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goldfire / howler.js

Javascript audio library for the modern web.
https://howlerjs.com
MIT License
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Pause/Play skips with long Web Audio sound #1408

Open mat100payette opened 4 years ago

mat100payette commented 4 years ago

I need to work with audio files that are (almost) arbitrarily big. The one I'm using is a mp3 file that is 28 minutes long, and takes 38Mb disk space.

I need high precision and high frequency seeking on the audio for animations.

That being said, when I call pause(), it takes about 10ms. However, when resuming using play(), I get a massive skip of about 300ms forward in the audio. I don't know what exactly causes this, but with shorter mp3s I don't get such a big skip. Also, the audio seems late to begin with, but doesnt diverge over time; it just stays offsync even after the skips.

When loading the sound as html5: true, I get really stuttery seek positions with all sizes of files, which is to be expected from that mode, however I do not get skipping on resuming large files.

Is there anything I can do to avoid that skip ?

mat100payette commented 4 years ago

Working on debugging the skip.

So far, I see that this line (Howler.js @ _refreshBuffer): sound._node.bufferSource.buffer = cache[self._src]; (more specifically, cache[self._src]) takes ~300ms alone with the large audio file, while smaller audio files only take ~15ms on that.

By duplicating that single line many times, I can make a super fast play-pause sequence skip the audio by any amount of time.

mat100payette commented 4 years ago

After some testing, here's the patch I have that works for a single sound Howl (won't work with multiple sounds):

Change the following: sound._node.bufferSource.buffer = cache[self._src];

To this: sound._node.bufferSource.buffer = Object.values(cache)[0];

The reason why the original cache lookup scales so badly is because the keys of the cache object are the full byte64 representations of the sounds, so a big audio file will make that key comparison super slow.

If there is a way to make that cache work by some id system, it'd effectively fix this problem completely.

EdgeCaseLord commented 3 months ago

This also seems to be a problem with streaming web radio, at least on some iOS devices. I don't know whether it's exactly the same problem, but it looks like.