8.19.聽Other visualization hardware8.19.聽Other visualization hardwarePrev聽Chapter聽8.聽Video output devices聽Next8.19.聽Other visualization hardware8.19.1.聽Zr
This is a display-driver (-vo zr) for a number of MJPEG
capture/playback cards (tested for DC10+ and Buz, and it should work for the
LML33, the DC10). The driver works by encoding the frame to JPEG and then
sending it to the card. For the JPEG encoding
libavcodec
is used, and required. With the special cinerama mode,
you can watch movies in true wide screen provided that you have two beamers
and two MJPEG cards. Depending on resolution and quality settings, this driver
may require a lot of CPU power, remember to specify -framedrop
if your machine is too slow. Note: My AMD K6-2 350MHz is (with
-framedrop) quite adequate for watching VCD sized material and
downscaled movies.
This driver talks to the kernel driver available at
http://mjpeg.sf.net, so
you must get it working first. The presence of an MJPEG card is autodetected by
the configure script, if autodetection fails, force
detection with
./configure --enable-zr
The output can be controlled by several options, a long description of the
options can be found in the man page, a short list of options can be viewed
by running
mplayer -zrhelp
Things like scaling and the OSD (on screen display) are not handled by
this driver but can be done using the video filters. For example, suppose
that you have a movie with a resolution of 512x272 and you want to view it
fullscreen on your DC10+. There are three main possibilities, you may scale
the movie to a width of 768, 384 or 192. For performance and quality reasons,
I would choose to scale the movie to 384x204 using the fast bilinear software
scaler. The command line is
mplayer -vo zr -sws 0 -vf scale=384:204 movie.avi
Cropping can be done by the crop filter and by this
driver itself. Suppose that a movie is too wide for display on your Buz and
that you want to use -zrcrop to make the movie less wide,
then you would issue the following command
mplayer -vo zr -zrcrop 720x320+80+0 benhur.avi
if you want to use the crop filter, you would do
mplayer -vo zr -vf crop=720:320:80:0 benhur.avi
Extra occurrences of -zrcrop invoke
cinerama mode, i.e. you can distribute the movie over
several TV's or beamers to create a larger screen.
Suppose you have two beamers. The left one is connected to your
Buz at /dev/video1 and the right one is connected to
your DC10+ at /dev/video0. The movie has a resolution
of 704x288. Suppose also that you want the right beamer in black and white and
that the left beamer should have JPEG frames at quality 10, then you would
issue the following command
mplayer -vo zr -zrdev /dev/video0 -zrcrop 352x288+352+0 -zrxdoff 0 -zrbw \
-zrcrop 352x288+0+0 -zrdev /dev/video1 -zrquality 10 \
movie.avi
You see that the options appearing before the second -zrcrop
only apply to the DC10+ and that the options after the second
-zrcrop apply to the Buz. The maximum number of MJPEG cards
participating in cinerama is four, so you can build a
2x2 vidiwall.
Finally an important remark: Do not start or stop XawTV on the playback device
during playback, it will crash your computer. It is, however, fine to
FIRST start XawTV,
THEN start MPlayer,
wait for MPlayer
to finish and THEN stop XawTV.
8.19.2.聽Blinkenlights
This driver is capable of playback using the Blinkenlights UDP protocol. If you
don't know what Blinkenlights
or its successor
Arcade
are, find it out. Although this is most probably the least used video output
driver, without a doubt it is the coolest MPlayer
has to offer. Just watch some of the
Blinkenlights documentation videos.
On the Arcade video you can see the Blinkenlights output driver in
action at 00:07:50.
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