Everything is being done in the front end.
My goal is to be able to create an audio track, in real time, and play it instantly for a user. The file would be roughly 10 minutes. However, the files are very simple, mostly silence, with a few sound clips (the sound clip is 2kb) sprinkled around. So the process for generating the data (the raw bytes) is very simple, it's either write the 2kb sound clip or place n amount of 00 for the silence. It's just that for 10 minutes. But instead of generating the entire file fully, and then playing it, I would like to stream the audio, ideally I would be generating more and more of the file while the audio was playing. It would prevent any noticeable delay between when the user clicks play and when the audio starts playing. The process of creating the file can take anywhere from 20 milliseconds to 500 milliseconds, different files are created based off user input.
The only problem is: I have no idea how to do this. I've read ideas about using web sockets, but that seems like the data would come from the server, I see no reason why to bother a server with this when the JavaScript can easily generate the audio data on its own.
I've been researching and experimenting with the Web Audio API and the Media Streams API for the past several hours, and I keep going in circles and I'm totally confused by it. I'm starting to think that these API are meant to be used for gathering data from a users mic or webcam, and not fed data directly from a readable stream.
Is what I want to do possible? Can it be achieved using something like a MediaStreamAudioSourceNode or is there another simpler way that I haven't noticed?
Any help on this topic would be so greatly appreciated. Examples of a simple working version would be even more appreciated. Thanks!
I'm going to follow this question, because a true streaming solution would be very nice to know about. My experience is limited to using WebAudio API to play to two sounds with a given pause in between them. The data is actually generated at the server and downloaded using Thymeleaf, into two javascript variables that hold the PCM data to be played. But this data could easily have been generated at the client itself via Javascript.
The following is not great, but almost could be workable, given that there are extensive silences. I'm thinking, manage an ordered FIFO queue with the variable name and some sort of timing value for when you want the associated audio played, and have a function that periodically polls the queue and loads commands into javascript setTimeout methods with the delay amount calculated based on the timing values given in the queue.
For the one limited app I have, the button calls the following (where I wrote a method that plays the sound held in the javascript variable)
playTone(pcmData1);
setTimeout(() => playTone(pcmData2), 3500);
I have the luxury of knowing that pcmData1 is 2 seconds long, and a fixed pause interval between the two sounds. I also am not counting on significant timing accuracy. For your continuous playback tool, it would just have the setTimeout part with values for the pcmData variable and the timing obtained from the scheduling FIFO queue.
Whether this is helpful and triggers a useful idea, IDK. Hopefully, someone with more experience will show us how to stream data on the fly. This is certainly something that can be easily done with Java, using it's SourceDataLine class which has useful blocking-queue aspects, but I haven't located a Javascript equivalent yet.