On 8/27/15, Robert O'Callahan <rob...@ocallahan.org> wrote:
> On Fri, Aug 28, 2015 at 6:02 AM, Garrett Smith <dhtmlkitc...@gmail.com>
> wrote:
>> It would be useful to have pitch adjustment for VIDEO element. There
>> is playbackRate, to control playback speed — useful!* And there is
>> vv.mozPreservesPitch, in Firefox, which can be set to false, so that
>> pitch will adjust to the speed of the video, sort of like old analog
>> gear (tapes and records).
> We should standardize mozPreservesPitch. I'm embarrassed that we haven't
> done so already.
> Negative playbackRate, to watch videos backwards, currently crashes
>> Safari 8; Firefox 40 says "not implemented". I think it would be
>> entertaining for example, to watch things like cars uncrashing. Should
>> this work? And if so, shouldn't audio match the video speed for
>> backwards playing? I think "yes, and yes."
> According to the spec it should work, but it's very low priority for us and
> implementing it would be very inefficient as Yay295 describes. So I don't
> think it's going to happen in Firefox in the forseeable future.
> But variable pitch control it would be useful for music adjustments
>> like "over the mountain",  "Black Star", "Take your Whiskey Home", all
>> originally recorded at half-step detuning (A=415), none of which match
>> "standard tuning" commonly used in schools, industry, etc. Recordings
>> of Baroque era music often use instruments tuned lower (and also
>> different scale temperment, but that is a different issue). So it
>> would be nice to adjust the pitch with a `pitchAdjustment` property,
>> as a double, to adjust pitch in cents.
> I'd prefer to focus on making sure that Web Audio's Audio Workers are
> powerful enough for Web developers to implement this themselves.

I don't know enough about Web Audio to comment on that. Most of what
I'm using is on YouTube.  And there are some video issues that I'd
like to comment on because it's such a common situation to have audio
as video MP4's. So here's two "video" user scenarios:

Want hear the audio at the desired pitch, while simultaneously
watching the video at the desired speed, to learn it.

For fine-grained adjustment for music performances that are in between
keys (off by a few cents) or need to be transcribed.

This guy's cover of "Over the Mountain" is pretty good.
https://www.youtube.com/watch?v=Ze6h1t7Z734 Right now, I can get that
up a half step to standard tuning by increasing the speed and setting

var vv = document.querySelector("video");
vv.mozPreservesPitch = false;
vv.playbackRate = 1.05;

But it's a little sped up. Not ideal for learning! I'd rather slow
down it a bit. Enter the Amazing Slow Downer … does what I want.

OK, there's my two user scenarios with an example. Thanks for reading!

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