Mathieu HENRI wrote:
Dr. Markus Walther wrote:
I have noted an asymmetry between <canvas> and <audio>:
<canvas> supports loading of ready-made images _and_ pixel
manipulation (get/putImageData).
<audio> supports loading of ready-made audio but _not_ sample
manipulation.
With browser JavaScript getting faster all the time (Squirrelfish...),
audio manipulation in the browser is within reach, if supported by
rich enough built-in objects.
Minimally, sample-accurate methods would be needed to
- get/set a sample value v at sample point t on channel c from audio
- play a region from sample point t1 to sample point t2
(Currently, everything is specified using absolute time, so rounding
errors might prevent sample-accurate work).
More powerful methods might cut/add silence/amplify/fade portions of
audio in a sample-accurate way.
It would be OK if this support were somewhat restricted, e.g. only for
certain uncompressed audio formats such as PCM WAVE.
Question: What do people think about making <audio> more like <canvas>
as sketched above?
My understanding of HTMLMediaElement is that the currentTime, volume and
playbackRate properties can be modified live.
So in a way Audio is already like Canvas : the developer modify things
on the go. There is no automated animations/transitions like in SVG for
instance.
Doing a cross fade in Audio is done exactly the same way as in Canvas.
And if you're thinking special effects ( e.g.: delay, chorus, flanger,
pass band, ... ) remember that with Canvas, advanced effects require
trickery and to composite multiple Canvas elements.
--
Mathieu 'p01' HENRI
JavaScript developer, Opera Software ASA
