doc: developer: Add a note about reserved system name space

[ffmpeg] / doc / indevs.texi

diff --git a/doc/indevs.texi b/doc/indevs.texi
index cf29c4c30607364634f8f92d2c090df314049949..868329799f0eff7a6c2dc13801ef1eab1fce666c 100644 (file)
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -1,12 +1,12 @@
 @chapter Input Devices
 @c man begin INPUT DEVICES
 
 @chapter Input Devices
 @c man begin INPUT DEVICES
 

-Input devices are configured elements in FFmpeg which allow to access
+Input devices are configured elements in Libav which allow to access

 the data coming from a multimedia device attached to your system.
 
 the data coming from a multimedia device attached to your system.
 

-When you configure your FFmpeg build, all the supported input devices
-are enabled by default. You can list them using the configure option
-"--list-indevs".
+When you configure your Libav build, all the supported input devices
+are enabled by default. You can list all available ones using the
+configure option "--list-indevs".

 
 You can disable all the input devices using the configure option
 "--disable-indevs", and selectively enable an input device using the
 
 You can disable all the input devices using the configure option
 "--disable-indevs", and selectively enable an input device using the


@@ -25,7 +25,7 @@ ALSA (Advanced Linux Sound Architecture) input device.
 To enable this input device during configuration you need libasound
 installed on your system.
 
 To enable this input device during configuration you need libasound
 installed on your system.
 

-This device allows to capture from an ALSA device. The name of the
+This device allows capturing from an ALSA device. The name of the

 device to capture has to be an ALSA card identifier.
 
 An ALSA identifier has the syntax:
 device to capture has to be an ALSA card identifier.
 
 An ALSA identifier has the syntax:


@@ -42,19 +42,15 @@ specify card number or identifier, device number and subdevice number
 To see the list of cards currently recognized by your system check the
 files @file{/proc/asound/cards} and @file{/proc/asound/devices}.
 
 To see the list of cards currently recognized by your system check the
 files @file{/proc/asound/cards} and @file{/proc/asound/devices}.
 

-For example to capture with @file{ffmpeg} from an alsa device with
+For example to capture with @command{avconv} from an ALSA device with

 card id 0, you may run the command:
 @example
 card id 0, you may run the command:
 @example

-ffmpeg -f alsa -i hw:0 alsaout.wav
+avconv -f alsa -i hw:0 alsaout.wav

 @end example
 
 For more information see:
 @url{http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html}
 
 @end example
 
 For more information see:
 @url{http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html}
 

-@section audio_beos
-
-BeOS audio input device.
-

 @section bktr
 
 BSD video input device.
 @section bktr
 
 BSD video input device.


@@ -63,50 +59,75 @@ BSD video input device.
 
 Linux DV 1394 input device.
 
 
 Linux DV 1394 input device.
 

+@section fbdev
+
+Linux framebuffer input device.
+
+The Linux framebuffer is a graphic hardware-independent abstraction
+layer to show graphics on a computer monitor, typically on the
+console. It is accessed through a file device node, usually
+@file{/dev/fb0}.
+
+For more detailed information read the file
+Documentation/fb/framebuffer.txt included in the Linux source tree.
+
+To record from the framebuffer device @file{/dev/fb0} with
+@command{avconv}:
+@example
+avconv -f fbdev -r 10 -i /dev/fb0 out.avi
+@end example
+
+You can take a single screenshot image with the command:
+@example
+avconv -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
+@end example
+
+See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
+

 @section jack
 
 @section jack
 

-Jack input device.
+JACK input device.

 
 To enable this input device during configuration you need libjack
 installed on your system.
 
 
 To enable this input device during configuration you need libjack
 installed on your system.
 

-A jack input device creates one or more jack writable clients, one for
+A JACK input device creates one or more JACK writable clients, one for

 each audio channel, with name @var{client_name}:input_@var{N}, where
 @var{client_name} is the name provided by the application, and @var{N}
 is a number which identifies the channel.
 each audio channel, with name @var{client_name}:input_@var{N}, where
 @var{client_name} is the name provided by the application, and @var{N}
 is a number which identifies the channel.

-Each writable client will send the acquired data to the FFmpeg input
+Each writable client will send the acquired data to the Libav input

 device.
 
 device.
 

-Once you have created one or more jack readable clients, you need to
-connect them to one or more jack writable clients.
+Once you have created one or more JACK readable clients, you need to
+connect them to one or more JACK writable clients.

 
 

-To connect or disconnect jack clients you can use the
+To connect or disconnect JACK clients you can use the

 @file{jack_connect} and @file{jack_disconnect} programs, or do it
 through a graphical interface, for example with @file{qjackctl}.
 
 @file{jack_connect} and @file{jack_disconnect} programs, or do it
 through a graphical interface, for example with @file{qjackctl}.
 

-To list the jack clients and their properties you can invoke the command
+To list the JACK clients and their properties you can invoke the command

 @file{jack_lsp}.
 
 @file{jack_lsp}.
 

-Follows an example which shows how to capture a jack readable client
-with @file{ffmpeg}.
+Follows an example which shows how to capture a JACK readable client
+with @command{avconv}.

 @example
 @example

-# create a jack writable client with name "ffmpeg"
-$ ffmpeg -f jack -i ffmpeg -y out.wav
+# Create a JACK writable client with name "libav".
+$ avconv -f jack -i libav -y out.wav

 
 

-# start the sample jack_metro readable client
+# Start the sample jack_metro readable client.

 $ jack_metro -b 120 -d 0.2 -f 4000
 
 $ jack_metro -b 120 -d 0.2 -f 4000
 

-# list the current jack clients
+# List the current JACK clients.

 $ jack_lsp -c
 system:capture_1
 system:capture_2
 system:playback_1
 system:playback_2
 $ jack_lsp -c
 system:capture_1
 system:capture_2
 system:playback_1
 system:playback_2

-ffmpeg:input_1
+libav:input_1

 metro:120_bpm
 
 metro:120_bpm
 

-# connect metro to the ffmpeg writable client
-$ jack_connect metro:120_bpm ffmpeg:input_1
+# Connect metro to the avconv writable client.
+$ jack_connect metro:120_bpm libav:input_1

 @end example
 
 For more information read:
 @end example
 
 For more information read:


@@ -122,54 +143,149 @@ Open Sound System input device.
 
 The filename to provide to the input device is the device node
 representing the OSS input device, and is usually set to
 
 The filename to provide to the input device is the device node
 representing the OSS input device, and is usually set to

-@file{/dev/dsp/}.
+@file{/dev/dsp}.

 
 

-For example to grab from @file{/dev/dsp/} using @file{ffmpeg} use the
+For example to grab from @file{/dev/dsp} using @command{avconv} use the

 command:
 @example
 command:
 @example

-ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
+avconv -f oss -i /dev/dsp /tmp/oss.wav

 @end example
 
 For more information about OSS see:
 @url{http://manuals.opensound.com/usersguide/dsp.html}
 
 @end example
 
 For more information about OSS see:
 @url{http://manuals.opensound.com/usersguide/dsp.html}
 

-@section video4linux and video4linux2
+@section pulse
+
+pulseaudio input device.
+
+To enable this input device during configuration you need libpulse-simple
+installed in your system.
+
+The filename to provide to the input device is a source device or the
+string "default"
+
+To list the pulse source devices and their properties you can invoke
+the command @file{pactl list sources}.
+
+@example
+avconv -f pulse -i default /tmp/pulse.wav
+@end example
+
+@subsection @var{server} AVOption
+
+The syntax is:
+@example
+-server @var{server name}
+@end example
+
+Connects to a specific server.
+
+@subsection @var{name} AVOption
+
+The syntax is:
+@example
+-name @var{application name}
+@end example
+
+Specify the application name pulse will use when showing active clients,
+by default it is "libav"
+
+@subsection @var{stream_name} AVOption
+
+The syntax is:
+@example
+-stream_name @var{stream name}
+@end example
+
+Specify the stream name pulse will use when showing active streams,
+by default it is "record"
+
+@subsection @var{sample_rate} AVOption
+
+The syntax is:
+@example
+-sample_rate @var{samplerate}
+@end example
+
+Specify the samplerate in Hz, by default 48kHz is used.
+
+@subsection @var{channels} AVOption
+
+The syntax is:
+@example
+-channels @var{N}
+@end example

 
 

-Video4Linux and Video4Linux2 input video devices.
+Specify the channels in use, by default 2 (stereo) is set.
+
+@subsection @var{frame_size} AVOption
+
+The syntax is:
+@example
+-frame_size @var{bytes}
+@end example
+
+Specify the number of byte per frame, by default it is set to 1024.
+
+@subsection @var{fragment_size} AVOption
+
+The syntax is:
+@example
+-fragment_size @var{bytes}
+@end example
+
+Specify the minimal buffering fragment in pulseaudio, it will affect the
+audio latency. By default it is unset.
+
+@section sndio
+
+sndio input device.
+
+To enable this input device during configuration you need libsndio
+installed on your system.
+
+The filename to provide to the input device is the device node
+representing the sndio input device, and is usually set to
+@file{/dev/audio0}.
+
+For example to grab from @file{/dev/audio0} using @command{avconv} use the
+command:
+@example
+avconv -f sndio -i /dev/audio0 /tmp/oss.wav
+@end example
+
+@section video4linux2
+
+Video4Linux2 input video device.

 
 The name of the device to grab is a file device node, usually Linux
 systems tend to automatically create such nodes when the device
 
 The name of the device to grab is a file device node, usually Linux
 systems tend to automatically create such nodes when the device

-(e.g. an USB webcam) is plugged to the system, and has a name of the
+(e.g. an USB webcam) is plugged into the system, and has a name of the

 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
 the device.
 
 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
 the device.
 

-Video4Linux and Video4Linux2 devices only support a limited set of
+Video4Linux2 devices usually support a limited set of

 @var{width}x@var{height} sizes and framerates. You can check which are
 @var{width}x@var{height} sizes and framerates. You can check which are

-supported for example using the command @file{dov4l} for Video4Linux
-devices, and the command @file{v4l-info} for Video4Linux2 devices.
+supported using @command{-list_formats all} for Video4Linux2 devices.

 
 

-If the size for the device is set to 0x0, the input device will
-try to autodetect the size to use.
+Some usage examples of the video4linux2 devices with avconv and avplay:

 
 

-Video4Linux support is deprecated since Linux 2.6.30, and will be
-dropped in later versions.
-
-Follow some usage examples of the video4linux devices with the ff*
-tools.

 @example
 @example

-# grab and show the input of a video4linux device
-ffplay -s 320x240 -f video4linux /dev/video0
-
-# grab and show the input of a video4linux2 device, autoadjust size
-ffplay -f video4linux2 /dev/video0
+# Grab and show the input of a video4linux2 device.
+avplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0

 
 

-# grab and record the input of a video4linux2 device, autoadjust size
-ffmpeg -f video4linux2 -i /dev/video0 out.mpeg
+# Grab and record the input of a video4linux2 device, leave the
+framerate and size as previously set.
+avconv -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg

 @end example
 
 @section vfwcap
 
 @end example
 
 @section vfwcap
 

-VFW (Video For Window) catpure input device.
+VfW (Video for Windows) capture input device.
+
+The filename passed as input is the capture driver number, ranging from
+0 to 9. You may use "list" as filename to print a list of drivers. Any
+other filename will be interpreted as device number 0.

 
 @section x11grab
 
 
 @section x11grab
 


@@ -177,32 +293,70 @@ X11 video input device.
 
 This device allows to capture a region of an X11 display.
 
 
 This device allows to capture a region of an X11 display.
 

-The filename passed in input has the syntax:
+The filename passed as input has the syntax:

 @example
 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
 @end example
 
 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
 @example
 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
 @end example
 
 @var{hostname}:@var{display_number}.@var{screen_number} specifies the

-X11 display name of the screen to grab from. @var{hostname} can be not
-specified, and defaults to "localhost". The environment variable
+X11 display name of the screen to grab from. @var{hostname} can be
+omitted, and defaults to "localhost". The environment variable

 @env{DISPLAY} contains the default display name.
 
 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
 @env{DISPLAY} contains the default display name.
 
 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed

-area with respect to the top/left border of the X11 screen image. They
+area with respect to the top-left border of the X11 screen. They

 default to 0.
 
 Check the X11 documentation (e.g. man X) for more detailed information.
 
 Use the @file{dpyinfo} program for getting basic information about the
 default to 0.
 
 Check the X11 documentation (e.g. man X) for more detailed information.
 
 Use the @file{dpyinfo} program for getting basic information about the

-properties of your X11 display screen (e.g. grep for "name" or
-"dimensions").
+properties of your X11 display (e.g. grep for "name" or "dimensions").
+
+For example to grab from @file{:0.0} using @command{avconv}:
+@example
+avconv -f x11grab -r 25 -s cif -i :0.0 out.mpg
+
+# Grab at position 10,20.
+avconv -f x11grab -r 25 -s cif -i :0.0+10,20 out.mpg
+@end example
+
+@subsection @var{follow_mouse} AVOption
+
+The syntax is:
+@example
+-follow_mouse centered|@var{PIXELS}
+@end example
+
+When it is specified with "centered", the grabbing region follows the mouse
+pointer and keeps the pointer at the center of region; otherwise, the region
+follows only when the mouse pointer reaches within @var{PIXELS} (greater than
+zero) to the edge of region.
+
+For example:
+@example
+avconv -f x11grab -follow_mouse centered -r 25 -s cif -i :0.0 out.mpg
+
+# Follows only when the mouse pointer reaches within 100 pixels to edge
+avconv -f x11grab -follow_mouse 100 -r 25 -s cif -i :0.0 out.mpg
+@end example
+
+@subsection @var{show_region} AVOption
+
+The syntax is:
+@example
+-show_region 1
+@end example
+
+If @var{show_region} AVOption is specified with @var{1}, then the grabbing
+region will be indicated on screen. With this option, it's easy to know what is
+being grabbed if only a portion of the screen is grabbed.

 
 

-For example to grab from @file{:0.0} using @file{ffmpeg}:
+For example:

 @example
 @example

-ffmpeg -f x11grab -r 25 -s cif -i :0.0 out.mpg
+avconv -f x11grab -show_region 1 -r 25 -s cif -i :0.0+10,20 out.mpg

 
 

-# grab at position 10,20
-ffmpeg -f x11grab -25 -s cif -i :0.0+10,20 out.mpg
+# With follow_mouse
+avconv -f x11grab -follow_mouse centered -show_region 1  -r 25 -s cif -i :0.0 out.mpg

 @end example
 
 @c man end INPUT DEVICES
 @end example
 
 @c man end INPUT DEVICES