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 "-devices" of the ff* tools will display the list of
17 supported input devices.
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 input filename has to be given in the following syntax:
63 -i "[[VIDEO]:[AUDIO]]"
65 The first entry selects the video input while the latter selects the audio input.
66 The stream has to be specified by the device name or the device index as shown by the device list.
67 Alternatively, the video and/or audio input device can be chosen by index using the
69 -video_device_index <INDEX>
73 -audio_device_index <INDEX>
76 device name or index given in the input filename.
78 All available devices can be enumerated by using @option{-list_devices true}, listing
79 all device names and corresponding indices.
81 There are two device name aliases:
85 Select the AVFoundation default device of the corresponding type.
88 Do not record the corresponding media type.
89 This is equivalent to specifying an empty device name or index.
95 AVFoundation supports the following options:
99 @item -list_devices <TRUE|FALSE>
100 If set to true, a list of all available input devices is given showing all
101 device names and indices.
103 @item -video_device_index <INDEX>
104 Specify the video device by its index. Overrides anything given in the input filename.
106 @item -audio_device_index <INDEX>
107 Specify the audio device by its index. Overrides anything given in the input filename.
109 @item -pixel_format <FORMAT>
110 Request the video device to use a specific pixel format.
111 If the specified format is not supported, a list of available formats is given
112 und the first one in this list is used instead. Available pixel formats are:
113 @code{monob, rgb555be, rgb555le, rgb565be, rgb565le, rgb24, bgr24, 0rgb, bgr0, 0bgr, rgb0,
114 bgr48be, uyvy422, yuva444p, yuva444p16le, yuv444p, yuv422p16, yuv422p10, yuv444p10,
115 yuv420p, nv12, yuyv422, gray}
124 Print the list of AVFoundation supported devices and exit:
126 $ ffmpeg -f avfoundation -list_devices true -i ""
130 Record video from video device 0 and audio from audio device 0 into out.avi:
132 $ ffmpeg -f avfoundation -i "0:0" out.avi
136 Record video from video device 2 and audio from audio device 1 into out.avi:
138 $ ffmpeg -f avfoundation -video_device_index 2 -i ":1" out.avi
142 Record video from the system default video device using the pixel format bgr0 and do not record any audio into out.avi:
144 $ ffmpeg -f avfoundation -pixel_format bgr0 -i "default:none" out.avi
151 BSD video input device.
155 Windows DirectShow input device.
157 DirectShow support is enabled when FFmpeg is built with the mingw-w64 project.
158 Currently only audio and video devices are supported.
160 Multiple devices may be opened as separate inputs, but they may also be
161 opened on the same input, which should improve synchronism between them.
163 The input name should be in the format:
166 @var{TYPE}=@var{NAME}[:@var{TYPE}=@var{NAME}]
169 where @var{TYPE} can be either @var{audio} or @var{video},
170 and @var{NAME} is the device's name.
174 If no options are specified, the device's defaults are used.
175 If the device does not support the requested options, it will
181 Set the video size in the captured video.
184 Set the frame rate in the captured video.
187 Set the sample rate (in Hz) of the captured audio.
190 Set the sample size (in bits) of the captured audio.
193 Set the number of channels in the captured audio.
196 If set to @option{true}, print a list of devices and exit.
199 If set to @option{true}, print a list of selected device's options
202 @item video_device_number
203 Set video device number for devices with same name (starts at 0,
206 @item audio_device_number
207 Set audio device number for devices with same name (starts at 0,
211 Select pixel format to be used by DirectShow. This may only be set when
212 the video codec is not set or set to rawvideo.
214 @item audio_buffer_size
215 Set audio device buffer size in milliseconds (which can directly
216 impact latency, depending on the device).
217 Defaults to using the audio device's
218 default buffer size (typically some multiple of 500ms).
219 Setting this value too low can degrade performance.
221 @url{http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx}
230 Print the list of DirectShow supported devices and exit:
232 $ ffmpeg -list_devices true -f dshow -i dummy
236 Open video device @var{Camera}:
238 $ ffmpeg -f dshow -i video="Camera"
242 Open second video device with name @var{Camera}:
244 $ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
248 Open video device @var{Camera} and audio device @var{Microphone}:
250 $ ffmpeg -f dshow -i video="Camera":audio="Microphone"
254 Print the list of supported options in selected device and exit:
256 $ ffmpeg -list_options true -f dshow -i video="Camera"
263 Linux DV 1394 input device.
267 Linux framebuffer input device.
269 The Linux framebuffer is a graphic hardware-independent abstraction
270 layer to show graphics on a computer monitor, typically on the
271 console. It is accessed through a file device node, usually
274 For more detailed information read the file
275 Documentation/fb/framebuffer.txt included in the Linux source tree.
277 To record from the framebuffer device @file{/dev/fb0} with
280 ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
283 You can take a single screenshot image with the command:
285 ffmpeg -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
288 See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
292 Win32 GDI-based screen capture device.
294 This device allows you to capture a region of the display on Windows.
296 There are two options for the input filename:
302 title=@var{window_title}
305 The first option will capture the entire desktop, or a fixed region of the
306 desktop. The second option will instead capture the contents of a single
307 window, regardless of its position on the screen.
309 For example, to grab the entire desktop using @command{ffmpeg}:
311 ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg
314 Grab a 640x480 region at position @code{10,20}:
316 ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg
319 Grab the contents of the window named "Calculator"
321 ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg
328 Specify whether to draw the mouse pointer. Use the value @code{0} to
329 not draw the pointer. Default value is @code{1}.
332 Set the grabbing frame rate. Default value is @code{ntsc},
333 corresponding to a frame rate of @code{30000/1001}.
336 Show grabbed region on screen.
338 If @var{show_region} is specified with @code{1}, then the grabbing
339 region will be indicated on screen. With this option, it is easy to
340 know what is being grabbed if only a portion of the screen is grabbed.
342 Note that @var{show_region} is incompatible with grabbing the contents
347 ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg
351 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.
354 When capturing a region with @var{video_size}, set the distance from the left edge of the screen or desktop.
356 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.
359 When capturing a region with @var{video_size}, set the distance from the top edge of the screen or desktop.
361 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.
367 FireWire DV/HDV input device using libiec61883.
369 To enable this input device, you need libiec61883, libraw1394 and
370 libavc1394 installed on your system. Use the configure option
371 @code{--enable-libiec61883} to compile with the device enabled.
373 The iec61883 capture device supports capturing from a video device
374 connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
375 FireWire stack (juju). This is the default DV/HDV input method in Linux
376 Kernel 2.6.37 and later, since the old FireWire stack was removed.
378 Specify the FireWire port to be used as input file, or "auto"
379 to choose the first port connected.
386 Override autodetection of DV/HDV. This should only be used if auto
387 detection does not work, or if usage of a different device type
388 should be prohibited. Treating a DV device as HDV (or vice versa) will
389 not work and result in undefined behavior.
390 The values @option{auto}, @option{dv} and @option{hdv} are supported.
393 Set maximum size of buffer for incoming data, in frames. For DV, this
394 is an exact value. For HDV, it is not frame exact, since HDV does
395 not have a fixed frame size.
398 Select the capture device by specifying it's GUID. Capturing will only
399 be performed from the specified device and fails if no device with the
400 given GUID is found. This is useful to select the input if multiple
401 devices are connected at the same time.
402 Look at /sys/bus/firewire/devices to find out the GUIDs.
411 Grab and show the input of a FireWire DV/HDV device.
413 ffplay -f iec61883 -i auto
417 Grab and record the input of a FireWire DV/HDV device,
418 using a packet buffer of 100000 packets if the source is HDV.
420 ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
429 To enable this input device during configuration you need libjack
430 installed on your system.
432 A JACK input device creates one or more JACK writable clients, one for
433 each audio channel, with name @var{client_name}:input_@var{N}, where
434 @var{client_name} is the name provided by the application, and @var{N}
435 is a number which identifies the channel.
436 Each writable client will send the acquired data to the FFmpeg input
439 Once you have created one or more JACK readable clients, you need to
440 connect them to one or more JACK writable clients.
442 To connect or disconnect JACK clients you can use the @command{jack_connect}
443 and @command{jack_disconnect} programs, or do it through a graphical interface,
444 for example with @command{qjackctl}.
446 To list the JACK clients and their properties you can invoke the command
449 Follows an example which shows how to capture a JACK readable client
450 with @command{ffmpeg}.
452 # Create a JACK writable client with name "ffmpeg".
453 $ ffmpeg -f jack -i ffmpeg -y out.wav
455 # Start the sample jack_metro readable client.
456 $ jack_metro -b 120 -d 0.2 -f 4000
458 # List the current JACK clients.
467 # Connect metro to the ffmpeg writable client.
468 $ jack_connect metro:120_bpm ffmpeg:input_1
471 For more information read:
472 @url{http://jackaudio.org/}
476 Libavfilter input virtual device.
478 This input device reads data from the open output pads of a libavfilter
481 For each filtergraph open output, the input device will create a
482 corresponding stream which is mapped to the generated output. Currently
483 only video data is supported. The filtergraph is specified through the
484 option @option{graph}.
491 Specify the filtergraph to use as input. Each video open output must be
492 labelled by a unique string of the form "out@var{N}", where @var{N} is a
493 number starting from 0 corresponding to the mapped input stream
494 generated by the device.
495 The first unlabelled output is automatically assigned to the "out0"
496 label, but all the others need to be specified explicitly.
498 The suffix "+subcc" can be appended to the output label to create an extra
499 stream with the closed captions packets attached to that output
500 (experimental; only for EIA-608 / CEA-708 for now).
501 The subcc streams are created after all the normal streams, in the order of
502 the corresponding stream.
503 For example, if there is "out19+subcc", "out7+subcc" and up to "out42", the
504 stream #43 is subcc for stream #7 and stream #44 is subcc for stream #19.
506 If not specified defaults to the filename specified for the input
510 Set the filename of the filtergraph to be read and sent to the other
511 filters. Syntax of the filtergraph is the same as the one specified by
512 the option @var{graph}.
520 Create a color video stream and play it back with @command{ffplay}:
522 ffplay -f lavfi -graph "color=c=pink [out0]" dummy
526 As the previous example, but use filename for specifying the graph
527 description, and omit the "out0" label:
529 ffplay -f lavfi color=c=pink
533 Create three different video test filtered sources and play them:
535 ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
539 Read an audio stream from a file using the amovie source and play it
540 back with @command{ffplay}:
542 ffplay -f lavfi "amovie=test.wav"
546 Read an audio stream and a video stream and play it back with
549 ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
553 Dump decoded frames to images and closed captions to a file (experimental):
555 ffmpeg -f lavfi -i "movie=test.ts[out0+subcc]" -map v frame%08d.png -map s -c copy -f rawvideo subcc.bin
562 Audio-CD input device based on cdio.
564 To enable this input device during configuration you need libcdio
565 installed on your system. Requires the configure option
566 @code{--enable-libcdio}.
568 This device allows playing and grabbing from an Audio-CD.
570 For example to copy with @command{ffmpeg} the entire Audio-CD in /dev/sr0,
571 you may run the command:
573 ffmpeg -f libcdio -i /dev/sr0 cd.wav
578 IIDC1394 input device, based on libdc1394 and libraw1394.
580 Requires the configure option @code{--enable-libdc1394}.
584 The OpenAL input device provides audio capture on all systems with a
585 working OpenAL 1.1 implementation.
587 To enable this input device during configuration, you need OpenAL
588 headers and libraries installed on your system, and need to configure
589 FFmpeg with @code{--enable-openal}.
591 OpenAL headers and libraries should be provided as part of your OpenAL
592 implementation, or as an additional download (an SDK). Depending on your
593 installation you may need to specify additional flags via the
594 @code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
595 system to locate the OpenAL headers and libraries.
597 An incomplete list of OpenAL implementations follows:
601 The official Windows implementation, providing hardware acceleration
602 with supported devices and software fallback.
603 See @url{http://openal.org/}.
605 Portable, open source (LGPL) software implementation. Includes
606 backends for the most common sound APIs on the Windows, Linux,
607 Solaris, and BSD operating systems.
608 See @url{http://kcat.strangesoft.net/openal.html}.
610 OpenAL is part of Core Audio, the official Mac OS X Audio interface.
611 See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
614 This device allows one to capture from an audio input device handled
617 You need to specify the name of the device to capture in the provided
618 filename. If the empty string is provided, the device will
619 automatically select the default device. You can get the list of the
620 supported devices by using the option @var{list_devices}.
627 Set the number of channels in the captured audio. Only the values
628 @option{1} (monaural) and @option{2} (stereo) are currently supported.
629 Defaults to @option{2}.
632 Set the sample size (in bits) of the captured audio. Only the values
633 @option{8} and @option{16} are currently supported. Defaults to
637 Set the sample rate (in Hz) of the captured audio.
638 Defaults to @option{44.1k}.
641 If set to @option{true}, print a list of devices and exit.
642 Defaults to @option{false}.
648 Print the list of OpenAL supported devices and exit:
650 $ ffmpeg -list_devices true -f openal -i dummy out.ogg
653 Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
655 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
658 Capture from the default device (note the empty string '' as filename):
660 $ ffmpeg -f openal -i '' out.ogg
663 Capture from two devices simultaneously, writing to two different files,
664 within the same @command{ffmpeg} command:
666 $ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
668 Note: not all OpenAL implementations support multiple simultaneous capture -
669 try the latest OpenAL Soft if the above does not work.
673 Open Sound System input device.
675 The filename to provide to the input device is the device node
676 representing the OSS input device, and is usually set to
679 For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the
682 ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
685 For more information about OSS see:
686 @url{http://manuals.opensound.com/usersguide/dsp.html}
690 PulseAudio input device.
692 To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
694 The filename to provide to the input device is a source device or the
697 To list the PulseAudio source devices and their properties you can invoke
698 the command @command{pactl list sources}.
700 More information about PulseAudio can be found on @url{http://www.pulseaudio.org}.
705 Connect to a specific PulseAudio server, specified by an IP address.
706 Default server is used when not provided.
709 Specify the application name PulseAudio will use when showing active clients,
710 by default it is the @code{LIBAVFORMAT_IDENT} string.
713 Specify the stream name PulseAudio will use when showing active streams,
714 by default it is "record".
717 Specify the samplerate in Hz, by default 48kHz is used.
720 Specify the channels in use, by default 2 (stereo) is set.
723 Specify the number of bytes per frame, by default it is set to 1024.
726 Specify the minimal buffering fragment in PulseAudio, it will affect the
727 audio latency. By default it is unset.
731 Record a stream from default device:
733 ffmpeg -f pulse -i default /tmp/pulse.wav
740 The filename passed as input is parsed to contain either a device name or index.
741 The device index can also be given by using -video_device_index.
742 A given device index will override any given device name.
743 If the desired device consists of numbers only, use -video_device_index to identify it.
744 The default device will be chosen if an empty string or the device name "default" is given.
745 The available devices can be enumerated by using -list_devices.
748 ffmpeg -f qtkit -i "0" out.mpg
752 ffmpeg -f qtkit -video_device_index 0 -i "" out.mpg
756 ffmpeg -f qtkit -i "default" out.mpg
760 ffmpeg -f qtkit -list_devices true -i ""
767 To enable this input device during configuration you need libsndio
768 installed on your system.
770 The filename to provide to the input device is the device node
771 representing the sndio input device, and is usually set to
774 For example to grab from @file{/dev/audio0} using @command{ffmpeg} use the
777 ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
780 @section video4linux2, v4l2
782 Video4Linux2 input video device.
784 "v4l2" can be used as alias for "video4linux2".
786 If FFmpeg is built with v4l-utils support (by using the
787 @code{--enable-libv4l2} configure option), it is possible to use it with the
788 @code{-use_libv4l2} input device option.
790 The name of the device to grab is a file device node, usually Linux
791 systems tend to automatically create such nodes when the device
792 (e.g. an USB webcam) is plugged into the system, and has a name of the
793 kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
796 Video4Linux2 devices usually support a limited set of
797 @var{width}x@var{height} sizes and frame rates. You can check which are
798 supported using @command{-list_formats all} for Video4Linux2 devices.
799 Some devices, like TV cards, support one or more standards. It is possible
800 to list all the supported standards using @command{-list_standards all}.
802 The time base for the timestamps is 1 microsecond. Depending on the kernel
803 version and configuration, the timestamps may be derived from the real time
804 clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
805 boot time, unaffected by NTP or manual changes to the clock). The
806 @option{-timestamps abs} or @option{-ts abs} option can be used to force
807 conversion into the real time clock.
809 Some usage examples of the video4linux2 device with @command{ffmpeg}
810 and @command{ffplay}:
813 Grab and show the input of a video4linux2 device:
815 ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
819 Grab and record the input of a video4linux2 device, leave the
820 frame rate and size as previously set:
822 ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
826 For more information about Video4Linux, check @url{http://linuxtv.org/}.
832 Set the standard. Must be the name of a supported standard. To get a
833 list of the supported standards, use the @option{list_standards}
837 Set the input channel number. Default to -1, which means using the
838 previously selected channel.
841 Set the video frame size. The argument must be a string in the form
842 @var{WIDTH}x@var{HEIGHT} or a valid size abbreviation.
845 Select the pixel format (only valid for raw video input).
848 Set the preferred pixel format (for raw video) or a codec name.
849 This option allows one to select the input format, when several are
853 Set the preferred video frame rate.
856 List available formats (supported pixel formats, codecs, and frame
859 Available values are:
862 Show all available (compressed and non-compressed) formats.
865 Show only raw video (non-compressed) formats.
868 Show only compressed formats.
872 List supported standards and exit.
874 Available values are:
877 Show all supported standards.
881 Set type of timestamps for grabbed frames.
883 Available values are:
886 Use timestamps from the kernel.
889 Use absolute timestamps (wall clock).
892 Force conversion from monotonic to absolute timestamps.
895 Default value is @code{default}.
900 VfW (Video for Windows) capture input device.
902 The filename passed as input is the capture driver number, ranging from
903 0 to 9. You may use "list" as filename to print a list of drivers. Any
904 other filename will be interpreted as device number 0.
908 X11 video input device.
910 Depends on X11, Xext, and Xfixes. Requires the configure option
911 @code{--enable-x11grab}.
913 This device allows one to capture a region of an X11 display.
915 The filename passed as input has the syntax:
917 [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
920 @var{hostname}:@var{display_number}.@var{screen_number} specifies the
921 X11 display name of the screen to grab from. @var{hostname} can be
922 omitted, and defaults to "localhost". The environment variable
923 @env{DISPLAY} contains the default display name.
925 @var{x_offset} and @var{y_offset} specify the offsets of the grabbed
926 area with respect to the top-left border of the X11 screen. They
929 Check the X11 documentation (e.g. man X) for more detailed information.
931 Use the @command{dpyinfo} program for getting basic information about the
932 properties of your X11 display (e.g. grep for "name" or "dimensions").
934 For example to grab from @file{:0.0} using @command{ffmpeg}:
936 ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg
939 Grab at position @code{10,20}:
941 ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
948 Specify whether to draw the mouse pointer. A value of @code{0} specify
949 not to draw the pointer. Default value is @code{1}.
952 Make the grabbed area follow the mouse. The argument can be
953 @code{centered} or a number of pixels @var{PIXELS}.
955 When it is specified with "centered", the grabbing region follows the mouse
956 pointer and keeps the pointer at the center of region; otherwise, the region
957 follows only when the mouse pointer reaches within @var{PIXELS} (greater than
958 zero) to the edge of region.
962 ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg
965 To follow only when the mouse pointer reaches within 100 pixels to edge:
967 ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg
971 Set the grabbing frame rate. Default value is @code{ntsc},
972 corresponding to a frame rate of @code{30000/1001}.
975 Show grabbed region on screen.
977 If @var{show_region} is specified with @code{1}, then the grabbing
978 region will be indicated on screen. With this option, it is easy to
979 know what is being grabbed if only a portion of the screen is grabbed.
983 ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
986 With @var{follow_mouse}:
988 ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg
992 Set the video frame size. Default value is @code{vga}.
995 Use the MIT-SHM extension for shared memory. Default value is @code{1}.
996 It may be necessary to disable it for remote displays.
1001 The decklink input device provides capture capabilities for Blackmagic
1004 To enable this input device, you need the Blackmagic DeckLink SDK and you
1005 need to configure with the appropriate @code{--extra-cflags}
1006 and @code{--extra-ldflags}.
1007 On Windows, you need to run the IDL files through @command{widl}.
1009 DeckLink is very picky about the formats it supports. Pixel format is always
1010 uyvy422, framerate and video size must be determined for your device with
1011 @command{-list_formats 1}. Audio sample rate is always 48 kHz and the number
1012 of channels currently is limited to 2 (stereo).
1019 If set to @option{true}, print a list of devices and exit.
1020 Defaults to @option{false}.
1023 If set to @option{true}, print a list of supported formats and exit.
1024 Defaults to @option{false}.
1028 @subsection Examples
1035 ffmpeg -f decklink -list_devices 1 -i dummy
1039 List supported formats:
1041 ffmpeg -f decklink -list_formats 1 -i 'Intensity Pro'
1045 Capture video clip at 1080i50 (format 11):
1047 ffmpeg -f decklink -i 'Intensity Pro@@11' -acodec copy -vcodec copy output.avi
1053 @c man end INPUT DEVICES