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csswg/css3-speech Overview.html,1.64,1.65 Overview.src.html,1.65,1.66

From: Daniel Weck via cvs-syncmail <cvsmail@w3.org>
Date: Thu, 07 Jul 2011 00:44:24 +0000
To: public-css-commits@w3.org
Message-Id: <E1Qechc-0005Mk-UV@lionel-hutz.w3.org>
Update of /sources/public/csswg/css3-speech
In directory hutz:/tmp/cvs-serv20578

Modified Files:
	Overview.html Overview.src.html 
Log Message:
fixed voice-volume, various minor fixes.


Index: Overview.html
===================================================================
RCS file: /sources/public/csswg/css3-speech/Overview.html,v
retrieving revision 1.64
retrieving revision 1.65
diff -u -d -r1.64 -r1.65
--- Overview.html	6 Jul 2011 21:41:03 -0000	1.64
+++ Overview.html	7 Jul 2011 00:44:22 -0000	1.65
@@ -90,13 +90,13 @@
 
    <h1 id=top>CSS Speech Module</h1>
 
-   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 06 July 2011</h2>
+   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 07 July 2011</h2>
 
    <dl>
     <dt>This version:
 
     <dd>
-     <!--<a href="http://www.w3.org/TR/2011/WD-css3-speech-20110706">http://www.w3.org/TR/2011/ED-css3-speech-20110706/</a>-->
+     <!--<a href="http://www.w3.org/TR/2011/WD-css3-speech-20110707">http://www.w3.org/TR/2011/ED-css3-speech-20110707/</a>-->
      <a
      href="http://dev.w3.org/csswg/css3-speech">http://dev.w3.org/csswg/css3-speech</a>
      
@@ -442,6 +442,7 @@
   voice-family: paul;
   voice-stress: moderate;
   cue-before: url(../audio/ping.wav);
+  voice-volume: medium 6dB;
 }
 p.heidi
 {
@@ -516,13 +517,13 @@
     <tr>
      <td> <em>Value:</em>
 
-     <td>normal | silent | x-soft | soft | medium | loud | x-loud |
-      &lt;decibel&gt;
+     <td>silent | [[x-soft | soft | medium | loud | x-loud] ||
+      &lt;decibel&gt;]
 
     <tr>
      <td> <em>Initial:</em>
 
-     <td>normal
+     <td>medium
 
     <tr>
      <td> <em>Applies&nbsp;to:</em>
@@ -547,7 +548,7 @@
     <tr>
      <td> <em>Computed value:</em>
 
-     <td>specified value
+     <td>keyword value, and decibel offset (if not zero)
   </table>
 
   <p>The &lsquo;<a href="#voice-volume"><code
@@ -563,12 +564,13 @@
    attribute of the <code>prosody</code> element</a> from the SSML markup
    language <a href="#SSML" rel=biblioentry>[SSML]<!--{{!SSML}}--></a>.
 
-  <dl>
-   <dt> <strong>normal</strong>
-
-   <dd>
-    <p> Corresponds to +0.0dB, which means that there is no modification of
-     volume level. This value overrides the inherited value.</p>
+  <dl><!-- dt>
+        <strong>normal</strong>
+      </dt>
+      <dd>
+        <p> Corresponds to +0.0dB, which means that there is no modification of volume level. This
+          value overrides the inherited value.</p>
+      </dd -->
 
    <dt> <strong>silent</strong>
 
@@ -582,9 +584,9 @@
      &lsquo;<code class=property>silent</code>&rsquo;, and an element whose
      &lsquo;<a href="#speak"><code class=property>speak</code></a>&rsquo;
      property has the value &lsquo;<code class=property>none</code>&rsquo;.
-     With the former, the selected takes up the same time as if it had been
-     spoken, including any pause before and after the element, but no sound
-     is generated (descendants can override the &lsquo;<a
+     With the former, the selected element takes up the same time as if it
+     was spoken, including any pause before and after the element, but no
+     sound is generated (descendants can override the &lsquo;<a
      href="#voice-volume"><code class=property>voice-volume</code></a>&rsquo;
      value and may therefore generate audio output). With the latter, the
      selected element is not rendered in the aural dimension and no time is
@@ -598,8 +600,8 @@
    <dd>
     <p> This sequence of keywords corresponds to monotonically non-decreasing
      volume levels, mapped to implementation-dependent values (i.e. inferred
-     by the user-agent) that meet user's requirements in terms of perceived
-     sound loudness . The keyword &lsquo;<code
+     by the user-agent) that meet the user's requirements in terms of
+     perceived sound loudness . The keyword &lsquo;<code
      class=property>x-soft</code>&rsquo; maps to the user's <em>minimum
      audible</em> volume level, &lsquo;<code
      class=property>x-loud</code>&rsquo; maps to the user's <em>maximum
@@ -614,10 +616,17 @@
    <dd>
     <p>A <a href="#number-def">number</a> immediately followed by "dB"
      (decibel unit). This represents a change (positive or negative) relative
-     to the default value for the root element, or to the inherited volume
-     level otherwise. This is expressed as the ratio of the squares of the
-     new signal amplitude (a1) and the current amplitude (a0), as per the
-     following logarithmic equation: volume(dB) = 20 log10 (a1 / a0)</p>
+     to the given keyword value (see enumeration above), or to the default
+     value for the root element, or otherwise to the inherited volume level
+     (which may itself be be a combination of a keyword value and of a
+     decibel offset). When the inherited volume level is &lsquo;<code
+     class=property>silent</code>&rsquo;, this &lsquo;<a
+     href="#voice-volume"><code class=property>voice-volume</code></a>&rsquo;
+     resolves to &lsquo;<code class=property>silent</code>&rsquo; too,
+     regardless of the provided &lt;decibel&gt; value. Decibels express the
+     ratio of the squares of the new signal amplitude (a1) and the current
+     amplitude (a0), as per the following logarithmic equation: volume(dB) =
+     20 log10 (a1 / a0)</p>
 
     <p class=note> Note that -6.0dB is approximately half the amplitude of
      the audio signal, and +6.0dB is approximately twice the amplitude.</p>
@@ -1369,9 +1378,8 @@
    <dt> <strong>none</strong>
 
    <dd>
-    <p> Equivalent to 0ms (no prosodic break in the speech output). This
-     value can be used to inhibit a prosodic break which the processor would
-     otherwise produce.</p>
+    <p> Equivalent to 0ms (no prosodic break is produced by the speech
+     processor).</p>
 
    <dt> <strong>x-weak</strong>, <strong>weak</strong>,
     <strong>medium</strong>, <strong>strong</strong>, and
@@ -1579,23 +1587,18 @@
    <dd>
     <p>A <a href="#number-def">number</a> immediately followed by "dB"
      (decibel unit). This represents a change (positive or negative) relative
-     to the default sound level of audio clip. This is expressed as the ratio
+     to the computed value of the &lsquo;<a href="#voice-volume"><code
+     class=property>voice-volume</code></a>&rsquo; property within the <a
+     href="#aural-model">aural "box" model</a> of the selected element. When
+     the &lsquo;<a href="#voice-volume"><code
+     class=property>voice-volume</code></a>&rsquo; property is set to
+     &lsquo;<code class=property>silent</code>&rsquo;, the audio cue is also
+     set to &lsquo;<code class=property>silent</code>&rsquo; (regardless of
+     the value provided for this &lt;decibel&gt;). Decibels express the ratio
      of the squares of the new signal amplitude (a1) and the current
      amplitude (a0), as per the following logarithmic equation: volume(dB) =
      20 log10 (a1 / a0)</p>
 
-    <p>Audio cues apply to the selected element within the <a
-     href="#aural-model">audio "box" model</a>, so when the inherited value
-     from the &lsquo;<a href="#voice-volume"><code
-     class=property>voice-volume</code></a>&rsquo; property is &lsquo;<code
-     class=property>silent</code>&rsquo;, the volume level for the audio cue
-     is resolved to -infinity decibels (which effectively silences the audio
-     cue), regardless of the value provided for this &lt;decibel&gt;. In
-     other words, a selected element can be entirely silenced (i.e. including
-     its associated audio cues) by setting the &lsquo;<a
-     href="#voice-volume"><code class=property>voice-volume</code></a>&rsquo;
-     property to &lsquo;<code class=property>silent</code>&rsquo;.</p>
-
     <p class=note> Note that -6.0dB is approximately half the amplitude of
      the audio signal, and +6.0dB is approximately twice the amplitude.</p>
 
@@ -1802,6 +1805,12 @@
      rel=biblioentry>[SSML]<!--{{!SSML}}--></a>, voice names are
      space-separated and cannot contain whitespace characters.</p>
 
+    <p> It is recommended to quote voice names that contain white space,
+     digits, or punctuation characters other than hyphens - even if these
+     voice names are valid in unquoted form - in order to improve code
+     clarity. For example: <code>voice-family: "john doe", "Henry
+     the-8th";</code></p>
+
    <dt> <strong>&lt;age&gt;</strong>
 
    <dd>
@@ -1855,15 +1864,6 @@
 voice-family: john 1st; /* identifier cannot start with digit */</pre>
   </div>
 
-  <div class=example>
-   <p> This is an example of valid voice names that contain white space,
-    digits, or punctuation characters other than hyphens, but which are
-    quoted nonetheless, for reading clarity.</p>
-
-   <pre>
-voice-family: "john doe", "Henry the-8th";</pre>
-  </div>
-
   <h4 class=no-toc id=voice-selection><span class=secno>10.1.1. </span>Voice
    selection, content language</h4>
 
@@ -2079,10 +2079,12 @@
 
   <p>The &lsquo;<a href="#voice-pitch"><code
    class=property>voice-pitch</code></a>&rsquo; property specifies the
-   average pitch of generated speech output, and depends on the &lsquo;<a
-   href="#voice-family"><code class=property>voice-family</code></a>&rsquo;.
-   For example, the default average pitch for a common male voice is around
-   120Hz, whereas it is around 210Hz for a female voice.
+   "baseline" pitch of the generated speech output, which depends on the used
+   &lsquo;<a href="#voice-family"><code
+   class=property>voice-family</code></a>&rsquo; instance, and varies across
+   speech synthesis processors (it approximately corresponds to the average
+   pitch of the output). For example, the common pitch for a male voice is
+   around 120Hz, whereas it is around 210Hz for a female voice.
 
   <p class=note> Note that the functionality provided by this property is
    related to the <a
@@ -2095,24 +2097,18 @@
 
    <dd>
     <p> A value in <a href="#frequency-def">frequency</a> units (Hertz or
-     kiloHertz, e.g. "100Hz", "+2kHz"). Unless the &lsquo;<code
-     class=property>relative</code>&rsquo; keyword is used, values are
-     restricted to positive numbers (using negative numbers results in the
-     property value being ignored). When the &lsquo;<code
-     class=property>relative</code>&rsquo; keyword is used, the provided
-     value specifies a relative change (decrement or increment) to the
-     inherited value. When the &lsquo;<code
-     class=property>relative</code>&rsquo; keyword is not used, the provided
-     value specifies the average pitch of the speaking voice, expressed as an
-     absolute frequency.</p>
+     kiloHertz, e.g. "100Hz", "+2kHz"). Values are restricted to positive
+     numbers (unless the &lsquo;<code class=property>relative</code>&rsquo;
+     keyword is used), and using negative numbers results in the property
+     value being ignored.</p>
 
    <dt> <strong>relative</strong>
 
    <dd>
     <p> This keyword specifies that the provided frequency value is expressed
-     relatively to another base value. This disambiguates absolute positive
-     &lt;frequency&gt; values from increments (e.g. "+2kHz" can either be an
-     increment or an absolute value).</p>
+     relatively to the inherited value, with positive or negative numbers.
+     For example, "+2kHz relative" is an increment, unlike "+2kHz" which is a
+     positive absolute value.</p>
 
    <dt> <strong>&lt;semitones&gt;</strong>
 
@@ -2132,7 +2128,7 @@
     <p> Only non-negative <a href="#percentage-def">percentage</a> values are
      allowed. Computed values are calculated relative to the inherited value.
      For example, 50% means that the inherited value gets multiplied by 0.5,
-     which results in half the inherited average pitch of the voice.</p>
+     which results in half the inherited pitch of the voice.</p>
 
    <dt><strong>x-low</strong>, <strong>low</strong>, <strong>medium</strong>,
     <strong>high</strong>, <strong>x-high</strong>
@@ -2150,8 +2146,10 @@
 h1 { voice-pitch: +250Hz; } /* identical to the line above */
 h2 { voice-pitch: +30Hz relative; }
 h2 { voice-pitch: 30Hz relative; } /* identical to the line above */
-h3 { voice-pitch: relative -2st; } /* the swapped keyword placement is a legal syntax */
-h4 { voice-pitch: -2st; } /* Illegal syntax ! ("relative" keyword is missing) */</pre>
+h3 { voice-pitch: relative -20Hz; } /* the swapped keyword placement is a legal syntax */
+h4 { voice-pitch: -20Hz; } /* Illegal syntax ! ("relative" keyword is missing for negative frequency) */
+h4 { voice-pitch: -3.5st; } /* Legal syntax: semitones are always relative, no need for the keyword. */
+      </pre>
   </div>
 
   <h3 id=voice-props-voice-pitch-range><span class=secno>10.4. </span>The
@@ -2204,11 +2202,12 @@
 
   <p> The &lsquo;<a href="#voice-pitch-range"><code
    class=property>voice-pitch-range</code></a>&rsquo; property specifies the
-   variability in average pitch, i.e. how much the fundamental frequency may
-   deviate from the average pitch. The dynamic pitch range of the generated
-   speech output typically increases for a highly animated voice, for example
-   when variations in inflection are used to convey meaning and emphasis in
-   speech.
+   variability in the "baseline" pitch, i.e. how much the fundamental
+   frequency may deviate from the average pitch of the speech output. The
+   dynamic pitch range of the generated speech generally increases for a
+   highly animated voice, for example when variations in inflection are used
+   to convey meaning and emphasis in speech. Typically, a low range produces
+   a flat, monotonic voice, whereas a high range produces an animated voice.
 
   <p class=note> Note that the functionality provided by this property is
    related to the <a
@@ -2221,27 +2220,18 @@
 
    <dd>
     <p> A value in <a href="#frequency-def">frequency</a> units (Hertz or
-     kiloHertz, e.g. "100Hz", "+2kHz"). Unless the &lsquo;<code
-     class=property>relative</code>&rsquo; keyword is used, values are
-     restricted to positive numbers (using negative numbers results in the
-     property value being ignored). When the &lsquo;<code
-     class=property>relative</code>&rsquo; keyword is used, the provided
-     value specifies a relative change (decrement or increment) to the
-     inherited value. When the &lsquo;<code
-     class=property>relative</code>&rsquo; keyword is not used, the provided
-     value specifies the average pitch of the speaking voice, expressed as an
-     absolute frequency.</p>
-
-    <p class=note> Low ranges produce a flat, monotonic voice. A high range
-     produces animated voices.</p>
+     kiloHertz, e.g. "100Hz", "+2kHz"). Values are restricted to positive
+     numbers (unless the &lsquo;<code class=property>relative</code>&rsquo;
+     keyword is used), and using negative numbers results in the property
+     value being ignored.</p>
 
    <dt> <strong>relative</strong>
 
    <dd>
     <p> This keyword specifies that the provided frequency value is expressed
-     relatively to another base value. This disambiguates absolute positive
-     &lt;frequency&gt; values from increments (e.g. "+2kHz" can either be an
-     increment or an absolute value).</p>
+     relatively to the inherited value, with positive or negative numbers.
+     For example, "+2kHz relative" is an increment, unlike "+2kHz" which is a
+     positive absolute value.</p>
 
    <dt> <strong>&lt;semitones&gt;</strong>
 
@@ -2260,7 +2250,7 @@
     <p> Only non-negative <a href="#percentage-def">percentage</a> values are
      allowed. Computed values are calculated relative to the inherited value.
      For example, 50% means that the inherited value gets multiplied by 0.5,
-     which results in half the inherited average pitch range of the voice.</p>
+     which results in half the inherited pitch range of the voice.</p>
 
    <dt><strong>x-low</strong>, <strong>low</strong>, <strong>medium</strong>,
     <strong>high</strong> and <strong>x-high</strong>
@@ -2958,10 +2948,10 @@
     <tr>
      <td><a class=property href="#voice-volume">voice-volume</a>
 
-     <td>normal | silent | x-soft | soft | medium | loud | x-loud |
-      &lt;decibel&gt;
+     <td>silent | [[x-soft | soft | medium | loud | x-loud] ||
+      &lt;decibel&gt;]
 
-     <td>normal
+     <td>medium
 
      <td>all elements
 

Index: Overview.src.html
===================================================================
RCS file: /sources/public/csswg/css3-speech/Overview.src.html,v
retrieving revision 1.65
retrieving revision 1.66
diff -u -d -r1.65 -r1.66
--- Overview.src.html	6 Jul 2011 21:41:03 -0000	1.65
+++ Overview.src.html	7 Jul 2011 00:44:22 -0000	1.66
@@ -197,6 +197,7 @@
   voice-family: paul;
   voice-stress: moderate;
   cue-before: url(../audio/ping.wav);
+  voice-volume: medium 6dB;
 }
 p.heidi
 {
@@ -255,13 +256,13 @@
           <td>
             <em>Value:</em>
           </td>
-          <td>normal | silent | x-soft | soft | medium | loud | x-loud | &lt;decibel&gt; </td>
+          <td>silent | [[x-soft | soft | medium | loud | x-loud] || &lt;decibel&gt;] </td>
         </tr>
         <tr>
           <td>
             <em>Initial:</em>
           </td>
-          <td>normal</td>
+          <td>medium</td>
         </tr>
         <tr>
           <td>
@@ -291,7 +292,7 @@
           <td>
             <em>Computed value:</em>
           </td>
-          <td>specified value</td>
+          <td>keyword value, and decibel offset (if not zero)</td>
         </tr>
       </tbody>
     </table>
@@ -302,13 +303,13 @@
         href="http://www.w3.org/TR/speech-synthesis11/#edef_prosody"><code>volume</code> attribute
         of the <code>prosody</code> element</a> from the SSML markup language [[!SSML]]. </p>
     <dl>
-      <dt>
+      <!-- dt>
         <strong>normal</strong>
       </dt>
       <dd>
         <p> Corresponds to +0.0dB, which means that there is no modification of volume level. This
           value overrides the inherited value.</p>
-      </dd>
+      </dd -->
       <dt>
         <strong>silent</strong>
       </dt>
@@ -317,7 +318,7 @@
           negative infinity in dB units.</p>
         <p class="note"> Note that there is a difference between an element whose 'voice-volume'
           property has a value of 'silent', and an element whose 'speak' property has the value
-          'none'. With the former, the selected takes up the same time as if it had been spoken,
+          'none'. With the former, the selected element takes up the same time as if it was spoken,
           including any pause before and after the element, but no sound is generated (descendants
           can override the 'voice-volume' value and may therefore generate audio output). With the
           latter, the selected element is not rendered in the aural dimension and no time is
@@ -328,7 +329,7 @@
           <strong>loud</strong>, <strong>x-loud</strong></dt>
       <dd>
         <p> This sequence of keywords corresponds to monotonically non-decreasing volume levels,
-          mapped to implementation-dependent values (i.e. inferred by the user-agent) that meet
+          mapped to implementation-dependent values (i.e. inferred by the user-agent) that meet the
           user's requirements in terms of perceived sound loudness . The keyword 'x-soft' maps to
           the user's <em>minimum audible</em> volume level, 'x-loud' maps to the user's <em>maximum
             tolerable</em> volume level, 'medium' maps to the user's <em>preferred</em> volume
@@ -339,10 +340,13 @@
       </dt>
       <dd>
         <p>A <a href="#number-def">number</a> immediately followed by "dB" (decibel unit). This
-          represents a change (positive or negative) relative to the default value for the root
-          element, or to the inherited volume level otherwise. This is expressed as the ratio of the
-          squares of the new signal amplitude (a1) and the current amplitude (a0), as per the
-          following logarithmic equation: volume(dB) = 20 log10 (a1 / a0) </p>
+          represents a change (positive or negative) relative to the given keyword value (see
+          enumeration above), or to the default value for the root element, or otherwise to the
+          inherited volume level (which may itself be be a combination of a keyword value and of a
+          decibel offset). When the inherited volume level is 'silent', this 'voice-volume' resolves
+          to 'silent' too, regardless of the provided &lt;decibel&gt; value. Decibels express the
+          ratio of the squares of the new signal amplitude (a1) and the current amplitude (a0), as
+          per the following logarithmic equation: volume(dB) = 20 log10 (a1 / a0) </p>
         <p class="note"> Note that -6.0dB is approximately half the amplitude of the audio signal,
           and +6.0dB is approximately twice the amplitude.</p>
       </dd>
@@ -1017,8 +1021,7 @@
         <strong>none</strong>
       </dt>
       <dd>
-        <p> Equivalent to 0ms (no prosodic break in the speech output). This value can be used to
-          inhibit a prosodic break which the processor would otherwise produce. </p>
+        <p> Equivalent to 0ms (no prosodic break is produced by the speech processor). </p>
       </dd>
       <dt>
         <strong>x-weak</strong>, <strong>weak</strong>, <strong>medium</strong>,
@@ -1222,16 +1225,13 @@
       </dt>
       <dd>
         <p>A <a href="#number-def">number</a> immediately followed by "dB" (decibel unit). This
-          represents a change (positive or negative) relative to the default sound level of audio
-          clip. This is expressed as the ratio of the squares of the new signal amplitude (a1) and
-          the current amplitude (a0), as per the following logarithmic equation: volume(dB) = 20
-          log10 (a1 / a0)</p>
-        <p>Audio cues apply to the selected element within the <a href="#aural-model">audio "box"
-            model</a>, so when the inherited value from the 'voice-volume' property is 'silent', the
-          volume level for the audio cue is resolved to -infinity decibels (which effectively
-          silences the audio cue), regardless of the value provided for this &lt;decibel&gt;. In
-          other words, a selected element can be entirely silenced (i.e. including its associated
-          audio cues) by setting the 'voice-volume' property to 'silent'. </p>
+          represents a change (positive or negative) relative to the computed value of the
+          'voice-volume' property within the <a href="#aural-model">aural "box" model</a> of the
+          selected element. When the 'voice-volume' property is set to 'silent', the audio cue is
+          also set to 'silent' (regardless of the value provided for this &lt;decibel&gt;). Decibels
+          express the ratio of the squares of the new signal amplitude (a1) and the current
+          amplitude (a0), as per the following logarithmic equation: volume(dB) = 20 log10 (a1 /
+          a0)</p>
         <p class="note"> Note that -6.0dB is approximately half the amplitude of the audio signal,
           and +6.0dB is approximately twice the amplitude.</p>
         <p class="note"> Note that there is a difference between an audio cue whose volume is set to
@@ -1412,6 +1412,11 @@
           future use and must also be quoted when used as voice names. </p>
         <p class="note"> Note that in [[!SSML]], voice names are space-separated and cannot contain
           whitespace characters.</p>
+        <p> It is recommended to quote voice names that contain white space, digits, or punctuation
+          characters other than hyphens - even if these voice names are valid in unquoted form - in
+          order to improve code clarity. For example: <code>voice-family: "john doe", "Henry
+            the-8th";</code>
+        </p>
       </dd>
       <dt>
         <strong>&lt;age&gt;</strong>
@@ -1458,12 +1463,6 @@
 voice-family: #john; /* identifier cannot start with hash character */
 voice-family: john 1st; /* identifier cannot start with digit */</pre>
     </div>
-    <div class="example">
-      <p> This is an example of valid voice names that contain white space, digits, or punctuation
-        characters other than hyphens, but which are quoted nonetheless, for reading clarity. </p>
-      <pre>
-voice-family: "john doe", "Henry the-8th";</pre>
-    </div>
     <h4 class="no-toc" id="voice-selection">Voice selection, content language</h4>
     <p>The 'voice-family' property is used to guide the selection of the speech synthesis voice
       instance. As part of this selection process, speech-capable user agents must also take into
@@ -1657,9 +1656,11 @@
         </tr>
       </tbody>
     </table>
-    <p>The 'voice-pitch' property specifies the average pitch of generated speech output, and
-      depends on the 'voice-family'. For example, the default average pitch for a common male voice
-      is around 120Hz, whereas it is around 210Hz for a female voice.</p>
+    <p>The 'voice-pitch' property specifies the "baseline" pitch of the generated speech output,
+      which depends on the used 'voice-family' instance, and varies across speech synthesis
+      processors (it approximately corresponds to the average pitch of the output). For example, the
+      common pitch for a male voice is around 120Hz, whereas it is around 210Hz for a female
+      voice.</p>
     <p class="note"> Note that the functionality provided by this property is related to the <a
         href="http://www.w3.org/TR/speech-synthesis11/#edef_prosody"><code>pitch</code> attribute of
         the <code>prosody</code> element</a> from the SSML markup language [[!SSML]]. </p>
@@ -1669,20 +1670,17 @@
       </dt>
       <dd>
         <p> A value in <a href="#frequency-def">frequency</a> units (Hertz or kiloHertz, e.g.
-          "100Hz", "+2kHz"). Unless the 'relative' keyword is used, values are restricted to
-          positive numbers (using negative numbers results in the property value being ignored).
-          When the 'relative' keyword is used, the provided value specifies a relative change
-          (decrement or increment) to the inherited value. When the 'relative' keyword is not used,
-          the provided value specifies the average pitch of the speaking voice, expressed as an
-          absolute frequency. </p>
+          "100Hz", "+2kHz"). Values are restricted to positive numbers (unless the 'relative'
+          keyword is used), and using negative numbers results in the property value being ignored.
+        </p>
       </dd>
       <dt>
         <strong>relative</strong>
       </dt>
       <dd>
-        <p> This keyword specifies that the provided frequency value is expressed relatively to
-          another base value. This disambiguates absolute positive &lt;frequency&gt; values from
-          increments (e.g. "+2kHz" can either be an increment or an absolute value). </p>
+        <p> This keyword specifies that the provided frequency value is expressed relatively to the
+          inherited value, with positive or negative numbers. For example, "+2kHz relative" is an
+          increment, unlike "+2kHz" which is a positive absolute value. </p>
       </dd>
       <dt>
         <strong>&lt;semitones&gt;</strong>
@@ -1701,8 +1699,8 @@
       <dd>
         <p> Only non-negative <a href="#percentage-def">percentage</a> values are allowed. Computed
           values are calculated relative to the inherited value. For example, 50% means that the
-          inherited value gets multiplied by 0.5, which results in half the inherited average pitch
-          of the voice. </p>
+          inherited value gets multiplied by 0.5, which results in half the inherited pitch of the
+          voice. </p>
       </dd>
       <dt><strong>x-low</strong>, <strong>low</strong>, <strong>medium</strong>,
           <strong>high</strong>, <strong>x-high</strong></dt>
@@ -1718,8 +1716,10 @@
 h1 { voice-pitch: +250Hz; } /* identical to the line above */
 h2 { voice-pitch: +30Hz relative; }
 h2 { voice-pitch: 30Hz relative; } /* identical to the line above */
-h3 { voice-pitch: relative -2st; } /* the swapped keyword placement is a legal syntax */
-h4 { voice-pitch: -2st; } /* Illegal syntax ! ("relative" keyword is missing) */</pre>
+h3 { voice-pitch: relative -20Hz; } /* the swapped keyword placement is a legal syntax */
+h4 { voice-pitch: -20Hz; } /* Illegal syntax ! ("relative" keyword is missing for negative frequency) */
+h4 { voice-pitch: -3.5st; } /* Legal syntax: semitones are always relative, no need for the keyword. */
+      </pre>
     </div>
     <h3 id="voice-props-voice-pitch-range">The 'voice-pitch-range' property</h3>
     <table class="propdef" summary="name: syntax">
@@ -1775,10 +1775,12 @@
         </tr>
       </tbody>
     </table>
-    <p> The 'voice-pitch-range' property specifies the variability in average pitch, i.e. how much
-      the fundamental frequency may deviate from the average pitch. The dynamic pitch range of the
-      generated speech output typically increases for a highly animated voice, for example when
-      variations in inflection are used to convey meaning and emphasis in speech. </p>
+    <p> The 'voice-pitch-range' property specifies the variability in the "baseline" pitch, i.e. how
+      much the fundamental frequency may deviate from the average pitch of the speech output. The
+      dynamic pitch range of the generated speech generally increases for a highly animated voice,
+      for example when variations in inflection are used to convey meaning and emphasis in speech.
+      Typically, a low range produces a flat, monotonic voice, whereas a high range produces an
+      animated voice. </p>
     <p class="note"> Note that the functionality provided by this property is related to the <a
         href="http://www.w3.org/TR/speech-synthesis11/#edef_prosody"><code>range</code> attribute of
         the <code>prosody</code> element</a> from the SSML markup language [[!SSML]]. </p>
@@ -1788,22 +1790,17 @@
       </dt>
       <dd>
         <p> A value in <a href="#frequency-def">frequency</a> units (Hertz or kiloHertz, e.g.
-          "100Hz", "+2kHz"). Unless the 'relative' keyword is used, values are restricted to
-          positive numbers (using negative numbers results in the property value being ignored).
-          When the 'relative' keyword is used, the provided value specifies a relative change
-          (decrement or increment) to the inherited value. When the 'relative' keyword is not used,
-          the provided value specifies the average pitch of the speaking voice, expressed as an
-          absolute frequency. </p>
-        <p class="note"> Low ranges produce a flat, monotonic voice. A high range produces animated
-          voices. </p>
+          "100Hz", "+2kHz"). Values are restricted to positive numbers (unless the 'relative'
+          keyword is used), and using negative numbers results in the property value being ignored.
+        </p>
       </dd>
       <dt>
         <strong>relative</strong>
       </dt>
       <dd>
-        <p> This keyword specifies that the provided frequency value is expressed relatively to
-          another base value. This disambiguates absolute positive &lt;frequency&gt; values from
-          increments (e.g. "+2kHz" can either be an increment or an absolute value). </p>
+        <p> This keyword specifies that the provided frequency value is expressed relatively to the
+          inherited value, with positive or negative numbers. For example, "+2kHz relative" is an
+          increment, unlike "+2kHz" which is a positive absolute value. </p>
       </dd>
       <dt>
         <strong>&lt;semitones&gt;</strong>
@@ -1822,8 +1819,8 @@
       <dd>
         <p> Only non-negative <a href="#percentage-def">percentage</a> values are allowed. Computed
           values are calculated relative to the inherited value. For example, 50% means that the
-          inherited value gets multiplied by 0.5, which results in half the inherited average pitch
-          range of the voice. </p>
+          inherited value gets multiplied by 0.5, which results in half the inherited pitch range of
+          the voice. </p>
       </dd>
       <dt><strong>x-low</strong>, <strong>low</strong>, <strong>medium</strong>,
           <strong>high</strong> and <strong>x-high</strong></dt>
Received on Thursday, 7 July 2011 00:44:27 GMT

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