[whatwg] Audio canvas?

Vladimir Vukicevic vladimir at pobox.com
Wed Jul 23 11:52:52 PDT 2008


On Jul 16, 2008, at 11:25 AM, Dave Singer wrote:

> At 20:18  +0200 16/07/08, Dr. Markus Walther wrote:
>>
>> get/setSample(<samplePoint> t, <sampleValue> v, <channel> c).
>>
>> For the sketched use case - in-browser audio editor -, functions on  
>> sample regions from {cut/add silence/amplify/fade} would be nice  
>> and were mentioned as an extended possibility, but that is optional.
>>
>> I don't understand the reference to MIDI, because my use case has  
>> no connection to musical notes, it's about arbitrary audio data on  
>> which MIDI has nothing to say.
>
> get/set sample are 'drawing primitives' that are the equivalent of  
> get/setting a single pixel in images.  Yes, you can draw anything a  
> pixel at a time, but it's mighty tedious.  You might want to lay  
> down a tone, or some noise, or shape the sound with an envelope, or  
> do a whole host of other operations at a higher level than sample-by- 
> sample, just as canvas supports drawing lines, shapes, and so on.   
> That's all I meant by the reference to MIDI.

I think an interesting approach for an audio canvas would be to allow  
you to both manipulate audio data directly (through a getSampleData/ 
putSampleData type interface), but also build up an audio filter  
graph, both with some predefined filters/generators and with the  
ability to do filters in javascript.  Would make for some interesting  
possibilities, esp. if it's able to take <audio> as input.

    - Vlad




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