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Rework definition of ABSN output behavior for rate-adjusted duration param #1681

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Merged
rtoy merged 6 commits into from
Jul 12, 2018
Merged

Rework definition of ABSN output behavior for rate-adjusted duration param #1681

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8411937
Rework definition of ABSN output behavior to account for playbackRate…
Jun 21, 2018
77670a7
Merge branch 'gh-pages' into 1660-duration-definition
Jun 27, 2018
ff4a0fe
Remove mention of stop() in definition of duration parameter.
Jun 27, 2018
5bee8b4
Regenerate index.html
Jun 27, 2018
992eda2
Initialize bufferDuration outside of process() in ABSN algorithm.
Jun 28, 2018
a57fe08
Address review comments
Jul 12, 2018
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Remove mention of stop() in definition of duration parameter.
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joeberkovitz committed Jun 27, 2018
commit ff4a0fed4e0543bf346012594560994ab43d9c41
2 changes: 1 addition & 1 deletion index.bs
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Expand Up @@ -4650,7 +4650,7 @@ Methods</h4>
<pre class=argumentdef for="AudioBufferSourceNode/start(when, offset, duration)">
when: The <code>when</code> parameter describes at what time (in seconds) the sound should start playing. It is in the same time coordinate system as the {{AudioContext}}'s {{BaseAudioContext/currentTime}} attribute. If 0 is passed in for this value or if the value is less than <b>currentTime</b>, then the sound will start playing immediately. <span class="synchronous">A {{RangeError}} exception MUST be thrown if <code>when</code> is negative.</span>
offset: The <code>offset</code> parameter supplies a <a>playhead position</a> where playback will begin. If 0 is passed in for this value, then playback will start from the beginning of the buffer. <span class="synchronous">A {{RangeError}} exception MUST be thrown if <code>offset</code> is negative.</span> If <code>offset</code> is greater than {{AudioBufferSourceNode/loopEnd}}, playback will begin at {{AudioBufferSourceNode/loopEnd}} (and immediately loop to {{AudioBufferSourceNode/loopStart}}). <code>offset</code> is silently clamped to [0, <code>duration</code>], when <code>startTime</code> is reached, where <code>duration</code> is the value of the <code>duration</code> attribute of the {{AudioBuffer}} set to the {{AudioBufferSourceNode/buffer}} attribute of this <code>AudioBufferSourceNode</code>.
duration: The {{AudioBufferSourceNode/start(when, offset, duration)/duration}} parameter describes the duration of sound to be played, expressed as seconds of total buffer content to be output, including any whole or partial loop iterations. The units of {{AudioBufferSourceNode/start(when, offset, duration)/duration}} are independent of the effects of {{AudioBufferSourceNode/playbackRate}}. This behavior contrasts with the absolute time units employed by {{AudioScheduledSourceNode/stop()}}. Thus, a {{AudioBufferSourceNode/start(when, offset, duration)/duration}} of 5 seconds with a playback rate of 0.5 will output 5 seconds of buffer content at half speed, producing 10 seconds of audible output. <span class="synchronous">A {{RangeError}} exception MUST be thrown if <code>duration</code> is negative.</span>
duration: The {{AudioBufferSourceNode/start(when, offset, duration)/duration}} parameter describes the duration of sound to be played, expressed as seconds of total buffer content to be output, including any whole or partial loop iterations. The units of {{AudioBufferSourceNode/start(when, offset, duration)/duration}} are independent of the effects of {{AudioBufferSourceNode/playbackRate}}. For example, a {{AudioBufferSourceNode/start(when, offset, duration)/duration}} of 5 seconds with a playback rate of 0.5 will output 5 seconds of buffer content at half speed, producing 10 seconds of audible output. <span class="synchronous">A {{RangeError}} exception MUST be thrown if <code>duration</code> is negative.</span>
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@rtoy rtoy Jun 27, 2018

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I think (as mentioned previously), we shouldn't really try to say in words what supposed to happen. Can we just refer to the algorithm?

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@joeberkovitz joeberkovitz Jun 28, 2018

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I feel strongly that here (as in many other places in the spec) it's valuable to have a short textual description of what a thing is, as a counterpoint to the algorithm.

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@rtoy rtoy Jun 28, 2018

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I'm only concerned if it's inconsistent with the fine details of the algorithm. A non-normative note is acceptable to me.

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@joeberkovitz joeberkovitz Jun 28, 2018

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I think it's consistent -- if you would like to rephrase it somehow, please propose (or commit) some alternate wording.

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@rtoy rtoy Jul 10, 2018

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As stated, I think a non-normative note would be fine. And I think the duration here also applies to looping. The looping playback will play for duration secs, taking into account the playback rate.

</pre>

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