In the new iPhone 3GS commercial, Apple shows voice control with a cool blue waveform animation. Is this visual effect for rendering the waveforms (or maybe just volumes) available as an API call or source code somewhere? (Not the voice control part, just the audio visualization)
I think you could get the sound info from AVAudioPlayer's averagePowerForChannel: method, but how would you show the waves moving up and down?
Thanks!
John,
That code that you found for drawing the sine wave is great. This sample code from Apple shows a sound meter with live audio recording. With those two resources, you should be on track to make the visual waveform.
The waveform in the apple commercials is very clearly just a plain old sine wave that looks like it's got its amplitude modulated by the volume of the input.
Related
I am creating one sound based application where I need to generate different oscillations for sound wave. One part that I need to achieve in this is the discontinuous or paused beep. I am trying to do this using I'm doing variations in the sine wave using Core Audio, but I'm not getting the desired output.
Basically I need to generate variable sound oscillation patterns like Dog Whistler app.
Can anyone help me in proper direction for this
have a look at my other answer how to loop background music. You can create an audio file with 0.5 sec beep and 1 sec silence and loop that file infinitely via AVAudioPlayer. As well as pausing the beep sequence via [player pause];
This will work if you have some predefined beep intervals/oscillations but not if you need 100% user customization. You can also look for sound effects to adjust the pitch and frequency.
I am working on a music player for the iPhone, and I would like to crossfade between songs. I know this is possible because My DJ does it...I can't find any documentation and don't even know where to begin on it. Can anyone give me a starting point or example code?
Thanks.
One option is to convert both songs into raw (linear PCM) samples. Then build your own mixer function or audio unit where the mix ratio of each sample comes from a ramp or custom mix curve function. Feed the output to the RemoteIO audio unit.
Sorry for my weak english
I've got some aif or MP3 tunes for plaing loud on the iPhone,
and I need to do some 'sound change' detections,
such I would use for some visualisations (jumping man or other)
how to do it 'easy' on iPhone or how to do it 'fine'?
should I do fft or such, or something different?
I have seen some sound visualisations back then but all they
seem not to much good (they seem not to be much clear in reactions on
music change).
Thanks
What are you currently using for playback? I would use audio queues or audio units - both give you access to buffers of audio samples as they're passed through to the hardware. At that point it's a matter of detecting peaks in the sound above a certain threshold, which you can do in a variety of different ways.
An FFT will not help you because you're interested in the time-domain waveform of the sound (its amplitude over time) not its frequency-domain characteristics (the relative strengths of different frequencies in different time windows.)
I'm recording audio using AVAudioRecorder and after recording I want to draw a wave form of the recorded audio. I've found a nice article about wave form drawing, but it first I need the frequencies at a certain sample rate as floats, right?
Do I need to do FFT on the audio and how do I do this? Is *AVAudioRecorder** even the API for this purpose? Or do I need to use some lower API to record the audio?
Hope someone can help me.
AVAudioRecorder doesn't look like it's much use for this (although it may be possible). You need to look at recording with AudioQueue.
The 'waveform' of the audio isn't the frequencies. The waveform is the value of the samples that make up the audio (you can get these when recording with an AudioQueue). FFT converts the audio samples from the time domain to the frequency domain - if you draw the output of the FFT you will have a Spectrograph instead of a waveform.
Within my iPhone application, how would I recognize the noise that a clap makes?
If you're talking about recognizing the sound of a clap, SCListener is a great and easy-to-use class that gives you simple audio levels. Then it's just a question of measuring peaks or even just high values.