PDA

Click to See Complete Forum and Search --> : Sound sync question



evolbeagle
12-27-2000, 01:17 PM
On this movie teaser I'm working on, I've noticed something about the sound sync. Everything syncs well every time I play the movie except for one item. The heartbeat-like sound that goes with each screenshot occasionally fires early. But here's the weird part: It's seems to be the only sound that ever gets out of sync, and it only does it sometimes (maybe 1 out of every 10 viewings). It never fires late, always (when it's off at all) early. And once the first instance of it fires early, the two subsequent instances fire early also. So:

1. Does anybody else notice this in this movie or is it just me?

2. Assuming it's a real phenomenon, is there a way to fix it?

http://demo.voikos.com/animation/remtease53.html

Thanks.

BradBradleySL
12-27-2000, 02:49 PM
Yeah I noticed that too! I have noticed that it seems to occur when sounds are overlapping. I never really thought much of it.

Brad

johnie
12-27-2000, 05:05 PM
If it is firing early its becuase the Flash player is eating to many resources at the moment to draw your picture but has enough to play the sound. The solution is to use a simpler frame folowing the sound. Macromedias solution , if you have Flash 5, is to not display all of the frames.

Bob Hartzell
12-27-2000, 05:28 PM
Out of curiosity, is this problem due to modem speed, cpu speed, or something else? Would it occur if the movie is played off the local disk?

johnie
12-27-2000, 05:35 PM
CPU speed effects it and memory. I haven't played too much with the streaming abilities of Flash but I know that effects the rendering of some animations and throws the sound out of sync also.

You can test to see if it is the modem by hiting the rewind and play buttons on the right click menu. Refresh will also work for this purposes.

evolbeagle
12-28-2000, 01:48 PM
Just wanted to follow up on this problem and see if I have a possible solution.

The sound that sometimes gets delayed is the drumbeat/heartbeat sound in my movie. This sound plays three times and if the first one gets delayed, they all do. It wouldn't be nearly as bad if only one instance got out of sync, but since they all do (on those relatively few times when this problem crops up), it looks pretty bad.

I'm wondering if, instead of having three instances of the same wav file, I had three different wav files for the same sound, would that alleviate the problem? So beat1.wav would play the first time, beat2.wav the second and so on. This would give a small increase in overall file size (about 14-22k), but if it would prevent this all or nothing sync problem, it'd be worth it.

So would that make a difference?

johnie
12-28-2000, 03:21 PM
If it is a streaming problem then yes it can help. If it is a CPU power problem again it can help. If you have one long loop then if it messes up anywhere it is off. If you have three you have more room for error. The only thing that may happen with the three sound loops is if 1 is off it may slightly overlap the next one.

BradBradleySL
12-29-2000, 04:28 PM
One thing I have noticed with sounds in KoolMoves is in order for it to play at the correct time, I have to start the sound a frame earlier then it is supposed to start. I don't believe this is do to KoolMoves but rather the flash player. Try that evolbeagle. Seperating the sounds would help, but would increase the file size, it would help simply because, editing a sound perfectly so the timing is exact in a film is difficult unless you are working with it directly in with the film. As johnie said, it could be CPU problem or a streaming problem. Perhaps you could figure out a way to preload the sounds with the javascript Johnie discovered thus decreasing the load on the flash player and the CPU.

Brad

Bob Hartzell
01-01-2001, 12:01 PM
Have you looked at the waveform of the sound? Maybe there is silence at the beginning.