Re: webtv-ISSUE-21: Time synchronisation

Dear Olivier

What is WebM, if not an attempt to redefine a video coding standard to 
get rid of H.264 ?
There was a LONG discussion of just this subject on the HTML5 list.

I am reacting to Russell's messages objecting to defining any feature 
already existing in UPnP.

May I remind you of the environment we are in ? We are operating in W3C 
with IPR-free constraints, so we are not allowed to mandate the use of 
an IPR-bearing standard such as UPnP. Not all alternatives to UPnP have 
the precise sync feature. For the sake of argument, let us say 
Bonjour/mDNS is relevant and does not have precise sync. The precise 
sync feature is an important feature for our constituency.

So we have to find a way to:
- allow the use of the UPnP precise sync feature.
- allow the use of Bonjour/mDNS together with PTP to achieve precise sync.

Best regards
JC

On 7/6/11 10:33 , Olivier Carmona wrote:
>
> JC,
>
> Reversely, an argument such as "let's implement it again" because it 
> does not follow W3C patent policy is not a better way to proceed. Up 
> to my knowledge, there are plenty of technology out on the market that 
> does not follow the W3C Patent Policy such as H.264, AAC, MPEG 4 
> Visual, etc... for instance and that are referenced by HTML5 (see 
> http://dev.w3.org/html5/spec-author-view/video.html).
>
> Don't you think that there is a middle way in between here?
>
> Regards,
>
> Olivier
>
> *From:*Jean-Claude Dufourd 
> [mailto:jean-claude.dufourd@telecom-paristech.fr]
> *Sent:* mardi 7 juin 2011 10:19
> *To:* public-web-and-tv@w3.org
> *Subject:* Re: webtv-ISSUE-21: Time synchronisation
>
> Thanks to Russell and Olivier for pointing out the precise technology 
> that allows this type of synchronisation.
>
> However, is this feature present in all discovery and service 
> protocols that HNTF has to consider ? I do not think so.
> So it may be a valid request to have this feature in HNTF, to provide 
> it when the underlying technologies don't.
>
> An argument such as "this feature is already in this standard so do 
> not touch it" is difficult to accept, specially if the standard in 
> question does not follow the W3C patent policy.
>
> Best regards
> JC
>
>
> On 7/6/11 08:05 , Olivier Carmona wrote:
>
> JC,
>
> As an example, AwoX achieves below +/-10ms using PTP (aka IEEE 
> 1588-2002) within its commercial synchronized solutions above UPnP AV.
>
> Regards,
>
> Olivier
>
> *From:*Russell Berkoff [mailto:r.berkoff@sisa.samsung.com]
> *Sent:* mardi 7 juin 2011 03:10
> *To:* Jean-Claude Dufourd; public-web-and-tv@w3.org 
> <mailto:public-web-and-tv@w3.org>
> *Subject:* RE: webtv-ISSUE-21: Time synchronisation
>
> Hello,
>
> I'm told that IEEE-802.1AS is quite good at getting devices to 
> synchronize to a common timebase (down to the 10's of nS).
>
> UPnP actions to do scheduled playback such as  SyncPlay() (based on 
> the availability of well synchronized device timebases) were added in 
> AV-4. This approach is different than the previous approach of having 
> a UPnP Control Point just send a Play command to the renderer at the 
> "right" moment.
>
> Sorry I couldn't provide the pointers to the specs earlier.
>
> Regards,
>
> Russell Berkoff
>
> *From:*public-web-and-tv-request@w3.org 
> <mailto:public-web-and-tv-request@w3.org> 
> [mailto:public-web-and-tv-request@w3.org] *On Behalf Of *Jean-Claude 
> Dufourd
> *Sent:* Monday, June 06, 2011 10:32 AM
> *To:* public-web-and-tv@w3.org <mailto:public-web-and-tv@w3.org>
> *Subject:* Re: webtv-ISSUE-21: Time synchronisation
>
> I would think the actual relevant section in the second document to be 
> 2.5.9 Clocksync (within the theory of operations you point to in 
> another email).
> All examples point to a synchronisation in seconds. I can believe that 
> this technology allows a synchronization with a precision of seconds.
> We believe there is no way to achieve lip-sync (-20ms to +40ms) with 
> such a mechanism based on UPnP 1.0, regardless of the media transport 
> technology used.
> Best regards
> JC
>
> On 6/6/11 10:47 , Russell Berkoff wrote:
>
> Hello,
>
> The submitted test case is redundant with facilities available in UPnP.
>
> UPnP AV-4 provides Linked Content Metadata (Object Linking) as well as 
> Precision Time Synchronization facilities. As previously mentioned in 
> this forum, the current UPnP specifications are now available at no 
> charge.
>
> Please refer to:
>
> http://www.upnp.org/specs/av/UPnP-av-ContentDirectory-v4-Service.pdf
>
> *Appendix G: Content Authoring with Object Linking*
>
> and
>
> http://www.upnp.org/specs/av/UPnP-av-AVTransport-v3-Service.pdf
>
> *2.4.25 SyncPlay()*
>
> Regards,
>
> Russell Berkoff
>
>
>
>
> -- 
> JC Dufourd
> Directeur d'Etudes/Professor
> Groupe Multimedia/Multimedia Group
> Traitement du Signal et Images/Signal and Image Processing
> Telecom ParisTech, 37-39 rue Dareau, 75014 Paris, France
> Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
>
>
>
> __________ Information provenant d'ESET NOD32 Antivirus, version de la 
> base des signatures de virus 6185 (20110606) __________
>
> Le message a été vérifié par ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>
> __________ Information provenant d'ESET NOD32 Antivirus, version de la 
> base des signatures de virus 6185 (20110606) __________
>
> Le message a été vérifié par ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>
>
> -- 
> JC Dufourd
> Directeur d'Etudes/Professor
> Groupe Multimedia/Multimedia Group
> Traitement du Signal et Images/Signal and Image Processing
> Telecom ParisTech, 37-39 rue Dareau, 75014 Paris, France
> Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
>
>
>
> __________ Information provenant d'ESET NOD32 Antivirus, version de la 
> base des signatures de virus 6185 (20110606) __________
>
> Le message a été vérifié par ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>
> __________ Information provenant d'ESET NOD32 Antivirus, version de la 
> base des signatures de virus 6185 (20110606) __________
>
> Le message a été vérifié par ESET NOD32 Antivirus.
>
> http://www.eset.com


-- 
JC Dufourd
Directeur d'Etudes/Professor
Groupe Multimedia/Multimedia Group
Traitement du Signal et Images/Signal and Image Processing
Telecom ParisTech, 37-39 rue Dareau, 75014 Paris, France
Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144