.org/2012/10/30-webrtc-minutes.html#action02]
>>>> [NEW] ACTION: Cullen to update draft to remove reference.
>>>> [recorded in
>>>> [21]http://www.w3.org/2012/10/30-webrtc-minutes.html#action06]
>>>> [NEW] ACTION: stefanh to propose priority API. [recorded in
>>>> [22]http://www.w3.org/2012/10/30-webrtc-minutes.html#action07]
>>>> [NEW] ACTION: Timothy to write up proposal for new stream event
>>>> names. [recorded in
>>>> [23]http://www.w3.org/2012/10/30-webrtc-minutes.html#action05]
>>>>
>>>> [End of minutes]
>>
>>
Received on Saturday, 17 November 2012 17:45:07 UTC