1 @chapter Output Devices
2 @c man begin OUTPUT DEVICES
4 Output devices are configured elements in FFmpeg that can write
5 multimedia data to an output device attached to your system.
7 When you configure your FFmpeg build, all the supported output devices
8 are enabled by default. You can list all available ones using the
9 configure option "--list-outdevs".
11 You can disable all the output devices using the configure option
12 "--disable-outdevs", and selectively enable an output device using the
13 option "--enable-outdev=@var{OUTDEV}", or you can disable a particular
14 input device using the option "--disable-outdev=@var{OUTDEV}".
16 The option "-formats" of the ff* tools will display the list of
17 enabled output devices (amongst the muxers).
19 A description of the currently available output devices follows.
23 ALSA (Advanced Linux Sound Architecture) output device.
29 This output device allows to show a video stream in CACA window.
30 Only one CACA window is allowed per application, so you can
31 have only one instance of this output device in an application.
33 To enable this output device you need to configure FFmpeg with
34 @code{--enable-libcaca}.
35 libcaca is a graphics library that outputs text instead of pixels.
37 For more information about libcaca, check:
38 @url{http://caca.zoy.org/wiki/libcaca}
45 Set the CACA window title, if not specified default to the filename
46 specified for the output device.
49 Set the CACA window size, can be a string of the form
50 @var{width}x@var{height} or a video size abbreviation.
51 If not specified it defaults to the size of the input video.
57 Set dithering algorithm. Dithering is necessary
58 because the picture being rendered has usually far more colours than
59 the available palette.
60 The accepted values are listed with @code{-list_dither algorithms}.
63 Set antialias method. Antialiasing smoothens the rendered
64 image and avoids the commonly seen staircase effect.
65 The accepted values are listed with @code{-list_dither antialiases}.
68 Set which characters are going to be used when rendering text.
69 The accepted values are listed with @code{-list_dither charsets}.
72 Set color to be used when rendering text.
73 The accepted values are listed with @code{-list_dither colors}.
76 If set to @option{true}, print a list of available drivers and exit.
79 List available dither options related to the argument.
80 The argument must be one of @code{algorithms}, @code{antialiases},
81 @code{charsets}, @code{colors}.
88 The following command shows the @command{ffmpeg} output is an
89 CACA window, forcing its size to 80x25:
91 ffmpeg -i INPUT -vcodec rawvideo -pix_fmt rgb24 -window_size 80x25 -f caca -
95 Show the list of available drivers and exit:
97 ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_drivers true -
101 Show the list of available dither colors and exit:
103 ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_dither colors -
109 Linux framebuffer output device.
111 The Linux framebuffer is a graphic hardware-independent abstraction
112 layer to show graphics on a computer monitor, typically on the
113 console. It is accessed through a file device node, usually
116 For more detailed information read the file
117 @file{Documentation/fb/framebuffer.txt} included in the Linux source tree.
124 Set x/y coordinate of top left corner. Default is 0.
128 Play a file on framebuffer device @file{/dev/fb0}.
129 Required pixel format depends on current framebuffer settings.
131 ffmpeg -re -i INPUT -vcodec rawvideo -pix_fmt bgra -f fbdev /dev/fb0
134 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
138 OSS (Open Sound System) output device.
142 PulseAudio output device.
144 To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
146 More information about PulseAudio can be found on @url{http://www.pulseaudio.org}
152 Connect to a specific PulseAudio server, specified by an IP address.
153 Default server is used when not provided.
156 Specify the application name PulseAudio will use when showing active clients,
157 by default it is the @code{LIBAVFORMAT_IDENT} string.
160 Specify the stream name PulseAudio will use when showing active streams,
161 by default it is set to the specified output name.
164 Specify the device to use. Default device is used when not provided.
165 List of output devices can be obtained with command @command{pactl list sinks}.
168 @item buffer_duration
169 Control the size and duration of the PulseAudio buffer. A small buffer
170 gives more control, but requires more frequent updates.
172 @option{buffer_size} specifies size in bytes while
173 @option{buffer_duration} specifies duration in milliseconds.
175 When both options are provided then the highest value is used
176 (duration is recalculated to bytes using stream parameters). If they
177 are set to 0 (which is default), the device will use the default
178 PulseAudio duration value. By default PulseAudio set buffer duration
183 Play a file on default device on default server:
185 ffmpeg -i INPUT -f pulse "stream name"
190 SDL (Simple DirectMedia Layer) output device.
192 This output device allows to show a video stream in an SDL
193 window. Only one SDL window is allowed per application, so you can
194 have only one instance of this output device in an application.
196 To enable this output device you need libsdl installed on your system
197 when configuring your build.
199 For more information about SDL, check:
200 @url{http://www.libsdl.org/}
207 Set the SDL window title, if not specified default to the filename
208 specified for the output device.
211 Set the name of the iconified SDL window, if not specified it is set
212 to the same value of @var{window_title}.
215 Set the SDL window size, can be a string of the form
216 @var{width}x@var{height} or a video size abbreviation.
217 If not specified it defaults to the size of the input video,
218 downscaled according to the aspect ratio.
220 @item window_fullscreen
221 Set fullscreen mode when non-zero value is provided.
222 Default value is zero.
225 @subsection Interactive commands
227 The window created by the device can be controlled through the
228 following interactive commands.
232 Quit the device immediately.
237 The following command shows the @command{ffmpeg} output is an
238 SDL window, forcing its size to the qcif format:
240 ffmpeg -i INPUT -vcodec rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"
245 sndio audio output device.
249 XV (XVideo) output device.
251 This output device allows to show a video stream in a X Window System
258 Specify the hardware display name, which determines the display and
259 communications domain to be used.
261 The display name or DISPLAY environment variable can be a string in
262 the format @var{hostname}[:@var{number}[.@var{screen_number}]].
264 @var{hostname} specifies the name of the host machine on which the
265 display is physically attached. @var{number} specifies the number of
266 the display server on that host machine. @var{screen_number} specifies
267 the screen to be used on that server.
269 If unspecified, it defaults to the value of the DISPLAY environment
272 For example, @code{dual-headed:0.1} would specify screen 1 of display
273 0 on the machine named ``dual-headed''.
275 Check the X11 specification for more detailed information about the
279 Set the created window size, can be a string of the form
280 @var{width}x@var{height} or a video size abbreviation. If not
281 specified it defaults to the size of the input video.
285 Set the X and Y window offsets for the created window. They are both
286 set to 0 by default. The values may be ignored by the window manager.
289 Set the window title, if not specified default to the filename
290 specified for the output device.
293 For more information about XVideo see @url{http://www.x.org/}.
299 Decode, display and encode video input with @command{ffmpeg} at the
302 ffmpeg -i INPUT OUTPUT -f xv display
306 Decode and display the input video to multiple X11 windows:
308 ffmpeg -i INPUT -f xv normal -vf negate -f xv negated
312 @c man end OUTPUT DEVICES