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 Play a file on default ALSA device:
31 ffmpeg -i INPUT -f alsa default
35 Play a file on soundcard 1, audio device 7:
37 ffmpeg -i INPUT -f alsa hw:1,7
45 This output device allows to show a video stream in CACA window.
46 Only one CACA window is allowed per application, so you can
47 have only one instance of this output device in an application.
49 To enable this output device you need to configure FFmpeg with
50 @code{--enable-libcaca}.
51 libcaca is a graphics library that outputs text instead of pixels.
53 For more information about libcaca, check:
54 @url{http://caca.zoy.org/wiki/libcaca}
61 Set the CACA window title, if not specified default to the filename
62 specified for the output device.
65 Set the CACA window size, can be a string of the form
66 @var{width}x@var{height} or a video size abbreviation.
67 If not specified it defaults to the size of the input video.
73 Set dithering algorithm. Dithering is necessary
74 because the picture being rendered has usually far more colours than
75 the available palette.
76 The accepted values are listed with @code{-list_dither algorithms}.
79 Set antialias method. Antialiasing smoothens the rendered
80 image and avoids the commonly seen staircase effect.
81 The accepted values are listed with @code{-list_dither antialiases}.
84 Set which characters are going to be used when rendering text.
85 The accepted values are listed with @code{-list_dither charsets}.
88 Set color to be used when rendering text.
89 The accepted values are listed with @code{-list_dither colors}.
92 If set to @option{true}, print a list of available drivers and exit.
95 List available dither options related to the argument.
96 The argument must be one of @code{algorithms}, @code{antialiases},
97 @code{charsets}, @code{colors}.
104 The following command shows the @command{ffmpeg} output is an
105 CACA window, forcing its size to 80x25:
107 ffmpeg -i INPUT -vcodec rawvideo -pix_fmt rgb24 -window_size 80x25 -f caca -
111 Show the list of available drivers and exit:
113 ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_drivers true -
117 Show the list of available dither colors and exit:
119 ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_dither colors -
125 Linux framebuffer output device.
127 The Linux framebuffer is a graphic hardware-independent abstraction
128 layer to show graphics on a computer monitor, typically on the
129 console. It is accessed through a file device node, usually
132 For more detailed information read the file
133 @file{Documentation/fb/framebuffer.txt} included in the Linux source tree.
140 Set x/y coordinate of top left corner. Default is 0.
144 Play a file on framebuffer device @file{/dev/fb0}.
145 Required pixel format depends on current framebuffer settings.
147 ffmpeg -re -i INPUT -vcodec rawvideo -pix_fmt bgra -f fbdev /dev/fb0
150 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
153 OpenGL output device.
155 To enable this output device you need to configure FFmpeg with @code{--enable-opengl}.
157 Device allows to render to OpenGL context.
158 Context may be provided by application or default SDL window is created.
160 When device renders to external context, application must implement handlers for following messages:
161 @code{AV_CTL_MESSAGE_CREATE_WINDOW_BUFFER} - create OpenGL context on current thread.
162 @code{AV_CTL_MESSAGE_PREPARE_WINDOW_BUFFER} - make OpenGL context current.
163 @code{AV_CTL_MESSAGE_DISPLAY_WINDOW_BUFFER} - swap buffers.
164 @code{AV_CTL_MESSAGE_DESTROY_WINDOW_BUFFER} - destroy OpenGL context.
165 Application is also required to inform a device about current resolution by sending @code{AV_DEVICE_WINDOW_RESIZED} message.
171 Set background color. Black is a default.
173 Disables default SDL window when set to non-zero value.
174 Application must provide OpenGL context and both @code{window_size_cb} and @code{window_swap_buffers_cb} callbacks when set.
176 Set the SDL window title, if not specified default to the filename specified for the output device.
177 Ignored when @option{no_window} is set.
182 Play a file on SDL window using OpenGL rendering:
184 ffmpeg -i INPUT -f opengl "window title"
189 OSS (Open Sound System) output device.
193 PulseAudio output device.
195 To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
197 More information about PulseAudio can be found on @url{http://www.pulseaudio.org}
203 Connect to a specific PulseAudio server, specified by an IP address.
204 Default server is used when not provided.
207 Specify the application name PulseAudio will use when showing active clients,
208 by default it is the @code{LIBAVFORMAT_IDENT} string.
211 Specify the stream name PulseAudio will use when showing active streams,
212 by default it is set to the specified output name.
215 Specify the device to use. Default device is used when not provided.
216 List of output devices can be obtained with command @command{pactl list sinks}.
219 @item buffer_duration
220 Control the size and duration of the PulseAudio buffer. A small buffer
221 gives more control, but requires more frequent updates.
223 @option{buffer_size} specifies size in bytes while
224 @option{buffer_duration} specifies duration in milliseconds.
226 When both options are provided then the highest value is used
227 (duration is recalculated to bytes using stream parameters). If they
228 are set to 0 (which is default), the device will use the default
229 PulseAudio duration value. By default PulseAudio set buffer duration
234 Play a file on default device on default server:
236 ffmpeg -i INPUT -f pulse "stream name"
241 SDL (Simple DirectMedia Layer) output device.
243 This output device allows to show a video stream in an SDL
244 window. Only one SDL window is allowed per application, so you can
245 have only one instance of this output device in an application.
247 To enable this output device you need libsdl installed on your system
248 when configuring your build.
250 For more information about SDL, check:
251 @url{http://www.libsdl.org/}
258 Set the SDL window title, if not specified default to the filename
259 specified for the output device.
262 Set the name of the iconified SDL window, if not specified it is set
263 to the same value of @var{window_title}.
266 Set the SDL window size, can be a string of the form
267 @var{width}x@var{height} or a video size abbreviation.
268 If not specified it defaults to the size of the input video,
269 downscaled according to the aspect ratio.
271 @item window_fullscreen
272 Set fullscreen mode when non-zero value is provided.
273 Default value is zero.
276 @subsection Interactive commands
278 The window created by the device can be controlled through the
279 following interactive commands.
283 Quit the device immediately.
288 The following command shows the @command{ffmpeg} output is an
289 SDL window, forcing its size to the qcif format:
291 ffmpeg -i INPUT -vcodec rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"
296 sndio audio output device.
300 XV (XVideo) output device.
302 This output device allows to show a video stream in a X Window System
309 Specify the hardware display name, which determines the display and
310 communications domain to be used.
312 The display name or DISPLAY environment variable can be a string in
313 the format @var{hostname}[:@var{number}[.@var{screen_number}]].
315 @var{hostname} specifies the name of the host machine on which the
316 display is physically attached. @var{number} specifies the number of
317 the display server on that host machine. @var{screen_number} specifies
318 the screen to be used on that server.
320 If unspecified, it defaults to the value of the DISPLAY environment
323 For example, @code{dual-headed:0.1} would specify screen 1 of display
324 0 on the machine named ``dual-headed''.
326 Check the X11 specification for more detailed information about the
330 Set the created window size, can be a string of the form
331 @var{width}x@var{height} or a video size abbreviation. If not
332 specified it defaults to the size of the input video.
336 Set the X and Y window offsets for the created window. They are both
337 set to 0 by default. The values may be ignored by the window manager.
340 Set the window title, if not specified default to the filename
341 specified for the output device.
344 For more information about XVideo see @url{http://www.x.org/}.
350 Decode, display and encode video input with @command{ffmpeg} at the
353 ffmpeg -i INPUT OUTPUT -f xv display
357 Decode and display the input video to multiple X11 windows:
359 ffmpeg -i INPUT -f xv normal -vf negate -f xv negated
363 @c man end OUTPUT DEVICES