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This file lists some example of using XAnim.
1) View one:
xanim anim.mov
2) View several:
xanim anim1.mov anim2.avi anim3.mpg
3) View one and find out what it is:
xanim +v anim.mov
4) For those with only a 256 color display(myself included), there
are many options that can control how XAnim deals with the
very limited number of colors.
4a) Private Colormap. (the option turns of the cmap_play_nice flag).
Now your X11 Window Manager(not XAnim) is responsible for
changing the Colormap as the ColorFocus changes(Color Focus
typically follows your mouse ptr. See your X11 Window Manager
documentation for more info).
xanim -Cn anim.mov
4b) Since XAnim can only use 256 colors(usually significantly less
because other applications are already using them), just
how does it pick when an animation is potentially made of
thousands of colors?
By default, XAnim creates an RGB332 colormap. Iterates between
every combination of 3 bits Red, 3 bits Green and 2 bits of
Blue(which just happens to be 256). With the -Cn option, this
is the colormap, without the -Cn option, this colormap is
further reduced depending on which of those colors, XAnim
can actually allocate.
BUT! We can do better. If you use the +CF4 option. XAnim
will scan a preset number of equally spaced frames from
the animation in order to sample what colors are being
used and then select the "best" 256 colors from the thousands
that are sampled. (NOTE: you can change the number of frames
that are prescanned with the +Cs# option). "best" actually
means XAnim uses a variation of the Median Cut algorithm.
Later it utilizes a colormap caches to help speed up remapping
each pixel in the animation to one of the available colors
in the colormap.
xanim +CF4 anim.mov
xanim +CF4 -Cn anim.mov
xanim +Cs20 +CF4 -Cn anim.mov
One other thing to note. The +CF4 will also trigger the -F option
which shuts off dithering for the Video Codecs that support it.
See 4c). You can turn dithering back on:
xanim +CF4 +F -Cn anim.mov
4c) Dithering. Dithering is slow and while it increases color resolution,
it does so at the expense of spatial resolution. In XAnim, I've
worked dithering into the decompression routines of several Video
Codecs(actually it's a separate alternative routine for each one
for speed reasons). The following Video Codecs/formats support
this low level dithering. Cinepak, Indeo, MPEG, JPEG, MJPG
and IJPG.
This option (+F) is on by default if you have a 256 color display.
As noted above in section 4b), it gets turned off by +CF4, but
can be overridden.
Dithering does slow things down, but since it's built into the
decompression routines, I can take several opportunities to
speed things up that I couldn't do if the dithering was done
later at a higher level.
If you have a 256 color display, you should really take the time
to experiment with dithering, -Cn and +CF4 options to get
a feel for how they affect video quality and playback speed for
various formats and Video Codecs.
To start with, find an animation that uses one of the above mentioned
codecs and then run the following command lines:
xanim anim # Dithering and shared colormap
xanim -F anim # No dithering and shared colormap
xanim -Cn anim # Dithering and private colormap
xanim -F -Cn anim # No dithering and private colormap
xanim +CF4 anim # Median Cut, no dithering, shared colormap
xanim +CF4 -Cn anim # Median Cut, no dithering, private colormap
xanim +CF4 +F -Cn anim # Median Cut, dithering, private colormap
5) Scaling animations. Scaling is very cpu intensive and will
cause slow downs in playback. Also, at the moment, XAnim
dithers before scaling and this causes/enhances artifacts in the
image. Best to use the +CF4 option instead.
On the fly scaling requires the +Sr option:
xanim +Sr anim.mov
See "xanim.readme" for a more detail discusion of image and buffer
scaling.
6) Need for Speed! Almost all animations formats indicate how fast
XAnim play each frame. You can over ride this with the [-] and [+]
buttons of the remote control OR you can force frame timing
with the +j# option where # is given in milliseconds. If # is 0,
then forced timing is turned off and the timing specified by the
animation is used again.
This is useful in benchmarking where you want XAnim to play as
fast as possible(NOTE: see 7) for the +t option)
xanim +j1 +t +l5 anim.mov
Or for slideshows
xanim +bC1d +j5000 image1.jpg image2.jpg +j8000 image3.jpg
7) Benchmarking. The +t option will indicate how long it took XAnim
to display the command line. Since XAnim loops on the command
line by default, you will get the time of each of these loops.
Typically, the +j1 option is used to force as-fast-as-possible
playback.
xanim +tj1 anim.mov
If the animation is short, you might want to time it over a longer
period of time. Since the timing is done over the entire command
line, you can use the +l# option to loop the animation. In the
example below, anim.mov is looped 5 times each time the command
line is looped.
xanim +tj1 +l5 anim.mov
Since +t also reports how many frames were dropped because of
audio/video synchronization, it's sometimes useful to not
specific +j1.
xanim +t anim.mov
8) Audio, what? AUDIO! Audio is enabled by default. You can
turn it off with -Ae
xanim -Ae anim.mov
You can select the speaker output with the SPEAKER env variable:
setenv SPEAKER INTERNAL
setenv SPEAKER HEADPHONES
setenv SPEAKER EXTERNAL
The above is for csh, for bourne shell(sh) do the following
SPEAKER=INTERNAL
export SPEAKER
Note: No spaces around the "=" sign are allowed.
You can also specify audio port with the +Ap# command. See xanim.readme.
Currently, XAnim automatically sets the volume. This will change in
the near future, but until then you can use the +Av# option to
set the volume. The range is bewteen 0 and 100. You can also
compile this in. See the DEFAULT_XA_AUDIO_VOLUME define in
the "xa_config.h" file.
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