Alter playback speed?

[andymcarter]

After a few teething problems due to my lack of experience, now enjoying building some multitracks with this! I teach a Brazilian style of music called choro and you can see the tracks I've built up below.

http://chorotest.hol.es/

Is there a way to implement the webaudio playback speed feature, using a global slider like the master volume control. Then my students could speed up or slow down the track slightly (within reason).

https://developer.mozilla.org/en-US/Apps/Fundamentals/Audio_and_video_delivery/WebAudio_playbackRate_explained

[naomiaro]

Hey! I'm checking out these site that you posted, but I'm getting some net::ERR_CONTENT_LENGTH_MISMATCH errors so I can't see the tracks loading.

I could try implementing a playback speed feature. There is nothing altering that parameter in the code so far. It will take just a bit of work I think to sync the changed playback rate with the UI, but it should be doable.

[naomiaro]

Maybe this was just my network in my coworking space, but it's working fine now from my home these examples.

[Willena]

I could try implementing a playback speed feature. There is nothing altering that parameter in the code so far. It will take just a bit of work I think to sync the changed playback rate with the UI, but it should be doable.

increase or slow down the speed is doable. In the current code as we did ( almost ) to create the master gain, we can modify the source playbackRate parameter . But as shown in this example, the audio is modified. And it might be very dificult to counter this modification.

[andymcarter]

http://hyperaud.io/lab/pbr-test/

The audio implementation at the bottom of the page doesn't change audio pitch.

PS. grateful for the responses :)

[Willena]

Having a look at https://developer.mozilla.org/en-US/Apps/Fundamentals/Audio_and_video_delivery/WebAudio_playbackRate_explained confirm what I was saying before. In Web Audio when you change the playback rate, the pitch also change and there are no automatic corrections. In your example when you are playing audio you are using html audio elements, which correct automaticaly the pitch. This project is build over web audio APIs, so we have to write our own pitch correction functions.

[andymcarter]

Hadn't appreciated the difference between the two APIs, thanks for explaining.

[naomiaro]

Looking into projects that do this with webaudio...

• https://github.com/dumbmatter/screw using https://github.com/also/soundtouch-js
• https://github.com/cutterbl/SoundTouchJS
• https://github.com/cutterbl/soundtouchjs-audio-worklet

Check AudioWorklet support

• support worklet webpack/webpack#11543

[PDL-II]

It seems to be very in demand this feature. Sometimes small tweaks like speeding up or down a file and it makes the whole difference. I really hope this feature gets added to this already amazing software! :)

[p-himik]

Currently, the page linked above, https://developer.mozilla.org/en-US/Apps/Fundamentals/Audio_and_video_delivery/WebAudio_playbackRate_explained, states:

The pitch of the audio track does not change when playBackRate is altered.

And I can confirm this in at least Chrome and Firefox on Ubuntu.

Update: huh, but it doesn't work with AudioBufferSourceNode.playbackRate - the pitch is changed.