[html5] r2491 - [gow] (2) Clarify the requirement that UAs must make the 'duration' attribute ac [...]
whatwg at whatwg.org
whatwg at whatwg.org
Mon Dec 1 01:53:20 PST 2008
Author: ianh
Date: 2008-12-01 01:53:20 -0800 (Mon, 01 Dec 2008)
New Revision: 2491
Modified:
index
source
Log:
[gow] (2) Clarify the requirement that UAs must make the 'duration' attribute accurate before playing any media..
Modified: index
===================================================================
--- index 2008-12-01 07:54:38 UTC (rev 2490)
+++ index 2008-12-01 09:53:20 UTC (rev 2491)
@@ -17568,9 +17568,14 @@
</li>
- </ol></dd>
+ </ol><p class=note>The user agent is <em>required</em> to
+ determine the duration of the <a href=#media-resource>media resource</a> and
+ go through this step before playing.</p> <!-- actually defined
+ in the 'duration' section -->
+ </dd>
+
<dt>If the connection is interrupted, causing the user agent to
give up trying to fetch the resource</dt>
@@ -17769,19 +17774,28 @@
<p>The <dfn id=dom-media-duration title=dom-media-duration><code>duration</code></dfn>
attribute must return the length of the <a href=#media-resource>media resource</a>,
in seconds. If no <a href=#media-data>media data</a> is available, then the
- attributes must return 0. If <a href=#media-data>media data</a> is available
- but the length is not known, the attribute must return the
- Not-a-Number (NaN) value. If the <a href=#media-resource>media resource</a> is
- known to be unbounded (e.g. a streaming radio), then the attribute
- must return the positive Infinity value.</p>
+ attributes must return the Not-a-Number (NaN) value. If the
+ <a href=#media-resource>media resource</a> is known to be unbounded (e.g. a
+ streaming radio), then the attribute must return the positive
+ Infinity value.</p>
+ <p>The user agent must determine the duration of the <a href=#media-resource>media
+ resource</a> before playing any part of the <a href=#media-data>media
+ data</a> and before setting <code title=dom-media-readyState><a href=#dom-media-readystate>readyState</a></code> to a value equal to
+ or greater than <code title=dom-media-HAVE_METADATA><a href=#dom-media-have_metadata>HAVE_METADATA</a></code>, even if doing
+ so requires seeking to multiple parts of the resource.</p>
+
<p id=durationChange>When the length of the <a href=#media-resource>media
- resource</a> changes (e.g. from being unknown to known, or from
- indeterminate to known, or from a previously established length to a
- new length) the user agent must <a href=#queue-a-task>queue a task</a> to
- <a href=#fire-a-simple-event>fire a simple event</a> called <code title=event-durationchange><a href=#event-durationchange>durationchange</a></code> at the
+ resource</a> changes (e.g. from being unknown to known, or from a
+ previously established length to a new length) the user agent must
+ <a href=#queue-a-task>queue a task</a> to <a href=#fire-a-simple-event>fire a simple event</a> called
+ <code title=event-durationchange><a href=#event-durationchange>durationchange</a></code> at the
<a href=#media-element>media element</a>.</p>
+ <p class=example>If an "infinite" stream ends for some reason,
+ then the duration would change from positive Infinity to the time of
+ the last frame or sample in the stream.</p>
+
<p><a href=#media-element title="media element">Media elements</a> have a
<dfn id=current-playback-position>current playback position</dfn>, which must initially be
zero. The current position is a time.</p>
@@ -53925,32 +53939,32 @@
L. Carlson, Laura Wisewell, Laurens Holst, Lee Kowalkowski, Leif
Halvard Silli, Lenny Domnitser, Léonard Bouchet, Leons
Petrazickis, Logan<!-- on moz irc -->, Loune, Maciej Stachowiak,
- Magnus Kristiansen<!-- Dashiva -->, Malcolm Rowe, Mark Nottingham,
- Mark Rowe<!--bdash-->, Mark Schenk, Martijn Wargers, Martin Atkins,
- Martin Dürst, Martin Honnen, Masataka Yakura, Mathieu Henri,
- Matthew Gregan, Matthew Mastracci, Matthew Raymond, Matthew Thomas,
- Mattias Waldau, Max Romantschuk, Michael 'Ratt' Iannarelli, Michael
- A. Nachbaur, Michael A. Puls II<!--Shadow2531-->, Michael Carter,
- Michael Gratton, Michael Nordman, Michael Powers, Michael(tm) Smith,
- Michel Fortin, Michiel van der Blonk, Mihai Şucan<!-- from
- ROBO Design -->, Mike Brown, Mike Dierken<!-- S. Mike Dierken -->,
- Mike Dixon, Mike Schinkel, Mike Shaver, Mikko Rantalainen, Neil
- Deakin, Neil Soiffer, Olaf Hoffmann, Olav Junker Kjær, Oliver
- Hunt, Peter Karlsson, Peter Kasting, Philip Jägenstedt, Philip
- Taylor, Philip TAYLOR<!-- a different one -->, Rachid Finge, Rajas
- Moonka, Ralf Stoltze, Ralph Giles, Raphael Champeimont, Rene
- Saarsoo, Richard Ishida, Rimantas Liubertas, Robert Blaut, Robert
- O'Callahan, Robert Sayre, Roman Ivanov, Ryan King, S. Mike Dierken,
- Sam Kuper, Sam Ruby, Sam Weinig, Scott Hess, Sean Knapp, Shaun
- Inman, Silvia Pfeiffer, Simon Pieters, Stefan Haustein, Steffen
- Meschkat, Stephen Ma, Steve Faulkner, Steve Runyon, Steven Garrity,
- Stewart Brodie, Stuart Parmenter, Sunava Dutta, Tantek Çelik,
- Terrence Wood, Thomas Broyer, Thomas O'Connor, Tim Altman, Tim
- Johansson, Travis Leithead, Tyler Close, Vladimir
- Vukićević, Wakaba, Wayne Pollock, Wellington Fernando
- de Macedo, William Swanson, Wolfram Kriesing, Yi-An Huang, and
- Øistein E. Andersen, for their useful and substantial
- comments.</p>
+ Magnus Kristiansen<!-- Dashiva -->, Maik Merten, Malcolm Rowe, Mark
+ Nottingham, Mark Rowe<!--bdash-->, Mark Schenk, Martijn Wargers,
+ Martin Atkins, Martin Dürst, Martin Honnen, Masataka Yakura,
+ Mathieu Henri, Matthew Gregan, Matthew Mastracci, Matthew Raymond,
+ Matthew Thomas, Mattias Waldau, Max Romantschuk, Michael 'Ratt'
+ Iannarelli, Michael A. Nachbaur, Michael A. Puls
+ II<!--Shadow2531-->, Michael Carter, Michael Gratton, Michael
+ Nordman, Michael Powers, Michael(tm) Smith, Michel Fortin, Michiel
+ van der Blonk, Mihai Şucan<!-- from ROBO Design -->, Mike
+ Brown, Mike Dierken<!-- S. Mike Dierken -->, Mike Dixon, Mike
+ Schinkel, Mike Shaver, Mikko Rantalainen, Neil Deakin, Neil Soiffer,
+ Olaf Hoffmann, Olav Junker Kjær, Oliver Hunt, Peter Karlsson,
+ Peter Kasting, Philip Jägenstedt, Philip Taylor, Philip
+ TAYLOR<!-- a different one -->, Rachid Finge, Rajas Moonka, Ralf
+ Stoltze, Ralph Giles, Raphael Champeimont, Rene Saarsoo, Richard
+ Ishida, Rimantas Liubertas, Robert Blaut, Robert O'Callahan, Robert
+ Sayre, Roman Ivanov, Ryan King, S. Mike Dierken, Sam Kuper, Sam
+ Ruby, Sam Weinig, Scott Hess, Sean Knapp, Shaun Inman, Silvia
+ Pfeiffer, Simon Pieters, Stefan Haustein, Steffen Meschkat, Stephen
+ Ma, Steve Faulkner, Steve Runyon, Steven Garrity, Stewart Brodie,
+ Stuart Parmenter, Sunava Dutta, Tantek Çelik, Terrence Wood,
+ Thomas Broyer, Thomas O'Connor, Tim Altman, Tim Johansson, Travis
+ Leithead, Tyler Close, Vladimir Vukićević, Wakaba,
+ Wayne Pollock, Wellington Fernando de Macedo, William Swanson,
+ Wolfram Kriesing, Yi-An Huang, and Øistein E. Andersen, for
+ their useful and substantial comments.</p>
<p>Thanks also to everyone who has ever posted about HTML5 to their
blogs, public mailing lists, or forums, including the <a href=http://lists.w3.org/Archives/Public/public-html/>W3C
Modified: source
===================================================================
--- source 2008-12-01 07:54:38 UTC (rev 2490)
+++ source 2008-12-01 09:53:20 UTC (rev 2491)
@@ -18934,6 +18934,11 @@
</ol>
+ <p class="note">The user agent is <em>required</em> to
+ determine the duration of the <span>media resource</span> and
+ go through this step before playing.</p> <!-- actually defined
+ in the 'duration' section -->
+
</dd>
@@ -19194,20 +19199,30 @@
<p>The <dfn title="dom-media-duration"><code>duration</code></dfn>
attribute must return the length of the <span>media resource</span>,
in seconds. If no <span>media data</span> is available, then the
- attributes must return 0. If <span>media data</span> is available
- but the length is not known, the attribute must return the
- Not-a-Number (NaN) value. If the <span>media resource</span> is
- known to be unbounded (e.g. a streaming radio), then the attribute
- must return the positive Infinity value.</p>
+ attributes must return the Not-a-Number (NaN) value. If the
+ <span>media resource</span> is known to be unbounded (e.g. a
+ streaming radio), then the attribute must return the positive
+ Infinity value.</p>
+ <p>The user agent must determine the duration of the <span>media
+ resource</span> before playing any part of the <span>media
+ data</span> and before setting <code
+ title="dom-media-readyState">readyState</code> to a value equal to
+ or greater than <code
+ title="dom-media-HAVE_METADATA">HAVE_METADATA</code>, even if doing
+ so requires seeking to multiple parts of the resource.</p>
+
<p id="durationChange">When the length of the <span>media
- resource</span> changes (e.g. from being unknown to known, or from
- indeterminate to known, or from a previously established length to a
- new length) the user agent must <span>queue a task</span> to
- <span>fire a simple event</span> called <code
- title="event-durationchange">durationchange</code> at the
+ resource</span> changes (e.g. from being unknown to known, or from a
+ previously established length to a new length) the user agent must
+ <span>queue a task</span> to <span>fire a simple event</span> called
+ <code title="event-durationchange">durationchange</code> at the
<span>media element</span>.</p>
+ <p class="example">If an "infinite" stream ends for some reason,
+ then the duration would change from positive Infinity to the time of
+ the last frame or sample in the stream.</p>
+
<p><span title="media element">Media elements</span> have a
<dfn>current playback position</dfn>, which must initially be
zero. The current position is a time.</p>
@@ -58883,32 +58898,32 @@
L. Carlson, Laura Wisewell, Laurens Holst, Lee Kowalkowski, Leif
Halvard Silli, Lenny Domnitser, Léonard Bouchet, Leons
Petrazickis, Logan<!-- on moz irc -->, Loune, Maciej Stachowiak,
- Magnus Kristiansen<!-- Dashiva -->, Malcolm Rowe, Mark Nottingham,
- Mark Rowe<!--bdash-->, Mark Schenk, Martijn Wargers, Martin Atkins,
- Martin Dürst, Martin Honnen, Masataka Yakura, Mathieu Henri,
- Matthew Gregan, Matthew Mastracci, Matthew Raymond, Matthew Thomas,
- Mattias Waldau, Max Romantschuk, Michael 'Ratt' Iannarelli, Michael
- A. Nachbaur, Michael A. Puls II<!--Shadow2531-->, Michael Carter,
- Michael Gratton, Michael Nordman, Michael Powers, Michael(tm) Smith,
- Michel Fortin, Michiel van der Blonk, Mihai Şucan<!-- from
- ROBO Design -->, Mike Brown, Mike Dierken<!-- S. Mike Dierken -->,
- Mike Dixon, Mike Schinkel, Mike Shaver, Mikko Rantalainen, Neil
- Deakin, Neil Soiffer, Olaf Hoffmann, Olav Junker Kjær, Oliver
- Hunt, Peter Karlsson, Peter Kasting, Philip Jägenstedt, Philip
- Taylor, Philip TAYLOR<!-- a different one -->, Rachid Finge, Rajas
- Moonka, Ralf Stoltze, Ralph Giles, Raphael Champeimont, Rene
- Saarsoo, Richard Ishida, Rimantas Liubertas, Robert Blaut, Robert
- O'Callahan, Robert Sayre, Roman Ivanov, Ryan King, S. Mike Dierken,
- Sam Kuper, Sam Ruby, Sam Weinig, Scott Hess, Sean Knapp, Shaun
- Inman, Silvia Pfeiffer, Simon Pieters, Stefan Haustein, Steffen
- Meschkat, Stephen Ma, Steve Faulkner, Steve Runyon, Steven Garrity,
- Stewart Brodie, Stuart Parmenter, Sunava Dutta, Tantek Çelik,
- Terrence Wood, Thomas Broyer, Thomas O'Connor, Tim Altman, Tim
- Johansson, Travis Leithead, Tyler Close, Vladimir
- Vukićević, Wakaba, Wayne Pollock, Wellington Fernando
- de Macedo, William Swanson, Wolfram Kriesing, Yi-An Huang, and
- Øistein E. Andersen, for their useful and substantial
- comments.</p>
+ Magnus Kristiansen<!-- Dashiva -->, Maik Merten, Malcolm Rowe, Mark
+ Nottingham, Mark Rowe<!--bdash-->, Mark Schenk, Martijn Wargers,
+ Martin Atkins, Martin Dürst, Martin Honnen, Masataka Yakura,
+ Mathieu Henri, Matthew Gregan, Matthew Mastracci, Matthew Raymond,
+ Matthew Thomas, Mattias Waldau, Max Romantschuk, Michael 'Ratt'
+ Iannarelli, Michael A. Nachbaur, Michael A. Puls
+ II<!--Shadow2531-->, Michael Carter, Michael Gratton, Michael
+ Nordman, Michael Powers, Michael(tm) Smith, Michel Fortin, Michiel
+ van der Blonk, Mihai Şucan<!-- from ROBO Design -->, Mike
+ Brown, Mike Dierken<!-- S. Mike Dierken -->, Mike Dixon, Mike
+ Schinkel, Mike Shaver, Mikko Rantalainen, Neil Deakin, Neil Soiffer,
+ Olaf Hoffmann, Olav Junker Kjær, Oliver Hunt, Peter Karlsson,
+ Peter Kasting, Philip Jägenstedt, Philip Taylor, Philip
+ TAYLOR<!-- a different one -->, Rachid Finge, Rajas Moonka, Ralf
+ Stoltze, Ralph Giles, Raphael Champeimont, Rene Saarsoo, Richard
+ Ishida, Rimantas Liubertas, Robert Blaut, Robert O'Callahan, Robert
+ Sayre, Roman Ivanov, Ryan King, S. Mike Dierken, Sam Kuper, Sam
+ Ruby, Sam Weinig, Scott Hess, Sean Knapp, Shaun Inman, Silvia
+ Pfeiffer, Simon Pieters, Stefan Haustein, Steffen Meschkat, Stephen
+ Ma, Steve Faulkner, Steve Runyon, Steven Garrity, Stewart Brodie,
+ Stuart Parmenter, Sunava Dutta, Tantek Çelik, Terrence Wood,
+ Thomas Broyer, Thomas O'Connor, Tim Altman, Tim Johansson, Travis
+ Leithead, Tyler Close, Vladimir Vukićević, Wakaba,
+ Wayne Pollock, Wellington Fernando de Macedo, William Swanson,
+ Wolfram Kriesing, Yi-An Huang, and Øistein E. Andersen, for
+ their useful and substantial comments.</p>
<p>Thanks also to everyone who has ever posted about HTML5 to their
blogs, public mailing lists, or forums, including the <a
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