2 @c man begin INPUT DEVICES
4 Input devices are configured elements in FFmpeg which allow to access
5 the data coming from a multimedia device attached to your system.
7 When you configure your FFmpeg build, all the supported input devices
8 are enabled by default. You can list all available ones using the
9 configure option "--list-indevs".
11 You can disable all the input devices using the configure option
12 "--disable-indevs", and selectively enable an input device using the
13 option "--enable-indev=@var{INDEV}", or you can disable a particular
14 input device using the option "--disable-indev=@var{INDEV}".
16 The option "-formats" of the ff* tools will display the list of
17 supported input devices (amongst the demuxers).
19 A description of the currently available input devices follows.
23 ALSA (Advanced Linux Sound Architecture) input device.
25 To enable this input device during configuration you need libasound
26 installed on your system.
28 This device allows capturing from an ALSA device. The name of the
29 device to capture has to be an ALSA card identifier.
31 An ALSA identifier has the syntax:
33 hw:@var{CARD}[,@var{DEV}[,@var{SUBDEV}]]
36 where the @var{DEV} and @var{SUBDEV} components are optional.
38 The three arguments (in order: @var{CARD},@var{DEV},@var{SUBDEV})
39 specify card number or identifier, device number and subdevice number
42 To see the list of cards currently recognized by your system check the
43 files @file{/proc/asound/cards} and @file{/proc/asound/devices}.
45 For example to capture with @file{ffmpeg} from an ALSA device with
46 card id 0, you may run the command:
48 ffmpeg -f alsa -i hw:0 alsaout.wav
51 For more information see:
52 @url{http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html}
56 BSD video input device.
60 Windows DirectShow input device.
62 DirectShow support is enabled when FFmpeg is built with mingw-w64.
63 Currently only audio and video devices are supported.
65 Multiple devices may be opened as separate inputs, but they may also be
66 opened on the same input, which should improve synchronism between them.
68 The input name should be in the format:
71 @var{TYPE}=@var{NAME}[:@var{TYPE}=@var{NAME}]
74 where @var{TYPE} can be either @var{audio} or @var{video},
75 and @var{NAME} is the device's name.
79 If no options are specified, the device's defaults are used.
80 If the device does not support the requested options, it will
86 Set the video size in the captured video.
89 Set the framerate in the captured video.
92 Set the sample rate (in Hz) of the captured audio.
95 Set the sample size (in bits) of the captured audio.
98 Set the number of channels in the captured audio.
101 If set to @option{true}, print a list of devices and exit.
104 If set to @option{true}, print a list of selected device's options
114 Print the list of DirectShow supported devices and exit:
116 $ ffmpeg -list_devices true -f dshow -i dummy
120 Open video device @var{Camera}:
122 $ ffmpeg -f dshow -i video="Camera"
126 Open video device @var{Camera} and audio device @var{Microphone}:
128 $ ffmpeg -f dshow -i video="Camera":audio="Microphone"
132 Print the list of supported options in selected device and exit:
134 $ ffmpeg -list_options true -f dshow -i video="Camera"
141 Linux DV 1394 input device.
145 Linux framebuffer input device.
147 The Linux framebuffer is a graphic hardware-independent abstraction
148 layer to show graphics on a computer monitor, typically on the
149 console. It is accessed through a file device node, usually
152 For more detailed information read the file
153 Documentation/fb/framebuffer.txt included in the Linux source tree.
155 To record from the framebuffer device @file{/dev/fb0} with
158 ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
161 You can take a single screenshot image with the command:
163 ffmpeg -f fbdev -vframes 1 -r 1 -i /dev/fb0 screenshot.jpeg
166 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
172 To enable this input device during configuration you need libjack
173 installed on your system.
175 A JACK input device creates one or more JACK writable clients, one for
176 each audio channel, with name @var{client_name}:input_@var{N}, where
177 @var{client_name} is the name provided by the application, and @var{N}
178 is a number which identifies the channel.
179 Each writable client will send the acquired data to the FFmpeg input
182 Once you have created one or more JACK readable clients, you need to
183 connect them to one or more JACK writable clients.
185 To connect or disconnect JACK clients you can use the
186 @file{jack_connect} and @file{jack_disconnect} programs, or do it
187 through a graphical interface, for example with @file{qjackctl}.
189 To list the JACK clients and their properties you can invoke the command
192 Follows an example which shows how to capture a JACK readable client
195 # Create a JACK writable client with name "ffmpeg".
196 $ ffmpeg -f jack -i ffmpeg -y out.wav
198 # Start the sample jack_metro readable client.
199 $ jack_metro -b 120 -d 0.2 -f 4000
201 # List the current JACK clients.
210 # Connect metro to the ffmpeg writable client.
211 $ jack_connect metro:120_bpm ffmpeg:input_1
214 For more information read:
215 @url{http://jackaudio.org/}
219 Libavfilter input virtual device.
221 This input device reads data from the open output pads of a libavfilter
224 For each filtergraph open output, the input device will create a
225 corresponding stream which is mapped to the generated output. Currently
226 only video data is supported. The filtergraph is specified through the
227 option @option{graph}.
234 Specify the filtergraph to use as input. Each video open output must be
235 labelled by a unique string of the form "out@var{N}", where @var{N} is a
236 number starting from 0 corresponding to the mapped input stream
237 generated by the device.
238 The first unlabelled output is automatically assigned to the "out0"
239 label, but all the others need to be specified explicitely.
241 If not specified defaults to the filename specified for the input
249 Create a color video stream and play it back with @file{ffplay}:
251 ffplay -f lavfi -graph "color=pink [out0]" dummy
255 As the previous example, but use filename for specifying the graph
256 description, and omit the "out0" label:
258 ffplay -f lavfi color=pink
262 Create three different video test filtered sources and play them:
264 ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
268 Read an audio stream from a file using the amovie source and play it
269 back with @file{ffplay}:
271 ffplay -f lavfi "amovie=test.wav"
275 Read an audio stream and a video stream and play it back with
278 ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
285 IIDC1394 input device, based on libdc1394 and libraw1394.
289 The OpenAL input device provides audio capture on all systems with a
290 working OpenAL 1.1 implementation.
292 To enable this input device during configuration, you need OpenAL
293 headers and libraries installed on your system, and need to configure
294 FFmpeg with @code{--enable-openal}.
296 OpenAL headers and libraries should be provided as part of your OpenAL
297 implementation, or as an additional download (an SDK). Depending on your
298 installation you may need to specify additional flags via the
299 @code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
300 system to locate the OpenAL headers and libraries.
302 An incomplete list of OpenAL implementations follows:
306 The official Windows implementation, providing hardware acceleration
307 with supported devices and software fallback.
308 See @url{http://openal.org/}.
310 Portable, open source (LGPL) software implementation. Includes
311 backends for the most common sound APIs on the Windows, Linux,
312 Solaris, and BSD operating systems.
313 See @url{http://kcat.strangesoft.net/openal.html}.
315 OpenAL is part of Core Audio, the official Mac OS X Audio interface.
316 See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
319 This device allows to capture from an audio input device handled
322 You need to specify the name of the device to capture in the provided
323 filename. If the empty string is provided, the device will
324 automatically select the default device. You can get the list of the
325 supported devices by using the option @var{list_devices}.
332 Set the number of channels in the captured audio. Only the values
333 @option{1} (monaural) and @option{2} (stereo) are currently supported.
334 Defaults to @option{2}.
337 Set the sample size (in bits) of the captured audio. Only the values
338 @option{8} and @option{16} are currently supported. Defaults to
342 Set the sample rate (in Hz) of the captured audio.
343 Defaults to @option{44.1k}.
346 If set to @option{true}, print a list of devices and exit.
347 Defaults to @option{false}.
353 Print the list of OpenAL supported devices and exit:
355 $ ffmpeg -list_devices true -f openal -i dummy out.ogg
358 Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
360 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
363 Capture from the default device (note the empty string '' as filename):
365 $ ffmpeg -f openal -i '' out.ogg
368 Capture from two devices simultaneously, writing to two different files,
369 within the same @file{ffmpeg} command:
371 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
373 Note: not all OpenAL implementations support multiple simultaneous capture -
374 try the latest OpenAL Soft if the above does not work.
378 Open Sound System input device.
380 The filename to provide to the input device is the device node
381 representing the OSS input device, and is usually set to
384 For example to grab from @file{/dev/dsp} using @file{ffmpeg} use the
387 ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
390 For more information about OSS see:
391 @url{http://manuals.opensound.com/usersguide/dsp.html}
395 pulseaudio input device.
397 To enable this input device during configuration you need libpulse-simple
398 installed in your system.
400 The filename to provide to the input device is a source device or the
403 To list the pulse source devices and their properties you can invoke
404 the command @file{pactl list sources}.
407 avconv -f pulse -i default /tmp/pulse.wav
410 @subsection @var{server} AVOption
414 -server @var{server name}
417 Connects to a specific server.
419 @subsection @var{name} AVOption
423 -name @var{application name}
426 Specify the application name pulse will use when showing active clients,
427 by default it is "libav"
429 @subsection @var{stream_name} AVOption
433 -stream_name @var{stream name}
436 Specify the stream name pulse will use when showing active streams,
437 by default it is "record"
439 @subsection @var{sample_rate} AVOption
443 -sample_rate @var{samplerate}
446 Specify the samplerate in Hz, by default 48kHz is used.
448 @subsection @var{channels} AVOption
455 Specify the channels in use, by default 2 (stereo) is set.
457 @subsection @var{frame_size} AVOption
461 -frame_size @var{bytes}
464 Specify the number of byte per frame, by default it is set to 1024.
466 @subsection @var{fragment_size} AVOption
470 -fragment_size @var{bytes}
473 Specify the minimal buffering fragment in pulseaudio, it will affect the
474 audio latency. By default it is unset.
480 To enable this input device during configuration you need libsndio
481 installed on your system.
483 The filename to provide to the input device is the device node
484 representing the sndio input device, and is usually set to
487 For example to grab from @file{/dev/audio0} using @file{ffmpeg} use the
490 ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
493 @section video4linux and video4linux2
495 Video4Linux and Video4Linux2 input video devices.
497 The name of the device to grab is a file device node, usually Linux
498 systems tend to automatically create such nodes when the device
499 (e.g. an USB webcam) is plugged into the system, and has a name of the
500 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
503 Video4Linux and Video4Linux2 devices only support a limited set of
504 @var{width}x@var{height} sizes and framerates. You can check which are
505 supported for example with the command @file{dov4l} for Video4Linux
506 devices and the command @file{v4l-info} for Video4Linux2 devices.
508 If the size for the device is set to 0x0, the input device will
509 try to autodetect the size to use.
510 Only for the video4linux2 device, if the frame rate is set to 0/0 the
511 input device will use the frame rate value already set in the driver.
513 Video4Linux support is deprecated since Linux 2.6.30, and will be
514 dropped in later versions.
516 Follow some usage examples of the video4linux devices with the ff*
519 # Grab and show the input of a video4linux device, frame rate is set
520 # to the default of 25/1.
521 ffplay -s 320x240 -f video4linux /dev/video0
523 # Grab and show the input of a video4linux2 device, autoadjust size.
524 ffplay -f video4linux2 /dev/video0
526 # Grab and record the input of a video4linux2 device, autoadjust size,
527 # frame rate value defaults to 0/0 so it is read from the video4linux2
529 ffmpeg -f video4linux2 -i /dev/video0 out.mpeg
534 VfW (Video for Windows) capture input device.
536 The filename passed as input is the capture driver number, ranging from
537 0 to 9. You may use "list" as filename to print a list of drivers. Any
538 other filename will be interpreted as device number 0.
542 X11 video input device.
544 This device allows to capture a region of an X11 display.
546 The filename passed as input has the syntax:
548 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
551 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
552 X11 display name of the screen to grab from. @var{hostname} can be
553 ommitted, and defaults to "localhost". The environment variable
554 @env{DISPLAY} contains the default display name.
556 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
557 area with respect to the top-left border of the X11 screen. They
560 Check the X11 documentation (e.g. man X) for more detailed information.
562 Use the @file{dpyinfo} program for getting basic information about the
563 properties of your X11 display (e.g. grep for "name" or "dimensions").
565 For example to grab from @file{:0.0} using @file{ffmpeg}:
567 ffmpeg -f x11grab -r 25 -s cif -i :0.0 out.mpg
569 # Grab at position 10,20.
570 ffmpeg -f x11grab -r 25 -s cif -i :0.0+10,20 out.mpg
573 @subsection @var{follow_mouse} AVOption
577 -follow_mouse centered|@var{PIXELS}
580 When it is specified with "centered", the grabbing region follows the mouse
581 pointer and keeps the pointer at the center of region; otherwise, the region
582 follows only when the mouse pointer reaches within @var{PIXELS} (greater than
583 zero) to the edge of region.
587 ffmpeg -f x11grab -follow_mouse centered -r 25 -s cif -i :0.0 out.mpg
589 # Follows only when the mouse pointer reaches within 100 pixels to edge
590 ffmpeg -f x11grab -follow_mouse 100 -r 25 -s cif -i :0.0 out.mpg
593 @subsection @var{show_region} AVOption
600 If @var{show_region} AVOption is specified with @var{1}, then the grabbing
601 region will be indicated on screen. With this option, it's easy to know what is
602 being grabbed if only a portion of the screen is grabbed.
606 ffmpeg -f x11grab -show_region 1 -r 25 -s cif -i :0.0+10,20 out.mpg
609 ffmpeg -f x11grab -follow_mouse centered -show_region 1 -r 25 -s cif -i :0.0 out.mpg
612 @c man end INPUT DEVICES