In earlier versions of Sparkle, encoding was done on a frame by frame basis. 
The encoder worked by saying ``Give me the first frame. Now the second. Now 
the third.''

The 2.3.1 version of Sparkle does all encoding on a time basis. 
The encoder effectively says ``Give me the frame for time=0. Now the frame
for time=.05s. Now the frame for time=.10s.''

Encoding based on timing has both advantages and disadvantages compared to the 
old method. The advantages are
* This is more in tune with the way QuickTime does things.
* Some QT mmovies that were encoded using all the smarts in QT would encode
  as MPEGs that had parts running too fast or too slow. Now those MPEGs should
  have all timing info accurate.
* This makes sound support possible.

What are the disadvantages? Well if you aren't careful, you can create MPEGs (or
QT movies, but that's not as likely) that are much larger than they need to be.
Suppose you have a QT movie encoded at 8fps. Now the minimum frame rate MPEG allows
for encoding (blame the MPEG designers, not me) is 24fps. That means that every QT 
frame will last across three MPEG frames, and will be encoded three times. This 
will bloat the size of your MPEG considerably. For now the only solution is to 
MPEG encode using a great many P- and B-frames which will, because of the extreme
similarity (identical) between the repeated frames, not take up much disk space.

A better solution is to somehow encode the MPEG at a lower, more appropriate frame 
rate like 8fps. Many MPEGs from PCs are encoded at 8fps. The problem is that there 
is no way to specify that the frame rate is 8fps (the MPEG info says that the 
frame rate is 24fps) and so the movie plays at the wrong speed. 

The 2.3.2 release of Sparkle allows you to encode either way. If you want to 
encode on a frame by frame basis, use the ``Best'' frame rate from the popup
menu when selecting an encoding frame rate. That is almost always the best 
option to use. However before you start encoding from an MPEG, do make sure 
the MPEG plays back at the correct rate. As stated above, many PC MPEGs are 
coded at non-MPEG standard rates (like 8fps) but the MPEG header info claims
the MPEG rate is 24fps, so on playback the MPEG runs way too fast. If this happens
choose ``Set Frame Rate...'' from the Playback menu, and set the frame rate to 
what you think is correct. Note that if the MPEG comes with an associated 
.AIFF sound file, it's frame rate will be calculated to get it to last as long
as the sound file.