March 29, 2011
ft-MarkerExporter: reuse layer markers
ft-MarkerExporter is a new After Effect script from Francois Tarlier that "exports layer markers to a XML file which can then be reimported and applied to an existing layer, a new layer or even a new comp."
December 15, 2010
LayerMarkers: split at markers or add markers
December 13, 2010
Frame Restorer script uses Timewarp
This script can quickly restore damaged or missing frames. Use layer markers to specify which frames to restore, or get the script to search for color bars and restore any missing frames. The script uses the Timewarp effect to create new in between frames.
November 28, 2010
Gravity preset, Unpack Precomp script + more
g = 1000; // gravitational constant
if (marker.numKeys > 0 && time > marker.key(1).time){
t = time - marker.key(1).time;
y = g*t*t/2;
value + [0,y]
}else{
value
}
September 27, 2010
Copy Paste Markers script + more
By the way, AE Scripts has a variety of scripts for markers, and AE Help has a list of scripts for manipulating markers and additional info too.
June 6, 2010
After Effects expressions: Time, Layer Numbers, Speed, and Velocity

"By default, expressions assume you are interested in values at the current time. If you need to know the current time, just use the keyword time in an expression, and After Effects will return the current time in seconds (not frames, as we discussed in the previous section).
However, expressions allow you to access values at different points in time. They also let you find out what time keyframes and markers are located at so you can have animations change as they approach or cross one of these keys, as well as reference what other layers are doing. In this installment, we’ll explore a couple of ways to exploit time. ...including having one layer echo the movements of another with delay."
July 29, 2009
How to shoot for planar tracking & place tracking markers

July 25, 2009
Markers Leaks: trigger actions using AE layer markers

Eran's methods and ones planned by Maltannon are similar to the more specific but limited examples in the Behaviors Presets in AE, which are discussed by Trish & Chris Meyer in Creating Motion Graphics (excerpt on Presets) and After Effects Apprentice.
January 8, 2009
Copy, remove, & everything else about markers

To learn more on markers in AE, see After Effects Help's Layer markers and composition markers, which explains in depth many aspects of using markers. Of special note is a subsection of that page that lists many scripts and utilities for working with markers.
Basic and useful among them are scripts by Jeff Almasol: Copy Markers and Remove Markers.
Also useful is a new feature in CS4, speech metadata, which imports with layer markers with the transcription as labels. The preference for this feature is off by default (via); the toggle is under Preferences > Media & Disk Cache > Create Layer Markers from Footage XMP Metadata. For additional info and video links, see the earlier post Metadata in After Effects & CS4.
November 16, 2008
Metadata in After Effects & CS4

In After Effects, speech metadata can help with syncing video and audio elements since speech metadata imports with layer markers with the transcription as labels. The preference for this feature is off by default (via); the toggle is under Preferences > Media & Disk Cache > Create Layer Markers from Footage XMP Metadata.
Depending on your success with a speech transcription in Premiere, in AE you might not even need to scrub with audio (CTL/COM +drag) to refine marker placement, as you would after using the asterisk key (*) on the numeric keypad during a RAM preview.
After Effects Help LiveDocs has additional details, for example:
"When you render and export a composition, you can write XMP metadata to the output file that includes all of the XMP metadata from the sources for that composition. This includes all of the composition markers and layer markers in the composition, all of the XMP metadata from the source files on which the layers in the composition are based, comments from the Comments columns in the Timeline panel and Project panel, and the project-level XMP metadata for the project in which the composition is contained. XMP metadata from nested compositions is recursively processed and included in the output.
[...] In addition to storing XMP metadata in After Effects project (.aep, .aepx) files and source documents used by Adobe applications (for example, .psd), After Effects can write XMP metadata directly into the files for many container formats [like MP4] ."
Of course this aspect of metadata piques the interest Flash developers like Brooks Andrus (Yes, the h.264 Specification is Freely Available), who shares some screencams from looking at MP4 files inside the Flex Debugger in The XMP Revolution is Here:
"...using XMP extends beyond standard file info and saving a video file’s editing history. Case in point, Premiere Pro CS4 has a killer 'speech to text' transcription feature. The transcription text is stored as XMP within the video file. This allows Premiere and other tools to accurately search for this data within a file (powers the search feature inside of Premiere and Bridge). As a special bonus, Flash Player 10 provides the same data in its onXMPData callback."
October 31, 2007
AIR application 'Convert Final Cut Pro Markers to Flash Video Cue Points'

