--- a/608toVTT/608toVTT.html Thu Nov 08 22:43:34 2012 +1100
+++ b/608toVTT/608toVTT.html Fri Nov 09 16:57:49 2012 +1100
@@ -226,8 +226,12 @@
<li>The line height is defined as 5.33% of the video height, because CEA-608 requires 15 character rows to be rendered on 80% of the video rendering area’s height.</li>
<li>The font size is defined from the line height by dividing it by 1.3; this is to make sure there is enough space for the characters in a line.</li>
<li>The column width is defined as 2.5% of the video width, because CEA-608 requires 32 columns of characters to be rendered on 80% of the video rendering area’s width.</li>
- <li>CEA-608 indent positions are every 10% of the video width, because CEA-68 defines a new indent position every 4 columns/characters.</li>
+ <li>CEA-608 indent positions are every 10% of the video width, because CEA-608 defines a new indent position every 4 columns/characters.</li>
+ <li>CEA-608 does not distinguish between different alignment, so all captions are left aligned and require a WebVTT align cue setting to override the default middle alignment:</li>
</ul>
+ <pre>
+align:left
+ </pre>
<p>
When translating to WebVTT only the final position of the caption text shall be translated. CEA-608 captions are generally translated to WebVTT cues with their position specified in cue settings. Only CEA-608 captions that are roll-up captions are rendered into WebVTT "Regions".
</p>
@@ -255,82 +259,82 @@
<thead>
<tr>
<td>CEA-608 PAC row</td>
- <td>WebVTT cue line value</td>
+ <td>WebVTT cue line setting</td>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
- <td>10%</td>
+ <td>line:10%</td>
</tr>
<tr>
<td>2</td>
- <td>15.33%</td>
+ <td>line:15.33%</td>
</tr>
<tr>
<td>3</td>
- <td>20.66%</td>
+ <td>line:20.66%</td>
</tr>
<tr>
<td>4</td>
- <td>26%</td>
+ <td>line:26%</td>
</tr>
<tr>
<td>5</td>
- <td>31.33%</td>
+ <td>line:31.33%</td>
</tr>
<tr>
<td>6</td>
- <td>36.66%</td>
+ <td>line:36.66%</td>
</tr>
<tr>
<td>7</td>
- <td>42%</td>
+ <td>line:42%</td>
</tr>
<tr>
<td>8</td>
- <td>47.33%</td>
+ <td>line:47.33%</td>
</tr>
<tr>
<td>9</td>
- <td>52.66%</td>
+ <td>line:52.66%</td>
</tr>
<tr>
<td>10</td>
- <td>58%</td>
+ <td>line:58%</td>
</tr>
<tr>
<td>11</td>
- <td>63.33%</td>
+ <td>line:63.33%</td>
</tr>
<tr>
<td>12</td>
- <td>68.66%</td>
+ <td>line:68.66%</td>
</tr>
<tr>
<td>13</td>
- <td>74%</td>
+ <td>line:74%</td>
</tr>
<tr>
<td>14</td>
- <td>79.33%</td>
+ <td>line:79.33%</td>
</tr>
<tr>
<td>15</td>
- <td>84.66%</td>
+ <td>line:84.66%</td>
</tr>
</tbody>
</table>
<p>
- The PAC indent position maps to a position cue setting in WebVTT CEA-608, which is a percentage offset within the video viewport:
+ The PAC indent position provides a column indent for lines of caption text. PAC can be different for different lines of captions. It is recommended to create a separate WebVTT cue when a different PAC is used for lines of captions that are on screen at the same time. A PAC indent position maps to a position cue setting in WebVTT CEA-608, which is a percentage offset within the video viewport:
</p>
<pre>
position:x%
</pre>
<p>
- For rollup captions the calculation is the same, but the resulting number is applied to the Region rather than the cue directly, as described in the "Rollup Captions" section.Use the following percentage values to represent CEA-608 indent positions:
+ Use the following position settings for PAC indent. Note that all WebVTT cues need to be explicitly left aligned for this position setting to be accurate, because WebVTT by default has middle aligned cues.
</p>
<table border="1">
@@ -343,39 +347,40 @@
<tbody>
<tr>
<td>indent 0/column 1</td>
- <td>10%</td>
+ <td>position:10%</td>
</tr>
<tr>
<td>indent 4/column 5</td>
- <td>20%</td>
+ <td>position:20%</td>
</tr>
<tr>
<td>indent 8/column 9</td>
- <td>30%</td>
+ <td>position:30%</td>
</tr>
<tr>
<td>indent 12/column 13</td>
- <td>40%</td>
+ <td>position:40%</td>
</tr>
<tr>
<td>indent 16/column 17</td>
- <td>50%</td>
+ <td>position:50%</td>
</tr>
<tr>
<td>indent 20/column 21</td>
- <td>60%</td>
+ <td>position:60%</td>
</tr>
<tr>
<td>indent 24/column 25</td>
- <td>70%</td>
+ <td>position:70%</td>
</tr>
<tr>
<td>indent 28/column 29</td>
- <td>80%</td>
+ <td>position:80%</td>
</tr>
</tbody>
</table>
+
<h3>(2) Tab Offset</h3>
<p>
CE-608 Tab Offset commands provide relative positioning based on the current cursor position and move the cursor 1, 2, or 3 columns to the right.
@@ -617,7 +622,7 @@
</section>
<section>
- <h2>Caption Text Settings in CEA-708</h2>
+ <h2>Caption Text and Region Settings in CEA-708</h2>
<p>
CEA-708 defines several settings of caption text within a Caption Window. This section explains how to convert them to WebVTT cue settings.
</p>
@@ -771,7 +776,7 @@
</pre>
<p>
- CEA-708 pop-on captions rely on a Caption Window to be defined and mapped to a WebVTT Region as described in the section on "Positioning in CEA-708". Further attributes both of the Region and the individual cue are described in section "Caption Text Settings in CEA-708".
+ CEA-708 pop-on captions rely on a Caption Window to be defined and mapped to a WebVTT Region as described in the section on "Positioning in CEA-708". Further attributes both of the Region and the individual cue are described in section "Caption Text and Region Settings in CEA-708".
</section>
<section>