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Video playback is a very new and rapidly developing application area. Be patient. Not everything is going to work as smoothly as it did with sound.
Before you begin, you should know the model of the video card you have and the chip it uses. While XFree86 supports a wide variety of video cards, fewer give good playback performance. To obtain a list of extensions supported by the X server using your card use the command xdpyinfo(1) while X11 is running.
It is a good idea to have a short MPEG file which can be treated as a test file for evaluating various players and options. Since some DVD players will look for DVD media in /dev/dvd by default, or have this device name hardcoded in them, you might find it useful to make symbolic links to the proper devices:
# ln -sf /dev/acd0c /dev/dvd
# ln -sf /dev/racd0c /dev/rdvd
On FreeBSD 5.X, which uses devfs(5) there is a slightly different set of recommended links:
# ln -sf /dev/acd0c /dev/dvd
# ln -sf /dev/acd0c /dev/rdvd
Additionally, DVD decryption, which requires invoking special DVD-ROM functions, requires write permission on the DVD devices.
Some of the ports discussed rely on the following kernel options to build correctly. Before attempting to build, add these options to the kernel configuration file, build a new kernel, and reboot:
option CPU_ENABLE_SSE
option USER_LDT
To enhance the shared memory X11 interface, it is recommended that the values of some sysctl(8) variables should be increased:
kern.ipc.shmmax=67108864
kern.ipc.shmall=32768
There are several possible ways to display video under X11. What will really work is largely hardware dependent. Each method described below will have varying quality across different hardware. Secondly, the rendering of video in X11 is a topic receiving a lot of attention lately, and with each version of XFree86 there may be significant improvement.
A list of common video interfaces:
X11: normal X11 output using shared memory.
XVideo: an extension to the X11 interface which supports video in any X11 drawable.
SDL: the Simple Directmedia Layer.
DGA: the Direct Graphics Access.
SVGAlib: low level console graphics layer.
XFree86 4.X has an extension called XVideo (aka Xvideo, aka Xv, aka xv) which allows video to be directly displayed in drawable objects through a special acceleration. This extension provides very good quality playback even on low-end machines (for example my PIII 400 Mhz laptop). Unfortunately, the list of cards in which this feature is supported ``out of the box'' is currently:
3DFX Voodoo 3
Intel i810 and i815
some S3 chips (such as Savage/IX and Savage/MX)
If your card is not one of these, do not be disappointed yet. XFree86 4.X adds new xv capabilities with each release [1]. To check whether the extension is running, use xvinfo:
% xvinfo
XVideo is supported for your card if the result looks like:
X-Video Extension version 2.2
screen #0
Adaptor #0: "Savage Streams Engine"
number of ports: 1
port base: 43
operations supported: PutImage
supported visuals:
depth 16, visualID 0x22
depth 16, visualID 0x23
number of attributes: 5
"XV_COLORKEY" (range 0 to 16777215)
client settable attribute
client gettable attribute (current value is 2110)
"XV_BRIGHTNESS" (range -128 to 127)
client settable attribute
client gettable attribute (current value is 0)
"XV_CONTRAST" (range 0 to 255)
client settable attribute
client gettable attribute (current value is 128)
"XV_SATURATION" (range 0 to 255)
client settable attribute
client gettable attribute (current value is 128)
"XV_HUE" (range -180 to 180)
client settable attribute
client gettable attribute (current value is 0)
maximum XvImage size: 1024 x 1024
Number of image formats: 7
id: 0x32595559 (YUY2)
guid: 59555932-0000-0010-8000-00aa00389b71
bits per pixel: 16
number of planes: 1
type: YUV (packed)
id: 0x32315659 (YV12)
guid: 59563132-0000-0010-8000-00aa00389b71
bits per pixel: 12
number of planes: 3
type: YUV (planar)
id: 0x30323449 (I420)
guid: 49343230-0000-0010-8000-00aa00389b71
bits per pixel: 12
number of planes: 3
type: YUV (planar)
id: 0x36315652 (RV16)
guid: 52563135-0000-0000-0000-000000000000
bits per pixel: 16
number of planes: 1
type: RGB (packed)
depth: 0
red, green, blue masks: 0x1f, 0x3e0, 0x7c00
id: 0x35315652 (RV15)
guid: 52563136-0000-0000-0000-000000000000
bits per pixel: 16
number of planes: 1
type: RGB (packed)
depth: 0
red, green, blue masks: 0x1f, 0x7e0, 0xf800
id: 0x31313259 (Y211)
guid: 59323131-0000-0010-8000-00aa00389b71
bits per pixel: 6
number of planes: 3
type: YUV (packed)
id: 0x0
guid: 00000000-0000-0000-0000-000000000000
bits per pixel: 0
number of planes: 0
type: RGB (packed)
depth: 1
red, green, blue masks: 0x0, 0x0, 0x0
Also note that the formats listed (YUV2, YUV12, etc) are not present with every implementation of XVideo and their absence may hinder some players.
If the result looks like:
X-Video Extension version 2.2
screen #0
no adaptors present
Then XVideo is probably not supported for your card.
If XVideo is not supported for your card, this only means that it will be more difficult for your display to meet the computational demands of rendering video. Depending on your video card and processor, though, you might still be able to have a satisfying experience. You should probably read about ways of improving performance in the advanced reading Section 16.4.3.
The Simple Directmedia Layer, SDL, was intended to be a porting layers between Microsoft Windows, BeOS, and Unix, allowing cross-platform applications to be developed which made efficient use of sound and graphics. The SDL layer provides a low-level abstraction to the hardware which can sometimes be more efficient than the X11 interface.
The SDL can be found at devel/sdl12
Direct Graphics Access is an XFree86 extension which allows a program to bypass the X server and directly alter the framebuffer. Because it relies on a low level memory mapping to effect this sharing, programs using it must must be run as root.
The DGA extension can be tested and benchmarked by dga(1). When dga is running, it changes the colors of the display whenever a key is pressed. To quit, use q.
This section discusses the software available from the FreeBSD Ports Collection which can be used for video playback. Video playback is a very active area of software development, and the capabilities of various applications are bound to diverge somewhat from the descriptions given here.
Firstly, it is important to know that most of the video applications which run on FreeBSD were developed as Linux applications, originating in the past year. For this reason, they are both very experimental and riddled with Linux-isms which might prevent them from working at full efficiency on FreeBSD.
By ``experimental'', I mean that you should expect re-encoders, players, and DVD decrypters to have some major bugs, or interoperability problems with other programs. Here is a short list of the sort of things I mean:
An application cannot playback a file which another application produced.
An application cannot playback a file which the application itself produced.
The same application on two different machines, rebuilt on each machine for that machine, plays back the same file differently.
A seemingly trivial filter like rescaling of the image size results in very bad artifacts from a buggy rescaling routine.
An application always dumping core.
Documentation is not installed with the port and can be found either on the web or under PORTPATH/work/ .
By ``Linux-isms'', I mean that there are some issues resulting from the way some standard libraries are implemented in the Linux distributions, or some features of the Linux kernel which have been assumed by the authors of the applications, because that is where the authors are primarily developing. These issues may not be noticed and worked around by the port maintainers which can lead to some problems like these:
The use of /proc/cpuinfo to detect processor characteristics.
A misuse of threads which causes a program to hang upon completion instead of truly terminating.
Software not yet in the FreeBSD Ports Collection which is commonly used in conjunction with the application.
So far, these application developers have been cooperative with port maintainers to minimize the work-arounds needed for port-ing.
MPlayer is a recently developed and rapidly developing video player. The goals of the MPlayer team are speed and flexibility on Linux and other Unices. The project was started when the team founder got fed up with bad playback performance on then available players. Some would say that interface has been sacrificed for streamlined design, but once you get used to the command line options and the key-stroke controls, it works very well.
MPlayer resides in graphics/mplayer. MPlayer performs a variety of hardware checks during the build process, resulting in a binary which will not be portable from one system to another. Thus it is important to build it from ports and not to use a binary package. Additionally, a number of options can be specified in the make which echo at the start of the build.
# cd /usr/ports/graphics/mplayer
# make
You can enable additional compilation optimizations
by defining WITH_OPTIMIZED_CFLAGS
You can enable GTK GUI by defining WITH_GUI.
You can enable DVD support by defining WITH_DVD.
You can enable SVGALIB support by defining WITH_SVGALIB.
You can enable VORBIS sound support by defining WITH_VORBIS.
You can enable XAnim DLL support by defining WITH_XANIM.
If you have x11-toolkits/gtk12 installed, then you might as well enable the GUI. Otherwise, it is not worth the effort. If you intend to play (possibly CSS encoded) DVD's with MPlayer you must enable the DVD support option here [2]. Some reasonable options are:
# make WITH_DVD=yes WITH_SVGALIB=yes
As of this writing, the MPlayer port will build its HTML documentation and one executable, mplayer. It can also be made to build an encoder, mencoder, which is a tool for re-encoding video. A modification to the Makefile can enable it. It may be enabled by default in subsequent versions of the port.
The HTML documentation to MPlayer is very informative. If the reader finds the information on video hardware and interfaces in the chapter lacking, the MPlayer documentation is a very thorough alternative. You should definitely take the time to read the documentation of MPlayer, if you are looking for information about video support in Unix.
Any user of MPlayer must set up a .mplayer subdirectory directory of her home directory. To create this necessary subdirectory, you can do the following:
% cd /usr/ports/graphics/mplayer
% make install-user
The command options for mplayer are listed in the manual page. For even more detail there is HTML documentation. In this section, we will give some of the common use cases.
To play from file, such as testfile.avi through one of the various video interfaces set the -vo:
% mplayer -vo xv testfile.avi
% mplayer -vo sdl testfile.avi
% mplayer -vo x11 testfile.avi
# mplayer -vo dga testfile.avi
# mplayer -vo 'sdl:dga' testfile.avi
It is worth trying all of these options, as their relative performance depends on many factors and will vary significantly with hardware.
To play from a DVD, replace the testfile.avi with -dvd <N> DEVICE where <N> is the title number to play and DEVICE is the device node for the DVD-ROM. For example, to play title 3 from /dev/dvd:
# mplayer -vo dga -dvd 2 /dev/dvd
To stop, pause, advance and so on, consult the keybindings, which are output by running mplayer -h or read the manual page.
Additional important options for playback are: -fs -zoom which engages the fullscreen mode and -framedrop which helps performance.
In order for the mplayer command line to not become too large, the user can create a file .mplayer/config and set default options there:
vo=xv
fs=yes
zoom=yes
Finally, mplayer can be used to rip a DVD title into a .vob file. To dump out title 2 from a DVD:
# mplayer -dumpstream -dumpfile out.vob -dvd 2 /dev/dvd
The output file, out.vob, will be MPEG and can be manipulated by the other packages described in this section.
If you opt to install mencoder when you build, be forewarned that it is still quite experimental.
To use mencoder it is a good idea to familiarize yourself with the options from the HTML documentation. There is a manual page, but it is not very useful without the HTML. There are innummerable ways to improve quality, lower bitrate, and change formats, and some of these tricks may make the difference between good or bad performance. Here are a couple of examples to get you going. First a simple copy:
% mencoder input.avi -oac copy -ovc copy -o output.avi
It is easy to find examples where the output is unplayable even by mplayer. Thus, if you just want to rip to a file, stick to the -dumpfile in mplayer.
To convert input.avi to the MPEG4 codec with MPEG3 audio encoding ( audio/lame is required):
% mencoder input.avi -oac mp3lame -lameopts br=192 \
-ovc lavc -lavcopts vcodec=mpeg4:vhq -o output.avi
This has produced output playable by mplayer and xine.
input.avi can be replaced with -dvd 1 /dev/dvd and run as root to re-encode a DVD title directly. Since you are likely to be dissatisfied with your results the first time around, it is recommended you dump the title to a file and work on the file.
The xine video player is a project of wide scope aiming not only at being an all in one video solution, but also in producing a reusable base library and a modular executable which can be extended with plugins. It comes both as a package and as a port, graphics/xine.
The good news is that the above is pretty much true. The xine player is still very rough around the edges, but it is clearly off to a good start. In practice, xine requires either a fast CPU with a fast video card, or support for the XVideo extension. The GUI is usable, but a bit clumsy.
As of this writing, there is no input module shipped with xine which will play CSS encoded DVD's. There are third party builds which do have modules for this built in them, but none of these are in the FreeBSD Ports Collection.
Compared to MPlayer, xine does more for the user, but at the same time, takes some of the more fine-grained control away from the user. The xine video player also may perform much worse on the non-XVideo interfaces and has very few good alternatives to it. The xine FAQ highly recommends that you have a video card which supports it.
The xine player can be started by itself:
% xine
The menus can then be used to open a file, or it can be started to play a file immediately without the GUI with the command:
% xine -g -p mymovie.avi
The software transcode is not a player, but a suite of tools for re-encoding .avi and .mpg files. With transcode, one has the ability to merge video files, repair broken files, using command line tools with stdin/stdout stream interfaces.
Like MPlayer, transcode is very experimental software which must be build from the port graphics/transcode. Using a great many options to the make command. I recommend:
# make WITH_LIBMPEG2=yes
If you plan to install graphics/avifile, then add the WITH_AVIFILE option to your make command line, as shown here:
# make WITH_AVIFILE=yes WITH_LIBMPEG2=yes
Here are two examples of using transcode for video conversion which produce rescaled output. The first encodes the output to an openDIVX AVI file, while the second encodes to the much more portable MPEG format.
% transcode -i input.vob -x vob -V -Z 320x240 \
-y opendivx -N 0x55 -o output.avi
% transcode -i input.vob -x vob -V -Z 320x240 \
-y mpeg -N 0x55 -o output.tmp
% tcmplex -o output.mpg -i output.tmp.m1v -p output.tmp.mpa -m 1
There is a manual page for transcode, but for the various tc* utilities (such as tcmplex) which are also installed, there is only a curt -h output.
In comparison, transcode runs significantly slower than mencoder, but it has a better chance of producing a more widely playable file. I can play transcode MPEGs on older copies of Windows Media Player and Apple's Quicktime, for example.
I have no doubt that within a year, much that is in this chapter will be out of date. Video will probably be much less problematic to get working well and a port will be in the collection which turns a FreeBSD system into a DVD-playing, PVR, and virtual A/V studio. Until that day arrives, those who want to get the very most out of FreeBSD's A/V capabilities will have to cobble together knowledge from several FAQs and tutorials and use a few different applications.
This section exists to give the reader some links to learn more in case this chapter was just helpful enough.
The MPlayer documentation is very technically informative. These documents should probably be consulted by anyone wishing to obtain a high level of expertise with Unix video. The MPlayer mailing list is hostile to anyone who has not bothered to read the documentation, so if you plan on making bug reports to them, RTFM.
The xine HOWTO contains a chapter on performance improvement which is general to all players.
Finally, there are some other promising applications which the reader may try:
Avifile which is also a port graphics/avifile.
Ogle which is also a port graphics/ogle.
| [1] |
A popular familiar graphics card with generally very good XFree86 performance, nVidia, has yet to release the specifications on their XVideo support to the XFree86 team. It may be some time before XFree86 fully support XVideo for these cards. |
| [2] |
Unauthorized DVD playback is a serious criminal act in some countries. Check local laws before enabling this option. |
This, and other documents, can be downloaded from ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/.
For questions about FreeBSD, read the
documentation
before contacting <[email protected]>.
For questions about this documentation, e-mail <[email protected]>.
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