- From: Joe Steele <steele@adobe.com>
- Date: Tue, 14 May 2013 09:12:39 -0700
- To: "public-html-media@w3.org" <public-html-media@w3.org>
- Message-ID: <24D59B61-2D7C-47F6-B089-54C349F4E2E5@adobe.com>
The minutes are available at: http://www.w3.org/2013/05/14-html-media-minutes.html ________________________________ [http://www.w3.org/Icons/w3c_home]<http://www.w3.org/> HTML Media Task Force Teleconference 14 May 2013 Agenda<http://lists.w3.org/Archives/Public/public-html-media/2013May/0082.html> See also: IRC log<http://www.w3.org/2013/05/14-html-media-irc> Attendees Present Bin_Hu, BobLund, Cyril, Michael_Thornburgh, acolwell, adrianba, ddorwin, glenn, jdsmith, joesteele, markw, pal, paulc, pladd Regrets John Simmons Chair Paul Cotton Scribe joesteele Contents * Topics<http://www.w3.org/2013/05/14-html-media-minutes.html#agenda> * Roll call<http://www.w3.org/2013/05/14-html-media-minutes.html#item01> * Previous Minutes<http://www.w3.org/2013/05/14-html-media-minutes.html#item02> * Action items and issues<http://www.w3.org/2013/05/14-html-media-minutes.html#item03> * ACTION 11<http://www.w3.org/2013/05/14-html-media-minutes.html#item04> * Open Issues<http://www.w3.org/2013/05/14-html-media-minutes.html#item05> * MSE status and bugs<http://www.w3.org/2013/05/14-html-media-minutes.html#item06> * Arrange pre-last call period for MSE<http://www.w3.org/2013/05/14-html-media-minutes.html#item07> * EME bugs<http://www.w3.org/2013/05/14-html-media-minutes.html#item08> * FPWD<http://www.w3.org/2013/05/14-html-media-minutes.html#item09> * Summary of Action Items<http://www.w3.org/2013/05/14-html-media-minutes.html#ActionSummary> ________________________________ Roll call Previous Minutes http://www.w3.org/2013/04/30-html-media-minutes.html http://www.w3.org/2013/05/07-html-media-minutes.html <paulc> VER 2 agenda: http://lists.w3.org/Archives/Public/public-html-media/2013May/0082.html paulc: using later version of the agenda Action items and issues paulc: 2 items and one issue ... ACTION 10 was on Adrian adrianba: there's an action for everyone to arrive at consensus on model for the session ... have not caught up on the status lately paulc: bug 19208 is still open? adrianba: may be paulc: resolved as a dup of 21855 <paulc> Bug 21855 - Avoid network traffic and duplicate sessions for the same key(s) <paulc> https://www.w3.org/Bugs/Public/show_bug.cgi?id=21855 ACTION 11 paulc: write a proposal for the JS -- Mark did this and the link is in the agenda <adrianba> ACTION-11? <trackbot> ACTION-11 -- Mark Watson to write a proposal for the case where the data is not available to the JS -- due 2013-04-16 -- OPEN <trackbot> http://www.w3.org/html/wg/media/track/actions/11 paulc: believe this is now done? markw: yes paulc: marking as closed ddorwin: showing as closed now Open Issues paulc: this is re: moving the ClearKey spec into a separate docs <paulc> https://www.w3.org/html/wg/media/track/issues/1 MSE status and bugs paulc: updated a couple of the sub agenda items based on Aarons status report ... Aaron has updated the editors draft which is in the agenda ... sent a message giving the update information ... Aaron do you want to add? acolwell: no - just working on editorial changes <paulc> Aarron's update on MSE: http://lists.w3.org/Archives/Public/public-html-media/2013May/0075.html acolwell: will provide some additional text this week paulc: any comments on this? ... assume that only outstanding bug it the splicing bug? <paulc> Bug 21431 - Specify splicing behavior for text tracks <paulc> https://www.w3.org/Bugs/Public/show_bug.cgi?id=21431 paulc: so you will impleent what is in comment #12? <paulc> Planning to implement: https://www.w3.org/Bugs/Public/show_bug.cgi?id=21431#c12 jdsmith: at the F2F talking about video quality we settled returning dropped frames as the indicator of quality ... it is actually difficult to measure dropped frames ... more accurate for us to measure rendered frames <adrianba> https://www.w3.org/Bugs/Public/show_bug.cgi?id=20760 jdsmith: original proposal was to return average frame rate of rendered frames ... returning dropped frames is problematic in our implementation paulc: bug number? <paulc> Current status of 20760 is RESOLVED FIXED acolwell: question is that we should have the total number and rendered frames, so should calc difference jdsmith: we have approximate average frame rate so we can approximate <paulc> [Paul apologizes for his rough cough if it is audible] acolwell: this should be accurate? paulc: are you asking to reconsider? jdsmith: yes -- would prefer to return the data points and let the app figure it out paulc: would prefer you reopen with explanation, possibly with revised text jdsmith: ok acolwell: not clear what the interval is that the frame rate is being measured on -- wary of that metric markw: re: dropped frames should be simple as possible for the user to understand ... don't want something simple for us but harder for users? ... approximation is fine for this purpose pal: wanted to follow up on the issue of supporting multiple frame rates ... is this really a requirement? acolwell: yes pal: so why not limit every buffer to a single framerate? acolwell: we don't guarantee a seamless splice between buffers paulc: do we have a separate bug for this question? acolwell: no - this discussion came up during time splice accuracy discussion <markw> In H.264/ISO media files at least there is no such thing as frame rate. Each sample has a timestamp, that is all paulc: if this is orthogonal - having a separate bug with a clear disposition would be a good paper trail ... leave it to others to decide acolwell: WebM also paulc: Jerry you will take the action to reopen as necessary cyril: question about the text track splicing <paulc> Bug 21431 - Specify splicing behavior for text tracks cyril: have not read carefully, but was something said about text tracks having variable frame rates? ... may not know the duration of the cue ... until the next track comes in ... might have some impact on the management of the cues acolwell: we are assuming we know the duration of cues now ... may be a requirement we need to state -- need text track experts to chime in cyril: for example video survellance vidoes may not know the frame rate until the vides come in ... may extend the duration of the previous sample acolwell: is this a common use case we need to solve now? not all MPEG-4 file supported now ... can file a bug to discuss more cyril: we can resolve later, but should recognize the issues acolwell: some discussion has been around defining simple behavior and adding more complex logic later to describe the outlier cases cyril: I will open a bug BobLund: comment on the idea of a cue with unknown length ... not really unknown from a media buffer perspective ... it will have an end, but player may not know the end ... HTML5 is clear on what should happen with the rendering of text tracks pal: confirm current thoughts on behavior ... for purposes of MSE, in the algorithm frames are replaced by cues acolwell: non-overlapping cues ... lots of nastiness when overlapping cues are allowed paulc: any other bugs for MSE we should discuss? cyril: have seen in the latest spec we say ... the MOOV is not allowed in a media segment ... will this trigger a decode error when encountered? ... spec says what is conformant but not non-conformant acolwell: let me look at the spec <acolwell> https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#sourcebuffer-segment-parser-loop acolwell: look at step 2 of the parsing loop <paulc> Quote: 2.If the input buffer starts with bytes that violate the byte stream format specifications, then run the end of stream algorithm with the error parameter set to "decode" and abort this algorithm. acolwell: this shows the signal of a decode error cyril: when you have a MUST and it is not fulfilled then it is a violation acolwell: yes ... if you have some text that would make it clearer please suggest it cyril: just in a different location, but I understand now paulc: cross-references in the spec to make it clearer are useful ... should be useful for 3rd parties who are not in these discussions cyril: so maybe a cross-ref to the byte stream specification would help acolwell: add a normative note Arrange pre-last call period for MSE paulc: this will close Wed May 22nd -- this email went out a couple of weeks ago ... we must know what bugs to process prior to Last Call cyril: if we want bugs resolved before must be filed by then? paulc: no -- any bugs filed before that date will be resolved before Last Call ... otherwise it prevents us from going into Last Call ... because we are not at 0 bugs paulc: this lets us identify the bugs that must really be addressed by Last Call ... moving on to EME? cyril: what is the status of the primer? paulc: did a call for volunteers -- have not received any volunteers as yet <paulc> Call for volunteers: http://lists.w3.org/Archives/Public/public-html-admin/2013May/0002.html cyril: might want to volunteer paulc: might want to have a conversation with the chairs to confirm what is wanted ... get some context on previous primers EME bugs http://dvcs.w3.org/hg/html-media/raw-file/tip/encrypted-media/encrypted-media.html paulc: David want to make any comments? ddorwin: no -- sent an email <paulc> https://dvcs.w3.org/hg/html-media/raw-file/tip/encrypted-media/encrypted-media.html FPWD <paulc> FPWD: http://www.w3.org/TR/2013/WD-encrypted-media-20130510/ <ddorwin> Also, http://www.w3.org/TR/encrypted-media/ paulc: need to update the copyright to match the editors draft Topic Outstanding Bugs paulc: 30 of them <paulc> http://tinyurl.com/7tfambo paulc: there are is an active email thread on ACTION-11 -- should we spend time on that? or avoid it? <paulc> http://lists.w3.org/Archives/Public/public-html-media/2013May/0068.html <markw_> I think it makes sense to talk about the ACTION-11 item ddorwin: marks email since there has been discussion paulc: intro to ACTION-11? markw: proposal was to define what might happen if CDM data is not available to the JS apis ... we know there will be CDMs that takes advantage of HW and data will not be available ... may be cases where it will be available ... need to define behavior when the data is not available ... two cases - audio and video ... Canvas could be used to access video data with getImageData to get raw YUV or RGBa data from Canvas ... with audio there is a Media Source Element source mode ... can do the processing for the audio node ... get back the raw PCM bytes ... could have the original APIs behave as if there was no media -- probably most likely to be implemented ... drawImage would do nothing, Media Element source mode would act as if there is no audio ... could image another scenario where they work but just not for the EME data <pal> Q: shouldn't the JS application be able to inform the user that video/audio is not available because it is protected? markw: would be much more complicated ... maybe we should not exclude this possibility ... maybe we just need to document this behavior? adrianba: since we won't be able to definitely describe the behavior for all possible APIs now and in the future for EME ... we should make this informative following the principle Mark outlined ... would act as if no data was available ... maybe we can use the Canvas and audio as examples ... let APIs define there own behavior based on this principle <markw_> What adrian says makes sense to me <ddorwin> +1 markw: that is question about the failure mode ... that would allow the JS to respond differently <adrianba> You can detect in JS that you're using EME since you have to do something explicit to use it. markw: something the owners of both APIS to specify ... app should know if it is dealing with encrypted media agree with the proposal -- however could be an issue with when some streams are encrypted and others are not, for example ads. <adrianba> i think we can wait to see if apps run into problems with not knowing whether failure was because of EME or otherwise before engineering a solution to what seems to me to be a corner case pal: to marks comment - the existnece of EME does not necessairly imply this, seems to be a reluctance to directly indicate this markw: the way to indicate if it is to be indicated it specific to the APIs (Canvas, audio) pal: the Canvas element has errors, conceivably we could file a bug that another error is needed e.g. CANNOT_COPY markw: could be fine to file a bug, up to them whether to expose this pal: more information better for the JS app adrianba: echo what Mark said, hard to enumerate all the places where this data might be consumed. ... this seems like an edge case as to why the data was encrypted ... unlikely that an app will have something the user can correct to handle this ... if that emerges we can solve the problem then paulc: what do we need to do to decrease the bug count? ... do we need to nominate a specific list of bugs? adrianba: bugs are waiting for feedback -- does not need to be in this meeting ... half of the bugs have proposed solutions ... should not be too difficult but folks need to reply to them <ddorwin> Most recently updated bugs: https://www.w3.org/Bugs/Public/buglist.cgi?bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&columnlist=short_desc%2Cassigned_to%2Cpriority%2Cbug_status%2Cresolution%2Ctarget_milestone%2Cchangeddate&component=Encrypted%20Media%20Extensions&product=HTML%20WG&query_format=advanced&list_id=11029 adrianba: most recent bugs would be a good target ... could have a conversation then <ddorwin> Sorry, this might be better: https://www.w3.org/Bugs/Public/buglist.cgi?bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&columnlist=short_desc%2Cassigned_to%2Cpriority%2Cbug_status%2Cresolution%2Ctarget_milestone%2Cchangeddate&component=Encrypted%20Media%20Extensions&list_id=11029&product=HTML%20WG&query_format=advanced&order=changeddate%20DESC%2Cbug_status%2Cpriority%2Cassigned_to%2Cbug_id&query_based_on= paulc: you are saying we need folks input before discussing in next weeks meeting ... could be more aggressive in proposing changes to force folks forward <ddorwin> Previous email listing of bugs to discuss: http://lists.w3.org/Archives/Public/public-html-media/2013May/0004.html paulc: resolving bugs as NEEDS_INFO ... nearly out of time -- please suggest a list of bugs and people whose input is needed <ddorwin> New bug: https://www.w3.org/Bugs/Public/show_bug.cgi?id=21977 paulc: will have a mtg next week starting with EME and could start assigning folks to make progress adrianba: filed a new bug about swapping parameters ... people should take a look <ddorwin> https://www.w3.org/Bugs/Public/show_bug.cgi?id=21977 - Swap isTypeSupported() parameter order so keySystem is first adrianba: link is pasted above paulc: done for today paulc: propose focusing on EME next week and MSE after paulc: done for today Summary of Action Items [End of minutes] ________________________________ Minutes formatted by David Booth's scribe.perl<http://dev.w3.org/cvsweb/~checkout~/2002/scribe/scribedoc.htm> version 1.138 (CVS log<http://dev.w3.org/cvsweb/2002/scribe/>) $Date: 2013-05-14 16:06:43 $
Received on Tuesday, 14 May 2013 16:13:21 UTC