Output Devices
**************

Output devices are configured elements in FFmpeg that can write multimedia data to an output device attached to your system.

When you configure your FFmpeg build, all the supported output devices are enabled by default. You can list all available ones using the configure option "--list-outdevs".

You can disable all the output devices using the configure option "--disable-outdevs", and selectively enable an output device using the option "--enable-outdev=OUTDEV", or you can disable a particular input device using the option "--disable-outdev=OUTDEV".

The option "-formats" of the ff* tools will display the list of enabled output devices (amongst the muxers).

A description of the currently available output devices follows.

alsa
====

ALSA (Advanced Linux Sound Architecture) output device.

caca
====

CACA output device.

This output device allows to show a video stream in CACA window. Only one CACA window is allowed per application, so you can have only one instance of this output device in an application.

To enable this output device you need to configure FFmpeg with --enable-libcaca. libcaca is a graphics library that outputs text instead of pixels.

For more information about libcaca, check: http://caca.zoy.org/wiki/libcaca

Options
-------

window_title
     Set the CACA window title, if not specified default to the filename specified for the output device.

window_size
     Set the CACA window size, can be a string of the form WIDTHxHEIGHT or a video size abbreviation. If not specified it defaults to the size of the input video.

driver
     Set display driver.

algorithm
     Set dithering algorithm. Dithering is necessary because the picture being rendered has usually far more colours than the available palette. The accepted values are listed with -list_dither algorithms.

antialias
     Set antialias method. Antialiasing smoothens the rendered image and avoids the commonly seen staircase effect. The accepted values are listed with -list_dither antialiases.

charset
     Set which characters are going to be used when rendering text. The accepted values are listed with -list_dither charsets.

color
     Set color to be used when rendering text. The accepted values are listed with -list_dither colors.

list_drivers
     If set to true, print a list of available drivers and exit.

list_dither
     List available dither options related to the argument. The argument must be one of algorithms, antialiases, charsets, colors.

Examples
--------

  * The following command shows the ffmpeg output is an CACA window, forcing its size to 80x25:

          ffmpeg -i INPUT -vcodec rawvideo -pix_fmt rgb24 -window_size 80x25 -f caca -

  * Show the list of available drivers and exit:

          ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_drivers true -

  * Show the list of available dither colors and exit:

          ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_dither colors -

fbdev
=====

Linux framebuffer output 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 /dev/fb0.

For more detailed information read the file Documentation/fb/framebuffer.txt included in the Linux source tree.

Options
-------

xoffset

yoffset
     Set x/y coordinate of top left corner. Default is 0.

Examples
--------

Play a file on framebuffer device /dev/fb0. Required pixel format depends on current framebuffer settings.

     ffmpeg -re -i INPUT -vcodec rawvideo -pix_fmt bgra -f fbdev /dev/fb0

See also http://linux-fbdev.sourceforge.net/, and fbset(1).

oss
===

OSS (Open Sound System) output device.

pulse
=====

PulseAudio output device.

To enable this output device you need to configure FFmpeg with --enable-libpulse.

More information about PulseAudio can be found on http://www.pulseaudio.org

Options
-------

server
     Connect to a specific PulseAudio server, specified by an IP address. Default server is used when not provided.

name
     Specify the application name PulseAudio will use when showing active clients, by default it is the LIBAVFORMAT_IDENT string.

stream_name
     Specify the stream name PulseAudio will use when showing active streams, by default it is set to the specified output name.

device
     Specify the device to use. Default device is used when not provided. List of output devices can be obtained with command pactl list sinks.

Examples
--------

Play a file on default device on default server:

     ffmpeg  -i INPUT -f pulse "stream name"

sdl
===

SDL (Simple DirectMedia Layer) output device.

This output device allows to show a video stream in an SDL window. Only one SDL window is allowed per application, so you can have only one instance of this output device in an application.

To enable this output device you need libsdl installed on your system when configuring your build.

For more information about SDL, check: http://www.libsdl.org/

Options
-------

window_title
     Set the SDL window title, if not specified default to the filename specified for the output device.

icon_title
     Set the name of the iconified SDL window, if not specified it is set to the same value of WINDOW_TITLE.

window_size
     Set the SDL window size, can be a string of the form WIDTHxHEIGHT or a video size abbreviation. If not specified it defaults to the size of the input video, downscaled according to the aspect ratio.

window_fullscreen
     Set fullscreen mode when non-zero value is provided. Zero is a default.

Examples
--------

The following command shows the ffmpeg output is an SDL window, forcing its size to the qcif format:

     ffmpeg -i INPUT -vcodec rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"

sndio
=====

sndio audio output device.

xv
==

XV (XVideo) output device.

This output device allows to show a video stream in a X Window System window.

Options
-------

display_name
     Specify the hardware display name, which determines the display and communications domain to be used.

     The display name or DISPLAY environment variable can be a string in the format HOSTNAME[:NUMBER[.SCREEN_NUMBER]].

     HOSTNAME specifies the name of the host machine on which the display is physically attached. NUMBER specifies the number of the display server on that host machine. SCREEN_NUMBER specifies the screen to be used on that server.

     If unspecified, it defaults to the value of the DISPLAY environment variable.

     For example, dual-headed:0.1 would specify screen 1 of display 0 on the machine named ``dual-headed''.

     Check the X11 specification for more detailed information about the display name format.

window_size
     Set the created window size, can be a string of the form WIDTHxHEIGHT or a video size abbreviation. If not specified it defaults to the size of the input video.

window_x

window_y
     Set the X and Y window offsets for the created window. They are both set to 0 by default. The values may be ignored by the window manager.

window_title
     Set the window title, if not specified default to the filename specified for the output device.

For more information about XVideo see http://www.x.org/.

Examples
--------

  * Decode, display and encode video input with ffmpeg at the same time:

          ffmpeg -i INPUT OUTPUT -f xv display

  * Decode and display the input video to multiple X11 windows:

          ffmpeg -i INPUT -f xv normal -vf negate -f xv negated