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}.
167 ffmpeg -i test.avi -f decklink -list_devices 1 dummy
171 List supported formats:
173 ffmpeg -i test.avi -f decklink -list_formats 1 'DeckLink Mini Monitor'
179 ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 'DeckLink Mini Monitor'
183 Play video clip with non-standard framerate or video size:
185 ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 -s 720x486 -r 24000/1001 'DeckLink Mini Monitor'
192 Linux framebuffer output device.
194 The Linux framebuffer is a graphic hardware-independent abstraction
195 layer to show graphics on a computer monitor, typically on the
196 console. It is accessed through a file device node, usually
199 For more detailed information read the file
200 @file{Documentation/fb/framebuffer.txt} included in the Linux source tree.
207 Set x/y coordinate of top left corner. Default is 0.
211 Play a file on framebuffer device @file{/dev/fb0}.
212 Required pixel format depends on current framebuffer settings.
214 ffmpeg -re -i INPUT -c:v rawvideo -pix_fmt bgra -f fbdev /dev/fb0
217 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
219 @section libndi_newtek
221 The libndi_newtek output device provides playback capabilities for using NDI (Network
222 Device Interface, standard created by NewTek).
224 Output filename is a NDI name.
226 To enable this output device, you need the NDI SDK and you
227 need to configure with the appropriate @code{--extra-cflags}
228 and @code{--extra-ldflags}.
230 NDI uses uyvy422 pixel format natively, but also supports bgra, bgr0, rgba and
237 @item reference_level
238 The audio reference level in dB. This specifies how many dB above the
239 reference level (+4dBU) is the full range of 16 bit audio.
240 Defaults to @option{0}.
243 These specify whether video "clock" themselves.
244 Defaults to @option{false}.
247 These specify whether audio "clock" themselves.
248 Defaults to @option{false}.
259 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
265 OpenGL output device.
267 To enable this output device you need to configure FFmpeg with @code{--enable-opengl}.
269 This output device allows one to render to OpenGL context.
270 Context may be provided by application or default SDL window is created.
272 When device renders to external context, application must implement handlers for following messages:
273 @code{AV_DEV_TO_APP_CREATE_WINDOW_BUFFER} - create OpenGL context on current thread.
274 @code{AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER} - make OpenGL context current.
275 @code{AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER} - swap buffers.
276 @code{AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER} - destroy OpenGL context.
277 Application is also required to inform a device about current resolution by sending @code{AV_APP_TO_DEV_WINDOW_SIZE} message.
283 Set background color. Black is a default.
285 Disables default SDL window when set to non-zero value.
286 Application must provide OpenGL context and both @code{window_size_cb} and @code{window_swap_buffers_cb} callbacks when set.
288 Set the SDL window title, if not specified default to the filename specified for the output device.
289 Ignored when @option{no_window} is set.
291 Set preferred window size, can be a string of the form widthxheight or a video size abbreviation.
292 If not specified it defaults to the size of the input video, downscaled according to the aspect ratio.
293 Mostly usable when @option{no_window} is not set.
298 Play a file on SDL window using OpenGL rendering:
300 ffmpeg -i INPUT -f opengl "window title"
305 OSS (Open Sound System) output device.
309 PulseAudio output device.
311 To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
313 More information about PulseAudio can be found on @url{http://www.pulseaudio.org}
319 Connect to a specific PulseAudio server, specified by an IP address.
320 Default server is used when not provided.
323 Specify the application name PulseAudio will use when showing active clients,
324 by default it is the @code{LIBAVFORMAT_IDENT} string.
327 Specify the stream name PulseAudio will use when showing active streams,
328 by default it is set to the specified output name.
331 Specify the device to use. Default device is used when not provided.
332 List of output devices can be obtained with command @command{pactl list sinks}.
335 @item buffer_duration
336 Control the size and duration of the PulseAudio buffer. A small buffer
337 gives more control, but requires more frequent updates.
339 @option{buffer_size} specifies size in bytes while
340 @option{buffer_duration} specifies duration in milliseconds.
342 When both options are provided then the highest value is used
343 (duration is recalculated to bytes using stream parameters). If they
344 are set to 0 (which is default), the device will use the default
345 PulseAudio duration value. By default PulseAudio set buffer duration
349 Specify pre-buffering size in bytes. The server does not start with
350 playback before at least @option{prebuf} bytes are available in the
351 buffer. By default this option is initialized to the same value as
352 @option{buffer_size} or @option{buffer_duration} (whichever is bigger).
355 Specify minimum request size in bytes. The server does not request less
356 than @option{minreq} bytes from the client, instead waits until the buffer
357 is free enough to request more bytes at once. It is recommended to not set
358 this option, which will initialize this to a value that is deemed sensible
364 Play a file on default device on default server:
366 ffmpeg -i INPUT -f pulse "stream name"
371 SDL (Simple DirectMedia Layer) output device.
373 This output device allows one to show a video stream in an SDL
374 window. Only one SDL window is allowed per application, so you can
375 have only one instance of this output device in an application.
377 To enable this output device you need libsdl installed on your system
378 when configuring your build.
380 For more information about SDL, check:
381 @url{http://www.libsdl.org/}
388 Set the SDL window title, if not specified default to the filename
389 specified for the output device.
392 Set the name of the iconified SDL window, if not specified it is set
393 to the same value of @var{window_title}.
396 Set the SDL window size, can be a string of the form
397 @var{width}x@var{height} or a video size abbreviation.
398 If not specified it defaults to the size of the input video,
399 downscaled according to the aspect ratio.
403 Set the position of the window on the screen.
405 @item window_fullscreen
406 Set fullscreen mode when non-zero value is provided.
407 Default value is zero.
409 @item window_enable_quit
410 Enable quit action (using window button or keyboard key)
411 when non-zero value is provided.
412 Default value is 1 (enable quit action)
415 @subsection Interactive commands
417 The window created by the device can be controlled through the
418 following interactive commands.
422 Quit the device immediately.
427 The following command shows the @command{ffmpeg} output is an
428 SDL window, forcing its size to the qcif format:
430 ffmpeg -i INPUT -c:v rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"
435 sndio audio output device.
439 Video4Linux2 output device.
443 XV (XVideo) output device.
445 This output device allows one to show a video stream in a X Window System
452 Specify the hardware display name, which determines the display and
453 communications domain to be used.
455 The display name or DISPLAY environment variable can be a string in
456 the format @var{hostname}[:@var{number}[.@var{screen_number}]].
458 @var{hostname} specifies the name of the host machine on which the
459 display is physically attached. @var{number} specifies the number of
460 the display server on that host machine. @var{screen_number} specifies
461 the screen to be used on that server.
463 If unspecified, it defaults to the value of the DISPLAY environment
466 For example, @code{dual-headed:0.1} would specify screen 1 of display
467 0 on the machine named ``dual-headed''.
469 Check the X11 specification for more detailed information about the
473 When set to non-zero value then device doesn't create new window,
474 but uses existing one with provided @var{window_id}. By default
475 this options is set to zero and device creates its own window.
478 Set the created window size, can be a string of the form
479 @var{width}x@var{height} or a video size abbreviation. If not
480 specified it defaults to the size of the input video.
481 Ignored when @var{window_id} is set.
485 Set the X and Y window offsets for the created window. They are both
486 set to 0 by default. The values may be ignored by the window manager.
487 Ignored when @var{window_id} is set.
490 Set the window title, if not specified default to the filename
491 specified for the output device. Ignored when @var{window_id} is set.
494 For more information about XVideo see @url{http://www.x.org/}.
500 Decode, display and encode video input with @command{ffmpeg} at the
503 ffmpeg -i INPUT OUTPUT -f xv display
507 Decode and display the input video to multiple X11 windows:
509 ffmpeg -i INPUT -f xv normal -vf negate -f xv negated
513 @c man end OUTPUT DEVICES