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 "-devices" of the ff* tools will display the list of
17 enabled output devices.
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 one 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 -c:v 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 The decklink output device provides playback capabilities for Blackmagic
128 To enable this output device, you need the Blackmagic DeckLink SDK and you
129 need to configure with the appropriate @code{--extra-cflags}
130 and @code{--extra-ldflags}.
131 On Windows, you need to run the IDL files through @command{widl}.
133 DeckLink is very picky about the formats it supports. Pixel format is always
134 uyvy422, framerate, field order and video size must be determined for your
135 device with @command{-list_formats 1}. Audio sample rate is always 48 kHz.
142 If set to @option{true}, print a list of devices and exit.
143 Defaults to @option{false}. Alternatively you can use the @code{-sinks}
144 option of ffmpeg to list the available output devices.
147 If set to @option{true}, print a list of supported formats and exit.
148 Defaults to @option{false}.
151 Amount of time to preroll video in seconds.
152 Defaults to @option{0.5}.
155 Sets the decklink device duplex mode. Must be @samp{unset}, @samp{half} or @samp{full}.
156 Defaults to @samp{unset}.
159 Sets the genlock timing pixel offset on the used output.
160 Defaults to @samp{unset}.
171 ffmpeg -i test.avi -f decklink -list_devices 1 dummy
175 List supported formats:
177 ffmpeg -i test.avi -f decklink -list_formats 1 'DeckLink Mini Monitor'
183 ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 'DeckLink Mini Monitor'
187 Play video clip with non-standard framerate or video size:
189 ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 -s 720x486 -r 24000/1001 'DeckLink Mini Monitor'
196 Linux framebuffer output device.
198 The Linux framebuffer is a graphic hardware-independent abstraction
199 layer to show graphics on a computer monitor, typically on the
200 console. It is accessed through a file device node, usually
203 For more detailed information read the file
204 @file{Documentation/fb/framebuffer.txt} included in the Linux source tree.
211 Set x/y coordinate of top left corner. Default is 0.
215 Play a file on framebuffer device @file{/dev/fb0}.
216 Required pixel format depends on current framebuffer settings.
218 ffmpeg -re -i INPUT -c:v rawvideo -pix_fmt bgra -f fbdev /dev/fb0
221 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
223 @section libndi_newtek
225 The libndi_newtek output device provides playback capabilities for using NDI (Network
226 Device Interface, standard created by NewTek).
228 Output filename is a NDI name.
230 To enable this output device, you need the NDI SDK and you
231 need to configure with the appropriate @code{--extra-cflags}
232 and @code{--extra-ldflags}.
234 NDI uses uyvy422 pixel format natively, but also supports bgra, bgr0, rgba and
241 @item reference_level
242 The audio reference level in dB. This specifies how many dB above the
243 reference level (+4dBU) is the full range of 16 bit audio.
244 Defaults to @option{0}.
247 These specify whether video "clock" themselves.
248 Defaults to @option{false}.
251 These specify whether audio "clock" themselves.
252 Defaults to @option{false}.
263 ffmpeg -i "udp://@@239.1.1.1:10480?fifo_size=1000000&overrun_nonfatal=1" -vf "scale=720:576,fps=fps=25,setdar=dar=16/9,format=pix_fmts=uyvy422" -f libndi_newtek NEW_NDI1
269 OpenGL output device.
271 To enable this output device you need to configure FFmpeg with @code{--enable-opengl}.
273 This output device allows one to render to OpenGL context.
274 Context may be provided by application or default SDL window is created.
276 When device renders to external context, application must implement handlers for following messages:
277 @code{AV_DEV_TO_APP_CREATE_WINDOW_BUFFER} - create OpenGL context on current thread.
278 @code{AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER} - make OpenGL context current.
279 @code{AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER} - swap buffers.
280 @code{AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER} - destroy OpenGL context.
281 Application is also required to inform a device about current resolution by sending @code{AV_APP_TO_DEV_WINDOW_SIZE} message.
287 Set background color. Black is a default.
289 Disables default SDL window when set to non-zero value.
290 Application must provide OpenGL context and both @code{window_size_cb} and @code{window_swap_buffers_cb} callbacks when set.
292 Set the SDL window title, if not specified default to the filename specified for the output device.
293 Ignored when @option{no_window} is set.
295 Set preferred window size, can be a string of the form widthxheight or a video size abbreviation.
296 If not specified it defaults to the size of the input video, downscaled according to the aspect ratio.
297 Mostly usable when @option{no_window} is not set.
302 Play a file on SDL window using OpenGL rendering:
304 ffmpeg -i INPUT -f opengl "window title"
309 OSS (Open Sound System) output device.
313 PulseAudio output device.
315 To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
317 More information about PulseAudio can be found on @url{http://www.pulseaudio.org}
323 Connect to a specific PulseAudio server, specified by an IP address.
324 Default server is used when not provided.
327 Specify the application name PulseAudio will use when showing active clients,
328 by default it is the @code{LIBAVFORMAT_IDENT} string.
331 Specify the stream name PulseAudio will use when showing active streams,
332 by default it is set to the specified output name.
335 Specify the device to use. Default device is used when not provided.
336 List of output devices can be obtained with command @command{pactl list sinks}.
339 @item buffer_duration
340 Control the size and duration of the PulseAudio buffer. A small buffer
341 gives more control, but requires more frequent updates.
343 @option{buffer_size} specifies size in bytes while
344 @option{buffer_duration} specifies duration in milliseconds.
346 When both options are provided then the highest value is used
347 (duration is recalculated to bytes using stream parameters). If they
348 are set to 0 (which is default), the device will use the default
349 PulseAudio duration value. By default PulseAudio set buffer duration
353 Specify pre-buffering size in bytes. The server does not start with
354 playback before at least @option{prebuf} bytes are available in the
355 buffer. By default this option is initialized to the same value as
356 @option{buffer_size} or @option{buffer_duration} (whichever is bigger).
359 Specify minimum request size in bytes. The server does not request less
360 than @option{minreq} bytes from the client, instead waits until the buffer
361 is free enough to request more bytes at once. It is recommended to not set
362 this option, which will initialize this to a value that is deemed sensible
368 Play a file on default device on default server:
370 ffmpeg -i INPUT -f pulse "stream name"
375 SDL (Simple DirectMedia Layer) output device.
377 This output device allows one to show a video stream in an SDL
378 window. Only one SDL window is allowed per application, so you can
379 have only one instance of this output device in an application.
381 To enable this output device you need libsdl installed on your system
382 when configuring your build.
384 For more information about SDL, check:
385 @url{http://www.libsdl.org/}
392 Set the SDL window title, if not specified default to the filename
393 specified for the output device.
396 Set the name of the iconified SDL window, if not specified it is set
397 to the same value of @var{window_title}.
400 Set the SDL window size, can be a string of the form
401 @var{width}x@var{height} or a video size abbreviation.
402 If not specified it defaults to the size of the input video,
403 downscaled according to the aspect ratio.
407 Set the position of the window on the screen.
409 @item window_fullscreen
410 Set fullscreen mode when non-zero value is provided.
411 Default value is zero.
413 @item window_enable_quit
414 Enable quit action (using window button or keyboard key)
415 when non-zero value is provided.
416 Default value is 1 (enable quit action)
419 @subsection Interactive commands
421 The window created by the device can be controlled through the
422 following interactive commands.
426 Quit the device immediately.
431 The following command shows the @command{ffmpeg} output is an
432 SDL window, forcing its size to the qcif format:
434 ffmpeg -i INPUT -c:v rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"
439 sndio audio output device.
443 Video4Linux2 output device.
447 XV (XVideo) output device.
449 This output device allows one to show a video stream in a X Window System
456 Specify the hardware display name, which determines the display and
457 communications domain to be used.
459 The display name or DISPLAY environment variable can be a string in
460 the format @var{hostname}[:@var{number}[.@var{screen_number}]].
462 @var{hostname} specifies the name of the host machine on which the
463 display is physically attached. @var{number} specifies the number of
464 the display server on that host machine. @var{screen_number} specifies
465 the screen to be used on that server.
467 If unspecified, it defaults to the value of the DISPLAY environment
470 For example, @code{dual-headed:0.1} would specify screen 1 of display
471 0 on the machine named ``dual-headed''.
473 Check the X11 specification for more detailed information about the
477 When set to non-zero value then device doesn't create new window,
478 but uses existing one with provided @var{window_id}. By default
479 this options is set to zero and device creates its own window.
482 Set the created window size, can be a string of the form
483 @var{width}x@var{height} or a video size abbreviation. If not
484 specified it defaults to the size of the input video.
485 Ignored when @var{window_id} is set.
489 Set the X and Y window offsets for the created window. They are both
490 set to 0 by default. The values may be ignored by the window manager.
491 Ignored when @var{window_id} is set.
494 Set the window title, if not specified default to the filename
495 specified for the output device. Ignored when @var{window_id} is set.
498 For more information about XVideo see @url{http://www.x.org/}.
504 Decode, display and encode video input with @command{ffmpeg} at the
507 ffmpeg -i INPUT OUTPUT -f xv display
511 Decode and display the input video to multiple X11 windows:
513 ffmpeg -i INPUT -f xv normal -vf negate -f xv negated
517 @c man end OUTPUT DEVICES