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895 lines
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895 lines
26 KiB
@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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@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 -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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|
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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 |
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@option{1} (monaural) and @option{2} (stereo) are currently supported. |
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Defaults to @option{2}. |
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@item sample_size |
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Set the sample size (in bits) of the captured audio. Only the values |
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@option{8} and @option{16} are currently supported. Defaults to |
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@option{16}. |
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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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Defaults to @option{44.1k}. |
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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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Defaults to @option{false}. |
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@end table |
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@subsection Examples |
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|
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Print the list of OpenAL supported devices and exit: |
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@example |
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$ ffmpeg -list_devices true -f openal -i dummy out.ogg |
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@end example |
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Capture from the OpenAL device @file{DR-BT101 via PulseAudio}: |
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@example |
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$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg |
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@end example |
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Capture from the default device (note the empty string '' as filename): |
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@example |
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$ ffmpeg -f openal -i '' out.ogg |
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@end example |
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Capture from two devices simultaneously, writing to two different files, |
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within the same @command{ffmpeg} command: |
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@example |
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$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg |
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@end example |
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Note: not all OpenAL implementations support multiple simultaneous capture - |
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try the latest OpenAL Soft if the above does not work. |
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|
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@section oss |
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Open Sound System input device. |
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|
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The filename to provide to the input device is the device node |
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representing the OSS input device, and is usually set to |
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@file{/dev/dsp}. |
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|
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For example to grab from @file{/dev/dsp} using @command{ffmpeg} use the |
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command: |
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@example |
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ffmpeg -f oss -i /dev/dsp /tmp/oss.wav |
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@end example |
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|
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For more information about OSS see: |
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@url{http://manuals.opensound.com/usersguide/dsp.html} |
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|
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@section pulse |
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|
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PulseAudio input device. |
|
|
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To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}. |
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|
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The filename to provide to the input device is a source device or the |
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string "default" |
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|
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To list the PulseAudio source devices and their properties you can invoke |
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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
|
|
|