I'm creating a component to view an audio file, that part I've already achieved, which can be seen in this image.
My biggest problem now is that I need a way to get all the bytes of the audio file, using the Web Audio API or some other method in typescript (preferably) or javascript.
I have researched and found the AnalyserNode, however it shows only a part of the audio being executed, it does not provide an array with all the bytes of the file.
Does anyone know of any other solution?
Thank you.
Related
I've played around with the web audio api before, but it's a very specific and unambiguous that it wants to connect all the sources together to the destination for it to work. However it seems given how iframes and other ways sound can be introduced there'd need to be an extremely elaborate script to tie in new sources to an analyzer node headed to the output.
Note I'm not talking about routing a stream from a microphone like here, there shouldn't be any permission required. Also I'm not talking about audio sources already hooked into the web audio api, there are a ton of examples about processing audio from inside the web audio api. I'm curious if there's a generic way to process audio on a page before (or after) it hits the speakers.
Essentially I was curious if anyone has seen or built an application that's reactive to audio in html and or has thoughts on putting something like this together.
The solution I have in mind would be a script which triggers when media is played and attaches the media source to the web audio api > an analyzer node > destination. I haven't found any javascript event that appears to work in this way.
In a Chrome extension, is it possible to create an waveform or spectrogram image (or canvas) element based on only a .wav file URL of an <audio> tag?
I assume that solving this will require multiple steps:
Load the sound file data.
Convert the data into a format that can be used for drawing, possibly an array of sample values, similar to the .dat format of soxformat.
Generate an image or draw on a canvas.
Please provide JavaScript code to turn this:
<audio src="http://goo.gl/hWyNYu" controls />
into this:
This needs to be done without having to play back the audio, as opposed to existing solutions and without using server-side solutions.
Rather than being a question about a specific step in the process, this question seeks a complete answer with complete code so anybody could test it first and understand it later.
Well, theoretically, you should be able to use those existing client-side solutions without playing back the audio, using an OfflineAudioContext. Unfortunately, those solutions both use ScriptProcessorNode, and from what I've heard, existing implementations are broken when using ScriptProcessorNode in an OfflineAudioContext, and not likely to be fixed. I suspect AnalyserNode may be broken in OfflineAudioContext too.
It would probably work to use an OfflineAudioContext to just "play back" the entire sound file, then draw your canvas based on the output buffer that is created.
Or you could use a regular AudioContext, but make sure the output isn't audible (say, by piping the sound through a gain node with gain of zero). This is really ugly, slow, and would interfere with any other Web Audio API usage on your page.
You could also try fetching the entire file just as a binary blob into an ArrayBuffer, and parse it yourself. The WAV file format is not all that complicated (or you might be able to find open source code to do this). If you wanted to handle compressed formats like MP3 this way, you would definitely not want to write the decoder from scratch.
EDIT:
I think the Web Audio-based solutions above are too complicated. You have to set up an AudioBuffer and decode the audio into it using decodeAudioData anyway. Once you've done that, there is no need to even create an AudioBufferSourceNode. You can just get the audio data directly from the AudioBuffer by calling getChannelData on it.
I am currently thinking about how to realise an app that feeds multiple audio interfaces with different sounds. For example if I have a second sound card at disposal.
As far as I researched the AudioContext of Web Audio only feeds a single destination. I haven't seen a way to select the actual destination hardware.
Can anyone think of a way to work around this?
Nope. It'll use whatever your system default is.
You can output audio from an audio/video element to a specified output device using setSinkid()
videoElement.setSinkId(deviceID).then().catch()
We are making an web based music editor and mixer based on the Web Audio api. Users can mix together multiple tracks, crop tracks, etc. The actual mixing together of the tracks just involves playing back all the sources at once.
We want to be able to add the option to save the mix and make it available for download to a user's computer. Is there some way to do this on the front end (like connecting all the sources to one destination/export node), or even the backend (we are using RoR)?
RecorderJS does exactly what you need, and it could not possibly be easier to use. Really, really great library.
https://github.com/mattdiamond/Recorderjs
P.S. Look into OfflineAudioContext and my answer to this question (Web audio API: scheduling sounds and exporting the mix) for info on doing a faster-than-realtime mixdown of your audio.
Users data looks to be on client side?
Basically when converting data with base64 into dataURI, datas are diplayed inline so they can be add 1 by 1 togheter into one single blob object, and be downloaded.
But this method is only good for smalls files, causing crash and freezing with most browser, this is only good for blob size less than 10mb after some personnal tests, this will be better soon for sure.
<audio controls><source src="data:audio/ogg;base64,BASE64.......BASE564......BASE64............."></audio>
or
<a href="data:audio/ogg;base64,BASE64...BASE64..BASE64....>Download</a>
Probably not your way, just an idea but your project is interesting ;)
I'm trying to build an mp3 player for my site using JavaScript (and any plugins/frameworks(jQuery)/libraries that are relevant) & html5. So I built the player (more accurately, I implemented jPlayer), and now I want to make a visualizer.
Ok maybe it's not a visualizer (all the names for ways to visualize sound always confused me), I guess what I want is something like this:
(source: anthonymattox.com)
Or just something that graphs the amplitude (loudness) of an MP3.
So to start, does anyone know an API that can do this?
If you don't that's ok; I guess I'll build my own. For which I need to know:
Does anybody know a way to get the amplitude/loudness of an mp3 at any given point using JavaScript?
EDIT
Changed to a question about php: Visualization of MP3 - PHP
You would need to be able to decode the MP3 yourself. The html5 audio element, and the browsers's implementations of it, don't expose this sort of data. For example, look at Firefox's exposed methods for JavaScript. The closest thing to what you want is the "volumechange" event. But that is in reference to the volume mixer on the browser's rendered control (i.e. output volume). It has nothing to do with the actual dB of the audio source.
I imagine that the only feasible way to do this is to render your waveform to a graphic ahead of time, and then "reveal" it as the song plays (e.g. with the "timeupdate" event).