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,
122 Print the list of DirectShow supported devices and exit:
124 $ ffmpeg -list_devices true -f dshow -i dummy
128 Open video device @var{Camera}:
130 $ ffmpeg -f dshow -i video="Camera"
134 Open second video device with name @var{Camera}:
136 $ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
140 Open video device @var{Camera} and audio device @var{Microphone}:
142 $ ffmpeg -f dshow -i video="Camera":audio="Microphone"
146 Print the list of supported options in selected device and exit:
148 $ ffmpeg -list_options true -f dshow -i video="Camera"
155 Linux DV 1394 input device.
159 Linux framebuffer input device.
161 The Linux framebuffer is a graphic hardware-independent abstraction
162 layer to show graphics on a computer monitor, typically on the
163 console. It is accessed through a file device node, usually
166 For more detailed information read the file
167 Documentation/fb/framebuffer.txt included in the Linux source tree.
169 To record from the framebuffer device @file{/dev/fb0} with
172 ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
175 You can take a single screenshot image with the command:
177 ffmpeg -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
180 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
184 FireWire DV/HDV input device using libiec61883.
186 To enable this input device, you need libiec61883, libraw1394 and
187 libavc1394 installed on your system. Use the configure option
188 @code{--enable-libiec61883} to compile with the device enabled.
190 The iec61883 capture device supports capturing from a video device
191 connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
192 FireWire stack (juju). This is the default DV/HDV input method in Linux
193 Kernel 2.6.37 and later, since the old FireWire stack was removed.
195 Specify the FireWire port to be used as input file, or "auto"
196 to choose the first port connected.
203 Override autodetection of DV/HDV. This should only be used if auto
204 detection does not work, or if usage of a different device type
205 should be prohibited. Treating a DV device as HDV (or vice versa) will
206 not work and result in undefined behavior.
207 The values @option{auto}, @option{dv} and @option{hdv} are supported.
210 Set maxiumum size of buffer for incoming data, in frames. For DV, this
211 is an exact value. For HDV, it is not frame exact, since HDV does
212 not have a fixed frame size.
221 Grab and show the input of a FireWire DV/HDV device.
223 ffplay -f iec61883 -i auto
227 Grab and record the input of a FireWire DV/HDV device,
228 using a packet buffer of 100000 packets if the source is HDV.
230 ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
239 To enable this input device during configuration you need libjack
240 installed on your system.
242 A JACK input device creates one or more JACK writable clients, one for
243 each audio channel, with name @var{client_name}:input_@var{N}, where
244 @var{client_name} is the name provided by the application, and @var{N}
245 is a number which identifies the channel.
246 Each writable client will send the acquired data to the FFmpeg input
249 Once you have created one or more JACK readable clients, you need to
250 connect them to one or more JACK writable clients.
252 To connect or disconnect JACK clients you can use the @command{jack_connect}
253 and @command{jack_disconnect} programs, or do it through a graphical interface,
254 for example with @command{qjackctl}.
256 To list the JACK clients and their properties you can invoke the command
259 Follows an example which shows how to capture a JACK readable client
260 with @command{ffmpeg}.
262 # Create a JACK writable client with name "ffmpeg".
263 $ ffmpeg -f jack -i ffmpeg -y out.wav
265 # Start the sample jack_metro readable client.
266 $ jack_metro -b 120 -d 0.2 -f 4000
268 # List the current JACK clients.
277 # Connect metro to the ffmpeg writable client.
278 $ jack_connect metro:120_bpm ffmpeg:input_1
281 For more information read:
282 @url{http://jackaudio.org/}
286 Libavfilter input virtual device.
288 This input device reads data from the open output pads of a libavfilter
291 For each filtergraph open output, the input device will create a
292 corresponding stream which is mapped to the generated output. Currently
293 only video data is supported. The filtergraph is specified through the
294 option @option{graph}.
301 Specify the filtergraph to use as input. Each video open output must be
302 labelled by a unique string of the form "out@var{N}", where @var{N} is a
303 number starting from 0 corresponding to the mapped input stream
304 generated by the device.
305 The first unlabelled output is automatically assigned to the "out0"
306 label, but all the others need to be specified explicitly.
308 If not specified defaults to the filename specified for the input
316 Create a color video stream and play it back with @command{ffplay}:
318 ffplay -f lavfi -graph "color=pink [out0]" dummy
322 As the previous example, but use filename for specifying the graph
323 description, and omit the "out0" label:
325 ffplay -f lavfi color=pink
329 Create three different video test filtered sources and play them:
331 ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
335 Read an audio stream from a file using the amovie source and play it
336 back with @command{ffplay}:
338 ffplay -f lavfi "amovie=test.wav"
342 Read an audio stream and a video stream and play it back with
345 ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
352 IIDC1394 input device, based on libdc1394 and libraw1394.
356 The OpenAL input device provides audio capture on all systems with a
357 working OpenAL 1.1 implementation.
359 To enable this input device during configuration, you need OpenAL
360 headers and libraries installed on your system, and need to configure
361 FFmpeg with @code{--enable-openal}.
363 OpenAL headers and libraries should be provided as part of your OpenAL
364 implementation, or as an additional download (an SDK). Depending on your
365 installation you may need to specify additional flags via the
366 @code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
367 system to locate the OpenAL headers and libraries.
369 An incomplete list of OpenAL implementations follows:
373 The official Windows implementation, providing hardware acceleration
374 with supported devices and software fallback.
375 See @url{http://openal.org/}.
377 Portable, open source (LGPL) software implementation. Includes
378 backends for the most common sound APIs on the Windows, Linux,
379 Solaris, and BSD operating systems.
380 See @url{http://kcat.strangesoft.net/openal.html}.
382 OpenAL is part of Core Audio, the official Mac OS X Audio interface.
383 See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
386 This device allows to capture from an audio input device handled
389 You need to specify the name of the device to capture in the provided
390 filename. If the empty string is provided, the device will
391 automatically select the default device. You can get the list of the
392 supported devices by using the option @var{list_devices}.
399 Set the number of channels in the captured audio. Only the values
400 @option{1} (monaural) and @option{2} (stereo) are currently supported.
401 Defaults to @option{2}.
404 Set the sample size (in bits) of the captured audio. Only the values
405 @option{8} and @option{16} are currently supported. Defaults to
409 Set the sample rate (in Hz) of the captured audio.
410 Defaults to @option{44.1k}.
413 If set to @option{true}, print a list of devices and exit.
414 Defaults to @option{false}.
420 Print the list of OpenAL supported devices and exit:
422 $ ffmpeg -list_devices true -f openal -i dummy out.ogg
425 Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
427 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
430 Capture from the default device (note the empty string '' as filename):
432 $ ffmpeg -f openal -i '' out.ogg
435 Capture from two devices simultaneously, writing to two different files,
436 within the same @command{ffmpeg} command:
438 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
440 Note: not all OpenAL implementations support multiple simultaneous capture -
441 try the latest OpenAL Soft if the above does not work.
445 Open Sound System input device.
447 The filename to provide to the input device is the device node
448 representing the OSS input device, and is usually set to
451 For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the
454 ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
457 For more information about OSS see:
458 @url{http://manuals.opensound.com/usersguide/dsp.html}
462 pulseaudio input device.
464 To enable this input device during configuration you need libpulse-simple
465 installed in your system.
467 The filename to provide to the input device is a source device or the
470 To list the pulse source devices and their properties you can invoke
471 the command @command{pactl list sources}.
474 ffmpeg -f pulse -i default /tmp/pulse.wav
477 @subsection @var{server} AVOption
481 -server @var{server name}
484 Connects to a specific server.
486 @subsection @var{name} AVOption
490 -name @var{application name}
493 Specify the application name pulse will use when showing active clients,
494 by default it is the LIBAVFORMAT_IDENT string
496 @subsection @var{stream_name} AVOption
500 -stream_name @var{stream name}
503 Specify the stream name pulse will use when showing active streams,
504 by default it is "record"
506 @subsection @var{sample_rate} AVOption
510 -sample_rate @var{samplerate}
513 Specify the samplerate in Hz, by default 48kHz is used.
515 @subsection @var{channels} AVOption
522 Specify the channels in use, by default 2 (stereo) is set.
524 @subsection @var{frame_size} AVOption
528 -frame_size @var{bytes}
531 Specify the number of byte per frame, by default it is set to 1024.
533 @subsection @var{fragment_size} AVOption
537 -fragment_size @var{bytes}
540 Specify the minimal buffering fragment in pulseaudio, it will affect the
541 audio latency. By default it is unset.
547 To enable this input device during configuration you need libsndio
548 installed on your system.
550 The filename to provide to the input device is the device node
551 representing the sndio input device, and is usually set to
554 For example to grab from @file{/dev/audio0} using @command{ffmpeg} use the
557 ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
560 @section video4linux2
562 Video4Linux2 input video device.
564 The name of the device to grab is a file device node, usually Linux
565 systems tend to automatically create such nodes when the device
566 (e.g. an USB webcam) is plugged into the system, and has a name of the
567 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
570 Video4Linux2 devices usually support a limited set of
571 @var{width}x@var{height} sizes and framerates. You can check which are
572 supported using @command{-list_formats all} for Video4Linux2 devices.
574 Some usage examples of the video4linux2 devices with ffmpeg and ffplay:
576 The time base for the timestamps is 1 microsecond. Depending on the kernel
577 version and configuration, the timestamps may be derived from the real time
578 clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
579 boot time, unaffected by NTP or manual changes to the clock). The
580 @option{-timestamps abs} or @option{-ts abs} option can be used to force
581 conversion into the real time clock.
583 Note that if FFmpeg is build with v4l-utils support ("--enable-libv4l2"
584 option), it will always be used.
586 # Grab and show the input of a video4linux2 device.
587 ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
589 # Grab and record the input of a video4linux2 device, leave the
590 framerate and size as previously set.
591 ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
594 "v4l" and "v4l2" can be used as aliases for the respective "video4linux" and
599 VfW (Video for Windows) capture input device.
601 The filename passed as input is the capture driver number, ranging from
602 0 to 9. You may use "list" as filename to print a list of drivers. Any
603 other filename will be interpreted as device number 0.
607 X11 video input device.
609 This device allows to capture a region of an X11 display.
611 The filename passed as input has the syntax:
613 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
616 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
617 X11 display name of the screen to grab from. @var{hostname} can be
618 omitted, and defaults to "localhost". The environment variable
619 @env{DISPLAY} contains the default display name.
621 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
622 area with respect to the top-left border of the X11 screen. They
625 Check the X11 documentation (e.g. man X) for more detailed information.
627 Use the @command{dpyinfo} program for getting basic information about the
628 properties of your X11 display (e.g. grep for "name" or "dimensions").
630 For example to grab from @file{:0.0} using @command{ffmpeg}:
632 ffmpeg -f x11grab -r 25 -s cif -i :0.0 out.mpg
634 # Grab at position 10,20.
635 ffmpeg -f x11grab -r 25 -s cif -i :0.0+10,20 out.mpg
638 @subsection @var{follow_mouse} AVOption
642 -follow_mouse centered|@var{PIXELS}
645 When it is specified with "centered", the grabbing region follows the mouse
646 pointer and keeps the pointer at the center of region; otherwise, the region
647 follows only when the mouse pointer reaches within @var{PIXELS} (greater than
648 zero) to the edge of region.
652 ffmpeg -f x11grab -follow_mouse centered -r 25 -s cif -i :0.0 out.mpg
654 # Follows only when the mouse pointer reaches within 100 pixels to edge
655 ffmpeg -f x11grab -follow_mouse 100 -r 25 -s cif -i :0.0 out.mpg
658 @subsection @var{show_region} AVOption
665 If @var{show_region} AVOption is specified with @var{1}, then the grabbing
666 region will be indicated on screen. With this option, it's easy to know what is
667 being grabbed if only a portion of the screen is grabbed.
671 ffmpeg -f x11grab -show_region 1 -r 25 -s cif -i :0.0+10,20 out.mpg
674 ffmpeg -f x11grab -follow_mouse centered -show_region 1 -r 25 -s cif -i :0.0 out.mpg
677 @c man end INPUT DEVICES