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 AVFoundation input device.
58 AVFoundation is the currently recommended framework by Apple for streamgrabbing on OSX >= 10.7 as well as on iOS.
59 The older QTKit framework has been marked deprecated since OSX version 10.7.
61 The filename passed as input is parsed to contain either a device name or index.
62 The device index can also be given by using -video_device_index.
63 A given device index will override any given device name.
64 If the desired device consists of numbers only, use -video_device_index to identify it.
65 The default device will be chosen if an empty string or the device name "default" is given.
66 The available devices can be enumerated by using -list_devices.
69 ffmpeg -f avfoundation -i "0" out.mpg
73 ffmpeg -f avfoundation -video_device_index 0 -i "" out.mpg
77 ffmpeg -f avfoundation -i "default" out.mpg
81 ffmpeg -f avfoundation -list_devices true -i ""
86 BSD video input device.
90 Windows DirectShow input device.
92 DirectShow support is enabled when FFmpeg is built with the mingw-w64 project.
93 Currently only audio and video devices are supported.
95 Multiple devices may be opened as separate inputs, but they may also be
96 opened on the same input, which should improve synchronism between them.
98 The input name should be in the format:
101 @var{TYPE}=@var{NAME}[:@var{TYPE}=@var{NAME}]
104 where @var{TYPE} can be either @var{audio} or @var{video},
105 and @var{NAME} is the device's name.
109 If no options are specified, the device's defaults are used.
110 If the device does not support the requested options, it will
116 Set the video size in the captured video.
119 Set the frame rate in the captured video.
122 Set the sample rate (in Hz) of the captured audio.
125 Set the sample size (in bits) of the captured audio.
128 Set the number of channels in the captured audio.
131 If set to @option{true}, print a list of devices and exit.
134 If set to @option{true}, print a list of selected device's options
137 @item video_device_number
138 Set video device number for devices with same name (starts at 0,
141 @item audio_device_number
142 Set audio device number for devices with same name (starts at 0,
146 Select pixel format to be used by DirectShow. This may only be set when
147 the video codec is not set or set to rawvideo.
149 @item audio_buffer_size
150 Set audio device buffer size in milliseconds (which can directly
151 impact latency, depending on the device).
152 Defaults to using the audio device's
153 default buffer size (typically some multiple of 500ms).
154 Setting this value too low can degrade performance.
156 @url{http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx}
165 Print the list of DirectShow supported devices and exit:
167 $ ffmpeg -list_devices true -f dshow -i dummy
171 Open video device @var{Camera}:
173 $ ffmpeg -f dshow -i video="Camera"
177 Open second video device with name @var{Camera}:
179 $ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
183 Open video device @var{Camera} and audio device @var{Microphone}:
185 $ ffmpeg -f dshow -i video="Camera":audio="Microphone"
189 Print the list of supported options in selected device and exit:
191 $ ffmpeg -list_options true -f dshow -i video="Camera"
198 Linux DV 1394 input device.
202 Linux framebuffer input device.
204 The Linux framebuffer is a graphic hardware-independent abstraction
205 layer to show graphics on a computer monitor, typically on the
206 console. It is accessed through a file device node, usually
209 For more detailed information read the file
210 Documentation/fb/framebuffer.txt included in the Linux source tree.
212 To record from the framebuffer device @file{/dev/fb0} with
215 ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
218 You can take a single screenshot image with the command:
220 ffmpeg -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
223 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
227 Win32 GDI-based screen capture device.
229 This device allows you to capture a region of the display on Windows.
231 There are two options for the input filename:
237 title=@var{window_title}
240 The first option will capture the entire desktop, or a fixed region of the
241 desktop. The second option will instead capture the contents of a single
242 window, regardless of its position on the screen.
244 For example, to grab the entire desktop using @command{ffmpeg}:
246 ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg
249 Grab a 640x480 region at position @code{10,20}:
251 ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg
254 Grab the contents of the window named "Calculator"
256 ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg
263 Specify whether to draw the mouse pointer. Use the value @code{0} to
264 not draw the pointer. Default value is @code{1}.
267 Set the grabbing frame rate. Default value is @code{ntsc},
268 corresponding to a frame rate of @code{30000/1001}.
271 Show grabbed region on screen.
273 If @var{show_region} is specified with @code{1}, then the grabbing
274 region will be indicated on screen. With this option, it is easy to
275 know what is being grabbed if only a portion of the screen is grabbed.
277 Note that @var{show_region} is incompatible with grabbing the contents
282 ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg
286 Set the video frame size. The default is to capture the full screen if @file{desktop} is selected, or the full window size if @file{title=@var{window_title}} is selected.
289 When capturing a region with @var{video_size}, set the distance from the left edge of the screen or desktop.
291 Note that the offset calculation is from the top left corner of the primary monitor on Windows. If you have a monitor positioned to the left of your primary monitor, you will need to use a negative @var{offset_x} value to move the region to that monitor.
294 When capturing a region with @var{video_size}, set the distance from the top edge of the screen or desktop.
296 Note that the offset calculation is from the top left corner of the primary monitor on Windows. If you have a monitor positioned above your primary monitor, you will need to use a negative @var{offset_y} value to move the region to that monitor.
302 FireWire DV/HDV input device using libiec61883.
304 To enable this input device, you need libiec61883, libraw1394 and
305 libavc1394 installed on your system. Use the configure option
306 @code{--enable-libiec61883} to compile with the device enabled.
308 The iec61883 capture device supports capturing from a video device
309 connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
310 FireWire stack (juju). This is the default DV/HDV input method in Linux
311 Kernel 2.6.37 and later, since the old FireWire stack was removed.
313 Specify the FireWire port to be used as input file, or "auto"
314 to choose the first port connected.
321 Override autodetection of DV/HDV. This should only be used if auto
322 detection does not work, or if usage of a different device type
323 should be prohibited. Treating a DV device as HDV (or vice versa) will
324 not work and result in undefined behavior.
325 The values @option{auto}, @option{dv} and @option{hdv} are supported.
328 Set maxiumum size of buffer for incoming data, in frames. For DV, this
329 is an exact value. For HDV, it is not frame exact, since HDV does
330 not have a fixed frame size.
333 Select the capture device by specifying it's GUID. Capturing will only
334 be performed from the specified device and fails if no device with the
335 given GUID is found. This is useful to select the input if multiple
336 devices are connected at the same time.
337 Look at /sys/bus/firewire/devices to find out the GUIDs.
346 Grab and show the input of a FireWire DV/HDV device.
348 ffplay -f iec61883 -i auto
352 Grab and record the input of a FireWire DV/HDV device,
353 using a packet buffer of 100000 packets if the source is HDV.
355 ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
364 To enable this input device during configuration you need libjack
365 installed on your system.
367 A JACK input device creates one or more JACK writable clients, one for
368 each audio channel, with name @var{client_name}:input_@var{N}, where
369 @var{client_name} is the name provided by the application, and @var{N}
370 is a number which identifies the channel.
371 Each writable client will send the acquired data to the FFmpeg input
374 Once you have created one or more JACK readable clients, you need to
375 connect them to one or more JACK writable clients.
377 To connect or disconnect JACK clients you can use the @command{jack_connect}
378 and @command{jack_disconnect} programs, or do it through a graphical interface,
379 for example with @command{qjackctl}.
381 To list the JACK clients and their properties you can invoke the command
384 Follows an example which shows how to capture a JACK readable client
385 with @command{ffmpeg}.
387 # Create a JACK writable client with name "ffmpeg".
388 $ ffmpeg -f jack -i ffmpeg -y out.wav
390 # Start the sample jack_metro readable client.
391 $ jack_metro -b 120 -d 0.2 -f 4000
393 # List the current JACK clients.
402 # Connect metro to the ffmpeg writable client.
403 $ jack_connect metro:120_bpm ffmpeg:input_1
406 For more information read:
407 @url{http://jackaudio.org/}
411 Libavfilter input virtual device.
413 This input device reads data from the open output pads of a libavfilter
416 For each filtergraph open output, the input device will create a
417 corresponding stream which is mapped to the generated output. Currently
418 only video data is supported. The filtergraph is specified through the
419 option @option{graph}.
426 Specify the filtergraph to use as input. Each video open output must be
427 labelled by a unique string of the form "out@var{N}", where @var{N} is a
428 number starting from 0 corresponding to the mapped input stream
429 generated by the device.
430 The first unlabelled output is automatically assigned to the "out0"
431 label, but all the others need to be specified explicitly.
433 If not specified defaults to the filename specified for the input
437 Set the filename of the filtergraph to be read and sent to the other
438 filters. Syntax of the filtergraph is the same as the one specified by
439 the option @var{graph}.
447 Create a color video stream and play it back with @command{ffplay}:
449 ffplay -f lavfi -graph "color=c=pink [out0]" dummy
453 As the previous example, but use filename for specifying the graph
454 description, and omit the "out0" label:
456 ffplay -f lavfi color=c=pink
460 Create three different video test filtered sources and play them:
462 ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
466 Read an audio stream from a file using the amovie source and play it
467 back with @command{ffplay}:
469 ffplay -f lavfi "amovie=test.wav"
473 Read an audio stream and a video stream and play it back with
476 ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
483 IIDC1394 input device, based on libdc1394 and libraw1394.
487 The OpenAL input device provides audio capture on all systems with a
488 working OpenAL 1.1 implementation.
490 To enable this input device during configuration, you need OpenAL
491 headers and libraries installed on your system, and need to configure
492 FFmpeg with @code{--enable-openal}.
494 OpenAL headers and libraries should be provided as part of your OpenAL
495 implementation, or as an additional download (an SDK). Depending on your
496 installation you may need to specify additional flags via the
497 @code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
498 system to locate the OpenAL headers and libraries.
500 An incomplete list of OpenAL implementations follows:
504 The official Windows implementation, providing hardware acceleration
505 with supported devices and software fallback.
506 See @url{http://openal.org/}.
508 Portable, open source (LGPL) software implementation. Includes
509 backends for the most common sound APIs on the Windows, Linux,
510 Solaris, and BSD operating systems.
511 See @url{http://kcat.strangesoft.net/openal.html}.
513 OpenAL is part of Core Audio, the official Mac OS X Audio interface.
514 See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
517 This device allows one to capture from an audio input device handled
520 You need to specify the name of the device to capture in the provided
521 filename. If the empty string is provided, the device will
522 automatically select the default device. You can get the list of the
523 supported devices by using the option @var{list_devices}.
530 Set the number of channels in the captured audio. Only the values
531 @option{1} (monaural) and @option{2} (stereo) are currently supported.
532 Defaults to @option{2}.
535 Set the sample size (in bits) of the captured audio. Only the values
536 @option{8} and @option{16} are currently supported. Defaults to
540 Set the sample rate (in Hz) of the captured audio.
541 Defaults to @option{44.1k}.
544 If set to @option{true}, print a list of devices and exit.
545 Defaults to @option{false}.
551 Print the list of OpenAL supported devices and exit:
553 $ ffmpeg -list_devices true -f openal -i dummy out.ogg
556 Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
558 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
561 Capture from the default device (note the empty string '' as filename):
563 $ ffmpeg -f openal -i '' out.ogg
566 Capture from two devices simultaneously, writing to two different files,
567 within the same @command{ffmpeg} command:
569 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
571 Note: not all OpenAL implementations support multiple simultaneous capture -
572 try the latest OpenAL Soft if the above does not work.
576 Open Sound System input device.
578 The filename to provide to the input device is the device node
579 representing the OSS input device, and is usually set to
582 For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the
585 ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
588 For more information about OSS see:
589 @url{http://manuals.opensound.com/usersguide/dsp.html}
593 PulseAudio input device.
595 To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
597 The filename to provide to the input device is a source device or the
600 To list the PulseAudio source devices and their properties you can invoke
601 the command @command{pactl list sources}.
603 More information about PulseAudio can be found on @url{http://www.pulseaudio.org}.
608 Connect to a specific PulseAudio server, specified by an IP address.
609 Default server is used when not provided.
612 Specify the application name PulseAudio will use when showing active clients,
613 by default it is the @code{LIBAVFORMAT_IDENT} string.
616 Specify the stream name PulseAudio will use when showing active streams,
617 by default it is "record".
620 Specify the samplerate in Hz, by default 48kHz is used.
623 Specify the channels in use, by default 2 (stereo) is set.
626 Specify the number of bytes per frame, by default it is set to 1024.
629 Specify the minimal buffering fragment in PulseAudio, it will affect the
630 audio latency. By default it is unset.
634 Record a stream from default device:
636 ffmpeg -f pulse -i default /tmp/pulse.wav
643 The filename passed as input is parsed to contain either a device name or index.
644 The device index can also be given by using -video_device_index.
645 A given device index will override any given device name.
646 If the desired device consists of numbers only, use -video_device_index to identify it.
647 The default device will be chosen if an empty string or the device name "default" is given.
648 The available devices can be enumerated by using -list_devices.
651 ffmpeg -f qtkit -i "0" out.mpg
655 ffmpeg -f qtkit -video_device_index 0 -i "" out.mpg
659 ffmpeg -f qtkit -i "default" out.mpg
663 ffmpeg -f qtkit -list_devices true -i ""
670 To enable this input device during configuration you need libsndio
671 installed on your system.
673 The filename to provide to the input device is the device node
674 representing the sndio input device, and is usually set to
677 For example to grab from @file{/dev/audio0} using @command{ffmpeg} use the
680 ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
683 @section video4linux2, v4l2
685 Video4Linux2 input video device.
687 "v4l2" can be used as alias for "video4linux2".
689 If FFmpeg is built with v4l-utils support (by using the
690 @code{--enable-libv4l2} configure option), it is possible to use it with the
691 @code{-use_libv4l2} input device option.
693 The name of the device to grab is a file device node, usually Linux
694 systems tend to automatically create such nodes when the device
695 (e.g. an USB webcam) is plugged into the system, and has a name of the
696 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
699 Video4Linux2 devices usually support a limited set of
700 @var{width}x@var{height} sizes and frame rates. You can check which are
701 supported using @command{-list_formats all} for Video4Linux2 devices.
702 Some devices, like TV cards, support one or more standards. It is possible
703 to list all the supported standards using @command{-list_standards all}.
705 The time base for the timestamps is 1 microsecond. Depending on the kernel
706 version and configuration, the timestamps may be derived from the real time
707 clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
708 boot time, unaffected by NTP or manual changes to the clock). The
709 @option{-timestamps abs} or @option{-ts abs} option can be used to force
710 conversion into the real time clock.
712 Some usage examples of the video4linux2 device with @command{ffmpeg}
713 and @command{ffplay}:
716 Grab and show the input of a video4linux2 device:
718 ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
722 Grab and record the input of a video4linux2 device, leave the
723 frame rate and size as previously set:
725 ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
729 For more information about Video4Linux, check @url{http://linuxtv.org/}.
735 Set the standard. Must be the name of a supported standard. To get a
736 list of the supported standards, use the @option{list_standards}
740 Set the input channel number. Default to -1, which means using the
741 previously selected channel.
744 Set the video frame size. The argument must be a string in the form
745 @var{WIDTH}x@var{HEIGHT} or a valid size abbreviation.
748 Select the pixel format (only valid for raw video input).
751 Set the preferred pixel format (for raw video) or a codec name.
752 This option allows one to select the input format, when several are
756 Set the preferred video frame rate.
759 List available formats (supported pixel formats, codecs, and frame
762 Available values are:
765 Show all available (compressed and non-compressed) formats.
768 Show only raw video (non-compressed) formats.
771 Show only compressed formats.
775 List supported standards and exit.
777 Available values are:
780 Show all supported standards.
784 Set type of timestamps for grabbed frames.
786 Available values are:
789 Use timestamps from the kernel.
792 Use absolute timestamps (wall clock).
795 Force conversion from monotonic to absolute timestamps.
798 Default value is @code{default}.
803 VfW (Video for Windows) capture input device.
805 The filename passed as input is the capture driver number, ranging from
806 0 to 9. You may use "list" as filename to print a list of drivers. Any
807 other filename will be interpreted as device number 0.
811 X11 video input device.
813 This device allows one to capture a region of an X11 display.
815 The filename passed as input has the syntax:
817 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
820 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
821 X11 display name of the screen to grab from. @var{hostname} can be
822 omitted, and defaults to "localhost". The environment variable
823 @env{DISPLAY} contains the default display name.
825 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
826 area with respect to the top-left border of the X11 screen. They
829 Check the X11 documentation (e.g. man X) for more detailed information.
831 Use the @command{dpyinfo} program for getting basic information about the
832 properties of your X11 display (e.g. grep for "name" or "dimensions").
834 For example to grab from @file{:0.0} using @command{ffmpeg}:
836 ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg
839 Grab at position @code{10,20}:
841 ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
848 Specify whether to draw the mouse pointer. A value of @code{0} specify
849 not to draw the pointer. Default value is @code{1}.
852 Make the grabbed area follow the mouse. The argument can be
853 @code{centered} or a number of pixels @var{PIXELS}.
855 When it is specified with "centered", the grabbing region follows the mouse
856 pointer and keeps the pointer at the center of region; otherwise, the region
857 follows only when the mouse pointer reaches within @var{PIXELS} (greater than
858 zero) to the edge of region.
862 ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg
865 To follow only when the mouse pointer reaches within 100 pixels to edge:
867 ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg
871 Set the grabbing frame rate. Default value is @code{ntsc},
872 corresponding to a frame rate of @code{30000/1001}.
875 Show grabbed region on screen.
877 If @var{show_region} is specified with @code{1}, then the grabbing
878 region will be indicated on screen. With this option, it is easy to
879 know what is being grabbed if only a portion of the screen is grabbed.
883 ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
886 With @var{follow_mouse}:
888 ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg
892 Set the video frame size. Default value is @code{vga}.
895 @c man end INPUT DEVICES