[Mo Dejong]

Matt, short answer is yes, it is possible to create a h.264 with an alpha channel for delivery on iOS.

This blog post shows how it can be done. A few things though. h.264 is a delivery codec, it should not be used as an intermediate in the video production process. Export from AE using the Quicktime Animation codec at 32 BPP (Millions+) to retain the alpha channel. Dave is correct that h.264 does not support an alpha channel by default, one needs to actually create 2 videos, one holds the RGB and the other holds the alpha pixels as a grayscale video. All the code to split the videos, convert to h.264 via ffmpeg+x264 and then recombine the videos on the iPad are already included with the AVAnimator tools. I think your will be quite impressed with the results as the generated file sizes are quite small and the .m4v files generated can be included directly to your xcode project.

[Mo Dejong]

Hi Eden

What you describe is not going to be easy to do in AA. Your best bet is to use another
piece of audio software to listen to the audio you have and create a new audio file
that contains a sound marker to indicate where the bass starts and stops. You could use
whatever audio software you want, audacity is free and would do what you want. Open the
audio you have, then create another file the exact same length but with no audio in it.
Then, get a sample like a snare drum hit, something with a clear transient. When the bass
starts, add copy and past a drum hit into the blank audio so that it lines up in time
with your audio. Then where the bass ends, put two snare hits in a row. Repeat until you
have created markers for all the start and stop points. Now export the WAV file you created
with just the snare hits and import it into AA as audio and put it in your comp. Expand
out the little triangle to the left of the track until you see the WAV display. Now, it
should be easy to see where each bass part starts and stops, so just create time remap
keyframes at those places. Set the hold property for the keyframes where the bass stops
playing so that time will not pass while the bass is not playing.

thanks should do the trick
Mo DeJong

[Mo Dejong]

> I have this expression which is giving me an error:
>
> if(thisComp.layer(“Null”).effect(“Layer Control”)(“Layer”) == “5”OR “6” OR “7”) “A” else “B”

You need to use (var == value1 || var == value2) in
expressions. For example:

var layer = thisComp.layer(“Null”).effect(“Layer Control”)(“Layer”);
if (layer == 5 || layer == 6 || layer == 7) {
A
} else {
B
}

cheers
Mo DeJong