[magick-users] "vbv_delay underflow" gives choppy playback/premature ending

[Michael Davidson]

Firstly, let me say that ImageMagick is a fantastic tool for creating
timelapse movies of mountain sunrises and sunsets.  (I butter you up first,
then I ask for your help.)

 

When I use "convert -delay 10 *.jpg filename.mpg", I get the following
results:

 

Warning: setting constrained_parameters_flag = 0

Encoding frame 0
............................................................

Encoding frame 1
............................................................

vbv_delay underflow! (decoding_time=22400.0, t_EOP=132920.6

)vbv_delay underflow: -106923

Encoding frame 2
............................................................

vbv_delay underflow! (decoding_time=26000.0, t_EOP=140823.1

)vbv_delay underflow: -111225

.

 

The playback of the resulting mpg exhibits different quirks depending on the
player.  For example, with a :21 second mpg, Quicktime 7 will stick on the
first frame for :04 seconds then play the rest very choppily.  Windows Media
Player 10 plays very choppily and it believes the :21 second video is 1:37
(but stops after :21).  VLC 0.8.6a plays smoothly and knows the proper
length.  Too bad for us, most people aren't viewing our MPGs with VLC.

 

Note: encoding without the '-delay 10' results in the same underflow
messages and same symptoms on playback (at a different pace, of course).

 

So, first, is my quirky playback a result of the underflow messages I'm
seeing?  Two, what can I do to get rid of the quirky playback?

 

Thank you,

 

Michael Davidson

Mount Washington Observatory

 

www.mountwashington.org