--- a/608toVTT/608toVTT.html Thu Aug 30 10:29:45 2012 +1000
+++ b/608toVTT/608toVTT.html Tue Sep 25 00:37:40 2012 +1000
@@ -16,7 +16,7 @@
specStatus: "unofficial",
// the specification's short name, as in http://www.w3.org/TR/short-name/
- shortName: "webvtt-608",
+ shortName: "webvtt-608-708",
// if your specification has a subtitle that goes below the main
// formal title, define it here
@@ -84,17 +84,23 @@
</p>
<section id='abstract'>
- This document specifies a method for converting CEA-608 data streams to [[WEBVTT]]. This document details how such a conversion can be made, and defines some constraints on the translation process so that the resulting [[WEBVTT]] file is interoperable between WebVTT implementations.
+
+ <p>This document specifies a method for converting CEA-608/708 data streams to [[WEBVTT]]. This document details how such a conversion can be made, and defines some constraints on the translation process so that the resulting [[WEBVTT]] file is interoperable between WebVTT implementations.</p>
+
+ <p>This document does not target user agent developers. User agents (UAs) are expected to implement support for the full [[WebVTT]] specification. Any conversion tool that follows the suggestions in this document and delivers WebVTT files as converted by the suggestions in this document together with an appropriate HTML page and a style sheet as explained in <a href="#browsers" class="sectionRef"></a> can expect UAs to render their WebVTT file on their videos correctly.</p>
+
+ <p>The aim of this document is to help developers of tools that convert between different caption formats to implement best practice for creating WebVTT files that support CEA-608 or CEA-708 features. It is non-normative.</p>
</section>
+
<section>
<h2>Translation</h2>
<p>
- This document defines conversion from CEA-608 data streams to a WebVTT document.
+ This document defines conversion from CEA-608 or CEA-708 data streams to a WebVTT document.
</p>
<p>
- A CEA-608 data stream consist of a sequence of bytes transferred to a video device which interprets the bytes as a combination of characters, character attributes, and commands to place the characters on screen in a pre-defined area. CEA-608 defines two 32x15 character memories one of which is currently displayed while the other is for off-screen composition in preparation for display.
+ A CEA-608 or CEA-708 data stream consist of a sequence of bytes transferred to a video device which interprets the bytes as a combination of characters, character attributes, and commands to place the characters on screen in a pre-defined area. CEA-608 defines two 32x15 character memories one of which is currently displayed while the other is for off-screen composition in preparation for display. CEA-708 defines different windows on top of the video viewport into which text is rendered.
</p>
<p>
@@ -102,7 +108,7 @@
</p>
<p>
- The command-based CEA-608 stream is mapped in the following to the file-based WebVTT format. The aim is to achieve the same visual experience, so for CEA-608 it is important what is in the display memory and not what is in the off-screen composition memory. The translation shall in particular preserve the colour, background, spacing, and timing of captions, including individual character timings in rollup and paint on mode.
+ The command-based CEA-608 and CEA-708 streams are mapped in the following to the file-based WebVTT format. The aim is to achieve the same visual experience, so for CEA-608 it is important what is in the display memory and not what is in the off-screen composition memory. Similarly, for CEA-708 it is important what is in the visible windows. The translation shall in particular preserve the colour, background, spacing, and timing of captions, including individual character timings in rollup and paint on mode.
</p>
<section>
@@ -112,25 +118,25 @@
</p>
<ul>
- <li>Each channel of a CEA-608 service creates a separate WebVTT file.</li>
- <li>CEA-608 commands that have no visual effect are not considered significant alterations and are not translated to WebVTT.</li>
- <li>Each significant CEA-608 command or command sequence that has a visual effect on screen will be mapped to a WebVTT cue with the exact time mapping of the video frame that contains that command sequence to cue start and end times. The video frame’s timing defines the timing of the WebVTT cues.</li>
+ <li>Each channel of a CEA-608 or CEA-708 service creates a separate WebVTT file.</li>
+ <li>CEA-608 and CEA-708 commands that have no visual effect are not considered significant alterations and are not translated to WebVTT.</li>
+ <li>Each significant CEA-608/708 command or command sequence that has a visual effect on screen will be mapped to a WebVTT cue with the exact time mapping of the video frame that contains that command sequence to cue start and end times. The video frame’s timing defines the timing of the WebVTT cues.</li>
</ul>
<p>
- For example, one particular CEA-608 control event that will normally result in a significant alteration in the caption display is the swapping of the offscreen and onscreen buffers caused by an End of Caption command in pop on mode. Similar commands that also cause creation of a new cue are the Erase Display Memory comment, the Backspace command, and the Delete to End of Row command. Typically in these situation a new cue will replace the current one in WebVTT at the time instant of the effect.
+ For example, one particular CEA-608 control event that will normally result in a significant alteration in the caption display is the swapping of the offscreen and onscreen buffers caused by an End of Caption command in pop on mode. Similar commands that also cause creation of a new cue are the Erase Display Memory command, the Backspace command, and the Delete to End of Row command. Typically in these situations a new cue will replace the current one in WebVTT at the time instant of the effect.
</p>
</section>
<section>
<h2>Header</h2>
<p>
- When a WebVTT file is created from a CEA-608 caption data stream using the conversion methods proposed in this document, it is suggested to use the following header for the WebVTT file, including a identification of the type of data contained:
+ When a WebVTT file is created from a CEA-608 or CEA-708 caption data stream using the conversion methods proposed in this document, it is suggested to use the following header for the WebVTT file, including an identification of the type of data contained:
</p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
+stylesheet: cea608.css
+kind: captions
</pre>
</section>
@@ -144,19 +150,19 @@
</p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
-Language: en-US
-Channel: CC1
-Station: Online ABC
-ProgramID: SH010855880000
-ProgramType: TV series
-ProgramName: Castle
-Title: Law & Murder
-Season: 3
-Episode: 19
-PublishDate: 2011-03-28
-ContentAdvisory: TV-14
+stylesheet: cea608.css
+kind: captions
+language: en-US
+channel: CC1
+station: Online ABC
+programID: SH010855880000
+programType: TV series
+programName: Castle
+title: Law & Murder
+season: 3
+episode: 19
+publishDate: 2011-03-28
+contentAdvisory: TV-14
</pre>
</section>
@@ -247,9 +253,9 @@
<p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
-Language: en-US
+stylesheet: cea608.css
+kind: captions
+language: en-US
00:00:01.373 --> 00:00:02.322
There are two kinds of folks
@@ -293,9 +299,9 @@
</p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
-Language: en-US
+stylesheet: cea608.css
+kind: captions
+language: en-US
00:00:00.000 --> 00:00:15.000
T<00:00:00.100>h<00:00:00.200>i<00:00:00.300>s
@@ -323,9 +329,9 @@
</p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
-Language: en-US
+stylesheet: cea608.css
+kind: captions
+language: en-US
00:00:00.000 --> 00:00:15.000
A <c.red>red piece of text</c>.
@@ -390,9 +396,9 @@
</p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
-Language: en-US
+stylesheet: cea608.css
+kind: captions
+language: en-US
00:00:00.000 --> 00:00:15.000
Nice <u>underlined</u> and <i>italicized</i> text.
@@ -410,9 +416,9 @@
</p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
-Language: en-US
+stylesheet: cea608.css
+kind: captions
+language: en-US
00:00:00.000 --> 00:00:15.000
A <c.red.italics.blink>flashing piece of text</c>.
@@ -526,9 +532,9 @@
</p>
<pre>
WEBVTT
-Stylesheet: cea608.css
-Kind: captions
-Language: en-US
+stylesheet: cea608.css
+kind: captions
+language: en-US
00:00:00.000 --> 00:00:15.000
A <c.mono_serif>different font</c> text.
@@ -618,7 +624,7 @@
</section>
</section>
- <section>
+ <section id="browsers">
<h2>Rendering in Web Browsers</h2>
<p>
The following HTML snippet is an example of how a WebVTT CEA-608 file may be included in a Web browser in relation to a video: