I am having a problem where sometimes the sound goes out of place (plays too late or too soon) and it sometimes skips frames. Has this happened to anyone else and can it be fixed?

Quote from JohnyBravo

I am having a problem where sometimes the sound goes out of place (plays too late or too soon) and it sometimes skips frames. Has this happened to anyone else and can it be fixed?

Pretty sure if you animate at 23.97 fps it fixes te sound.

Okay I notice this comes up a lot and even though I've never really needed to think about the .97 audio syncing fix because my default frame rate is set to 29.97 I'm still interested in why this works exactly. I know a lot of people use this trick but I've never really seen anyone explain why it works, so I went ahead and did the research for myself and I'm gonna post my findings here for posterity. This might get a bit technical but I'm gonna try to be succinct.

In digital audio there is something called a Sample Rate. The sample rate is basically the average number of samples (samples in this case are the amplitude of the audio at certain points in time) taken from an audio signal in a second. That's a bit technical but if I were to relate it to something animators would understand, it's SORT OF like frames per second but for audio. There's more to it than that, but I think that will help illustrate my explanation further on, so keep in it in mind.

So when you're working with audio you have to keep the Sample Rate in mind. The current MUSIC industry standard is 44.1 kHz, and that's what Flash uses to work with audio. This is why Flash gives you shit if you try to import an audio file that's not 44.1 kHz, because it just doesn't understand anything else. Luckily since 44.1 kHz is the industry standard, most audio files you have on your computer already use this so it's rarely something you need to think about.

The 44.1 kHz standard was composed partially based on the video standards NTSC and PAL. Now interestingly NTSC used to be transmitted at 30 FPS up until the introduction of color. When they tried to add color to NTSC broadcasts, they basically realized there wasn't enough "room" (it's more complex than that but I don't want to get in to explaining analog transmissions) in the transmission for it, so they reduced the frame rate less than 0.1% to 29.970 to accommodate the extra data. Equipment at the time handled the difference fine and no one can tell the difference between 29.97 and 30 fps so it's pretty much a win/win. Since 44.1 kHz was created in part using the NTSC standard, and the NTSC standard is 29.97 fps, that's what it syncs up with best.

The difference between 29.97 and 30 is so negligible that most wont notice it, but over time the difference in frames piles up and that's when the audio gets out of sync. It's more noticeable with lip syncing since that requires very precise timing with the audio. This wouldn't happen if Flash used 48 kHz audio since 48,000 divides pretty easily into 24, 25, and 30 which are the current digital standard fps for video production.

Hopefully this makes sense. 44.1 kHz is becoming less relevant because now we're in a digital age we don't have to worry about analog restrictions which is what 44.1 kHz was made from. It's weird that Flash hasn't updated yet, considering other Adobe products will let you use either.

Quote from Jeff

Okay I notice this comes up a lot and even though I've never really needed to think about the .97 audio syncing fix because my default frame rate is set to 29.97 I'm still interested in why this works exactly. I know a lot of people use this trick but I've never really seen anyone explain why it works, so I went ahead and did the research for myself and I'm gonna post my findings here for posterity. This might get a bit technical but I'm gonna try to be succinct.

In digital audio there is something called a Sample Rate. The sample rate is basically the average number of samples (samples in this case are the amplitude of the audio at certain points in time) taken from an audio signal in a second. That's a bit technical but if I were to relate it to something animators would understand, it's SORT OF like frames per second but for audio. There's more to it than that, but I think that will help illustrate my explanation further on, so keep in it in mind.

So when you're working with audio you have to keep the Sample Rate in mind. The current MUSIC industry standard is 44.1 kHz, and that's what Flash uses to work with audio. This is why Flash gives you shit if you try to import an audio file that's not 44.1 kHz, because it just doesn't understand anything else. Luckily since 44.1 kHz is the industry standard, most audio files you have on your computer already use this so it's rarely something you need to think about.

The 44.1 kHz standard was composed partially based on the video standards NTSC and PAL. Now interestingly NTSC used to be transmitted at 30 FPS up until the introduction of color. When they tried to add color to NTSC broadcasts, they basically realized there wasn't enough "room" (it's more complex than that but I don't want to get in to explaining analog transmissions) in the transmission for it, so they reduced the frame rate less than 0.1% to 29.970 to accommodate the extra data. Equipment at the time handled the difference fine and no one can tell the difference between 29.97 and 30 fps so it's pretty much a win/win. Since 44.1 kHz was created in part using the NTSC standard, and the NTSC standard is 29.97 fps, that's what it syncs up with best.

The difference between 29.97 and 30 is so negligible that most wont notice it, but over time the difference in frames piles up and that's when the audio gets out of sync. It's more noticeable with lip syncing since that requires very precise timing with the audio. This wouldn't happen if Flash used 48 kHz audio since 48,000 divides pretty easily into 24, 25, and 30 which are the current digital standard fps for video production.

Hopefully this makes sense. 44.1 kHz is becoming less relevant because now we're in a digital age we don't have to worry about analog restrictions which is what 44.1 kHz was made from. It's weird that Flash hasn't updated yet, considering other Adobe products will let you use either.

Thanks a lot! And so making my animation from 25fps to 24.97fps should fix the problem right?