flash (macromedia): We are attempting to use buttons to jump to sync points with flash. We are
using a tutorial provided from this website. It works, however, not accurately.

There are 2 areas where we can provide specific timecode information for this.
One is in the actions panel...and the other is in the component inspector for
the media display.

The video imported is 15fps and is set to 15fps in all necessary places. (we
have also tied 30 but it still does the same thing)

It does not seem to reference the timecode accurately at all. It gives a 1-3
second jump even when typing in frames only or a once second number.

Is there a way we can accurately reference the material?

You probably need to include more video keyframes when you are generating your
FLV. Flash can only jump to specific video keyframes when jumping around in a
FLV.

Recode with a higher keyframe rate. For something at 15 fps, I would suggest
every 5 or 10 frames.

Unless of course you mean something else. It is hard to tell from your post.

Thanks...we tried your suggestion. The video we are using is 1 min. 9 sec. we
even did a version with over 1000 keyframes...thinking that would give us
greater accuracy in putting cue points in specific places throughout the video,
but it didn't work.

Do you need more information to help us out?

Yup, I certainly need more info. Really don't know enough about what you
believe you are trying to do. :)

How are you making your FLV? In Squeeze the lower the number the more
keyframes you will have.

What is the code you are using to jump?

Cuepoints are something different. If you are using them to start and action
or something then they can be at any point in time. But if you then are going
to try and jump the head to them ? in that case you will need more keyframes.

I built a tool that allows you to synchronize other events with a video
http://iveyleague.com/downloads/core/

However, getting an .flv to jump to a certain point is difficult - especially
if you are using progressive download, (since the part of the video you are
requesting has to already be buffered in order for you to be able to access
it). The flash video codec is only accurate to within +/- one second, and will
simply seek the nearest keyframe.

The best way to ensure that you jump to the correct point without encoding a
monster file with tons of keyframes is to separate your scenes with a solid
colour background or title screen that is present for more than one second, and
then seek the second where it is first present. Generally, a keyframe will be
present every time the background of your video changes significantly, even
with a high compression rate and few keyframes.

Remember that increasing the number of keyframes in your video will increase
its size dramatically.

The solid colour background idea will only work if you have your encoder set up
to automatically insert keyframes at scene changes. If you don't then there is
no guarantee that there will be a keyframe in that location.

While I agree that increasing the number of keyframes will increase the size
of your video, but I'm not sure I agree about the dramatically bit. I just did
a test with an 18 second video encoded at 30fps. In one case I put a keyframe
every 3 frames and in the other I set it to every 300 frames. I also turned off
the auto scene change detection, just in case that would overwhelm the regular
keyframe placement. The one with keyframes every 300 was 2,393,352 bytes and
the other was 2,403,422 which is a less than 1/2 of one percent increase.

You're absolutely right about it being necessary to ensure that your codec
settings will automatically insert keyframes at scene changes.

I should have elaborated a little more about file size. Again, you're right
in that in some cases there's barely any difference in file size (esp. with
talking heads), but I have found that in some cases, if there's a lot of
detail in the background, or if a large part of the image changes from frame to
frame, the "cost" of keyframes can be pretty high.

I found that out when I accidentally set the video to encode with a keyframe
on every frame on one occasion, and ended up with a 900 MB file for a 10 minute
video. ;)

I generally opt to insert keyframes with scene changes, and then insert a
keyframe every half-second. This way, a seek action will be just about as
accurate as it can get in Flash. (within one second).

I've been doing a bit more testing and it seems to really make more of a
difference at lower data rates. But in general I would still advise to not be
afraid of more keyframes ? use as many frames as you need, but no more! There
are lots of dimensions to getting a file of the size and quality that you need
to get the job done.