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 @command{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 the mingw-w64 project.
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
107 @item video_device_number
108 Set video device number for devices with same name (starts at 0,
111 @item audio_device_number
112 Set audio device number for devices with same name (starts at 0,
116 Select pixel format to be used by DirectShow. This may only be set when
117 the video codec is not set or set to rawvideo.
119 @item audio_buffer_size
120 Set audio device buffer size in milliseconds (which can directly
121 impact latency, depending on the device).
122 Defaults to using the audio device's
123 default buffer size (typically some multiple of 500ms).
124 Setting this value too low can degrade performance.
126 @url{http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx}
135 Print the list of DirectShow supported devices and exit:
137 $ ffmpeg -list_devices true -f dshow -i dummy
141 Open video device @var{Camera}:
143 $ ffmpeg -f dshow -i video="Camera"
147 Open second video device with name @var{Camera}:
149 $ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
153 Open video device @var{Camera} and audio device @var{Microphone}:
155 $ ffmpeg -f dshow -i video="Camera":audio="Microphone"
159 Print the list of supported options in selected device and exit:
161 $ ffmpeg -list_options true -f dshow -i video="Camera"
168 Linux DV 1394 input device.
172 Linux framebuffer input device.
174 The Linux framebuffer is a graphic hardware-independent abstraction
175 layer to show graphics on a computer monitor, typically on the
176 console. It is accessed through a file device node, usually
179 For more detailed information read the file
180 Documentation/fb/framebuffer.txt included in the Linux source tree.
182 To record from the framebuffer device @file{/dev/fb0} with
185 ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
188 You can take a single screenshot image with the command:
190 ffmpeg -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
193 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
197 FireWire DV/HDV input device using libiec61883.
199 To enable this input device, you need libiec61883, libraw1394 and
200 libavc1394 installed on your system. Use the configure option
201 @code{--enable-libiec61883} to compile with the device enabled.
203 The iec61883 capture device supports capturing from a video device
204 connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
205 FireWire stack (juju). This is the default DV/HDV input method in Linux
206 Kernel 2.6.37 and later, since the old FireWire stack was removed.
208 Specify the FireWire port to be used as input file, or "auto"
209 to choose the first port connected.
216 Override autodetection of DV/HDV. This should only be used if auto
217 detection does not work, or if usage of a different device type
218 should be prohibited. Treating a DV device as HDV (or vice versa) will
219 not work and result in undefined behavior.
220 The values @option{auto}, @option{dv} and @option{hdv} are supported.
223 Set maxiumum size of buffer for incoming data, in frames. For DV, this
224 is an exact value. For HDV, it is not frame exact, since HDV does
225 not have a fixed frame size.
234 Grab and show the input of a FireWire DV/HDV device.
236 ffplay -f iec61883 -i auto
240 Grab and record the input of a FireWire DV/HDV device,
241 using a packet buffer of 100000 packets if the source is HDV.
243 ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
252 To enable this input device during configuration you need libjack
253 installed on your system.
255 A JACK input device creates one or more JACK writable clients, one for
256 each audio channel, with name @var{client_name}:input_@var{N}, where
257 @var{client_name} is the name provided by the application, and @var{N}
258 is a number which identifies the channel.
259 Each writable client will send the acquired data to the FFmpeg input
262 Once you have created one or more JACK readable clients, you need to
263 connect them to one or more JACK writable clients.
265 To connect or disconnect JACK clients you can use the @command{jack_connect}
266 and @command{jack_disconnect} programs, or do it through a graphical interface,
267 for example with @command{qjackctl}.
269 To list the JACK clients and their properties you can invoke the command
272 Follows an example which shows how to capture a JACK readable client
273 with @command{ffmpeg}.
275 # Create a JACK writable client with name "ffmpeg".
276 $ ffmpeg -f jack -i ffmpeg -y out.wav
278 # Start the sample jack_metro readable client.
279 $ jack_metro -b 120 -d 0.2 -f 4000
281 # List the current JACK clients.
290 # Connect metro to the ffmpeg writable client.
291 $ jack_connect metro:120_bpm ffmpeg:input_1
294 For more information read:
295 @url{http://jackaudio.org/}
299 Libavfilter input virtual device.
301 This input device reads data from the open output pads of a libavfilter
304 For each filtergraph open output, the input device will create a
305 corresponding stream which is mapped to the generated output. Currently
306 only video data is supported. The filtergraph is specified through the
307 option @option{graph}.
314 Specify the filtergraph to use as input. Each video open output must be
315 labelled by a unique string of the form "out@var{N}", where @var{N} is a
316 number starting from 0 corresponding to the mapped input stream
317 generated by the device.
318 The first unlabelled output is automatically assigned to the "out0"
319 label, but all the others need to be specified explicitly.
321 If not specified defaults to the filename specified for the input
329 Create a color video stream and play it back with @command{ffplay}:
331 ffplay -f lavfi -graph "color=pink [out0]" dummy
335 As the previous example, but use filename for specifying the graph
336 description, and omit the "out0" label:
338 ffplay -f lavfi color=pink
342 Create three different video test filtered sources and play them:
344 ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
348 Read an audio stream from a file using the amovie source and play it
349 back with @command{ffplay}:
351 ffplay -f lavfi "amovie=test.wav"
355 Read an audio stream and a video stream and play it back with
358 ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
365 IIDC1394 input device, based on libdc1394 and libraw1394.
369 The OpenAL input device provides audio capture on all systems with a
370 working OpenAL 1.1 implementation.
372 To enable this input device during configuration, you need OpenAL
373 headers and libraries installed on your system, and need to configure
374 FFmpeg with @code{--enable-openal}.
376 OpenAL headers and libraries should be provided as part of your OpenAL
377 implementation, or as an additional download (an SDK). Depending on your
378 installation you may need to specify additional flags via the
379 @code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
380 system to locate the OpenAL headers and libraries.
382 An incomplete list of OpenAL implementations follows:
386 The official Windows implementation, providing hardware acceleration
387 with supported devices and software fallback.
388 See @url{http://openal.org/}.
390 Portable, open source (LGPL) software implementation. Includes
391 backends for the most common sound APIs on the Windows, Linux,
392 Solaris, and BSD operating systems.
393 See @url{http://kcat.strangesoft.net/openal.html}.
395 OpenAL is part of Core Audio, the official Mac OS X Audio interface.
396 See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
399 This device allows to capture from an audio input device handled
402 You need to specify the name of the device to capture in the provided
403 filename. If the empty string is provided, the device will
404 automatically select the default device. You can get the list of the
405 supported devices by using the option @var{list_devices}.
412 Set the number of channels in the captured audio. Only the values
413 @option{1} (monaural) and @option{2} (stereo) are currently supported.
414 Defaults to @option{2}.
417 Set the sample size (in bits) of the captured audio. Only the values
418 @option{8} and @option{16} are currently supported. Defaults to
422 Set the sample rate (in Hz) of the captured audio.
423 Defaults to @option{44.1k}.
426 If set to @option{true}, print a list of devices and exit.
427 Defaults to @option{false}.
433 Print the list of OpenAL supported devices and exit:
435 $ ffmpeg -list_devices true -f openal -i dummy out.ogg
438 Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
440 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
443 Capture from the default device (note the empty string '' as filename):
445 $ ffmpeg -f openal -i '' out.ogg
448 Capture from two devices simultaneously, writing to two different files,
449 within the same @command{ffmpeg} command:
451 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
453 Note: not all OpenAL implementations support multiple simultaneous capture -
454 try the latest OpenAL Soft if the above does not work.
458 Open Sound System input device.
460 The filename to provide to the input device is the device node
461 representing the OSS input device, and is usually set to
464 For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the
467 ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
470 For more information about OSS see:
471 @url{http://manuals.opensound.com/usersguide/dsp.html}
475 pulseaudio input device.
477 To enable this input device during configuration you need libpulse-simple
478 installed in your system.
480 The filename to provide to the input device is a source device or the
483 To list the pulse source devices and their properties you can invoke
484 the command @command{pactl list sources}.
487 ffmpeg -f pulse -i default /tmp/pulse.wav
490 @subsection @var{server} AVOption
494 -server @var{server name}
497 Connects to a specific server.
499 @subsection @var{name} AVOption
503 -name @var{application name}
506 Specify the application name pulse will use when showing active clients,
507 by default it is the LIBAVFORMAT_IDENT string
509 @subsection @var{stream_name} AVOption
513 -stream_name @var{stream name}
516 Specify the stream name pulse will use when showing active streams,
517 by default it is "record"
519 @subsection @var{sample_rate} AVOption
523 -sample_rate @var{samplerate}
526 Specify the samplerate in Hz, by default 48kHz is used.
528 @subsection @var{channels} AVOption
535 Specify the channels in use, by default 2 (stereo) is set.
537 @subsection @var{frame_size} AVOption
541 -frame_size @var{bytes}
544 Specify the number of byte per frame, by default it is set to 1024.
546 @subsection @var{fragment_size} AVOption
550 -fragment_size @var{bytes}
553 Specify the minimal buffering fragment in pulseaudio, it will affect the
554 audio latency. By default it is unset.
560 To enable this input device during configuration you need libsndio
561 installed on your system.
563 The filename to provide to the input device is the device node
564 representing the sndio input device, and is usually set to
567 For example to grab from @file{/dev/audio0} using @command{ffmpeg} use the
570 ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
573 @section video4linux2
575 Video4Linux2 input video device.
577 The name of the device to grab is a file device node, usually Linux
578 systems tend to automatically create such nodes when the device
579 (e.g. an USB webcam) is plugged into the system, and has a name of the
580 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
583 Video4Linux2 devices usually support a limited set of
584 @var{width}x@var{height} sizes and framerates. You can check which are
585 supported using @command{-list_formats all} for Video4Linux2 devices.
587 Some usage examples of the video4linux2 devices with ffmpeg and ffplay:
589 The time base for the timestamps is 1 microsecond. Depending on the kernel
590 version and configuration, the timestamps may be derived from the real time
591 clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
592 boot time, unaffected by NTP or manual changes to the clock). The
593 @option{-timestamps abs} or @option{-ts abs} option can be used to force
594 conversion into the real time clock.
596 Note that if FFmpeg is build with v4l-utils support ("--enable-libv4l2"
597 option), it will always be used.
599 # Grab and show the input of a video4linux2 device.
600 ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
602 # Grab and record the input of a video4linux2 device, leave the
603 framerate and size as previously set.
604 ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
607 "v4l" and "v4l2" can be used as aliases for the respective "video4linux" and
612 VfW (Video for Windows) capture input device.
614 The filename passed as input is the capture driver number, ranging from
615 0 to 9. You may use "list" as filename to print a list of drivers. Any
616 other filename will be interpreted as device number 0.
620 X11 video input device.
622 This device allows to capture a region of an X11 display.
624 The filename passed as input has the syntax:
626 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
629 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
630 X11 display name of the screen to grab from. @var{hostname} can be
631 omitted, and defaults to "localhost". The environment variable
632 @env{DISPLAY} contains the default display name.
634 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
635 area with respect to the top-left border of the X11 screen. They
638 Check the X11 documentation (e.g. man X) for more detailed information.
640 Use the @command{dpyinfo} program for getting basic information about the
641 properties of your X11 display (e.g. grep for "name" or "dimensions").
643 For example to grab from @file{:0.0} using @command{ffmpeg}:
645 ffmpeg -f x11grab -r 25 -s cif -i :0.0 out.mpg
648 Grab at position @code{10,20}:
650 ffmpeg -f x11grab -r 25 -s cif -i :0.0+10,20 out.mpg
657 Specify whether to draw the mouse pointer. A value of @code{0} specify
658 not to draw the pointer. Default value is @code{1}.
661 Make the grabbed area follow the mouse. The argument can be
662 @code{centered} or a number of pixels @var{PIXELS}.
664 When it is specified with "centered", the grabbing region follows the mouse
665 pointer and keeps the pointer at the center of region; otherwise, the region
666 follows only when the mouse pointer reaches within @var{PIXELS} (greater than
667 zero) to the edge of region.
671 ffmpeg -f x11grab -follow_mouse centered -r 25 -s cif -i :0.0 out.mpg
674 To follow only when the mouse pointer reaches within 100 pixels to edge:
676 ffmpeg -f x11grab -follow_mouse 100 -r 25 -s cif -i :0.0 out.mpg
680 Set the grabbing frame rate. Default value is @code{ntsc},
681 corresponding to a framerate of @code{30000/1001}.
684 Show grabbed region on screen.
686 If @var{show_region} is specified with @code{1}, then the grabbing
687 region will be indicated on screen. With this option, it is easy to
688 know what is being grabbed if only a portion of the screen is grabbed.
692 ffmpeg -f x11grab -show_region 1 -r 25 -s cif -i :0.0+10,20 out.mpg
695 With @var{follow_mouse}:
697 ffmpeg -f x11grab -follow_mouse centered -show_region 1 -r 25 -s cif -i :0.0 out.mpg
701 Set the video frame size. Default value is @code{vga}.
704 @c man end INPUT DEVICES