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 frame rate 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 Win32 GDI-based screen capture device.
199 This device allows you to capture a region of the display on Windows.
201 There are two options for the input filename:
207 title=@var{window_title}
210 The first option will capture the entire desktop, or a fixed region of the
211 desktop. The second option will instead capture the contents of a single
212 window, regardless of its position on the screen.
214 For example, to grab the entire desktop using @command{ffmpeg}:
216 ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg
219 Grab a 640x480 region at position @code{10,20}:
221 ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg
224 Grab the contents of the window named "Calculator"
226 ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg
233 Specify whether to draw the mouse pointer. Use the value @code{0} to
234 not draw the pointer. Default value is @code{1}.
237 Set the grabbing frame rate. Default value is @code{ntsc},
238 corresponding to a frame rate of @code{30000/1001}.
241 Show grabbed region on screen.
243 If @var{show_region} is specified with @code{1}, then the grabbing
244 region will be indicated on screen. With this option, it is easy to
245 know what is being grabbed if only a portion of the screen is grabbed.
247 Note that @var{show_region} is incompatible with grabbing the contents
252 ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg
256 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.
259 When capturing a region with @var{video_size}, set the distance from the left edge of the screen or desktop.
261 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.
264 When capturing a region with @var{video_size}, set the distance from the top edge of the screen or desktop.
266 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.
272 FireWire DV/HDV input device using libiec61883.
274 To enable this input device, you need libiec61883, libraw1394 and
275 libavc1394 installed on your system. Use the configure option
276 @code{--enable-libiec61883} to compile with the device enabled.
278 The iec61883 capture device supports capturing from a video device
279 connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
280 FireWire stack (juju). This is the default DV/HDV input method in Linux
281 Kernel 2.6.37 and later, since the old FireWire stack was removed.
283 Specify the FireWire port to be used as input file, or "auto"
284 to choose the first port connected.
291 Override autodetection of DV/HDV. This should only be used if auto
292 detection does not work, or if usage of a different device type
293 should be prohibited. Treating a DV device as HDV (or vice versa) will
294 not work and result in undefined behavior.
295 The values @option{auto}, @option{dv} and @option{hdv} are supported.
298 Set maxiumum size of buffer for incoming data, in frames. For DV, this
299 is an exact value. For HDV, it is not frame exact, since HDV does
300 not have a fixed frame size.
303 Select the capture device by specifying it's GUID. Capturing will only
304 be performed from the specified device and fails if no device with the
305 given GUID is found. This is useful to select the input if multiple
306 devices are connected at the same time.
307 Look at /sys/bus/firewire/devices to find out the GUIDs.
316 Grab and show the input of a FireWire DV/HDV device.
318 ffplay -f iec61883 -i auto
322 Grab and record the input of a FireWire DV/HDV device,
323 using a packet buffer of 100000 packets if the source is HDV.
325 ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
334 To enable this input device during configuration you need libjack
335 installed on your system.
337 A JACK input device creates one or more JACK writable clients, one for
338 each audio channel, with name @var{client_name}:input_@var{N}, where
339 @var{client_name} is the name provided by the application, and @var{N}
340 is a number which identifies the channel.
341 Each writable client will send the acquired data to the FFmpeg input
344 Once you have created one or more JACK readable clients, you need to
345 connect them to one or more JACK writable clients.
347 To connect or disconnect JACK clients you can use the @command{jack_connect}
348 and @command{jack_disconnect} programs, or do it through a graphical interface,
349 for example with @command{qjackctl}.
351 To list the JACK clients and their properties you can invoke the command
354 Follows an example which shows how to capture a JACK readable client
355 with @command{ffmpeg}.
357 # Create a JACK writable client with name "ffmpeg".
358 $ ffmpeg -f jack -i ffmpeg -y out.wav
360 # Start the sample jack_metro readable client.
361 $ jack_metro -b 120 -d 0.2 -f 4000
363 # List the current JACK clients.
372 # Connect metro to the ffmpeg writable client.
373 $ jack_connect metro:120_bpm ffmpeg:input_1
376 For more information read:
377 @url{http://jackaudio.org/}
381 Libavfilter input virtual device.
383 This input device reads data from the open output pads of a libavfilter
386 For each filtergraph open output, the input device will create a
387 corresponding stream which is mapped to the generated output. Currently
388 only video data is supported. The filtergraph is specified through the
389 option @option{graph}.
396 Specify the filtergraph to use as input. Each video open output must be
397 labelled by a unique string of the form "out@var{N}", where @var{N} is a
398 number starting from 0 corresponding to the mapped input stream
399 generated by the device.
400 The first unlabelled output is automatically assigned to the "out0"
401 label, but all the others need to be specified explicitly.
403 If not specified defaults to the filename specified for the input
407 Set the filename of the filtergraph to be read and sent to the other
408 filters. Syntax of the filtergraph is the same as the one specified by
409 the option @var{graph}.
417 Create a color video stream and play it back with @command{ffplay}:
419 ffplay -f lavfi -graph "color=c=pink [out0]" dummy
423 As the previous example, but use filename for specifying the graph
424 description, and omit the "out0" label:
426 ffplay -f lavfi color=c=pink
430 Create three different video test filtered sources and play them:
432 ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
436 Read an audio stream from a file using the amovie source and play it
437 back with @command{ffplay}:
439 ffplay -f lavfi "amovie=test.wav"
443 Read an audio stream and a video stream and play it back with
446 ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
453 IIDC1394 input device, based on libdc1394 and libraw1394.
457 The OpenAL input device provides audio capture on all systems with a
458 working OpenAL 1.1 implementation.
460 To enable this input device during configuration, you need OpenAL
461 headers and libraries installed on your system, and need to configure
462 FFmpeg with @code{--enable-openal}.
464 OpenAL headers and libraries should be provided as part of your OpenAL
465 implementation, or as an additional download (an SDK). Depending on your
466 installation you may need to specify additional flags via the
467 @code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
468 system to locate the OpenAL headers and libraries.
470 An incomplete list of OpenAL implementations follows:
474 The official Windows implementation, providing hardware acceleration
475 with supported devices and software fallback.
476 See @url{http://openal.org/}.
478 Portable, open source (LGPL) software implementation. Includes
479 backends for the most common sound APIs on the Windows, Linux,
480 Solaris, and BSD operating systems.
481 See @url{http://kcat.strangesoft.net/openal.html}.
483 OpenAL is part of Core Audio, the official Mac OS X Audio interface.
484 See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
487 This device allows one to capture from an audio input device handled
490 You need to specify the name of the device to capture in the provided
491 filename. If the empty string is provided, the device will
492 automatically select the default device. You can get the list of the
493 supported devices by using the option @var{list_devices}.
500 Set the number of channels in the captured audio. Only the values
501 @option{1} (monaural) and @option{2} (stereo) are currently supported.
502 Defaults to @option{2}.
505 Set the sample size (in bits) of the captured audio. Only the values
506 @option{8} and @option{16} are currently supported. Defaults to
510 Set the sample rate (in Hz) of the captured audio.
511 Defaults to @option{44.1k}.
514 If set to @option{true}, print a list of devices and exit.
515 Defaults to @option{false}.
521 Print the list of OpenAL supported devices and exit:
523 $ ffmpeg -list_devices true -f openal -i dummy out.ogg
526 Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
528 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
531 Capture from the default device (note the empty string '' as filename):
533 $ ffmpeg -f openal -i '' out.ogg
536 Capture from two devices simultaneously, writing to two different files,
537 within the same @command{ffmpeg} command:
539 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
541 Note: not all OpenAL implementations support multiple simultaneous capture -
542 try the latest OpenAL Soft if the above does not work.
546 Open Sound System input device.
548 The filename to provide to the input device is the device node
549 representing the OSS input device, and is usually set to
552 For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the
555 ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
558 For more information about OSS see:
559 @url{http://manuals.opensound.com/usersguide/dsp.html}
563 PulseAudio input device.
565 To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
567 The filename to provide to the input device is a source device or the
570 To list the PulseAudio source devices and their properties you can invoke
571 the command @command{pactl list sources}.
573 More information about PulseAudio can be found on @url{http://www.pulseaudio.org}.
578 Connect to a specific PulseAudio server, specified by an IP address.
579 Default server is used when not provided.
582 Specify the application name PulseAudio will use when showing active clients,
583 by default it is the @code{LIBAVFORMAT_IDENT} string.
586 Specify the stream name PulseAudio will use when showing active streams,
587 by default it is "record".
590 Specify the samplerate in Hz, by default 48kHz is used.
593 Specify the channels in use, by default 2 (stereo) is set.
596 Specify the number of bytes per frame, by default it is set to 1024.
599 Specify the minimal buffering fragment in PulseAudio, it will affect the
600 audio latency. By default it is unset.
604 Record a stream from default device:
606 ffmpeg -f pulse -i default /tmp/pulse.wav
613 The filename passed as input is parsed to contain either a device name or index.
614 The device index can also be given by using -video_device_index.
615 A given device index will override any given device name.
616 If the desired device consists of numbers only, use -video_device_index to identify it.
617 The default device will be chosen if an empty string or the device name "default" is given.
618 The available devices can be enumerated by using -list_devices.
621 ffmpeg -f qtkit -i "0" out.mpg
625 ffmpeg -f qtkit -video_device_index 0 -i "" out.mpg
629 ffmpeg -f qtkit -i "default" out.mpg
633 ffmpeg -f qtkit -list_devices true -i ""
640 To enable this input device during configuration you need libsndio
641 installed on your system.
643 The filename to provide to the input device is the device node
644 representing the sndio input device, and is usually set to
647 For example to grab from @file{/dev/audio0} using @command{ffmpeg} use the
650 ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
653 @section video4linux2, v4l2
655 Video4Linux2 input video device.
657 "v4l2" can be used as alias for "video4linux2".
659 If FFmpeg is built with v4l-utils support (by using the
660 @code{--enable-libv4l2} configure option), it is possible to use it with the
661 @code{-use_libv4l2} input device option.
663 The name of the device to grab is a file device node, usually Linux
664 systems tend to automatically create such nodes when the device
665 (e.g. an USB webcam) is plugged into the system, and has a name of the
666 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
669 Video4Linux2 devices usually support a limited set of
670 @var{width}x@var{height} sizes and frame rates. You can check which are
671 supported using @command{-list_formats all} for Video4Linux2 devices.
672 Some devices, like TV cards, support one or more standards. It is possible
673 to list all the supported standards using @command{-list_standards all}.
675 The time base for the timestamps is 1 microsecond. Depending on the kernel
676 version and configuration, the timestamps may be derived from the real time
677 clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
678 boot time, unaffected by NTP or manual changes to the clock). The
679 @option{-timestamps abs} or @option{-ts abs} option can be used to force
680 conversion into the real time clock.
682 Some usage examples of the video4linux2 device with @command{ffmpeg}
683 and @command{ffplay}:
686 Grab and show the input of a video4linux2 device:
688 ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
692 Grab and record the input of a video4linux2 device, leave the
693 frame rate and size as previously set:
695 ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
699 For more information about Video4Linux, check @url{http://linuxtv.org/}.
705 Set the standard. Must be the name of a supported standard. To get a
706 list of the supported standards, use the @option{list_standards}
710 Set the input channel number. Default to -1, which means using the
711 previously selected channel.
714 Set the video frame size. The argument must be a string in the form
715 @var{WIDTH}x@var{HEIGHT} or a valid size abbreviation.
718 Select the pixel format (only valid for raw video input).
721 Set the preferred pixel format (for raw video) or a codec name.
722 This option allows one to select the input format, when several are
726 Set the preferred video frame rate.
729 List available formats (supported pixel formats, codecs, and frame
732 Available values are:
735 Show all available (compressed and non-compressed) formats.
738 Show only raw video (non-compressed) formats.
741 Show only compressed formats.
745 List supported standards and exit.
747 Available values are:
750 Show all supported standards.
754 Set type of timestamps for grabbed frames.
756 Available values are:
759 Use timestamps from the kernel.
762 Use absolute timestamps (wall clock).
765 Force conversion from monotonic to absolute timestamps.
768 Default value is @code{default}.
773 VfW (Video for Windows) capture input device.
775 The filename passed as input is the capture driver number, ranging from
776 0 to 9. You may use "list" as filename to print a list of drivers. Any
777 other filename will be interpreted as device number 0.
781 X11 video input device.
783 This device allows one to capture a region of an X11 display.
785 The filename passed as input has the syntax:
787 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
790 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
791 X11 display name of the screen to grab from. @var{hostname} can be
792 omitted, and defaults to "localhost". The environment variable
793 @env{DISPLAY} contains the default display name.
795 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
796 area with respect to the top-left border of the X11 screen. They
799 Check the X11 documentation (e.g. man X) for more detailed information.
801 Use the @command{dpyinfo} program for getting basic information about the
802 properties of your X11 display (e.g. grep for "name" or "dimensions").
804 For example to grab from @file{:0.0} using @command{ffmpeg}:
806 ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg
809 Grab at position @code{10,20}:
811 ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
818 Specify whether to draw the mouse pointer. A value of @code{0} specify
819 not to draw the pointer. Default value is @code{1}.
822 Make the grabbed area follow the mouse. The argument can be
823 @code{centered} or a number of pixels @var{PIXELS}.
825 When it is specified with "centered", the grabbing region follows the mouse
826 pointer and keeps the pointer at the center of region; otherwise, the region
827 follows only when the mouse pointer reaches within @var{PIXELS} (greater than
828 zero) to the edge of region.
832 ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg
835 To follow only when the mouse pointer reaches within 100 pixels to edge:
837 ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg
841 Set the grabbing frame rate. Default value is @code{ntsc},
842 corresponding to a frame rate of @code{30000/1001}.
845 Show grabbed region on screen.
847 If @var{show_region} is specified with @code{1}, then the grabbing
848 region will be indicated on screen. With this option, it is easy to
849 know what is being grabbed if only a portion of the screen is grabbed.
853 ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
856 With @var{follow_mouse}:
858 ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg
862 Set the video frame size. Default value is @code{vga}.
865 @c man end INPUT DEVICES