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,
115 @item audio_buffer_size
116 Set audio device buffer size in milliseconds (which can directly
117 impact latency, depending on the device).
118 Defaults to using the audio device's
119 default buffer size (typically some multiple of 500ms).
120 Setting this value too low can degrade performance.
122 @url{http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx}
131 Print the list of DirectShow supported devices and exit:
133 $ ffmpeg -list_devices true -f dshow -i dummy
137 Open video device @var{Camera}:
139 $ ffmpeg -f dshow -i video="Camera"
143 Open second video device with name @var{Camera}:
145 $ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
149 Open video device @var{Camera} and audio device @var{Microphone}:
151 $ ffmpeg -f dshow -i video="Camera":audio="Microphone"
155 Print the list of supported options in selected device and exit:
157 $ ffmpeg -list_options true -f dshow -i video="Camera"
164 Linux DV 1394 input device.
168 Linux framebuffer input device.
170 The Linux framebuffer is a graphic hardware-independent abstraction
171 layer to show graphics on a computer monitor, typically on the
172 console. It is accessed through a file device node, usually
175 For more detailed information read the file
176 Documentation/fb/framebuffer.txt included in the Linux source tree.
178 To record from the framebuffer device @file{/dev/fb0} with
181 ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
184 You can take a single screenshot image with the command:
186 ffmpeg -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
189 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
193 FireWire DV/HDV input device using libiec61883.
195 To enable this input device, you need libiec61883, libraw1394 and
196 libavc1394 installed on your system. Use the configure option
197 @code{--enable-libiec61883} to compile with the device enabled.
199 The iec61883 capture device supports capturing from a video device
200 connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
201 FireWire stack (juju). This is the default DV/HDV input method in Linux
202 Kernel 2.6.37 and later, since the old FireWire stack was removed.
204 Specify the FireWire port to be used as input file, or "auto"
205 to choose the first port connected.
212 Override autodetection of DV/HDV. This should only be used if auto
213 detection does not work, or if usage of a different device type
214 should be prohibited. Treating a DV device as HDV (or vice versa) will
215 not work and result in undefined behavior.
216 The values @option{auto}, @option{dv} and @option{hdv} are supported.
219 Set maxiumum size of buffer for incoming data, in frames. For DV, this
220 is an exact value. For HDV, it is not frame exact, since HDV does
221 not have a fixed frame size.
230 Grab and show the input of a FireWire DV/HDV device.
232 ffplay -f iec61883 -i auto
236 Grab and record the input of a FireWire DV/HDV device,
237 using a packet buffer of 100000 packets if the source is HDV.
239 ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
248 To enable this input device during configuration you need libjack
249 installed on your system.
251 A JACK input device creates one or more JACK writable clients, one for
252 each audio channel, with name @var{client_name}:input_@var{N}, where
253 @var{client_name} is the name provided by the application, and @var{N}
254 is a number which identifies the channel.
255 Each writable client will send the acquired data to the FFmpeg input
258 Once you have created one or more JACK readable clients, you need to
259 connect them to one or more JACK writable clients.
261 To connect or disconnect JACK clients you can use the @command{jack_connect}
262 and @command{jack_disconnect} programs, or do it through a graphical interface,
263 for example with @command{qjackctl}.
265 To list the JACK clients and their properties you can invoke the command
268 Follows an example which shows how to capture a JACK readable client
269 with @command{ffmpeg}.
271 # Create a JACK writable client with name "ffmpeg".
272 $ ffmpeg -f jack -i ffmpeg -y out.wav
274 # Start the sample jack_metro readable client.
275 $ jack_metro -b 120 -d 0.2 -f 4000
277 # List the current JACK clients.
286 # Connect metro to the ffmpeg writable client.
287 $ jack_connect metro:120_bpm ffmpeg:input_1
290 For more information read:
291 @url{http://jackaudio.org/}
295 Libavfilter input virtual device.
297 This input device reads data from the open output pads of a libavfilter
300 For each filtergraph open output, the input device will create a
301 corresponding stream which is mapped to the generated output. Currently
302 only video data is supported. The filtergraph is specified through the
303 option @option{graph}.
310 Specify the filtergraph to use as input. Each video open output must be
311 labelled by a unique string of the form "out@var{N}", where @var{N} is a
312 number starting from 0 corresponding to the mapped input stream
313 generated by the device.
314 The first unlabelled output is automatically assigned to the "out0"
315 label, but all the others need to be specified explicitly.
317 If not specified defaults to the filename specified for the input
325 Create a color video stream and play it back with @command{ffplay}:
327 ffplay -f lavfi -graph "color=pink [out0]" dummy
331 As the previous example, but use filename for specifying the graph
332 description, and omit the "out0" label:
334 ffplay -f lavfi color=pink
338 Create three different video test filtered sources and play them:
340 ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
344 Read an audio stream from a file using the amovie source and play it
345 back with @command{ffplay}:
347 ffplay -f lavfi "amovie=test.wav"
351 Read an audio stream and a video stream and play it back with
354 ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
361 IIDC1394 input device, based on libdc1394 and libraw1394.
365 The OpenAL input device provides audio capture on all systems with a
366 working OpenAL 1.1 implementation.
368 To enable this input device during configuration, you need OpenAL
369 headers and libraries installed on your system, and need to configure
370 FFmpeg with @code{--enable-openal}.
372 OpenAL headers and libraries should be provided as part of your OpenAL
373 implementation, or as an additional download (an SDK). Depending on your
374 installation you may need to specify additional flags via the
375 @code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
376 system to locate the OpenAL headers and libraries.
378 An incomplete list of OpenAL implementations follows:
382 The official Windows implementation, providing hardware acceleration
383 with supported devices and software fallback.
384 See @url{http://openal.org/}.
386 Portable, open source (LGPL) software implementation. Includes
387 backends for the most common sound APIs on the Windows, Linux,
388 Solaris, and BSD operating systems.
389 See @url{http://kcat.strangesoft.net/openal.html}.
391 OpenAL is part of Core Audio, the official Mac OS X Audio interface.
392 See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
395 This device allows to capture from an audio input device handled
398 You need to specify the name of the device to capture in the provided
399 filename. If the empty string is provided, the device will
400 automatically select the default device. You can get the list of the
401 supported devices by using the option @var{list_devices}.
408 Set the number of channels in the captured audio. Only the values
409 @option{1} (monaural) and @option{2} (stereo) are currently supported.
410 Defaults to @option{2}.
413 Set the sample size (in bits) of the captured audio. Only the values
414 @option{8} and @option{16} are currently supported. Defaults to
418 Set the sample rate (in Hz) of the captured audio.
419 Defaults to @option{44.1k}.
422 If set to @option{true}, print a list of devices and exit.
423 Defaults to @option{false}.
429 Print the list of OpenAL supported devices and exit:
431 $ ffmpeg -list_devices true -f openal -i dummy out.ogg
434 Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
436 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
439 Capture from the default device (note the empty string '' as filename):
441 $ ffmpeg -f openal -i '' out.ogg
444 Capture from two devices simultaneously, writing to two different files,
445 within the same @command{ffmpeg} command:
447 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
449 Note: not all OpenAL implementations support multiple simultaneous capture -
450 try the latest OpenAL Soft if the above does not work.
454 Open Sound System input device.
456 The filename to provide to the input device is the device node
457 representing the OSS input device, and is usually set to
460 For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the
463 ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
466 For more information about OSS see:
467 @url{http://manuals.opensound.com/usersguide/dsp.html}
471 pulseaudio input device.
473 To enable this input device during configuration you need libpulse-simple
474 installed in your system.
476 The filename to provide to the input device is a source device or the
479 To list the pulse source devices and their properties you can invoke
480 the command @command{pactl list sources}.
483 ffmpeg -f pulse -i default /tmp/pulse.wav
486 @subsection @var{server} AVOption
490 -server @var{server name}
493 Connects to a specific server.
495 @subsection @var{name} AVOption
499 -name @var{application name}
502 Specify the application name pulse will use when showing active clients,
503 by default it is the LIBAVFORMAT_IDENT string
505 @subsection @var{stream_name} AVOption
509 -stream_name @var{stream name}
512 Specify the stream name pulse will use when showing active streams,
513 by default it is "record"
515 @subsection @var{sample_rate} AVOption
519 -sample_rate @var{samplerate}
522 Specify the samplerate in Hz, by default 48kHz is used.
524 @subsection @var{channels} AVOption
531 Specify the channels in use, by default 2 (stereo) is set.
533 @subsection @var{frame_size} AVOption
537 -frame_size @var{bytes}
540 Specify the number of byte per frame, by default it is set to 1024.
542 @subsection @var{fragment_size} AVOption
546 -fragment_size @var{bytes}
549 Specify the minimal buffering fragment in pulseaudio, it will affect the
550 audio latency. By default it is unset.
556 To enable this input device during configuration you need libsndio
557 installed on your system.
559 The filename to provide to the input device is the device node
560 representing the sndio input device, and is usually set to
563 For example to grab from @file{/dev/audio0} using @command{ffmpeg} use the
566 ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
569 @section video4linux2
571 Video4Linux2 input video device.
573 The name of the device to grab is a file device node, usually Linux
574 systems tend to automatically create such nodes when the device
575 (e.g. an USB webcam) is plugged into the system, and has a name of the
576 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
579 Video4Linux2 devices usually support a limited set of
580 @var{width}x@var{height} sizes and framerates. You can check which are
581 supported using @command{-list_formats all} for Video4Linux2 devices.
583 Some usage examples of the video4linux2 devices with ffmpeg and ffplay:
585 The time base for the timestamps is 1 microsecond. Depending on the kernel
586 version and configuration, the timestamps may be derived from the real time
587 clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
588 boot time, unaffected by NTP or manual changes to the clock). The
589 @option{-timestamps abs} or @option{-ts abs} option can be used to force
590 conversion into the real time clock.
592 Note that if FFmpeg is build with v4l-utils support ("--enable-libv4l2"
593 option), it will always be used.
595 # Grab and show the input of a video4linux2 device.
596 ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
598 # Grab and record the input of a video4linux2 device, leave the
599 framerate and size as previously set.
600 ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
603 "v4l" and "v4l2" can be used as aliases for the respective "video4linux" and
608 VfW (Video for Windows) capture input device.
610 The filename passed as input is the capture driver number, ranging from
611 0 to 9. You may use "list" as filename to print a list of drivers. Any
612 other filename will be interpreted as device number 0.
616 X11 video input device.
618 This device allows to capture a region of an X11 display.
620 The filename passed as input has the syntax:
622 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
625 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
626 X11 display name of the screen to grab from. @var{hostname} can be
627 omitted, and defaults to "localhost". The environment variable
628 @env{DISPLAY} contains the default display name.
630 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
631 area with respect to the top-left border of the X11 screen. They
634 Check the X11 documentation (e.g. man X) for more detailed information.
636 Use the @command{dpyinfo} program for getting basic information about the
637 properties of your X11 display (e.g. grep for "name" or "dimensions").
639 For example to grab from @file{:0.0} using @command{ffmpeg}:
641 ffmpeg -f x11grab -r 25 -s cif -i :0.0 out.mpg
644 Grab at position @code{10,20}:
646 ffmpeg -f x11grab -r 25 -s cif -i :0.0+10,20 out.mpg
653 Specify whether to draw the mouse pointer. A value of @code{0} specify
654 not to draw the pointer. Default value is @code{1}.
657 Make the grabbed area follow the mouse. The argument can be
658 @code{centered} or a number of pixels @var{PIXELS}.
660 When it is specified with "centered", the grabbing region follows the mouse
661 pointer and keeps the pointer at the center of region; otherwise, the region
662 follows only when the mouse pointer reaches within @var{PIXELS} (greater than
663 zero) to the edge of region.
667 ffmpeg -f x11grab -follow_mouse centered -r 25 -s cif -i :0.0 out.mpg
670 To follow only when the mouse pointer reaches within 100 pixels to edge:
672 ffmpeg -f x11grab -follow_mouse 100 -r 25 -s cif -i :0.0 out.mpg
676 Set the grabbing frame rate. Default value is @code{ntsc},
677 corresponding to a framerate of @code{30000/1001}.
680 Show grabbed region on screen.
682 If @var{show_region} is specified with @code{1}, then the grabbing
683 region will be indicated on screen. With this option, it is easy to
684 know what is being grabbed if only a portion of the screen is grabbed.
688 ffmpeg -f x11grab -show_region 1 -r 25 -s cif -i :0.0+10,20 out.mpg
691 With @var{follow_mouse}:
693 ffmpeg -f x11grab -follow_mouse centered -show_region 1 -r 25 -s cif -i :0.0 out.mpg
697 Set the video frame size. Default value is @code{vga}.
700 @c man end INPUT DEVICES