Simon Fraser [no longer active] Assignee
	Description • 23 years ago

On Mac, nsSound has very poor performance, for a number of reasons:
1. It doesn't do any cacheing, so *every* time we play a sound, we render it to a 
new QuickTime movie.
2. The movie is played synchronously, preventing the user from doing anything 
while the sound plays.

	Simon Fraser [no longer active] Assignee
	Comment 1 • 23 years ago

Note that this was fixed in Windows recently, and sound has always been async on 
Unix.

	Simon Fraser [no longer active] Assignee
	Comment 2 • 23 years ago

I'm working on this.

	Simon Fraser [no longer active] Assignee
	Comment 4 • 23 years ago

The attached patch greatly enhances nsSound on Mac, adding the following features 
(without interface changes):
1. Sounds are now played asynchronously
2. Rendered sounds (as QuickTime movies) are stored per-session in the necko 
memory cache.
3. Multiple different sounds can be played concurrently.
4. The same sound can be played several times concurrently.
5. Different sound formats are identified by sniffing the data (WAVE, uLaw, midi)
   or looking at the MIME type (MP3), and imported appropriately.

How it works:
nsSound has become more like a sound service; it just spawns URL loads, and deals 
with necko caching of rendered sounds. For each unique sound (keyed by URL) that 
is playing, we create an nsSoundRequest, which is what handles rendering to a 
movie, and creates a timer which calls MoviesTask(). nsSoundRequests get stuffed 
into the necko cache (memory cache only).

Additional code is necessary to deal with playing the same sound several times 
simultaneously. Because the sound is in a movie, and the movie contains playback 
state information, we have to clone the movie each additional time we need to 
play it while another copy is playing. Luckily, cloning a movie just copies data 
refs, so this is cheap.

We use a timer that fires every 250ms to call MoviesTask(); there is one timer 
per nsSoundRequest, that fires as long as any movie in that nsSoundRequest is 
playing.

	Simon Fraser [no longer active] Assignee
	Comment 6 • 23 years ago

New patch removes printfs, and disposes of movies after they finish playing, 
rather than when the nsSoundRequest is deleted.

Reviews please.

	Mike Pinkerton (not reading bugmail)
	Comment 7 • 23 years ago

Comment on attachment 52819 [details] [diff] [review]
Better nsSound patch

r=pink

	(not reading, please use seth@sspitzer.org instead)
	Comment 8 • 23 years ago

Comment on attachment 52819 [details] [diff] [review]
Better nsSound patch

sr=sspitzer

	Simon Fraser [no longer active] Assignee
	Comment 9 • 23 years ago

Checked in.