- From: Jean-Claude Dufourd <jean-claude.dufourd@telecom-paristech.fr>
- Date: Fri, 10 Sep 2010 13:40:14 +0200
- To: www-svg@w3.org
- Message-ID: <4C8A191E.6020703@telecom-paristech.fr>
Dear all, Here are preliminary results from my action, for discussion. The MAE state chart is at: http://www.w3.org/TR/MediaAccessEvents/images/stateChart.png The HTML5 video does not have a state chart, and I have tried to reconstruct one from the events definition, attached. I am not sure about the two arrows in deeper blue (one missing transition, one that may not apply to the wait state) As far as states are concerned, we can match: - MAE "setting session" with HTML5 "beginning" (the state names are mine) - MAE "session set up" with HTML5 "got metadata" - MAE "reception state" with HTML5 "got data" - MAE "reception and playing state" with HTML5 "playing" MAE "playing state" is unmatched: HTML5 does not distinguish the case where the data reception is complete and the playing goes on, but it looks like a compatible extension of HTML5. The HTML5 suspended state is unmatched in MAE, but it could be thought of as refinement of "reception state". For events, we can match: - MAE BeginSessionSetup with HTML5 loadstart - MAE EndsessionSetup with HTML5 loadedmetadata - MAE Playable and NotPlayable with HTML5 playing and waiting - MAE DataReceptionProgress with HTML5 progress It is more difficult to match: - MAE DataRequest is sent upon sending a data request to the server, whereas HTML5 loadeddata is sent when the user agent can render the media data <http://www.w3.org/TR/html5/video.html#media-data> at the current playback position <http://www.w3.org/TR/html5/video.html#current-playback-position> for the first time. - HTML5 play and pause are only related to the script function calls play() and pause(); I do not see them as very useful. HTML5 suspend, canplay and canplaythrough are compatible extensions of MAE. The definition of HTML5 play event is incoherent: if play() happens before the video is in "got data" state, then the play event cannot yet be sent. There is a missing transition back from the HTML5 suspend state: I think it should be added. HTML5 video is definitely geared toward "download and play", and "http streaming" (or "pseudo streaming"). MAE was geared toward RTP/RTSP, which are dead, or other forms (?) of true streaming. The decline of true streaming is removing arguments for MAE. Question: would the HTML5 guys accept to add a state chart ? one more state ? fixing the play and pause definitions, maybe removing them ? Best regards JC -- JC Dufourd Directeur d'Etudes/Professor Groupe Multimedia/Multimedia Group Traitement du Signal et Images/Signal and Image Processing Telecom ParisTech, 46 rue Barrault, 75 013 Paris, France Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
Attachments
- image/png attachment: Screen_shot_2010-09-10_at_13.36.10_.png
Received on Friday, 10 September 2010 11:40:45 UTC