W3C home > Mailing lists > Public > public-ddwg@w3.org > October 2007

RE: Video Streaming Properties [WAS RE: Meeting Summary - 15 October 2007]

From: Runar J. Solberg <runar.solberg@adactus.no>
Date: Fri, 19 Oct 2007 15:37:31 +0200
To: "'Rotan Hanrahan'" <rotan.hanrahan@mobileaware.com>
Cc: <public-ddwg@w3.org>, <public-uwa@w3.org>
Message-Id: <20071019133838.E44A7193872@bud.itea.ntnu.no>
Rotan,

 

Thank you for your detailed and enlightening reply. It will be interesting
to see the evolution of such a video vocabulary. I hope that process can be
as open to the public as the Core vocabulary process, and that information
on such work can be posted on these list. 

 

Best regards

 

Runar

 

 

  _____  

From: public-ddwg-request@w3.org [mailto:public-ddwg-request@w3.org] On
Behalf Of Rotan Hanrahan
Sent: Friday, October 19, 2007 11:58 AM
To: Runar J. Solberg
Cc: public-ddwg@w3.org; public-uwa@w3.org
Subject: Video Streaming Properties [WAS RE: Meeting Summary - 15 October
2007]

 

Thank you Runar for your comments and your detailed information.

 

The main reason the group decided that the video streaming property was not
to be in the DDR Core Vocabulary was because of the nature of the
vocabulary. The big challenge facing the mobile aspect of the Web is just
getting a functional presentation of ordinary Web content in such a diverse
context. The core vocabulary is there to capture the absolutely essential
properties that will enable a typical Web page to be adapted to mobile
contexts.

 

For more complex content, or more complex adaptation strategies, the group
envisages a set of additional vocabularies to accompany the DDR Core
Vocabulary. To ensure compatibility across these vocabularies, it is
expected that all will reference a common ontology, which provides the
semantics for all of the concepts and data represented in the vocabularies.
The W3C UWA WG is the group responsible for maintaining the ontology.

 

Any properties that the DDWG believes are not core for the objectives set
out in our charter, will not be abandoned. Instead, two further steps are
taken:

 

First, we determine if the proposed property represents something not
already captured in the UWA ontology, and if so, we submit it to the UWA for
consideration. This means that although the property would not be
represented in our core, it would be possible to have an additional
vocabulary that includes the property and also references the common
ontology.

 

Second, we make contact with the proposer and other (specialist) groups to
see if they would be interested in creating a vocabulary that references the
ontology entry so that more advanced adaptation solutions can make use of
it. For example, we are already working closely with the OMA who will have a
vocabulary of their own for their particular needs, and we have made contact
with the OpenAjax Alliance to propose that they too would have a vocabulary
for Ajax-related properties.

 

In time, adaptation systems will be able to make use of Device Description
Repositories that contain data belonging to several vocabularies. We also
expect that advanced adaptation solutions will have custom vocabularies of
their own, possibly with their own ontologies, though our preference is that
the UWA's ontology should be sufficient for any vocabulary.

 

The reason why Supported Image Formats was considered to be an important
property is because of the many years in which images have been part of Web
content, the fact that almost every Web page contains at least one image,
and the fact that almost all mobile devices support at least one image
format thus making it possible for them to render most of the Web if
appropriately adapted.

 

One might think that having a property in the core that says "this device is
capable of video stream playback" would be a good property to include.
However, to make use of the fact you would then have to have additional
properties to determine which particular formats, bit rates etc are
applicable. It sounds like a whole new vocabulary for video is required. For
this more specialised case, an adaptation system would connect to a DDR that
had a Video Vocabulary and it would ask "does this device support video
streaming?" and subsequently it could ask other questions relating to video,
assuming the right properties were in the vocabulary (and the repository
contained data to go with those properties).

 

The DDWG will consider the groups that should be contacted in order to
propose the creation of a video vocabulary. Meanwhile, the information you
have provided will be forwarded to the UWA for consideration by means of
copying this response to the public list of the UWA.

 

Thanks again.

 

---Rotan (chair).

 

 

 

From: Runar J. Solberg [mailto:runar.solberg@adactus.no] 
Sent: 19 October 2007 08:48
To: Rotan Hanrahan
Cc: public-ddwg@w3.org
Subject: RE: Meeting Summary - 15 October 2007

 

Hi,

 

I have a comment regarding the H.264 property. I was the one that proposed
it. I appreciate that the group has taken the time to consider it. Based on
the group's feedback I realize my proposal was badly formulated. 

 

My intention of the proposal was rather to indicate if the device can
playback H.264 for videos. This is regardless if the delivery method is
streaming or download. In this context the property should have been called
"video of H264 Baseline Profile Level 1.0" not "Streaming video of H264
Baseline Profile Level 1.0". I apologize for this bad naming. 

 

Nevertheless the bit rates stipulated are characteristics of a video
conformant with the corresponding profile, but have little to do with the
delivery method of the bits. It is actually the bit rate of the H.264 video.
How the bits got to the device (Streaming, download) I now realize is out
side the scope of the Core Vocabulary. But is the playback capabilities also
outside the scope? I see you have approved gif87 and gif89a for gif images,
so I am curious to know the groups stand on video capabilities? 

 

I am happy to submit a new proposal illustrating this, if it is any chance
of getting it accepted. Based on the emphasis of delivery bitrates
(streaming) I understand that the groups decision to mark it as "Not Core".
However I hope you will reconsider the new proposals below: 

 


Name

Description

Measurement

Justification


Video h264 Baseline  Level 10

Device is capable of playing a video of H264 Baseline Profile (BP) Level
1.0. 

Measured by trying to playback a conformant H264 video at baseline profile
level 1, to the device. Playback should be successful.   

Primarily for lower-cost applications with limited computing resources, this
profile is used widely in videoconferencing and mobile applications.


Video h264 Baseline  Level 1.b

Device is capable of playing a video of H264 Baseline Profile (BP) Level
1.b.

Measured by trying to playback a conformant H264 video at baseline profile
level 1.b, to the device.

Playback should be successful. 

Primarily for lower-cost applications with limited computing resources, this
profile is used widely in videoconferencing and mobile applications.


Video h264 Baseline  Level 1.1

Device is capable of playing a video of H264 Baseline Profile (BP) Level
1.1.

Measured by trying to playback a conformant H264 video at baseline profile
level 1.1, to the device. Playback should be successful.   

Primarily for lower-cost applications with limited computing resources, this
profile is used widely in videoconferencing and mobile applications.


Video h264 Baseline  Level 1.2

Device is capable of playing a video of H264 Baseline Profile (BP) Level
1.2.

Measured by trying to  playback a conformant H264 video at baseline profile
level 1.2, to the device. Playback should be successful.    

Primarily for lower-cost applications with limited computing resources, this
profile is used widely in videoconferencing and mobile applications.

 

 

Regards

 

Runar J. Solberg

 

 

[...]
Received on Friday, 19 October 2007 13:39:15 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Sunday, 6 December 2009 12:13:51 GMT