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diff --git a/DOCS/xml/en/usage.xml b/DOCS/xml/en/usage.xml index b851dd087d..1ac732c832 100644 --- a/DOCS/xml/en/usage.xml +++ b/DOCS/xml/en/usage.xml @@ -1311,4 +1311,308 @@ your sound card data that is outside the allowable range; this will result in distorted audio. </para> </sect1> + +<!-- ********** --> + +<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>. See the man page for a description +of TV options and keyboard controls. +</para> + +<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: + +<itemizedlist> +<listitem><para> + Make sure your tuner works with another TV software in Linux, for + example <application>XawTV</application>. +</para></listitem> +<listitem><para> + Use the <option>channels</option> option. An example: + <screen>-tv 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), then the + 'frames' you get will really be interleaved pairs of fields. + Depending on what you want to do with the video you may leave it in + this form, destructively deinterlace, or break the pairs apart into + individual fields. + </para> + <para> + 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>-vf 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, <application>MEncoder</application> + 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), <application>MEncoder</application> 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 + <systemitem class="library">libavcodec</systemitem> 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> + There are several ways of capturing audio. You can grab the sound either using + your sound card 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 <application>MPlayer</application>'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 sound card + (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> +</para> +</sect2> + +<sect2 id="tv-examples"> +<title>Examples</title> + +<informalexample><para> +Dummy output, to AAlib :) +<screen>mplayer -tv driver=dummy:width=640:height=480 -vo aa tv://</screen> +</para></informalexample> + +<informalexample><para> +Input from standard V4L: +<screen> +mplayer -tv driver=v4l:width=640:height=480:outfmt=i420 -vc rawi420 -vo xv tv:// +</screen> +</para></informalexample> + +<informalexample><para> +A more sophisticated example. This makes <application>MEncoder</application> +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 driver=v4l:width=768:height=576 -oac mp3lame -lameopts cbr:br=64\ + -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=900 \ + -vf crop=720:544:24:16,pp=lb -o <replaceable>output.avi</replaceable> tv:// +</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 actually 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 driver=v4l:width=768:height=576 \ + -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=350:vhq:vqmax=31:keyint=300 \ + -oac mp3lame -lameopts cbr:br=48 -sws 1 -o <replaceable>output.avi</replaceable>\ + -vf crop=720:540:24:18,pp=lb,scale=384:288 tv:// +</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> + +<!-- ********** --> + +<sect1 id="tv-teletext"> +<title>Teletext</title> + +<para> + Teletext is currently available only in <application>MPlayer</application> + for v4l and v4l2 drivers. +</para> + +<sect2 id="tv-teletext-implementation-notes"> +<title>Implementation notes</title> + +<para> +<application>MPlayer</application> supports regular text, graphics and navigation links. +Unfortunately, colored pages are not fully supported yet - all pages are shown as grayscaled. +Subtitle pages (also known as Closed Captions) are supported, too. +</para> + +<para> +<application>MPlayer</application> starts caching all teletext pages upon +starting to receive TV input, so you do not need to wait until the requested page is loaded. +</para> + +<para> +Note: Using teletext with <option>-vo xv</option> causes strange colors. +</para> +</sect2> + +<sect2 id="tv-teletext-usage"> +<title>Using teletext</title> + +<para> +To enable teletext decoding you must specify the VBI device to get teletext data +from (usually <filename>/dev/vbi0</filename> for Linux). This can be done by specifying +<option>tdevice</option> in your configuration file, like shown below: +<screen>tv=tdevice=/dev/vbi0</screen> +</para> + +<para> +You might need to specify the teletext language code for your country. +To list all available country codes use +<screen>tv=tdevice=/dev/vbi0:tlang=<replaceable>-1</replaceable></screen> +Here is an example for Russian: +<screen>tv=tdevice=/dev/vbi0:tlang=<replaceable>33</replaceable></screen> +</para> +</sect2> + +</sect1> + +<!-- ********** --> + +<sect1 id="radio"> +<title>Radio</title> + +<para> +This section is about how to enable listening to radio from +a V4L-compatible radio tuner. See the man page for a +description of radio options and keyboard controls. +</para> + +<!-- ********** --> + +<sect2 id="radio-tips"> +<title>Usage tips</title> + +<para> +The full listing of the options is available in the manual page. +Here are just a few tips: + +<itemizedlist> +<listitem><para> + Make sure your tuner works with another radio software in Linux, for + example <application>XawTV</application>. +</para></listitem> +<listitem><para> + Use the <option>channels</option> option. An example: + <screen>-radio channels=104.4-Sibir,103.9-Maximum</screen> + Explanation: With this option, only the 104.4 and 103.9 radio stations + will be usable. 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> + There are several ways of capturing audio. You can grab the sound either using + your sound card via an external cable connection between video card and + line-in, or using the built-in ADC in the saa7134 chip. In the latter case, + you have to load the <systemitem>saa7134-alsa</systemitem> or + <systemitem>saa7134-oss</systemitem> driver. +</para></listitem> +<listitem><para> + <application>MEncoder</application> cannot be used for audio capture, + because it requires a video stream to work. So your can either use + <application>arecord</application> from ALSA project or + use <option>-ao pcm:file=file.wav</option>. In the latter case you + will not hear any sound (unless you are using a line-in cable and + have switched line-in mute off). +</para></listitem> +</itemizedlist> +</para> +</sect2> + +<!-- ********** --> + +<sect2 id="radio-examples"> +<title>Examples</title> + +<informalexample><para> +Input from standard V4L (using line-in cable, capture switched off): +<screen>mplayer radio://104.4</screen> +</para></informalexample> + +<informalexample><para> +Input from standard V4L (using line-in cable, capture switched off, +V4Lv1 interface): +<screen>mplayer -radio driver=v4l radio://104.4</screen> +</para></informalexample> + +<informalexample><para> +Playing second channel from channel list: +<screen>mplayer -radio channels=104.4=Sibir,103.9=Maximm radio://2</screen> +</para></informalexample> + +<informalexample> +<para> +Passing sound over the PCI bus from the radio card's internal ADC. +In this example the tuner is used as a second sound card +(ALSA device hw:1,0). For saa7134-based cards either the +<systemitem>saa7134-alsa</systemitem> or <systemitem>saa7134-oss</systemitem> +module must be loaded. +<screen> +mplayer -rawaudio rate=32000 radio://2/capture \ + -radio adevice=hw=1.0:arate=32000:channels=104.4=Sibir,103.9=Maximm +</screen> +<note><para> +When using ALSA device names colons must be replaced +by equal signs, commas by periods. +</para></note> +</para> +</informalexample> +</sect2> + +</sect1> </chapter> |