[MEDIA_PIPELINE_TF] Teleconference Notes- 04 August 2011

Media Pipeline Teleconference Notes

 

04 August 2011

 

Chair

                Clarke Stevens (Cablelabs)

 

Attendees

 

Duncan Rowden (BBC)

Bob Lund (Cablelabs)

Clarke Stevens (Cablelabs)

Mark Vickers (Comcast)

Nilo Mitra (Ericsson)

Narm Gadiraju (Intel)

Giuseppe Pascale (Opera)

Russell Berkoff (Samsung)

Tatsuya Igarashi (Sony)

Hiroyuki Aizu (Toshiba)

Shunichi Gondo (Toshiba)

Francois Daoust (W3C)

Kazuyuki  Ashimura (W3C)

 

Scribe

                Russell Berkoff (Samsung)

 

Agenda

 

Clarke:
http://www.w3.org/2011/webtv/wiki/MPTF/Agenda_Telco_4th_August_2011

Clarke: Continue review of use cases

Clarke: Video support of MPEG transport

<scribe>Review of Last Call bugs</scribe>

 

Topic: ISSUE-37 - Viewport support for video (Duncan)

 

Clarke: ISSUE 37 - Viewport support for video (Duncan)

Duncan: For broadcast, video is handled via mosaic

Bob:  Can provide input focus?

Duncan: Yes

Bob: Are there other aspects of control?

Duncan: Mosaic is transmitted as a picture

Clarke: Mosaic not composed on client side?

Duncan: Correct - Client would select part of picture provided by server

Clarke: Could select part of picture to provide audio for?

<scribe> I recall answer was no??</scribe>

Clarke: Comments? 

Francois: Sounds like mosaic are user interfaces. How to make it a good
user interface such as providing animations for zoom operations. Provide
offsets for horz, vertical viewport. Provide styling.

Duncan: May not always need to provide animation. May just need to
switch between viewports w/o animation.

Francois: May want to draw border around tiles. Possibly overlay canvas?

Bob: Lot of this already exists using <map>. Let you break component
into images and apply styling? Don't have capability to select portion
of video and provide styling.

Narm: Does map also allow regions of map to have styling? 

Bob: Map doesn't provide this. Animations would need to be overlaid. Map
doesn't provide manipulation of image.

Francois:  Map is restricted to image tag. Need to extend to <video>
element.

Clarke: Need to see if this can be done with existing facilities.

AR: Duncan - See if this can already be done with existing facilities

 

Topic: ISSUE-18 - Video tag support of MEPG2-TS

 

Clarke: Asked for Jan Lindquist  - <scribe>Not on call</scribe>

Clarke: Jan took video use case see if this can be done using existing
use case see ISSUE-18 in HNTF

Clarke: 35 elements in ISSUE data base

<scribe>Some discussion of sharing Track database between WebTV
TFs</scribe>

Clarke: Request for Jan to restate use case as new issue

AR: Jan summarize ISSUE-18 as new use-case

 

Topic: ISSUE-35 Continuous Streaming

 

                <scribe>Some difficulty identifying speakers</scribe>

 

Clarke: Continuous streams

Clarke: Does encoding of TV channels [consist of] continuous stream with
time-coding? 

Clarke: Alternative multiple segments with time-stamps, starting at 0
for each segment. 

Clarke: Need to be able to sync adverts with underlying stream.

                Bob?:  May be media encoding requirements. Encoders
normalize time into single time base. 

Clarke: Does W3C need to do anything? Is this out of scope. 

Mark?: HTML5 provides support for multiple audio video specifically.
Specify one of resources as master and sync other streams to it.

Bob: May have specific use cases not accommodated? For a stream time
starts at zero and increases. Timestamps may wrap but only after long
time.

Clarke: Will keep issue open for additional comments. Probably do not
need new use-case.

Kaz: Even if use-case is covered. May want to keep this in UC document.
Maybe in separate section. <scribe>Post topic - Was on mute</scribe>

 

Topic: HTML5 Last Call Bugs (13333 13357 13358 13359 13625)

 

Clarke: HTML5 last call bugs.

Clarke: Two last-call bugs. Request update on bugs. Anything for MPTF to
do?

Mark: Five bugs that have been submitted. One rejected/closed with
escalation 13333 

                Mark: [Remaining:] 13357 13358 13359 13625 no action /
discussion

Clarke?: Suggest supporting bugs

Clarke: Suggest going through bugs

Bob?: 13358 - Event needed to signal change in track for media resource.
LP media streams. 

Bob?: Today you can multiple video, audio tracks with single event. UA
fires event indicating all tracks are available, but no event when
tracks available change. UA should detect [this] event. 

Clarke: Any objections to bug? MPTF to support bug.

Francois: Generic question: What does MTPF endorsement mean?

Clarke: Acknowledges Web & TV indicates bug is important. Up to HTML5 to
pick solution/

Francois: <scribe>Missed comment</scribe>

Kaz: Talked to domain leader. Review period ends on Aug 3 yesterday. WG
won't accept comments after this period but will accept comments for
following period. 

Kaz: Endorsement not relevant but comments are relevant.

Giuseppe: Send message to HTTP group that MPTF considers issue
important. 

Giuseppe: Bugs were submitted before deadline so all bugs are approved
for LastCall_1. Can send message to list.

Bob: Review last two bugs.

Bob: 13359 Way need to id type of data in track element.

Bob: Way to carry captions subtitles, metadata without defined type to
be acted upon by JS. 

Bob: North American Cable plans ETV Signaling to sync application with
video/audio. Can provide more info by clicking video.

Bob: Text track today does not id type of data in track. In the case of
captions, format of caption can vary by region. 

Bob: All that is exposed that there is a caption. Need to sniff content
to detect type of caption data.

Giuseppe: Was this by design? Use mimetype to detect type of data.

Bob: For in-band tracks there are no mimetypes available. For metadata
tracks can have different types of tracks. 

Bob: Tells format of track rather than format of metadata. Can have
add-insertion opportunities.

Giuseppe: For out-of-band case need to define type

Bob: Request to provide mimetype for track?

Giuseppe: Both User Agent and application deals with data types?

Bob: User Agent needs to know type anyway. Use-case is for a user-script
rather than User Agent?

Francois: Type attribute is a hint for the application.

Bob: Bug may not be clearly worded. Request to add mimetype for
out-of-band tracks. Generated by User-Agent for in-band tracks.

??: May not be useful to add type attribute. Up to HTML5 WG?

Clarke: Any objections to endorsing bug. <scribe>None</scribe>

Bob: 13625 - Alternate mechanism for 13333. Comment on 13333 question on
real world use-case. 

Bob: No way to pass AV metadata to User Agent for playback. Problem
statement identifies HTML5 User Agent need additional info for Home
Network content. 

Bob: Mimetype, @protocolInfo, @linkprotection 

Bob: User Agent needs info to undo link protection before playback. Also
size of content. 

Bob: Third [is[ metadata is for protection  (DRM scheme). Mimetype may
signal content protection but may need additional metadata for content
protection. 

Bob: May be applied to other content types. Proposed solution to add 3
new attributes to<video>, <audio> element to pass this metadata info.

Kaz: May need additional information in future. May need more general
attribute scheme. 

Bob: May have other metadata type in future. May be better to have
single attribute containing additional metadata?

Kaz: Content-feature may contain arbitrary information.

                Mark: May want to add to 13625?

Giuseppe: May want to use different method? Pass parameters as strings.
GetUserMedia (<scribe>method?</scribe>).

Bob: How is this data conveyed to User Agent?

Clarke: Endorse bug as a concern, rather than particular solutions.

AR: Chairs to draft message to indicate we are interested in outcome of
these bugs.

Clarke: Address table on next call

 

AR Summary

 

AR: Duncan - See if this [ISSUE-37] can already be done with existing
facilities

AR: Jan - Summarize ISSUE-18 as new use-case

AR: Chairs -  to draft message to indicate we are interested in outcome
of these [Last Call] bugs.