diff options
author | nicolas <nicolas@b3059339-0415-0410-9bf9-f77b7e298cf2> | 2003-03-23 23:35:12 +0000 |
---|---|---|
committer | nicolas <nicolas@b3059339-0415-0410-9bf9-f77b7e298cf2> | 2003-03-23 23:35:12 +0000 |
commit | 413a60419542895a13fa54640b44e074df8de162 (patch) | |
tree | 6f4940f2ac5bf154f5586f7436d6cca12546ec1c /DOCS/xml/en/tvinput.xml | |
parent | 5b1bd414021a75c10bcff405266df99f729a91da (diff) | |
download | mpv-413a60419542895a13fa54640b44e074df8de162.tar.bz2 mpv-413a60419542895a13fa54640b44e074df8de162.tar.xz |
XML version of MPlayer's doc
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@9676 b3059339-0415-0410-9bf9-f77b7e298cf2
Diffstat (limited to 'DOCS/xml/en/tvinput.xml')
-rw-r--r-- | DOCS/xml/en/tvinput.xml | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/DOCS/xml/en/tvinput.xml b/DOCS/xml/en/tvinput.xml new file mode 100644 index 0000000000..a0b7efd997 --- /dev/null +++ b/DOCS/xml/en/tvinput.xml @@ -0,0 +1,203 @@ +<?xml version="1.0" encoding="iso-8859-1"?> +<sect1 id="tv-input" xreflabel="TV input"> +<title>TV input</title> + +<para> +This section is about how to enable <emphasis role="bold">watching/grabbing +from V4L compatible TV tuner</emphasis>. +</para> + + +<sect2 id="tv-compilation"> +<title>Compilation</title> + +<procedure> +<step><para> + First, you have to recompile. <filename>./configure</filename> will + autodetect kernel headers of v4l stuff and the existence of + <filename>/dev/video*</filename> entries. If they exist, TV support will + be built (see the output of <filename>./configure</filename>). + </para></step> +<step><para> + Make sure your tuner works with another TV software in Linux, for + example xawtv. + </para></step> +</procedure> +</sect2> + +<sect2 id="tv-tips"> +<title>Usage tips</title> +<para> +The full listing of the options is available on the manual page. +Here are just a few tips: +</para> +<itemizedlist> +<listitem> +<para> +Use the <option>channels</option> option. An example: +<screen>-tv on:channels=26-MTV1,23-TV2</screen> +Explanation: using this option, only the 26 and 23 channels will be usable, +and there will be a nice OSD text upon channel switching, displaying the +channel's name. Spaces in the channel name must be replaced by the +"_" character. +</para> +</listitem> + +<listitem> +<para> +Choose some sane image dimensions. The dimensions of the resulting image should +be divisible by 16. +</para> +</listitem> + +<listitem> +<para> +If you capture the video with the vertical resolution higher than half of +the full resolution (i.e. 288 for PAL or 240 for NTSC), make sure you turned +deinterlacing on. Otherwise you'll get a movie which is distorted during +fast-motion scenes and the bitrate controller will be probably even unable +to retain the specified bitrate as the interlacing artifacts produce high +amount of detail and thus consume lot of bandwidth. You can enable +deinterlacing with <option>-vop pp=DEINT_TYPE</option>. Usually +<option>pp=lb</option> does a good job, but it can be matter of personal +preference. See other deinterlacing algorithms in the manual and give it a try. +</para> +</listitem> + +<listitem> +<para> +Crop out the dead space. When you capture the video, the areas at the edges +are usually black or contain some noise. These again consume lots of +unnecessary bandwidth. More precisely it's not the black areas themselves +but the sharp transitions between the black and the brighter video image +which do but that's not important for now. Before you start capturing, +adjust the arguments of the <option>crop</option> option so that all the +crap at the margins is cropped out. Again, don't forget to keep the resulting +dimensions sane. +</para> +</listitem> + +<listitem> +<para> +Watch out for CPU load. It shouldn't cross the 90% boundary for most of the +time. If you have a large capture buffer, MEncoder can survive an overload +for few seconds but nothing more. It's better to turn off the 3D OpenGL +screensavers and similar stuff. +</para> +</listitem> + +<listitem> +<para> +Don't mess with the system clock. <application>MEncoder</application> uses the +system clock for doing A/V sync. If you adjust the system clock (especially +backwards in time), MEncoder gets confused and you will lose frames. This is +an important issue if you are hooked to a network and run some time +synchronization software like NTP. You have to turn NTP off during the capture +process if you want to capture reliably. +</para> +</listitem> + +<listitem> +<para> +Don't change the <option>outfmt</option> unless you know what you are doing +or your card/driver really doesn't support the default (YV12 colorspace). +In the older versions of <application>MPlayer</application>/ +<application>MEncoder</application> it was necessary to specify the output +format. This issue should be fixed in the current releases and <option>outfmt</option> +isn't required anymore, and the default suits the most purposes. For example, +if you are capturing into DivX using libavcodec and specify +<option>outfmt=RGB24</option> in order to increase the quality of the captured +images, the captured image will be actually later converted back into YV12 so +the only thing you achieve is a massive waste of CPU power. +</para> +</listitem> + +<listitem> +<para> +To specify the I420 colorspace (<option>outfmt=i420</option>), you have to add an +option <option>-vc rawi420</option> due to a fourcc conflict with an Intel Indeo +video codec. +</para> +</listitem> + +<listitem> +<para> +There are several ways of capturing audio. You can grab the sound either using +your soundcard via an external cable connection between video card and line-in, +or using the built-in ADC in the bt878 chip. In the latter case, you have to +load the <emphasis role="bold">btaudio</emphasis> driver. Read the +<filename>linux/Documentation/sound/btaudio</filename> file (in the kernel +tree, not MPlayer's) for some instructions on using this driver. +</para> +</listitem> + +<listitem> +<para> +If <application>MEncoder</application> cannot open the audio device, make +sure that it is really available. There can be some trouble with the sound +servers like arts (KDE) or esd (GNOME). If you have a full duplex soundcard +(almost any decent card supports it today), and you are using KDE, try to +check the "full duplex" option in the sound server preference menu. +</para> +</listitem> +</itemizedlist> +</sect2> + + +<sect2 id="tv-examples"> +<title>Examples</title> + +<informalexample> +<para> +Dummy output, to AAlib :) +<screen> +mplayer -tv on:driver=dummy:width=640:height=480 -vo aa<!-- +--></screen> +</para> +</informalexample> + +<informalexample> +<para> +Input from standard V4L: +<screen> +mplayer -tv on:driver=v4l:width=640:height=480:outfmt=i420 -vc rawi420 -vo xv<!-- +--></screen> +</para> +</informalexample> + +<informalexample> +<para> +A more sophisticated example. This makes MEncoder capture the full PAL +image, crop the margins, and deinterlace the picture using a linear blend +algorithm. Audio is compressed with a constant bitrate of 64kbps, using +LAME codec. This setup is suitable for capturing movies. +<screen> + mencoder -tv on:driver=v4l:width=768:height=576 \ + -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=900 \ + -oac mp3lame -lameopts cbr:br=64 \ + -vop pp=lb,crop=720:544:24:16 -o output.avi +</screen> +</para> +</informalexample> + +<informalexample> +<para> +This will additionally rescale the image to 384x288 and compresses the +video with the bitrate of 350kbps in high quality mode. The vqmax option +looses the quantizer and allows the video compressor to actualy reach so +low bitrate even at the expense of the quality. This can be used for +capturing long TV series, where the video quality isn't so important. +<screen> + mencoder -tv on:driver=v4l:width=768:height=576 \ + -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=350:vhq:vqmax=31:keyint=300 \ + -oac mp3lame -lameopts cbr:br=48 \ + -vop scale=384:288,pp=tn/lb,crop=720:540:24:18 -sws 1 -o output.avi +</screen> +It's also possible to specify smaller image dimensions in the <option>-tv</option> +option and omit the software scaling but this approach uses the maximum available +information and is a little more resistant to noise. The bt8x8 chips can do the +pixel averaging only in the horizontal direction due to a hardware limitation. +</para> +</informalexample> +</sect2> +</sect1> |