Date: Mon, 3 Jun 2002 19:20:24 -0700 (PDT) From: Ross Lippert <ripper@eskimo.com> To: ue@nathan.ruhr.de Cc: freebsd-doc@FreeBSD.ORG Subject: Re: A video chapter (pr doc/31653) Message-ID: <200206040220.TAA24404@eskimo.com> In-Reply-To: <20020603060702.GO65310@nathan.ruhr.de> (message from Udo Erdelhoff on Mon, 3 Jun 2002 08:07:03 %2B0200)
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OK, I thnk I have addressed your points. Again, I am not sure how
to build the man entities, but I have de-amp-ed them so as not to
cause confusion.
But I think the question is still open as to whether to turn the sound
chapter into a multimedia chapter or have a chapter on its own. I'm
leaning towards expanding the sound chapter into multimedia, but there
is some issue of integration, like should the current sound chapter
be turned into half a chapter with this the other half? Or should the
sections be flattened together or what.
If I'm given license I'll integrate with the sound chapter myself as
I judge fit, but if there is someone maintaining it, let's talk.
-r
ps the current version -- still wanting feedback
<!--
The FreeBSD Documentation Project
-->
<chapter id="video">
<chapterinfo>
<authorgroup>
<author>
<firstname>Ross</firstname>
<surname>Lippert</surname>
<contrib>Contributed by </contrib>
</author>
</authorgroup>
<!-- 31 May 2002 -->
</chapterinfo>
<title>Video Playback</title>
<sect1 id="video-synopsis">
<title>Synopsis</title>
<para>With some willingness to experiment, FreeBSD can support
playback of video files and DVD's. The number of applications to
encode, re-encode, and playback various video media is more
limited than the number of sound applications. For example as of
this writing, there is no good transcoding application in the
FreeBSD Ports Collection, which could be use to interconvert
between formats, as there is with <filename
role="package">audio/sox</filename>. However, the software
landscape in this area is changing rapidly.</para>
<para>After reading this chapter, you will know:</para>
<itemizedlist>
<listitem><para>Some ways in which video is supported by XFree86.</para></listitem>
<listitem><para>Some ports/packages of video players/encoders which give good results.</para></listitem>
<listitem><para>How to playback DVD's, .mpg and .avi files.</para></listitem>
<listitem><para>How to rip DVD video titles into data files.</para></listitem>
</itemizedlist>
<para>Before reading this chapter, you should:</para>
<itemizedlist>
<listitem><para>Know how to configure your soundcard (<xref
linkend="sound">).</para></listitem>
<listitem><para>Know how to configure and install XFree86 (<xref
linkend="x11">)
</para>
</listitem>
</itemizedlist>
<para>It is assumed that XFree86 4.X is being used. XFree86 3.X
may work, but this author has not made the attempt.</para>
</sect1>
<sect1 id="video-interface">
<title>Determining Video capabilities</title>
<indexterm><primary>Xvideo</primary></indexterm>
<indexterm><primary>Xv</primary></indexterm>
<indexterm><primary>sdl</primary></indexterm>
<indexterm><primary>SDL</primary></indexterm>
<indexterm><primary>dga</primary></indexterm>
<indexterm><primary>DGA</primary></indexterm>
<indexterm>
<primary>kernel configuration</primary>
<secondary>options CPU_ENABLE_SSE</secondary>
</indexterm>
<indexterm>
<primary>kernel configuration</primary>
<secondary>options USER_LDT</secondary>
</indexterm>
<para>Video display under X11 suffers from a multitude of
possibilities, what will each works 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.</para>
<para>A list of common video interfaces:</para>
<orderedlist>
<listitem>
<para> X11 : normal X11 output using shared memory</para>
</listitem>
<listitem>
<para> XVideo : an extension to the X11
interface which supports video in any X11 drawable.</para>
</listitem>
<listitem>
<para> SDL : the Simple Directmedia Layer</para>
</listitem>
<listitem>
<para> DGA : the Direct Graphics Access</para>
</listitem>
<listitem>
<para> SVGAlib : low level console graphics layer</para>
</listitem>
</orderedlist>
<para>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, a much smaller number give good
playback performance. To obtain a list of extensions supported
by the X-server using your card use the command
&man.xdpyinfo.1; while X11 is running.</para>
<para>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 players default or are hardcoded to look
for DVD media in <filename>/dev/dvd</filename>, it is also a
good idea to have a symbolic link to the appropriate device:</para>
<screen>&prompt.root; ln -sf /dev/acd0c /dev/dvd
&prompt.root; ln -sf /dev/racd0c /dev/rdvd</screen>
<para>On FreeBSD-5.X, which uses <filename>devfs</filename>
there is a slightly different set of recommended links:</para>
<screen>&prompt.root; ln -sf /dev/acd0c /dev/dvd
&prompt.root; ln -sf /dev/acd0c /dev/rdvd</screen>
<para>Some of the packages discussed in the next section rely on the
following kernel options to build correctly. Before attempting to
build, add these options to the kernel and reboot:</para>
<programlisting>option CPU_ENABLE_SSE
option USER_LDT</programlisting>
<para>To enhance the shared memory X11 interface, it is recommended
that the values of some &man.sysctl.1; variables should be increase:
</para>
<programlisting>kern.ipc.shmmax=67108864
kern.ipc.shmall=32768</programlisting>
<sect2 id="video-interface-xvideo">
<title>XVideo</title>
<para>XFree86 4.X has an extension called
<emphasis>XVideo</emphasis> (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 on even low-end machines (for example my
PIII 400Mhz laptop). Unfortunately, the list of cards in which
this feature is supported <quote>out of the box</quote> is
currently:</para>
<orderedlist>
<listitem>
<para>3DFX Voodoo 3</para>
</listitem>
<listitem>
<para>Intel i810 and i815</para>
</listitem>
<listitem>
<para>some S3 chips (such as Savage/IX and Savage/MX)</para>
</listitem>
</orderedlist>
<para>If your card is not one of these, do not be disappointed yet.
XFree86 4.X adds new xv capabilities with each release
<footnote>
<para>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.</para>
</footnote>.
To check whether the extension is running, use <command>xvinfo</command>:
</para>
<screen>&prompt.user; xvinfo</screen>
<para>XVideo is supported for your card if the result looks like:</para>
<screen>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</screen>
<para>Also note that the formats listed (YUV2, YUV12, etc) are not
present with every implementation of Xvideo and their absense may
hinder some players.</para>
<para>If the result looks like:</para>
<screen>X-Video Extension version 2.2
screen #0
no adaptors present</screen>
<para>Then XVideo is probably not supported for your card.</para>
<para>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 probably should read about
ways to improving performance in the advanced reading <xref
linkend="video-further-reading">.</para>
</sect2>
<sect2 id="video-interface-SDL">
<title>Simple Directmedia Layer</title>
<para>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.</para>
<para>The SDL can be found at <filename role="package">sdl12</filename></para>
</sect2>
<sect2 id="video-interface-DGA">
<title>Direct Graphics Access</title>
<para>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
<username>root</username></para>
<para>The DGA extension can be tested and benchmarked by
&man.dga.1;. When <command>dga</command> is running, it
changes the colors of the display whenever a key is pressed. To
quit, use <keycap>q</keycap>.</para>
</sect2>
</sect1>
<sect1 id="video-ports">
<title>Ports and Packages Dealing with Video</title>
<indexterm><primary>video ports</primary></indexterm>
<indexterm><primary>video packages</primary></indexterm>
<para>This section will discuss 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.</para>
<para>Firstly, it is important to know that most of the video
applications which run of FreeBSD were developed as Linux
applications, originating in the past year. For this reason,
they are both, very experimental and also riddled with
Linux-isms which might prevent them from working at full
efficiency on FreeBSD.</para>
<para>By "experimental", I mean that you can expect re-encoders,
players, and DVD decrypters to all have some major bugs, or
interoperability problems with other programs. Here is a short
list of the sorts of things I mean:</para>
<orderedlist>
<listitem><para>An application cannot playback a file which another
application produced.</para></listitem>
<listitem><para>An application cannot playback a file which the
application itself produced.</para></listitem>
<listitem><para>The same application on two different machines,
rebuilt on each machine for that machine, plays back the same
file differently </para></listitem>
<listitem><para>A seemingly trivial filter like
rescaling of the image size
results in very bad artifacts from a buggy rescaling routine.
</para></listitem>
<listitem><para>Application always dumping core.</para></listitem>
<listitem><para>Documentation is not installed with the port and can
be found either on the web or under <filename>${PORTPATH}/work/
</filename>.</para></listitem>
</orderedlist>
<para>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:</para>
<orderedlist>
<listitem><para>The use of <filename>/proc/cpuinfo</filename> to detect
processor characteristics.</para></listitem>
<listitem><para>A misuse of threads which causes a program to hang upon
completion than truly terminate.</para></listitem>
<listitem><para>Software not yet in the FreeBSD Ports Collection
which is commonly used in conjunction with the application.</para>
</listitem>
</orderedlist>
<para>So far, these application developers have been cooperative with
port maintainers to minimize the work-arounds needed for
port-ing.</para>
<sect2 id="video-mplayer">
<title>MPlayer</title>
<para>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.</para>
<sect3 id="video-mplayer-building">
<title>Building MPlayer</title>
<indexterm><primary>mplayer</primary>
<secondary>making</secondary></indexterm>
<para>MPlayer resides in <filename
role="package">graphics/mplayer</filename>. 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
<command>make</command> which echo at the start of the
build.
</para>
<screen>&prompt.root; cd /usr/ports/graphics/mplayer
&prompt.root; 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.
</screen>
<para>If you have <filename
role="package">x11-toolkits/gtk12</filename> installed, then
you might as well enable to GUI. Otherwise, it is not worth
the effort. If you intend to play (possibly CSS encoded) DVD's with
MPlayer you must enable to DVD support option here
<footnote><para>SOME SORT OF DISCLAIMER ABOUT CSS HERE</para>
</footnote>. Some reasonable options are:</para>
<screen>&prompt.root; make WITH_DVD=yes WITH_SVGALIB=yes</screen>
<para>As of this writing, the MPlayer port will build its HTML
documentation and one executable,
<command>mplayer</command>. It can also be made to build an
encoder, <command>mencoder</command>, which is a tool for
re-encoding video. A modification to the
<filename>Makefile</filename> can enable it. It may be
enabled by default in subsequent versions of the port.</para>
<para>The HTML documentation to MPlayer is very informative.
If the reader finds the information on video hardware and
interfaces in thie chapter lacking, the MPlayer
documentation is a very thorough alternative. I urge its
reading by anyone wishing to obtain expertise in Unix
video.</para>
</sect3>
<sect3 id="video-mplayer-using">
<title>Using mplayer</title>
<indexterm><primary>mplayer</primary>
<secondary>use</secondary></indexterm>
<para>Any user of mplayer must set up a
<filename>.mplayer</filename> subdirectory directory of her
home directory. to create this necessary subdirectory,
you can do the following:</para>
<screen>&prompt.user; cd /usr/ports/graphics/mplayer
&prompt.user; make install-user</screen>
<para>The command options for <command>mplayer</command> 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.</para>
<para>To play from file, such as
<filename>testfile.avi</filename> through one of the various
video interfaces set the <option>-vo</option>:
<screen>&prompt.user; mplayer -vo xv testfile.avi</screen>
<screen>&prompt.user; mplayer -vo sdl testfile.avi</screen>
<screen>&prompt.user; mplayer -vo x11 testfile.avi</screen>
<screen>&prompt.root; mplayer -vo dga testfile.avi</screen>
<screen>&prompt.root; mplayer -vo 'sdl:dga' testfile.avi</screen>
<para>It is worth trying all of these options, as their relative
performance depends on many factors and will vary significantly
with hardware.
</para>
<para>To play from a DVD, replace the
<filename>testfile.avi</filename> with <option>-dvd
<N> ${DEVICE}</option> where <N> is the title number to
play and <filename>${DEVICE}</filename> is the device file for the
DVD-ROM. For example, to play title 3 from <filename>/dev/dvd</filename>:</para>
<screen>&prompt.root; mplayer -vo dga -dvd 2 /dev/dvd</screen>
<para>To stop, pause, advance and so on, consult the
keybindings, which are output by running <command>mplayer
-h</command> or read the manual page.</para>
<para>Additional important options for playback are:
<option>-fs -zoom</option> which engages the fullscreen mode
and <option>-framedrop</option> which helps performance.
</para>
<para>In order for the mplayer command line to not become too
large, the user can create a file
<filename>.mplayer/config</filename> and set default options
there:</para>
<programlisting>vo=xv
fs=yes
zoom=yes</programlisting>
<para>Remember, if you are going to run as <username>root</username>
then set this in the <username>root</username> home directory as
well.</para>
<para>Finally, <command>mplayer</command> can be used to rip a
DVD title into a .vob file. To dump out title 2 from a DVD:</para>
<screen>&prompt.root; mplayer -dumpstream -dumpfile out.vob -dvd 2 /dev/dvd</screen>
<para>The output file, <filename>out.vob</filename>, will be
MPEG and can be manipulated by the other packages discussed
in this section.</para>
</sect3>
<sect3 id="video-mencoder">
<title>mencoder</title>
<indexterm>
<primary>mencoder</primary>
</indexterm>
<para>If you opt to install <command>mencoder</command> when
you build, be forewarned that it is still quite
experimental.</para>
<para>To use <command>mencoder</command> 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 playback
performance and bad. Here are a couple of examples to get
you going. First a simple copy:</para>
<screen>&prompt.user; mencoder input.avi -oac copy -ovc copy -o output.avi</screen>
<para>It is easy to find examples where the output is
unplayable even by <command>mplayer</command>. Thus, if you
just want to rip to a file, stick to the <option>-dumpfile</option>
in <command>mplayer</command>.</para>
<para>To re-encode <filename>input.avi</filename> in the MPEG4
codec with MPEG3 audio encoding (<filename role="package">
audio/lame</filename> is required):</para>
<screen>&prompt.user; mencoder input.avi -oac mp3lame -lameopts br=192 \
-ovc lavc -lavcopts vcodec=mpeg4:vhq -o output.avi</screen>
<para>This has produced output playable by <command>mplayer</command>
and <command>Xine</command>.</para>
<para><filename>input.avi</filename> can be replaced with
<option>-dvd 1 /dev/dvd</option> and run as
<username>root</username> 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.
</para>
</sect2>
<sect2 id="video-xine">
<title>Xine</title>
<para>Xine 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, <filename
role="package">graphics/xine</filename>.</para>
<para>The good news is that the above is pretty much true. Xine
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. </para>
<para>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. </para>
<para>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. Xine 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.</para>
<para>Xine can be started by itself:</para>
<screen>&prompt.user; xine</screen>
<para>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:</para>
<screen>&prompt.user; xine -g -p mymovie.avi</screen>
</sect2>
<sect2 id="video-ports-transcode">
<title>Transcode</title>
<para>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 <filename>stdin/stdout</filename> stream
interfaces.</para>
<para>Like MPlayer, Transcode is very experimental software which
must be build from the port <filename
role="package">graphics/transcode</filename>. Using a great
many options to the <command>make</command>. I
recommend:</para>
<screen>&prompt.root; make WITH_LIBMPEG2=yes</screen>
<para>If you plan to install <filename
role="package">graphics/avifile</filename>, then add that
option:</para>
<screen>&prompt.root; make WITH_AVIFILE=yes WITH_LIBMPEG2=yes</screen>
<para>Here are two examples of <command>transcode</command> 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.</para>
<screen>&prompt.user; transcode -i input.vob -x vob -V -Z 320x240 \
-y opendivx -N 0x55 -o output.avi</screen>
<screen>&prompt.user; 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</screen>
<para>There is a manual page for <command>transcode</command>, but for the
various <command>tc*</command> utilities which are also installed, there
is only a curt <option>-h</option> output.</para>
<para>In comparison, <command>transcode</command> runs
significantly slower than <command>mencoder</command>, but it
has a better chance of producing a more widely playable file. I
can play <command>transcode</command> MPEGs on older copies of
Windows Media Player and Apple's Quicktime, for example.</para>
</sect2>
</sect1>
<sect1 id="video-further-reading">
<title>Further Reading</title>
<para>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.
</para>
<para>This section exists to give the reader some links to learn
more in case this chapter was just helpful enough.</para>
<para>The
<ulink url="http://www.mplayerhq.hu/DOCS/">;
MPlayer documentation</ulink> 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.</para>
<para>The
<ulink url="http://dvd.sourceforge.net/xine-howto/en_GB/html/howto.html">;
Xine HOWTO</ulink> contains a chapter on performance improvement
which is general to all players.</para>
<para>Finally, there are some other promising applications which
may become useful additions to the FreeBSD Ports Collection:</para>
<itemizedlist>
<listitem>
<para>
<ulink url="http://xtheater.sourceforge.net/">XTheater</ulink>;
</para>
</listitem>
<listitem>
<para>
<ulink url="http://avifile.sourceforge.net/">AVIFile</ulink>;
</para>
</listitem>
</itemizedlist>
</sect1>
</chapter>
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