allow to change speed without changing the pitch

[amir ramezani]

hi,
this is in my idea is very good thing, but maybe it's very very hard to do
in audacity, they used soundtouch library to do that
this is it's website:
http://www.surina.net/soundtouch/

[eXpl0it3r]

It would certainly be a nice feature, however this goes quite a bit into audio processing, thus I wonder if it should really be part of SFML itself. I'm not sure how well SFML lets the users process the audio themselves, but personally I'd say it would be better if we get easily access to the audio data via SFML and then anyone can choose what they want to do with that data.

As for SoundTouch, given that it's under LGPL it's not an option for SFML.

Btw. the links in your signature are broken!

[Lo-X]

If openAL allows it, I don't see why SFML wouldn't.
And indeed, I needed that feature for the last LD48 but I had to use the pitch instead.

[amir ramezani]

It would certainly be a nice feature, however this goes quite a bit into audio processing, thus I wonder if it should really be part of SFML itself. I'm not sure how well SFML lets the users process the audio themselves, but personally I'd say it would be better if we get easily access to the audio data via SFML and then anyone can choose what they want to do with that data.

As for SoundTouch, given that it's under LGPL it's not an option for SFML.

Btw. the links in your signature are broken!

firstly, boath of them are open source
so, it's not be a problem
secondly, I've update my links
thanks for your report
if they don't load, report here

[Nexus]

firstly, boath of them are open source
so, it's not be a problem

But you know what LGPL means? There exist many open-source licenses, a lot of which are incompatible to each other.

[amir ramezani]

But you know what LGPL means? There exist many open-source licenses, a lot of which are incompatible to each other.

an OS developer must know that
but, libsndfile and OpenAL are open source and boath of them are in LGPL license

[Laurent]

If openAL allows it, I don't see why SFML wouldn't.

It doesn't. That's why it requires another third-party library.

[eXpl0it3r]

but, libsndfile and OpenAL are open source and boath of them are in LGPL license

True forgot that they are LGPL as well, but that's also a bit of a pain, because we'll always have to link them dynamically.

Btw. when talking about licenses or even in general, it's mostly of no use to say "it's open source", because that just means we can look at the source. But since we're mostly interested in how we can use the code, it's way better to name the license directly.

[Lo-X]

If openAL allows it, I don't see why SFML wouldn't.

It doesn't. That's why it requires another third-party library.

Bad Well, we'll wait for that for a future version, someday

[amir ramezani]

I know that and of course saw that
you can compile it as a dynamic library and use it in your apps
it is not hard!
what do you think?

[zsbzsb]

I know that and of course saw that
you can compile it as a dynamic library and use it in your apps
it is not hard!
what do you think?

If you want to use it then go for it, however this is out of the scope of SFML since it is high level audio processing. But feel free to integrate it yourself into your own application 

[amir ramezani]

what can I say?
i'll use it but I don't know about SFML

[Foaly]

I don't really think that changing speed and pitch is highlevel audio processing, but it might still be a little out of SFMLs scope (although it would be really nice!) and there is the licensing issue.
Processing on sf::SoundBuffer is quiet easy, due to the getBuffer() method. I have done that before.
But I have not succeeded to manipulate sf::Music in real time. So like suggested it would be an awesome addition if there was a way to access the musics samples for processing. This would give everybody the freedom to do what they like (FFT analysis, pitch, distort...)

[amir ramezani]

it help's many thing related to sound and sound processing

[Cornstalks]

A former coworker of mine wrote the atempo filter in FFmpeg, which allows audio to be sped up/slowed down without changing the pitch. The source can be found here for FFmpeg's atempo. If you look at that file, you'll see that it's LGPL, but he links to another (original) implementation that's licensed under the MIT license: Apprentice Video Player (specifically, the yaeAudioTempoFilter.h and yaeAudioFragment.h files).

You could strip out that code and turn it into a library, all based on the MIT license, if you felt so inclined.

But I'd have to agree this is beyond SFML's scope.