Ingesting Your Source Content - A Practical Guide to Video and Audio Compression - page 534

L-shaped edit

Video timeline

Audio timeline

Figure 32-2 An L-shaped edit.

Cutting so as to place the scene change on a group of pictures (GOP) boundary
might help some compression engines, but the main thing is to minimize the number of
frames whose pixels are drastically different from the preceding and following frames
(Figure 32-3).
A human being is unlikely to be able to place an edit in the right place, but an edit-
ing system could provide a lot of help. Final Cut Pro implements an extra track of hinting
information that is maintained as you edit your sequence. The compression-markers track
contains details of cut points, transitions, and edits as well as user-inserted data. This
informs the compression engine that a complex section is about to be processed, and the
encoder optimizes the process accordingly.

32.6.2 Dissolves

Avoid dissolves whenever possible—anything that causes a large area of the picture to
change from one frame to the next and continues that change for a few subsequent frames
is very bad for the compressor. If you want a special transition, use a wipe instead.

Edit point in the middle of a GOP

Scene 1 Scene 2

GOP GOP GOP GOP GOP GOP

Optimal edit point between GOPs

Scene 1 Scene 2

GOP GOP GOP GOP GOP GOP

Figure 32-3 Cutting around group of pictures (GOP) structures.