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ffe6ecc418
Signed-off-by: Thilo Borgmann <thilo.borgmann@mail.de> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
901 lines
26 KiB
Plaintext
901 lines
26 KiB
Plaintext
@chapter Input Devices
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@c man begin INPUT DEVICES
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Input devices are configured elements in FFmpeg which allow to access
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the data coming from a multimedia device attached to your system.
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When you configure your FFmpeg build, all the supported input devices
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are enabled by default. You can list all available ones using the
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configure option "--list-indevs".
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You can disable all the input devices using the configure option
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"--disable-indevs", and selectively enable an input device using the
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option "--enable-indev=@var{INDEV}", or you can disable a particular
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input device using the option "--disable-indev=@var{INDEV}".
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The option "-devices" of the ff* tools will display the list of
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supported input devices.
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A description of the currently available input devices follows.
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@section alsa
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ALSA (Advanced Linux Sound Architecture) input device.
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To enable this input device during configuration you need libasound
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installed on your system.
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This device allows capturing from an ALSA device. The name of the
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device to capture has to be an ALSA card identifier.
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An ALSA identifier has the syntax:
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@example
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hw:@var{CARD}[,@var{DEV}[,@var{SUBDEV}]]
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@end example
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where the @var{DEV} and @var{SUBDEV} components are optional.
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The three arguments (in order: @var{CARD},@var{DEV},@var{SUBDEV})
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specify card number or identifier, device number and subdevice number
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(-1 means any).
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To see the list of cards currently recognized by your system check the
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files @file{/proc/asound/cards} and @file{/proc/asound/devices}.
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For example to capture with @command{ffmpeg} from an ALSA device with
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card id 0, you may run the command:
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@example
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ffmpeg -f alsa -i hw:0 alsaout.wav
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@end example
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For more information see:
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@url{http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html}
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@section avfoundation
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AVFoundation input device.
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AVFoundation is the currently recommended framework by Apple for streamgrabbing on OSX >= 10.7 as well as on iOS.
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The older QTKit framework has been marked deprecated since OSX version 10.7.
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The filename passed as input is parsed to contain either a device name or index.
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The device index can also be given by using -video_device_index.
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A given device index will override any given device name.
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If the desired device consists of numbers only, use -video_device_index to identify it.
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The default device will be chosen if an empty string or the device name "default" is given.
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The available devices can be enumerated by using -list_devices.
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The pixel format can be set using -pixel_format.
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Available formats:
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monob, rgb555be, rgb555le, rgb565be, rgb565le, rgb24, bgr24, 0rgb, bgr0, 0bgr, rgb0,
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bgr48be, uyvy422, yuva444p, yuva444p16le, yuv444p, yuv422p16, yuv422p10, yuv444p10,
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yuv420p, nv12, yuyv422, gray
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@example
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ffmpeg -f avfoundation -i "0" out.mpg
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@end example
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@example
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ffmpeg -f avfoundation -video_device_index 0 -i "" out.mpg
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@end example
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@example
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ffmpeg -f avfoundation -pixel_format bgr0 -i "default" out.mpg
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@end example
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@example
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ffmpeg -f avfoundation -list_devices true -i ""
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@end example
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@section bktr
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BSD video input device.
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@section dshow
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Windows DirectShow input device.
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DirectShow support is enabled when FFmpeg is built with the mingw-w64 project.
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Currently only audio and video devices are supported.
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Multiple devices may be opened as separate inputs, but they may also be
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opened on the same input, which should improve synchronism between them.
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The input name should be in the format:
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@example
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@var{TYPE}=@var{NAME}[:@var{TYPE}=@var{NAME}]
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@end example
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where @var{TYPE} can be either @var{audio} or @var{video},
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and @var{NAME} is the device's name.
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@subsection Options
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If no options are specified, the device's defaults are used.
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If the device does not support the requested options, it will
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fail to open.
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@table @option
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@item video_size
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Set the video size in the captured video.
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@item framerate
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Set the frame rate in the captured video.
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@item sample_rate
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Set the sample rate (in Hz) of the captured audio.
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@item sample_size
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Set the sample size (in bits) of the captured audio.
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@item channels
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Set the number of channels in the captured audio.
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@item list_devices
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If set to @option{true}, print a list of devices and exit.
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@item list_options
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If set to @option{true}, print a list of selected device's options
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and exit.
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@item video_device_number
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Set video device number for devices with same name (starts at 0,
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defaults to 0).
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@item audio_device_number
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Set audio device number for devices with same name (starts at 0,
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defaults to 0).
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@item pixel_format
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Select pixel format to be used by DirectShow. This may only be set when
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the video codec is not set or set to rawvideo.
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@item audio_buffer_size
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Set audio device buffer size in milliseconds (which can directly
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impact latency, depending on the device).
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Defaults to using the audio device's
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default buffer size (typically some multiple of 500ms).
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Setting this value too low can degrade performance.
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See also
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@url{http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx}
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@end table
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@subsection Examples
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@itemize
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@item
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Print the list of DirectShow supported devices and exit:
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@example
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$ ffmpeg -list_devices true -f dshow -i dummy
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@end example
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@item
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Open video device @var{Camera}:
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@example
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$ ffmpeg -f dshow -i video="Camera"
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@end example
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@item
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Open second video device with name @var{Camera}:
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@example
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$ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
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@end example
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@item
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Open video device @var{Camera} and audio device @var{Microphone}:
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@example
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$ ffmpeg -f dshow -i video="Camera":audio="Microphone"
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@end example
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@item
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Print the list of supported options in selected device and exit:
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@example
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$ ffmpeg -list_options true -f dshow -i video="Camera"
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@end example
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@end itemize
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@section dv1394
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Linux DV 1394 input device.
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@section fbdev
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Linux framebuffer input device.
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The Linux framebuffer is a graphic hardware-independent abstraction
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layer to show graphics on a computer monitor, typically on the
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console. It is accessed through a file device node, usually
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@file{/dev/fb0}.
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For more detailed information read the file
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Documentation/fb/framebuffer.txt included in the Linux source tree.
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To record from the framebuffer device @file{/dev/fb0} with
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@command{ffmpeg}:
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@example
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ffmpeg -f fbdev -r 10 -i /dev/fb0 out.avi
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@end example
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You can take a single screenshot image with the command:
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@example
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ffmpeg -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg
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@end example
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See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
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@section gdigrab
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Win32 GDI-based screen capture device.
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This device allows you to capture a region of the display on Windows.
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There are two options for the input filename:
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@example
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desktop
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@end example
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or
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@example
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title=@var{window_title}
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@end example
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The first option will capture the entire desktop, or a fixed region of the
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desktop. The second option will instead capture the contents of a single
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window, regardless of its position on the screen.
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For example, to grab the entire desktop using @command{ffmpeg}:
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@example
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ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg
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@end example
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Grab a 640x480 region at position @code{10,20}:
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@example
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ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg
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@end example
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Grab the contents of the window named "Calculator"
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@example
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ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg
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@end example
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@subsection Options
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@table @option
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@item draw_mouse
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Specify whether to draw the mouse pointer. Use the value @code{0} to
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not draw the pointer. Default value is @code{1}.
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@item framerate
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Set the grabbing frame rate. Default value is @code{ntsc},
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corresponding to a frame rate of @code{30000/1001}.
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@item show_region
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Show grabbed region on screen.
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If @var{show_region} is specified with @code{1}, then the grabbing
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region will be indicated on screen. With this option, it is easy to
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know what is being grabbed if only a portion of the screen is grabbed.
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Note that @var{show_region} is incompatible with grabbing the contents
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of a single window.
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For example:
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@example
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ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg
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@end example
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@item video_size
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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.
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@item offset_x
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When capturing a region with @var{video_size}, set the distance from the left edge of the screen or desktop.
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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.
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@item offset_y
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When capturing a region with @var{video_size}, set the distance from the top edge of the screen or desktop.
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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.
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@end table
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@section iec61883
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FireWire DV/HDV input device using libiec61883.
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To enable this input device, you need libiec61883, libraw1394 and
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libavc1394 installed on your system. Use the configure option
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@code{--enable-libiec61883} to compile with the device enabled.
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The iec61883 capture device supports capturing from a video device
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connected via IEEE1394 (FireWire), using libiec61883 and the new Linux
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FireWire stack (juju). This is the default DV/HDV input method in Linux
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Kernel 2.6.37 and later, since the old FireWire stack was removed.
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Specify the FireWire port to be used as input file, or "auto"
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to choose the first port connected.
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@subsection Options
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@table @option
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@item dvtype
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Override autodetection of DV/HDV. This should only be used if auto
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detection does not work, or if usage of a different device type
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should be prohibited. Treating a DV device as HDV (or vice versa) will
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not work and result in undefined behavior.
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The values @option{auto}, @option{dv} and @option{hdv} are supported.
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@item dvbuffer
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Set maxiumum size of buffer for incoming data, in frames. For DV, this
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is an exact value. For HDV, it is not frame exact, since HDV does
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not have a fixed frame size.
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@item dvguid
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Select the capture device by specifying it's GUID. Capturing will only
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be performed from the specified device and fails if no device with the
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given GUID is found. This is useful to select the input if multiple
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devices are connected at the same time.
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Look at /sys/bus/firewire/devices to find out the GUIDs.
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@end table
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@subsection Examples
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@itemize
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@item
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Grab and show the input of a FireWire DV/HDV device.
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@example
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ffplay -f iec61883 -i auto
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@end example
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@item
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Grab and record the input of a FireWire DV/HDV device,
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using a packet buffer of 100000 packets if the source is HDV.
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@example
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ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg
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@end example
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@end itemize
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@section jack
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JACK input device.
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To enable this input device during configuration you need libjack
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installed on your system.
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A JACK input device creates one or more JACK writable clients, one for
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each audio channel, with name @var{client_name}:input_@var{N}, where
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@var{client_name} is the name provided by the application, and @var{N}
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is a number which identifies the channel.
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Each writable client will send the acquired data to the FFmpeg input
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device.
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Once you have created one or more JACK readable clients, you need to
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connect them to one or more JACK writable clients.
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To connect or disconnect JACK clients you can use the @command{jack_connect}
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and @command{jack_disconnect} programs, or do it through a graphical interface,
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for example with @command{qjackctl}.
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To list the JACK clients and their properties you can invoke the command
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@command{jack_lsp}.
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Follows an example which shows how to capture a JACK readable client
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with @command{ffmpeg}.
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@example
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# Create a JACK writable client with name "ffmpeg".
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$ ffmpeg -f jack -i ffmpeg -y out.wav
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# Start the sample jack_metro readable client.
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$ jack_metro -b 120 -d 0.2 -f 4000
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# List the current JACK clients.
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$ jack_lsp -c
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system:capture_1
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system:capture_2
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system:playback_1
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system:playback_2
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ffmpeg:input_1
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metro:120_bpm
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# Connect metro to the ffmpeg writable client.
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$ jack_connect metro:120_bpm ffmpeg:input_1
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@end example
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For more information read:
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@url{http://jackaudio.org/}
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@section lavfi
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Libavfilter input virtual device.
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This input device reads data from the open output pads of a libavfilter
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filtergraph.
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For each filtergraph open output, the input device will create a
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corresponding stream which is mapped to the generated output. Currently
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only video data is supported. The filtergraph is specified through the
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option @option{graph}.
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@subsection Options
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@table @option
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@item graph
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Specify the filtergraph to use as input. Each video open output must be
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labelled by a unique string of the form "out@var{N}", where @var{N} is a
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number starting from 0 corresponding to the mapped input stream
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generated by the device.
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The first unlabelled output is automatically assigned to the "out0"
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label, but all the others need to be specified explicitly.
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If not specified defaults to the filename specified for the input
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device.
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@item graph_file
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Set the filename of the filtergraph to be read and sent to the other
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filters. Syntax of the filtergraph is the same as the one specified by
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the option @var{graph}.
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@end table
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@subsection Examples
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@itemize
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@item
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Create a color video stream and play it back with @command{ffplay}:
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@example
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ffplay -f lavfi -graph "color=c=pink [out0]" dummy
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@end example
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@item
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As the previous example, but use filename for specifying the graph
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description, and omit the "out0" label:
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@example
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ffplay -f lavfi color=c=pink
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@end example
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@item
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Create three different video test filtered sources and play them:
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@example
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ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
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@end example
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@item
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Read an audio stream from a file using the amovie source and play it
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back with @command{ffplay}:
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@example
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ffplay -f lavfi "amovie=test.wav"
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@end example
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@item
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Read an audio stream and a video stream and play it back with
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@command{ffplay}:
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@example
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ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
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@end example
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@end itemize
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@section libdc1394
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IIDC1394 input device, based on libdc1394 and libraw1394.
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@section openal
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The OpenAL input device provides audio capture on all systems with a
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working OpenAL 1.1 implementation.
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To enable this input device during configuration, you need OpenAL
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headers and libraries installed on your system, and need to configure
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FFmpeg with @code{--enable-openal}.
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OpenAL headers and libraries should be provided as part of your OpenAL
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implementation, or as an additional download (an SDK). Depending on your
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installation you may need to specify additional flags via the
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@code{--extra-cflags} and @code{--extra-ldflags} for allowing the build
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system to locate the OpenAL headers and libraries.
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An incomplete list of OpenAL implementations follows:
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@table @strong
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@item Creative
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The official Windows implementation, providing hardware acceleration
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with supported devices and software fallback.
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See @url{http://openal.org/}.
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@item OpenAL Soft
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Portable, open source (LGPL) software implementation. Includes
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backends for the most common sound APIs on the Windows, Linux,
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Solaris, and BSD operating systems.
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See @url{http://kcat.strangesoft.net/openal.html}.
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@item Apple
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OpenAL is part of Core Audio, the official Mac OS X Audio interface.
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See @url{http://developer.apple.com/technologies/mac/audio-and-video.html}
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@end table
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This device allows one to capture from an audio input device handled
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through OpenAL.
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You need to specify the name of the device to capture in the provided
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filename. If the empty string is provided, the device will
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automatically select the default device. You can get the list of the
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supported devices by using the option @var{list_devices}.
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@subsection Options
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@table @option
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@item channels
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Set the number of channels in the captured audio. Only the values
|
|
@option{1} (monaural) and @option{2} (stereo) are currently supported.
|
|
Defaults to @option{2}.
|
|
|
|
@item sample_size
|
|
Set the sample size (in bits) of the captured audio. Only the values
|
|
@option{8} and @option{16} are currently supported. Defaults to
|
|
@option{16}.
|
|
|
|
@item sample_rate
|
|
Set the sample rate (in Hz) of the captured audio.
|
|
Defaults to @option{44.1k}.
|
|
|
|
@item list_devices
|
|
If set to @option{true}, print a list of devices and exit.
|
|
Defaults to @option{false}.
|
|
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
Print the list of OpenAL supported devices and exit:
|
|
@example
|
|
$ ffmpeg -list_devices true -f openal -i dummy out.ogg
|
|
@end example
|
|
|
|
Capture from the OpenAL device @file{DR-BT101 via PulseAudio}:
|
|
@example
|
|
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
|
|
@end example
|
|
|
|
Capture from the default device (note the empty string '' as filename):
|
|
@example
|
|
$ ffmpeg -f openal -i '' out.ogg
|
|
@end example
|
|
|
|
Capture from two devices simultaneously, writing to two different files,
|
|
within the same @command{ffmpeg} command:
|
|
@example
|
|
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
|
|
@end example
|
|
Note: not all OpenAL implementations support multiple simultaneous capture -
|
|
try the latest OpenAL Soft if the above does not work.
|
|
|
|
@section oss
|
|
|
|
Open Sound System input device.
|
|
|
|
The filename to provide to the input device is the device node
|
|
representing the OSS input device, and is usually set to
|
|
@file{/dev/dsp}.
|
|
|
|
For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the
|
|
command:
|
|
@example
|
|
ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
|
|
@end example
|
|
|
|
For more information about OSS see:
|
|
@url{http://manuals.opensound.com/usersguide/dsp.html}
|
|
|
|
@section pulse
|
|
|
|
PulseAudio input device.
|
|
|
|
To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
|
|
|
|
The filename to provide to the input device is a source device or the
|
|
string "default"
|
|
|
|
To list the PulseAudio source devices and their properties you can invoke
|
|
the command @command{pactl list sources}.
|
|
|
|
More information about PulseAudio can be found on @url{http://www.pulseaudio.org}.
|
|
|
|
@subsection Options
|
|
@table @option
|
|
@item server
|
|
Connect to a specific PulseAudio server, specified by an IP address.
|
|
Default server is used when not provided.
|
|
|
|
@item name
|
|
Specify the application name PulseAudio will use when showing active clients,
|
|
by default it is the @code{LIBAVFORMAT_IDENT} string.
|
|
|
|
@item stream_name
|
|
Specify the stream name PulseAudio will use when showing active streams,
|
|
by default it is "record".
|
|
|
|
@item sample_rate
|
|
Specify the samplerate in Hz, by default 48kHz is used.
|
|
|
|
@item channels
|
|
Specify the channels in use, by default 2 (stereo) is set.
|
|
|
|
@item frame_size
|
|
Specify the number of bytes per frame, by default it is set to 1024.
|
|
|
|
@item fragment_size
|
|
Specify the minimal buffering fragment in PulseAudio, it will affect the
|
|
audio latency. By default it is unset.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
Record a stream from default device:
|
|
@example
|
|
ffmpeg -f pulse -i default /tmp/pulse.wav
|
|
@end example
|
|
|
|
@section qtkit
|
|
|
|
QTKit input device.
|
|
|
|
The filename passed as input is parsed to contain either a device name or index.
|
|
The device index can also be given by using -video_device_index.
|
|
A given device index will override any given device name.
|
|
If the desired device consists of numbers only, use -video_device_index to identify it.
|
|
The default device will be chosen if an empty string or the device name "default" is given.
|
|
The available devices can be enumerated by using -list_devices.
|
|
|
|
@example
|
|
ffmpeg -f qtkit -i "0" out.mpg
|
|
@end example
|
|
|
|
@example
|
|
ffmpeg -f qtkit -video_device_index 0 -i "" out.mpg
|
|
@end example
|
|
|
|
@example
|
|
ffmpeg -f qtkit -i "default" out.mpg
|
|
@end example
|
|
|
|
@example
|
|
ffmpeg -f qtkit -list_devices true -i ""
|
|
@end example
|
|
|
|
@section sndio
|
|
|
|
sndio input device.
|
|
|
|
To enable this input device during configuration you need libsndio
|
|
installed on your system.
|
|
|
|
The filename to provide to the input device is the device node
|
|
representing the sndio input device, and is usually set to
|
|
@file{/dev/audio0}.
|
|
|
|
For example to grab from @file{/dev/audio0} using @command{ffmpeg} use the
|
|
command:
|
|
@example
|
|
ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
|
|
@end example
|
|
|
|
@section video4linux2, v4l2
|
|
|
|
Video4Linux2 input video device.
|
|
|
|
"v4l2" can be used as alias for "video4linux2".
|
|
|
|
If FFmpeg is built with v4l-utils support (by using the
|
|
@code{--enable-libv4l2} configure option), it is possible to use it with the
|
|
@code{-use_libv4l2} input device option.
|
|
|
|
The name of the device to grab is a file device node, usually Linux
|
|
systems tend to automatically create such nodes when the device
|
|
(e.g. an USB webcam) is plugged into the system, and has a name of the
|
|
kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
|
|
the device.
|
|
|
|
Video4Linux2 devices usually support a limited set of
|
|
@var{width}x@var{height} sizes and frame rates. You can check which are
|
|
supported using @command{-list_formats all} for Video4Linux2 devices.
|
|
Some devices, like TV cards, support one or more standards. It is possible
|
|
to list all the supported standards using @command{-list_standards all}.
|
|
|
|
The time base for the timestamps is 1 microsecond. Depending on the kernel
|
|
version and configuration, the timestamps may be derived from the real time
|
|
clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
|
|
boot time, unaffected by NTP or manual changes to the clock). The
|
|
@option{-timestamps abs} or @option{-ts abs} option can be used to force
|
|
conversion into the real time clock.
|
|
|
|
Some usage examples of the video4linux2 device with @command{ffmpeg}
|
|
and @command{ffplay}:
|
|
@itemize
|
|
@item
|
|
Grab and show the input of a video4linux2 device:
|
|
@example
|
|
ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
|
|
@end example
|
|
|
|
@item
|
|
Grab and record the input of a video4linux2 device, leave the
|
|
frame rate and size as previously set:
|
|
@example
|
|
ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
|
|
@end example
|
|
@end itemize
|
|
|
|
For more information about Video4Linux, check @url{http://linuxtv.org/}.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
@item standard
|
|
Set the standard. Must be the name of a supported standard. To get a
|
|
list of the supported standards, use the @option{list_standards}
|
|
option.
|
|
|
|
@item channel
|
|
Set the input channel number. Default to -1, which means using the
|
|
previously selected channel.
|
|
|
|
@item video_size
|
|
Set the video frame size. The argument must be a string in the form
|
|
@var{WIDTH}x@var{HEIGHT} or a valid size abbreviation.
|
|
|
|
@item pixel_format
|
|
Select the pixel format (only valid for raw video input).
|
|
|
|
@item input_format
|
|
Set the preferred pixel format (for raw video) or a codec name.
|
|
This option allows one to select the input format, when several are
|
|
available.
|
|
|
|
@item framerate
|
|
Set the preferred video frame rate.
|
|
|
|
@item list_formats
|
|
List available formats (supported pixel formats, codecs, and frame
|
|
sizes) and exit.
|
|
|
|
Available values are:
|
|
@table @samp
|
|
@item all
|
|
Show all available (compressed and non-compressed) formats.
|
|
|
|
@item raw
|
|
Show only raw video (non-compressed) formats.
|
|
|
|
@item compressed
|
|
Show only compressed formats.
|
|
@end table
|
|
|
|
@item list_standards
|
|
List supported standards and exit.
|
|
|
|
Available values are:
|
|
@table @samp
|
|
@item all
|
|
Show all supported standards.
|
|
@end table
|
|
|
|
@item timestamps, ts
|
|
Set type of timestamps for grabbed frames.
|
|
|
|
Available values are:
|
|
@table @samp
|
|
@item default
|
|
Use timestamps from the kernel.
|
|
|
|
@item abs
|
|
Use absolute timestamps (wall clock).
|
|
|
|
@item mono2abs
|
|
Force conversion from monotonic to absolute timestamps.
|
|
@end table
|
|
|
|
Default value is @code{default}.
|
|
@end table
|
|
|
|
@section vfwcap
|
|
|
|
VfW (Video for Windows) capture input device.
|
|
|
|
The filename passed as input is the capture driver number, ranging from
|
|
0 to 9. You may use "list" as filename to print a list of drivers. Any
|
|
other filename will be interpreted as device number 0.
|
|
|
|
@section x11grab
|
|
|
|
X11 video input device.
|
|
|
|
This device allows one to capture a region of an X11 display.
|
|
|
|
The filename passed as input has the syntax:
|
|
@example
|
|
[@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}]
|
|
@end example
|
|
|
|
@var{hostname}:@var{display_number}.@var{screen_number} specifies the
|
|
X11 display name of the screen to grab from. @var{hostname} can be
|
|
omitted, and defaults to "localhost". The environment variable
|
|
@env{DISPLAY} contains the default display name.
|
|
|
|
@var{x_offset} and @var{y_offset} specify the offsets of the grabbed
|
|
area with respect to the top-left border of the X11 screen. They
|
|
default to 0.
|
|
|
|
Check the X11 documentation (e.g. man X) for more detailed information.
|
|
|
|
Use the @command{dpyinfo} program for getting basic information about the
|
|
properties of your X11 display (e.g. grep for "name" or "dimensions").
|
|
|
|
For example to grab from @file{:0.0} using @command{ffmpeg}:
|
|
@example
|
|
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg
|
|
@end example
|
|
|
|
Grab at position @code{10,20}:
|
|
@example
|
|
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
|
|
@end example
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
@item draw_mouse
|
|
Specify whether to draw the mouse pointer. A value of @code{0} specify
|
|
not to draw the pointer. Default value is @code{1}.
|
|
|
|
@item follow_mouse
|
|
Make the grabbed area follow the mouse. The argument can be
|
|
@code{centered} or a number of pixels @var{PIXELS}.
|
|
|
|
When it is specified with "centered", the grabbing region follows the mouse
|
|
pointer and keeps the pointer at the center of region; otherwise, the region
|
|
follows only when the mouse pointer reaches within @var{PIXELS} (greater than
|
|
zero) to the edge of region.
|
|
|
|
For example:
|
|
@example
|
|
ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg
|
|
@end example
|
|
|
|
To follow only when the mouse pointer reaches within 100 pixels to edge:
|
|
@example
|
|
ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg
|
|
@end example
|
|
|
|
@item framerate
|
|
Set the grabbing frame rate. Default value is @code{ntsc},
|
|
corresponding to a frame rate of @code{30000/1001}.
|
|
|
|
@item show_region
|
|
Show grabbed region on screen.
|
|
|
|
If @var{show_region} is specified with @code{1}, then the grabbing
|
|
region will be indicated on screen. With this option, it is easy to
|
|
know what is being grabbed if only a portion of the screen is grabbed.
|
|
|
|
For example:
|
|
@example
|
|
ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
|
|
@end example
|
|
|
|
With @var{follow_mouse}:
|
|
@example
|
|
ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg
|
|
@end example
|
|
|
|
@item video_size
|
|
Set the video frame size. Default value is @code{vga}.
|
|
@end table
|
|
|
|
@c man end INPUT DEVICES
|