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=encoding utf8

=head1 NAME

ffmpeg-devices - FFmpeg devices

=head1 DESCRIPTION

This document describes the input and output devices provided by the

libavdevice library.

=head1 DEVICE OPTIONS

The libavdevice library provides the same interface as

libavformat. Namely, an input device is considered like a demuxer, and

an output device like a muxer, and the interface and generic device

options are the same provided by libavformat (see the ffmpeg-formats

manual).

In addition each input or output device may support so-called private

options, which are specific for that component.

Options may be set by specifying -I I in the

FFmpeg tools, or by setting the value explicitly in the device

C options or using the F API

for programmatic use.

=head1 INPUT DEVICES

Input devices are configured elements in FFmpeg which enable accessing

the data coming from a multimedia device attached to your system.

When you configure your FFmpeg build, all the supported input devices

are enabled by default. You can list all available ones using the

configure option "--list-indevs".

You can disable all the input devices using the configure option

"--disable-indevs", and selectively enable an input device using the

option "--enable-indev=I", or you can disable a particular

input device using the option "--disable-indev=I".

The option "-devices" of the ff* tools will display the list of

supported input devices.

A description of the currently available input devices follows.

=head2 alsa

ALSA (Advanced Linux Sound Architecture) input device.

To enable this input device during configuration you need libasound

installed on your system.

This device allows capturing from an ALSA device. The name of the

device to capture has to be an ALSA card identifier.

An ALSA identifier has the syntax:

	hw:[,[,]]

where the I and I components are optional.

The three arguments (in order: I,I,I)

specify card number or identifier, device number and subdevice number

(-1 means any).

To see the list of cards currently recognized by your system check the

files F and F.

For example to capture with B from an ALSA device with

card id 0, you may run the command:

	ffmpeg -f alsa -i hw:0 alsaout.wav

For more information see:

EBE

=head3 Options

=over 4

=item B

Set the sample rate in Hz. Default is 48000.

=item B

Set the number of channels. Default is 2.

=back

=head2 avfoundation

AVFoundation input device.

AVFoundation is the currently recommended framework by Apple for streamgrabbing on OSX E= 10.7 as well as on iOS.

The older QTKit framework has been marked deprecated since OSX version 10.7.

The input filename has to be given in the following syntax:

	-i "[[VIDEO]:[AUDIO]]"

The first entry selects the video input while the latter selects the audio input.

The stream has to be specified by the device name or the device index as shown by the device list.

Alternatively, the video and/or audio input device can be chosen by index using the

    B<-video_device_index EINDEXE>

and/or

    B<-audio_device_index EINDEXE>

, overriding any

device name or index given in the input filename.

All available devices can be enumerated by using B<-list_devices true>, listing

all device names and corresponding indices.

There are two device name aliases:

=over 4

=item C

Select the AVFoundation default device of the corresponding type.

=item C

Do not record the corresponding media type.

This is equivalent to specifying an empty device name or index.

=back

=head3 Options

AVFoundation supports the following options:

=over 4

=item B<-list_devices ETRUE|FALSEE>

If set to true, a list of all available input devices is given showing all

device names and indices.

=item B<-video_device_index EINDEXE>

Specify the video device by its index. Overrides anything given in the input filename.

=item B<-audio_device_index EINDEXE>

Specify the audio device by its index. Overrides anything given in the input filename.

=item B<-pixel_format EFORMATE>

Request the video device to use a specific pixel format.

If the specified format is not supported, a list of available formats is given

und the first one in this list is used instead. Available pixel formats are:

C

 bgr48be, uyvy422, yuva444p, yuva444p16le, yuv444p, yuv422p16, yuv422p10, yuv444p10,

 yuv420p, nv12, yuyv422, gray>

=item B<-framerate>

Set the grabbing frame rate. Default is C, corresponding to a

frame rate of C<30000/1001>.

=item B<-video_size>

Set the video frame size.

=item B<-capture_cursor>

Capture the mouse pointer. Default is 0.

=item B<-capture_mouse_clicks>

Capture the screen mouse clicks. Default is 0.

=back

=head3 Examples

=over 4

=item *

Print the list of AVFoundation supported devices and exit:

	$ ffmpeg -f avfoundation -list_devices true -i ""

=item *

Record video from video device 0 and audio from audio device 0 into out.avi:

	$ ffmpeg -f avfoundation -i "0:0" out.avi

=item *

Record video from video device 2 and audio from audio device 1 into out.avi:

	$ ffmpeg -f avfoundation -video_device_index 2 -i ":1" out.avi

=item *

Record video from the system default video device using the pixel format bgr0 and do not record any audio into out.avi:

	$ ffmpeg -f avfoundation -pixel_format bgr0 -i "default:none" out.avi

=back

=head2 bktr

BSD video input device.

=head3 Options

=over 4

=item B

Set the frame rate.

=item B

Set the video frame size. Default is C.

=item B

Available values are:

=over 4

=item B

=item B

=item B

=item B

=item B

=item B

=back

=back

=head2 decklink

The decklink input device provides capture capabilities for Blackmagic

DeckLink devices.

To enable this input device, you need the Blackmagic DeckLink SDK and you

need to configure with the appropriate C<--extra-cflags>

and C<--extra-ldflags>.

On Windows, you need to run the IDL files through B.

DeckLink is very picky about the formats it supports. Pixel format is

uyvy422 or v210, framerate and video size must be determined for your device with

B<-list_formats 1>. Audio sample rate is always 48 kHz and the number

of channels can be 2, 8 or 16.

=head3 Options

=over 4

=item B

If set to B, print a list of devices and exit.

Defaults to B.

=item B

If set to B, print a list of supported formats and exit.

Defaults to B.

=item B

If set to B<1>, video is captured in 10 bit v210 instead

of uyvy422. Not all Blackmagic devices support this option.

=back

=head3 Examples

=over 4

=item *

List input devices:

	ffmpeg -f decklink -list_devices 1 -i dummy

=item *

List supported formats:

	ffmpeg -f decklink -list_formats 1 -i 'Intensity Pro'

=item *

Capture video clip at 1080i50 (format 11):

	ffmpeg -f decklink -i 'Intensity Pro@11' -acodec copy -vcodec copy output.avi

=item *

Capture video clip at 1080i50 10 bit:

	ffmpeg -bm_v210 1 -f decklink -i 'UltraStudio Mini Recorder@11' -acodec copy -vcodec copy output.avi

=back

=head2 dshow

Windows DirectShow input device.

DirectShow support is enabled when FFmpeg is built with the mingw-w64 project.

Currently only audio and video devices are supported.

Multiple devices may be opened as separate inputs, but they may also be

opened on the same input, which should improve synchronism between them.

The input name should be in the format:

	=[:=]

where I can be either I

and I is the device's name or alternative name..

=head3 Options

If no options are specified, the device's defaults are used.

If the device does not support the requested options, it will

fail to open.

=over 4

=item B

Set the video size in the captured video.

=item B

Set the frame rate in the captured video.

=item B

Set the sample rate (in Hz) of the captured audio.

=item B

Set the sample size (in bits) of the captured audio.

=item B

Set the number of channels in the captured audio.

=item B

If set to B, print a list of devices and exit.

=item B

If set to B, print a list of selected device's options

and exit.

=item B

Set video device number for devices with the same name (starts at 0,

defaults to 0).

=item B

Set audio device number for devices with the same name (starts at 0,

defaults to 0).

=item B

Select pixel format to be used by DirectShow. This may only be set when

the video codec is not set or set to rawvideo.

=item B

Set audio device buffer size in milliseconds (which can directly

impact latency, depending on the device).

Defaults to using the audio device's

default buffer size (typically some multiple of 500ms).

Setting this value too low can degrade performance.

See also

EBE

=item B

Select video capture pin to use by name or alternative name.

=item B

Select audio capture pin to use by name or alternative name.

=item B

Select video input pin number for crossbar device. This will be

routed to the crossbar device's Video Decoder output pin.

Note that changing this value can affect future invocations

(sets a new default) until system reboot occurs.

=item B

Select audio input pin number for crossbar device. This will be

routed to the crossbar device's Audio Decoder output pin.

Note that changing this value can affect future invocations

(sets a new default) until system reboot occurs.

=item B

If set to B, before capture starts, popup a display dialog

to the end user, allowing them to change video filter properties

and configurations manually.

Note that for crossbar devices, adjusting values in this dialog

may be needed at times to toggle between PAL (25 fps) and NTSC (29.97)

input frame rates, sizes, interlacing, etc.  Changing these values can

enable different scan rates/frame rates and avoiding green bars at

the bottom, flickering scan lines, etc.

Note that with some devices, changing these properties can also affect future

invocations (sets new defaults) until system reboot occurs.

=item B

If set to B, before capture starts, popup a display dialog

to the end user, allowing them to change audio filter properties

and configurations manually.

=item B

If set to B, before capture starts, popup a display

dialog to the end user, allowing them to manually

modify crossbar pin routings, when it opens a video device.

=item B

If set to B, before capture starts, popup a display

dialog to the end user, allowing them to manually

modify crossbar pin routings, when it opens an audio device.

=item B

If set to B, before capture starts, popup a display

dialog to the end user, allowing them to manually

modify TV channels and frequencies.

=item B

If set to B, before capture starts, popup a display

dialog to the end user, allowing them to manually

modify TV audio (like mono vs. stereo, Language A,B or C).

=item B

Load an audio capture filter device from file instead of searching

it by name. It may load additional parameters too, if the filter

supports the serialization of its properties to.

To use this an audio capture source has to be specified, but it can

be anything even fake one.

=item B

Save the currently used audio capture filter device and its

parameters (if the filter supports it) to a file.

If a file with the same name exists it will be overwritten.

=item B

Load a video capture filter device from file instead of searching

it by name. It may load additional parameters too, if the filter

supports the serialization of its properties to.

To use this a video capture source has to be specified, but it can

be anything even fake one.

=item B

Save the currently used video capture filter device and its

parameters (if the filter supports it) to a file.

If a file with the same name exists it will be overwritten.

=back

=head3 Examples

=over 4

=item *

Print the list of DirectShow supported devices and exit:

	$ ffmpeg -list_devices true -f dshow -i dummy

=item *

Open video device I:

	$ ffmpeg -f dshow -i video="Camera"

=item *

Open second video device with name I:

	$ ffmpeg -f dshow -video_device_number 1 -i video="Camera"

=item *

Open video device I and audio device I:

	$ ffmpeg -f dshow -i video="Camera":audio="Microphone"

=item *

Print the list of supported options in selected device and exit:

	$ ffmpeg -list_options true -f dshow -i video="Camera"

=item *

Specify pin names to capture by name or alternative name, specify alternative device name:

	$ ffmpeg -f dshow -audio_pin_name "Audio Out" -video_pin_name 2 -i video=video="@device_pnp_\\?\pci#ven_1a0a&dev_6200&subsys_62021461&rev_01#4&e2c7dd6&0&00e1#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\{ca465100-deb0-4d59-818f-8c477184adf6}":audio="Microphone"

=item *

Configure a crossbar device, specifying crossbar pins, allow user to adjust video capture properties at startup:

	$ ffmpeg -f dshow -show_video_device_dialog true -crossbar_video_input_pin_number 0

	     -crossbar_audio_input_pin_number 3 -i video="AVerMedia BDA Analog Capture":audio="AVerMedia BDA Analog Capture"

=back

=head2 dv1394

Linux DV 1394 input device.

=head3 Options

=over 4

=item B

Set the frame rate. Default is 25.

=item B

Available values are:

=over 4

=item B

=item B

=back

Default value is C.

=back

=head2 fbdev

Linux framebuffer input device.

The Linux framebuffer is a graphic hardware-independent abstraction

layer to show graphics on a computer monitor, typically on the

console. It is accessed through a file device node, usually

F.

For more detailed information read the file

Documentation/fb/framebuffer.txt included in the Linux source tree.

See also EBE, and fbset(1).

To record from the framebuffer device F with

B:

	ffmpeg -f fbdev -framerate 10 -i /dev/fb0 out.avi

You can take a single screenshot image with the command:

	ffmpeg -f fbdev -framerate 1 -i /dev/fb0 -frames:v 1 screenshot.jpeg

=head3 Options

=over 4

=item B

Set the frame rate. Default is 25.

=back

=head2 gdigrab

Win32 GDI-based screen capture device.

This device allows you to capture a region of the display on Windows.

There are two options for the input filename:

	desktop

or

	title=

The first option will capture the entire desktop, or a fixed region of the

desktop. The second option will instead capture the contents of a single

window, regardless of its position on the screen.

For example, to grab the entire desktop using B:

	ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg

Grab a 640x480 region at position C<10,20>:

	ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg

Grab the contents of the window named "Calculator"

	ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg

=head3 Options

=over 4

=item B

Specify whether to draw the mouse pointer. Use the value C<0> to

not draw the pointer. Default value is C<1>.

=item B

Set the grabbing frame rate. Default value is C,

corresponding to a frame rate of C<30000/1001>.

=item B

Show grabbed region on screen.

If I is specified with C<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.

Note that I is incompatible with grabbing the contents

of a single window.

For example:

	ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg

=item B

Set the video frame size. The default is to capture the full screen if F is selected, or the full window size if F> is selected.

=item B

When capturing a region with I, set the distance from the left edge of the screen or desktop.

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 I value to move the region to that monitor.

=item B

When capturing a region with I, set the distance from the top edge of the screen or desktop.

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 I value to move the region to that monitor.

=back

=head2 iec61883

FireWire DV/HDV input device using libiec61883.

To enable this input device, you need libiec61883, libraw1394 and

libavc1394 installed on your system. Use the configure option

C<--enable-libiec61883> to compile with the device enabled.

The iec61883 capture device supports capturing from a video device

connected via IEEE1394 (FireWire), using libiec61883 and the new Linux

FireWire stack (juju). This is the default DV/HDV input method in Linux

Kernel 2.6.37 and later, since the old FireWire stack was removed.

Specify the FireWire port to be used as input file, or "auto"

to choose the first port connected.

=head3 Options

=over 4

=item B

Override autodetection of DV/HDV. This should only be used if auto

detection does not work, or if usage of a different device type

should be prohibited. Treating a DV device as HDV (or vice versa) will

not work and result in undefined behavior.

The values B, B and B are supported.

=item B

Set maximum size of buffer for incoming data, in frames. For DV, this

is an exact value. For HDV, it is not frame exact, since HDV does

not have a fixed frame size.

=item B

Select the capture device by specifying it's GUID. Capturing will only

be performed from the specified device and fails if no device with the

given GUID is found. This is useful to select the input if multiple

devices are connected at the same time.

Look at /sys/bus/firewire/devices to find out the GUIDs.

=back

=head3 Examples

=over 4

=item *

Grab and show the input of a FireWire DV/HDV device.

	ffplay -f iec61883 -i auto

=item *

Grab and record the input of a FireWire DV/HDV device,

using a packet buffer of 100000 packets if the source is HDV.

	ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg

=back

=head2 jack

JACK input device.

To enable this input device during configuration you need libjack

installed on your system.

A JACK input device creates one or more JACK writable clients, one for

each audio channel, with name I:input_I, where

I is the name provided by the application, and I

is a number which identifies the channel.

Each writable client will send the acquired data to the FFmpeg input

device.

Once you have created one or more JACK readable clients, you need to

connect them to one or more JACK writable clients.

To connect or disconnect JACK clients you can use the B

and B programs, or do it through a graphical interface,

for example with B.

To list the JACK clients and their properties you can invoke the command

B.

Follows an example which shows how to capture a JACK readable client

with B.

	# Create a JACK writable client with name "ffmpeg".

	$ ffmpeg -f jack -i ffmpeg -y out.wav

	# Start the sample jack_metro readable client.

	$ jack_metro -b 120 -d 0.2 -f 4000

	# List the current JACK clients.

	$ jack_lsp -c

	system:capture_1

	system:capture_2

	system:playback_1

	system:playback_2

	ffmpeg:input_1

	metro:120_bpm

	# Connect metro to the ffmpeg writable client.

	$ jack_connect metro:120_bpm ffmpeg:input_1

For more information read:

EBE

=head3 Options

=over 4

=item B

Set the number of channels. Default is 2.

=back

=head2 lavfi

Libavfilter input virtual device.

This input device reads data from the open output pads of a libavfilter

filtergraph.

For each filtergraph open output, the input device will create a

corresponding stream which is mapped to the generated output. Currently

only video data is supported. The filtergraph is specified through the

option B.

=head3 Options

=over 4

=item B

Specify the filtergraph to use as input. Each video open output must be

labelled by a unique string of the form "outI", where I is a

number starting from 0 corresponding to the mapped input stream

generated by the device.

The first unlabelled output is automatically assigned to the "out0"

label, but all the others need to be specified explicitly.

The suffix "+subcc" can be appended to the output label to create an extra

stream with the closed captions packets attached to that output

(experimental; only for EIA-608 / CEA-708 for now).

The subcc streams are created after all the normal streams, in the order of

the corresponding stream.

For example, if there is "out19+subcc", "out7+subcc" and up to "out42", the

stream #43 is subcc for stream #7 and stream #44 is subcc for stream #19.

If not specified defaults to the filename specified for the input

device.

=item B

Set the filename of the filtergraph to be read and sent to the other

filters. Syntax of the filtergraph is the same as the one specified by

the option I.

=item B

Dump graph to stderr.

=back

=head3 Examples

=over 4

=item *

Create a color video stream and play it back with B:

	ffplay -f lavfi -graph "color=c=pink [out0]" dummy