FFMPEG-DEVICES(1) FFMPEG-DEVICES(1)
NAME
ffmpeg-devices - FFmpeg devices
DESCRIPTION
This document describes the input and output devices provided by the
libavdevice library.
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 -option value in the FFmpeg tools, or
by setting the value explicitly in the device "AVFormatContext" options
or using the libavutil/opt.h API for programmatic use.
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=INDEV", or you can disable a particular input
device using the option "--disable-indev=INDEV".
The option "-devices" of the ff* tools will display the list of
supported input devices.
A description of the currently available input devices follows.
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:<CARD>[,<DEV>[,<SUBDEV>]]
where the DEV and SUBDEV components are optional.
The three arguments (in order: CARD,DEV,SUBDEV) 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 /proc/asound/cards and /proc/asound/devices.
For example to capture with ffmpeg 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:
<http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html>
Options
sample_rate
Set the sample rate in Hz. Default is 48000.
channels
Set the number of channels. Default is 2.
android_camera
Android camera input device.
This input devices uses the Android Camera2 NDK API which is available
on devices with API level 24+. The availability of android_camera is
autodetected during configuration.
This device allows capturing from all cameras on an Android device,
which are integrated into the Camera2 NDK API.
The available cameras are enumerated internally and can be selected with
the camera_index parameter. The input file string is discarded.
Generally the back facing camera has index 0 while the front facing
camera has index 1.
Options
video_size
Set the video size given as a string such as 640x480 or hd720.
Falls back to the first available configuration reported by Android
if requested video size is not available or by default.
framerate
Set the video framerate. Falls back to the first available
configuration reported by Android if requested framerate is not
available or by default (-1).
camera_index
Set the index of the camera to use. Default is 0.
input_queue_size
Set the maximum number of frames to buffer. Default is 5.
avfoundation
AVFoundation input device.
AVFoundation is the currently recommended framework by Apple for
streamgrabbing on OSX >= 10.7 as well as on iOS.
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 E<lt>INDEXE<gt>>
and/or
B<-audio_device_index E<lt>INDEXE<gt>>
, overriding any device name or index given in the input filename.
All available devices can be enumerated by using -list_devices true,
listing all device names and corresponding indices.
There are two device name aliases:
"default"
Select the AVFoundation default device of the corresponding type.
"none"
Do not record the corresponding media type. This is equivalent to
specifying an empty device name or index.
Options
AVFoundation supports the following options:
-list_devices <TRUE|FALSE>
If set to true, a list of all available input devices is given
showing all device names and indices.
-video_device_index <INDEX>
Specify the video device by its index. Overrides anything given in
the input filename.
-audio_device_index <INDEX>
Specify the audio device by its index. Overrides anything given in
the input filename.
-pixel_format <FORMAT>
Request the video device to use a specific pixel format. If the
specified format is not supported, a list of available formats is
given and the first one in this list is used instead. Available
pixel formats are: "monob, rgb555be, rgb555le, rgb565be, rgb565le,
rgb24, bgr24, 0rgb, bgr0, 0bgr, rgb0,
bgr48be, uyvy422, yuva444p, yuva444p16le, yuv444p, yuv422p16,
yuv422p10, yuv444p10,
yuv420p, nv12, yuyv422, gray"
-framerate
Set the grabbing frame rate. Default is "ntsc", corresponding to a
frame rate of "30000/1001".
-video_size
Set the video frame size.
-capture_cursor
Capture the mouse pointer. Default is 0.
-capture_mouse_clicks
Capture the screen mouse clicks. Default is 0.
-capture_raw_data
Capture the raw device data. Default is 0. Using this option may
result in receiving the underlying data delivered to the
AVFoundation framework. E.g. for muxed devices that sends raw DV
data to the framework (like tape-based camcorders), setting this
option to false results in extracted video frames captured in the
designated pixel format only. Setting this option to true results in
receiving the raw DV stream untouched.
Examples
• Print the list of AVFoundation supported devices and exit:
$ ffmpeg -f avfoundation -list_devices true -i ""
• Record video from video device 0 and audio from audio device 0 into
out.avi:
$ ffmpeg -f avfoundation -i "0:0" out.avi
• 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
• 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
• Record raw DV data from a suitable input device and write the output
into out.dv:
$ ffmpeg -f avfoundation -capture_raw_data true -i "zr100:none" out.dv
bktr
BSD video input device. Deprecated and will be removed - please contact
the developers if you are interested in maintaining it.
Options
framerate
Set the frame rate.
video_size
Set the video frame size. Default is "vga".
standard
Available values are:
pal
ntsc
secam
paln
palm
ntscj
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 "--extra-cflags" and
"--extra-ldflags". On Windows, you need to run the IDL files through
widl.
DeckLink is very picky about the formats it supports. Pixel format of
the input can be set with raw_format. Framerate and video size must be
determined for your device with -list_formats 1. Audio sample rate is
always 48 kHz and the number of channels can be 2, 8 or 16. Note that
all audio channels are bundled in one single audio track.
Options
list_devices
If set to true, print a list of devices and exit. Defaults to
false. This option is deprecated, please use the "-sources" option
of ffmpeg to list the available input devices.
list_formats
If set to true, print a list of supported formats and exit.
Defaults to false.
format_code <FourCC>
This sets the input video format to the format given by the FourCC.
To see the supported values of your device(s) use list_formats.
Note that there is a FourCC 'pal ' that can also be used as pal (3
letters). Default behavior is autodetection of the input video
format, if the hardware supports it.
raw_format
Set the pixel format of the captured video. Available values are:
auto
This is the default which means 8-bit YUV 422 or 8-bit ARGB if
format autodetection is used, 8-bit YUV 422 otherwise.
uyvy422
8-bit YUV 422.
yuv422p10
10-bit YUV 422.
argb
8-bit RGB.
bgra
8-bit RGB.
rgb10
10-bit RGB.
teletext_lines
If set to nonzero, an additional teletext stream will be captured
from the vertical ancillary data. Both SD PAL (576i) and HD (1080i
or 1080p) sources are supported. In case of HD sources, OP47 packets
are decoded.
This option is a bitmask of the SD PAL VBI lines captured,
specifically lines 6 to 22, and lines 318 to 335. Line 6 is the LSB
in the mask. Selected lines which do not contain teletext
information will be ignored. You can use the special all constant to
select all possible lines, or standard to skip lines 6, 318 and 319,
which are not compatible with all receivers.
For SD sources, ffmpeg needs to be compiled with "--enable-libzvbi".
For HD sources, on older (pre-4K) DeckLink card models you have to
capture in 10 bit mode.
channels
Defines number of audio channels to capture. Must be 2, 8 or 16.
Defaults to 2.
duplex_mode
Sets the decklink device duplex/profile mode. Must be unset, half,
full, one_sub_device_full, one_sub_device_half, two_sub_device_full,
four_sub_device_half Defaults to unset.
Note: DeckLink SDK 11.0 have replaced the duplex property by a
profile property. For the DeckLink Duo 2 and DeckLink Quad 2, a
profile is shared between any 2 sub-devices that utilize the same
connectors. For the DeckLink 8K Pro, a profile is shared between all
4 sub-devices. So DeckLink 8K Pro support four profiles.
Valid profile modes for DeckLink 8K Pro(with DeckLink SDK >= 11.0):
one_sub_device_full, one_sub_device_half, two_sub_device_full,
four_sub_device_half
Valid profile modes for DeckLink Quad 2 and DeckLink Duo 2: half,
full
timecode_format
Timecode type to include in the frame and video stream metadata.
Must be none, rp188vitc, rp188vitc2, rp188ltc, rp188hfr, rp188any,
vitc, vitc2, or serial. Defaults to none (not included).
In order to properly support 50/60 fps timecodes, the ordering of
the queried timecode types for rp188any is HFR, VITC1, VITC2 and LTC
for >30 fps content. Note that this is slightly different to the
ordering used by the DeckLink API, which is HFR, VITC1, LTC, VITC2.
video_input
Sets the video input source. Must be unset, sdi, hdmi, optical_sdi,
component, composite or s_video. Defaults to unset.
audio_input
Sets the audio input source. Must be unset, embedded, aes_ebu,
analog, analog_xlr, analog_rca or microphone. Defaults to unset.
video_pts
Sets the video packet timestamp source. Must be video, audio,
reference, wallclock or abs_wallclock. Defaults to video.
audio_pts
Sets the audio packet timestamp source. Must be video, audio,
reference, wallclock or abs_wallclock. Defaults to audio.
draw_bars
If set to true, color bars are drawn in the event of a signal loss.
Defaults to true. This option is deprecated, please use the
"signal_loss_action" option.
signal_loss_action
Sets the action to take in the event of a signal loss. Accepts one
of the following values:
1, none
Do nothing on signal loss. This usually results in black frames.
2, bars
Draw color bars on signal loss. Only supported for 8-bit input
signals.
3, repeat
Repeat the last video frame on signal loss.
Defaults to bars.
queue_size
Sets maximum input buffer size in bytes. If the buffering reaches
this value, incoming frames will be dropped. Defaults to
1073741824.
audio_depth
Sets the audio sample bit depth. Must be 16 or 32. Defaults to 16.
decklink_copyts
If set to true, timestamps are forwarded as they are without
removing the initial offset. Defaults to false.
timestamp_align
Capture start time alignment in seconds. If set to nonzero, input
frames are dropped till the system timestamp aligns with configured
value. Alignment difference of up to one frame duration is
tolerated. This is useful for maintaining input synchronization
across N different hardware devices deployed for 'N-way' redundancy.
The system time of different hardware devices should be synchronized
with protocols such as NTP or PTP, before using this option. Note
that this method is not foolproof. In some border cases input
synchronization may not happen due to thread scheduling jitters in
the OS. Either sync could go wrong by 1 frame or in a rarer case
timestamp_align seconds. Defaults to 0.
wait_for_tc (bool)
Drop frames till a frame with timecode is received. Sometimes serial
timecode isn't received with the first input frame. If that happens,
the stored stream timecode will be inaccurate. If this option is set
to true, input frames are dropped till a frame with timecode is
received. Option timecode_format must be specified. Defaults to
false.
enable_klv(bool)
If set to true, extracts KLV data from VANC and outputs KLV packets.
KLV VANC packets are joined based on MID and PSC fields and
aggregated into one KLV packet. Defaults to false.
Examples
• List input devices:
ffmpeg -sources decklink
• List supported formats:
ffmpeg -f decklink -list_formats 1 -i 'Intensity Pro'
• Capture video clip at 1080i50:
ffmpeg -format_code Hi50 -f decklink -i 'Intensity Pro' -c:a copy -c:v copy output.avi
• Capture video clip at 1080i50 10 bit:
ffmpeg -raw_format yuv422p10 -format_code Hi50 -f decklink -i 'UltraStudio Mini Recorder' -c:a copy -c:v copy output.avi
• Capture video clip at 1080i50 with 16 audio channels:
ffmpeg -channels 16 -format_code Hi50 -f decklink -i 'UltraStudio Mini Recorder' -c:a copy -c:v copy output.avi
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:
<TYPE>=<NAME>[:<TYPE>=<NAME>]
where TYPE can be either audio or video, and NAME is the device's name
or alternative name..
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.
video_size
Set the video size in the captured video.
framerate
Set the frame rate in the captured video.
sample_rate
Set the sample rate (in Hz) of the captured audio.
sample_size
Set the sample size (in bits) of the captured audio.
channels
Set the number of channels in the captured audio.
list_devices
If set to true, print a list of devices and exit.
list_options
If set to true, print a list of selected device's options and exit.
video_device_number
Set video device number for devices with the same name (starts at 0,
defaults to 0).
audio_device_number
Set audio device number for devices with the same name (starts at 0,
defaults to 0).
pixel_format
Select pixel format to be used by DirectShow. This may only be set
when the video codec is not set or set to rawvideo.
audio_buffer_size
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
<http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx>
video_pin_name
Select video capture pin to use by name or alternative name.
audio_pin_name
Select audio capture pin to use by name or alternative name.
crossbar_video_input_pin_number
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.
crossbar_audio_input_pin_number
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.
show_video_device_dialog
If set to true, 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.
show_audio_device_dialog
If set to true, before capture starts, popup a display dialog to the
end user, allowing them to change audio filter properties and
configurations manually.
show_video_crossbar_connection_dialog
If set to true, 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.
show_audio_crossbar_connection_dialog
If set to true, 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.
show_analog_tv_tuner_dialog
If set to true, before capture starts, popup a display dialog to the
end user, allowing them to manually modify TV channels and
frequencies.
show_analog_tv_tuner_audio_dialog
If set to true, 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).
audio_device_load
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.
audio_device_save
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.
video_device_load
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.
video_device_save
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.
use_video_device_timestamps
If set to false, the timestamp for video frames will be derived from
the wallclock instead of the timestamp provided by the capture
device. This allows working around devices that provide unreliable
timestamps.
Examples
• Print the list of DirectShow supported devices and exit:
$ ffmpeg -list_devices true -f dshow -i dummy
• Open video device Camera:
$ ffmpeg -f dshow -i video="Camera"
• Open second video device with name Camera:
$ ffmpeg -f dshow -video_device_number 1 -i video="Camera"
• Open video device Camera and audio device Microphone:
$ ffmpeg -f dshow -i video="Camera":audio="Microphone"
• Print the list of supported options in selected device and exit:
$ ffmpeg -list_options true -f dshow -i video="Camera"
• 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"
• 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"
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 /dev/fb0.
For more detailed information read the file
Documentation/fb/framebuffer.txt included in the Linux source tree.
See also <http://linux-fbdev.sourceforge.net/>, and fbset(1).
To record from the framebuffer device /dev/fb0 with ffmpeg:
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
Options
framerate
Set the frame rate. Default is 25.
gdigrab
Win32 GDI-based screen capture device.
This device allows you to capture a region of the display on Windows.
Amongst options for the imput filenames are such elements as:
desktop
or
title=<window_title>
or
hwnd=<window_hwnd>
The first option will capture the entire desktop, or a fixed region of
the desktop. The second and third options will instead capture the
contents of a single window, regardless of its position on the screen.
For example, to grab the entire desktop using ffmpeg:
ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg
Grab a 640x480 region at position "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
Options
draw_mouse
Specify whether to draw the mouse pointer. Use the value 0 to not
draw the pointer. Default value is 1.
framerate
Set the grabbing frame rate. Default value is "ntsc", corresponding
to a frame rate of "30000/1001".
show_region
Show grabbed region on screen.
If show_region is specified with 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 show_region 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
video_size
Set the video frame size. The default is to capture the full screen
if desktop is selected, or the full window size if
title=window_title is selected.
offset_x
When capturing a region with video_size, 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
offset_x value to move the region to that monitor.
offset_y
When capturing a region with video_size, 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 offset_y value
to move the region to that monitor.
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
"--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.
Options
dvtype
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 auto, dv
and hdv are supported.
dvbuffer
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.
dvguid
Select the capture device by specifying its 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.
Examples
• Grab and show the input of a FireWire DV/HDV device.
ffplay -f iec61883 -i auto
• 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 -dvbuffer 100000 out.mpg
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 client_name:input_N, where client_name is
the name provided by the application, and N 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 jack_connect and
jack_disconnect programs, or do it through a graphical interface, for
example with qjackctl.
To list the JACK clients and their properties you can invoke the command
jack_lsp.
Follows an example which shows how to capture a JACK readable client
with ffmpeg.
# 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: <http://jackaudio.org/>
Options
channels
Set the number of channels. Default is 2.
kmsgrab
KMS video input device.
Captures the KMS scanout framebuffer associated with a specified CRTC or
plane as a DRM object that can be passed to other hardware functions.
Requires either DRM master or CAP_SYS_ADMIN to run.
If you don't understand what all of that means, you probably don't want
this. Look at x11grab instead.
Options
device
DRM device to capture on. Defaults to /dev/dri/card0.
format
Pixel format of the framebuffer. This can be autodetected if you
are running Linux 5.7 or later, but needs to be provided for earlier
versions. Defaults to bgr0, which is the most common format used by
the Linux console and Xorg X server.
format_modifier
Format modifier to signal on output frames. This is necessary to
import correctly into some APIs. It can be autodetected if you are
running Linux 5.7 or later, but will need to be provided explicitly
when needed in earlier versions. See the libdrm documentation for
possible values.
crtc_id
KMS CRTC ID to define the capture source. The first active plane on
the given CRTC will be used.
plane_id
KMS plane ID to define the capture source. Defaults to the first
active plane found if neither crtc_id nor plane_id are specified.
framerate
Framerate to capture at. This is not synchronised to any page
flipping or framebuffer changes - it just defines the interval at
which the framebuffer is sampled. Sampling faster than the
framebuffer update rate will generate independent frames with the
same content. Defaults to 30.
Examples
• Capture from the first active plane, download the result to normal
frames and encode. This will only work if the framebuffer is both
linear and mappable - if not, the result may be scrambled or fail to
download.
ffmpeg -f kmsgrab -i - -vf 'hwdownload,format=bgr0' output.mp4
• Capture from CRTC ID 42 at 60fps, map the result to VAAPI, convert
to NV12 and encode as H.264.
ffmpeg -crtc_id 42 -framerate 60 -f kmsgrab -i - -vf 'hwmap=derive_device=vaapi,scale_vaapi=w=1920:h=1080:format=nv12' -c:v h264_vaapi output.mp4
• To capture only part of a plane the output can be cropped - this can
be used to capture a single window, as long as it has a known
absolute position and size. For example, to capture and encode the
middle quarter of a 1920x1080 plane:
ffmpeg -f kmsgrab -i - -vf 'hwmap=derive_device=vaapi,crop=960:540:480:270,scale_vaapi=960:540:nv12' -c:v h264_vaapi output.mp4
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. The
filtergraph is specified through the option graph.
Options
graph
Specify the filtergraph to use as input. Each video open output must
be labelled by a unique string of the form "outN", where N 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.
graph_file
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 graph.
dumpgraph
Dump graph to stderr.
Examples
• Create a color video stream and play it back with ffplay:
ffplay -f lavfi -graph "color=c=pink [out0]" dummy
• As the previous example, but use filename for specifying the graph
description, and omit the "out0" label:
ffplay -f lavfi color=c=pink
• Create three different video test filtered sources and play them:
ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
• Read an audio stream from a file using the amovie source and play it
back with ffplay:
ffplay -f lavfi "amovie=test.wav"
• Read an audio stream and a video stream and play it back with
ffplay:
ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
• Dump decoded frames to images and Closed Captions to an RCWT backup:
ffmpeg -f lavfi -i "movie=test.ts[out0+subcc]" -map v frame%08d.png -map s -c copy -f rcwt subcc.bin
libcdio
Audio-CD input device based on libcdio.
To enable this input device during configuration you need libcdio
installed on your system. It requires the configure option
"--enable-libcdio".
This device allows playing and grabbing from an Audio-CD.
For example to copy with ffmpeg the entire Audio-CD in /dev/sr0, you may
run the command:
ffmpeg -f libcdio -i /dev/sr0 cd.wav
Options
speed
Set drive reading speed. Default value is 0.
The speed is specified CD-ROM speed units. The speed is set through
the libcdio "cdio_cddap_speed_set" function. On many CD-ROM drives,
specifying a value too large will result in using the fastest speed.
paranoia_mode
Set paranoia recovery mode flags. It accepts one of the following
values:
disable
verify
overlap
neverskip
full
Default value is disable.
For more information about the available recovery modes, consult the
paranoia project documentation.
libdc1394
IIDC1394 input device, based on libdc1394 and libraw1394.
Requires the configure option "--enable-libdc1394".
Options
framerate
Set the frame rate. Default is "ntsc", corresponding to a frame rate
of "30000/1001".
pixel_format
Select the pixel format. Default is "uyvy422".
video_size
Set the video size given as a string such as "640x480" or "hd720".
Default is "qvga".
openal
The OpenAL input device provides audio capture on all systems with a
working OpenAL 1.1 implementation.
To enable this input device during configuration, you need OpenAL
headers and libraries installed on your system, and need to configure
FFmpeg with "--enable-openal".
OpenAL headers and libraries should be provided as part of your OpenAL
implementation, or as an additional download (an SDK). Depending on your
installation you may need to specify additional flags via the
"--extra-cflags" and "--extra-ldflags" for allowing the build system to
locate the OpenAL headers and libraries.
An incomplete list of OpenAL implementations follows:
Creative
The official Windows implementation, providing hardware acceleration
with supported devices and software fallback. See
<http://openal.org/>.
OpenAL Soft
Portable, open source (LGPL) software implementation. Includes
backends for the most common sound APIs on the Windows, Linux,
Solaris, and BSD operating systems. See
<http://kcat.strangesoft.net/openal.html>.
Apple
OpenAL is part of Core Audio, the official Mac OS X Audio interface.
See
<http://developer.apple.com/technologies/mac/audio-and-video.html>
This device allows one to capture from an audio input device handled
through OpenAL.
You need to specify the name of the device to capture in the provided
filename. If the empty string is provided, the device will automatically
select the default device. You can get the list of the supported devices
by using the option list_devices.
Options
channels
Set the number of channels in the captured audio. Only the values 1
(monaural) and 2 (stereo) are currently supported. Defaults to 2.
sample_size
Set the sample size (in bits) of the captured audio. Only the values
8 and 16 are currently supported. Defaults to 16.
sample_rate
Set the sample rate (in Hz) of the captured audio. Defaults to
44.1k.
list_devices
If set to true, print a list of devices and exit. Defaults to
false.
Examples
Print the list of OpenAL supported devices and exit:
$ ffmpeg -list_devices true -f openal -i dummy out.ogg
Capture from the OpenAL device DR-BT101 via PulseAudio:
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg
Capture from the default device (note the empty string '' as filename):
$ ffmpeg -f openal -i '' out.ogg
Capture from two devices simultaneously, writing to two different files,
within the same ffmpeg command:
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg
Note: not all OpenAL implementations support multiple simultaneous
capture - try the latest OpenAL Soft if the above does not work.
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 /dev/dsp.
For example to grab from /dev/dsp using ffmpeg use the command:
ffmpeg -f oss -i /dev/dsp /tmp/oss.wav
For more information about OSS see:
<http://manuals.opensound.com/usersguide/dsp.html>
Options
sample_rate
Set the sample rate in Hz. Default is 48000.
channels
Set the number of channels. Default is 2.
pulse
PulseAudio input device.
To enable this output device you need to configure FFmpeg with
"--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 pactl list sources.
More information about PulseAudio can be found on
<http://www.pulseaudio.org>.
Options
server
Connect to a specific PulseAudio server, specified by an IP address.
Default server is used when not provided.
name
Specify the application name PulseAudio will use when showing active
clients, by default it is the "LIBAVFORMAT_IDENT" string.
stream_name
Specify the stream name PulseAudio will use when showing active
streams, by default it is "record".
sample_rate
Specify the samplerate in Hz, by default 48kHz is used.
channels
Specify the channels in use, by default 2 (stereo) is set.
frame_size
This option does nothing and is deprecated.
fragment_size
Specify the size in bytes of the minimal buffering fragment in
PulseAudio, it will affect the audio latency. By default it is set
to 50 ms amount of data.
wallclock
Set the initial PTS using the current time. Default is 1.
Examples
Record a stream from default device:
ffmpeg -f pulse -i default /tmp/pulse.wav
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 /dev/audio0.
For example to grab from /dev/audio0 using ffmpeg use the command:
ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
Options
sample_rate
Set the sample rate in Hz. Default is 48000.
channels
Set the number of channels. Default is 2.
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
"--enable-libv4l2" configure option), it is possible to use it with the
"-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
/dev/videoN, where N is a number associated to the device.
Video4Linux2 devices usually support a limited set of widthxheight sizes
and frame rates. You can check which are supported using -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 -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 -timestamps abs or -ts abs option can be used to force
conversion into the real time clock.
Some usage examples of the video4linux2 device with ffmpeg and ffplay:
• List supported formats for a video4linux2 device:
ffplay -f video4linux2 -list_formats all /dev/video0
• Grab and show the input of a video4linux2 device:
ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
• Grab and record the input of a video4linux2 device, leave the frame
rate and size as previously set:
ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
For more information about Video4Linux, check <http://linuxtv.org/>.
Options
standard
Set the standard. Must be the name of a supported standard. To get a
list of the supported standards, use the list_standards option.
channel
Set the input channel number. Default to -1, which means using the
previously selected channel.
video_size
Set the video frame size. The argument must be a string in the form
WIDTHxHEIGHT or a valid size abbreviation.
pixel_format
Select the pixel format (only valid for raw video input).
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.
framerate
Set the preferred video frame rate.
list_formats
List available formats (supported pixel formats, codecs, and frame
sizes) and exit.
Available values are:
all Show all available (compressed and non-compressed) formats.
raw Show only raw video (non-compressed) formats.
compressed
Show only compressed formats.
list_standards
List supported standards and exit.
Available values are:
all Show all supported standards.
timestamps, ts
Set type of timestamps for grabbed frames.
Available values are:
default
Use timestamps from the kernel.
abs Use absolute timestamps (wall clock).
mono2abs
Force conversion from monotonic to absolute timestamps.
Default value is "default".
use_libv4l2
Use libv4l2 (v4l-utils) conversion functions. Default is 0.
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.
Options
video_size
Set the video frame size.
framerate
Set the grabbing frame rate. Default value is "ntsc", corresponding
to a frame rate of "30000/1001".
x11grab
X11 video input device.
To enable this input device during configuration you need libxcb
installed on your system. It will be automatically detected during
configuration.
This device allows one to capture a region of an X11 display.
The filename passed as input has the syntax:
[<hostname>]:<display_number>.<screen_number>[+<x_offset>,<y_offset>]
hostname:display_number.screen_number specifies the X11 display name of
the screen to grab from. hostname can be omitted, and defaults to
"localhost". The environment variable DISPLAY contains the default
display name.
x_offset and 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 xdpyinfo program for getting basic information about the
properties of your X11 display (e.g. grep for "name" or "dimensions").
For example to grab from :0.0 using ffmpeg:
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg
Grab at position "10,20":
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
Options
select_region
Specify whether to select the grabbing area graphically using the
pointer. A value of 1 prompts the user to select the grabbing area
graphically by clicking and dragging. A single click with no
dragging will select the whole screen. A region with zero width or
height will also select the whole screen. This option overwrites the
video_size, grab_x, and grab_y options. Default value is 0.
draw_mouse
Specify whether to draw the mouse pointer. A value of 0 specifies
not to draw the pointer. Default value is 1.
follow_mouse
Make the grabbed area follow the mouse. The argument can be
"centered" or a number of pixels 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 PIXELS (greater than zero) to the edge of region.
For example:
ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg
To follow only when the mouse pointer reaches within 100 pixels to
edge:
ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg
framerate
Set the grabbing frame rate. Default value is "ntsc", corresponding
to a frame rate of "30000/1001".
show_region
Show grabbed region on screen.
If show_region is specified with 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.
region_border
Set the region border thickness if -show_region 1 is used. Range is
1 to 128 and default is 3 (XCB-based x11grab only).
For example:
ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg
With follow_mouse:
ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg
window_id
Grab this window, instead of the whole screen. Default value is 0,
which maps to the whole screen (root window).
The id of a window can be found using the xwininfo program, possibly
with options -tree and -root.
If the window is later enlarged, the new area is not recorded. Video
ends when the window is closed, unmapped (i.e., iconified) or shrunk
beyond the video size (which defaults to the initial window size).
This option disables options follow_mouse and select_region.
video_size
Set the video frame size. Default is the full desktop or window.
grab_x
grab_y
Set the grabbing region coordinates. They are expressed as offset
from the top left corner of the X11 window and correspond to the
x_offset and y_offset parameters in the device name. The default
value for both options is 0.
OUTPUT DEVICES
Output devices are configured elements in FFmpeg that can write
multimedia data to an output device attached to your system.
When you configure your FFmpeg build, all the supported output devices
are enabled by default. You can list all available ones using the
configure option "--list-outdevs".
You can disable all the output devices using the configure option
"--disable-outdevs", and selectively enable an output device using the
option "--enable-outdev=OUTDEV", or you can disable a particular input
device using the option "--disable-outdev=OUTDEV".
The option "-devices" of the ff* tools will display the list of enabled
output devices.
A description of the currently available output devices follows.
alsa
ALSA (Advanced Linux Sound Architecture) output device.
Examples
• Play a file on default ALSA device:
ffmpeg -i INPUT -f alsa default
• Play a file on soundcard 1, audio device 7:
ffmpeg -i INPUT -f alsa hw:1,7
AudioToolbox
AudioToolbox output device.
Allows native output to CoreAudio devices on OSX.
The output filename can be empty (or "-") to refer to the default system
output device or a number that refers to the device index as shown
using: "-list_devices true".
Alternatively, the audio input device can be chosen by index using the
B<-audio_device_index E<lt>INDEXE<gt>>
, overriding any device name or index given in the input filename.
All available devices can be enumerated by using -list_devices true,
listing all device names, UIDs and corresponding indices.
Options
AudioToolbox supports the following options:
-audio_device_index <INDEX>
Specify the audio device by its index. Overrides anything given in
the output filename.
Examples
• Print the list of supported devices and output a sine wave to the
default device:
$ ffmpeg -f lavfi -i sine=r=44100 -f audiotoolbox -list_devices true -
• Output a sine wave to the device with the index 2, overriding any
output filename:
$ ffmpeg -f lavfi -i sine=r=44100 -f audiotoolbox -audio_device_index 2 -
caca
CACA output device.
This output device allows one to show a video stream in CACA window.
Only one CACA window is allowed per application, so you can have only
one instance of this output device in an application.
To enable this output device you need to configure FFmpeg with
"--enable-libcaca". libcaca is a graphics library that outputs text
instead of pixels.
For more information about libcaca, check:
<http://caca.zoy.org/wiki/libcaca>
Options
window_title
Set the CACA window title, if not specified default to the filename
specified for the output device.
window_size
Set the CACA window size, can be a string of the form widthxheight
or a video size abbreviation. If not specified it defaults to the
size of the input video.
driver
Set display driver.
algorithm
Set dithering algorithm. Dithering is necessary because the picture
being rendered has usually far more colours than the available
palette. The accepted values are listed with "-list_dither
algorithms".
antialias
Set antialias method. Antialiasing smoothens the rendered image and
avoids the commonly seen staircase effect. The accepted values are
listed with "-list_dither antialiases".
charset
Set which characters are going to be used when rendering text. The
accepted values are listed with "-list_dither charsets".
color
Set color to be used when rendering text. The accepted values are
listed with "-list_dither colors".
list_drivers
If set to true, print a list of available drivers and exit.
list_dither
List available dither options related to the argument. The argument
must be one of "algorithms", "antialiases", "charsets", "colors".
Examples
• The following command shows the ffmpeg output is an CACA window,
forcing its size to 80x25:
ffmpeg -i INPUT -c:v rawvideo -pix_fmt rgb24 -window_size 80x25 -f caca -
• Show the list of available drivers and exit:
ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_drivers true -
• Show the list of available dither colors and exit:
ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_dither colors -
decklink
The decklink output device provides playback capabilities for Blackmagic
DeckLink devices.
To enable this output device, you need the Blackmagic DeckLink SDK and
you need to configure with the appropriate "--extra-cflags" and
"--extra-ldflags". On Windows, you need to run the IDL files through
widl.
DeckLink is very picky about the formats it supports. Pixel format is
always uyvy422, framerate, field order and video size must be determined
for your device with -list_formats 1. Audio sample rate is always 48
kHz.
Options
list_devices
If set to true, print a list of devices and exit. Defaults to
false. This option is deprecated, please use the "-sinks" option of
ffmpeg to list the available output devices.
list_formats
If set to true, print a list of supported formats and exit.
Defaults to false.
preroll
Amount of time to preroll video in seconds. Defaults to 0.5.
duplex_mode
Sets the decklink device duplex/profile mode. Must be unset, half,
full, one_sub_device_full, one_sub_device_half, two_sub_device_full,
four_sub_device_half Defaults to unset.
Note: DeckLink SDK 11.0 have replaced the duplex property by a
profile property. For the DeckLink Duo 2 and DeckLink Quad 2, a
profile is shared between any 2 sub-devices that utilize the same
connectors. For the DeckLink 8K Pro, a profile is shared between all
4 sub-devices. So DeckLink 8K Pro support four profiles.
Valid profile modes for DeckLink 8K Pro(with DeckLink SDK >= 11.0):
one_sub_device_full, one_sub_device_half, two_sub_device_full,
four_sub_device_half
Valid profile modes for DeckLink Quad 2 and DeckLink Duo 2: half,
full
timing_offset
Sets the genlock timing pixel offset on the used output. Defaults
to unset.
link
Sets the SDI video link configuration on the used output. Must be
unset, single link SDI, dual link SDI or quad link SDI. Defaults to
unset.
sqd Enable Square Division Quad Split mode for Quad-link SDI output.
Must be unset, true or false. Defaults to unset.
level_a
Enable SMPTE Level A mode on the used output. Must be unset, true
or false. Defaults to unset.
vanc_queue_size
Sets maximum output buffer size in bytes for VANC data. If the
buffering reaches this value, outgoing VANC data will be dropped.
Defaults to 1048576.
Examples
• List output devices:
ffmpeg -sinks decklink
• List supported formats:
ffmpeg -i test.avi -f decklink -list_formats 1 'DeckLink Mini Monitor'
• Play video clip:
ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 'DeckLink Mini Monitor'
• Play video clip with non-standard framerate or video size:
ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 -s 720x486 -r 24000/1001 'DeckLink Mini Monitor'
fbdev
Linux framebuffer output 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 /dev/fb0.
For more detailed information read the file
Documentation/fb/framebuffer.txt included in the Linux source tree.
Options
xoffset
yoffset
Set x/y coordinate of top left corner. Default is 0.
Examples
Play a file on framebuffer device /dev/fb0. Required pixel format
depends on current framebuffer settings.
ffmpeg -re -i INPUT -c:v rawvideo -pix_fmt bgra -f fbdev /dev/fb0
See also <http://linux-fbdev.sourceforge.net/>, and fbset(1).
opengl
OpenGL output device. Deprecated and will be removed.
To enable this output device you need to configure FFmpeg with
"--enable-opengl".
This output device allows one to render to OpenGL context. Context may
be provided by application or default SDL window is created.
When device renders to external context, application must implement
handlers for following messages: "AV_DEV_TO_APP_CREATE_WINDOW_BUFFER" -
create OpenGL context on current thread.
"AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER" - make OpenGL context current.
"AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER" - swap buffers.
"AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER" - destroy OpenGL context.
Application is also required to inform a device about current resolution
by sending "AV_APP_TO_DEV_WINDOW_SIZE" message.
Options
background
Set background color. Black is a default.
no_window
Disables default SDL window when set to non-zero value. Application
must provide OpenGL context and both "window_size_cb" and
"window_swap_buffers_cb" callbacks when set.
window_title
Set the SDL window title, if not specified default to the filename
specified for the output device. Ignored when no_window is set.
window_size
Set preferred window size, can be a string of the form widthxheight
or a video size abbreviation. If not specified it defaults to the
size of the input video, downscaled according to the aspect ratio.
Mostly usable when no_window is not set.
Examples
Play a file on SDL window using OpenGL rendering:
ffmpeg -i INPUT -f opengl "window title"
oss
OSS (Open Sound System) output device.
pulse
PulseAudio output device.
To enable this output device you need to configure FFmpeg with
"--enable-libpulse".
More information about PulseAudio can be found on
<http://www.pulseaudio.org>
Options
server
Connect to a specific PulseAudio server, specified by an IP address.
Default server is used when not provided.
name
Specify the application name PulseAudio will use when showing active
clients, by default it is the "LIBAVFORMAT_IDENT" string.
stream_name
Specify the stream name PulseAudio will use when showing active
streams, by default it is set to the specified output name.
device
Specify the device to use. Default device is used when not provided.
List of output devices can be obtained with command pactl list
sinks.
buffer_size
buffer_duration
Control the size and duration of the PulseAudio buffer. A small
buffer gives more control, but requires more frequent updates.
buffer_size specifies size in bytes while buffer_duration specifies
duration in milliseconds.
When both options are provided then the highest value is used
(duration is recalculated to bytes using stream parameters). If they
are set to 0 (which is default), the device will use the default
PulseAudio duration value. By default PulseAudio set buffer duration
to around 2 seconds.
prebuf
Specify pre-buffering size in bytes. The server does not start with
playback before at least prebuf bytes are available in the buffer.
By default this option is initialized to the same value as
buffer_size or buffer_duration (whichever is bigger).
minreq
Specify minimum request size in bytes. The server does not request
less than minreq bytes from the client, instead waits until the
buffer is free enough to request more bytes at once. It is
recommended to not set this option, which will initialize this to a
value that is deemed sensible by the server.
Examples
Play a file on default device on default server:
ffmpeg -i INPUT -f pulse "stream name"
sdl
SDL (Simple DirectMedia Layer) output device. Deprecated and will be
removed.
For monitoring purposes in FFmpeg, pipes and a video player such as
ffplay can be used:
ffmpeg -i INPUT -f nut -c:v rawvideo - | ffplay -
"sdl2" can be used as alias for "sdl".
This output device allows one to show a video stream in an SDL window.
Only one SDL window is allowed per application, so you can have only one
instance of this output device in an application.
To enable this output device you need libsdl installed on your system
when configuring your build.
For more information about SDL, check: <http://www.libsdl.org/>
Options
window_borderless
Set SDL window border off. Default value is 0 (enable window
border).
window_enable_quit
Enable quit action (using window button or keyboard key) when non-
zero value is provided. Default value is 1 (enable quit action).
window_fullscreen
Set fullscreen mode when non-zero value is provided. Default value
is zero.
window_size
Set the SDL window size, can be a string of the form widthxheight or
a video size abbreviation. If not specified it defaults to the size
of the input video, downscaled according to the aspect ratio.
window_title
Set the SDL window title, if not specified default to the filename
specified for the output device.
window_x
window_y
Set the position of the window on the screen.
Interactive commands
The window created by the device can be controlled through the following
interactive commands.
q, ESC
Quit the device immediately.
Examples
The following command shows the ffmpeg output is an SDL window, forcing
its size to the qcif format:
ffmpeg -i INPUT -c:v rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"
sndio
sndio audio output device.
v4l2
Video4Linux2 output device.
xv
XV (XVideo) output device.
This output device allows one to show a video stream in a X Window
System window.
Options
display_name
Specify the hardware display name, which determines the display and
communications domain to be used.
The display name or DISPLAY environment variable can be a string in
the format hostname[:number[.screen_number]].
hostname specifies the name of the host machine on which the display
is physically attached. number specifies the number of the display
server on that host machine. screen_number specifies the screen to
be used on that server.
If unspecified, it defaults to the value of the DISPLAY environment
variable.
For example, "dual-headed:0.1" would specify screen 1 of display 0
on the machine named ``dual-headed''.
Check the X11 specification for more detailed information about the
display name format.
window_id
When set to non-zero value then device doesn't create new window,
but uses existing one with provided window_id. By default this
options is set to zero and device creates its own window.
window_size
Set the created window size, can be a string of the form
widthxheight or a video size abbreviation. If not specified it
defaults to the size of the input video. Ignored when window_id is
set.
window_x
window_y
Set the X and Y window offsets for the created window. They are both
set to 0 by default. The values may be ignored by the window
manager. Ignored when window_id is set.
window_title
Set the window title, if not specified default to the filename
specified for the output device. Ignored when window_id is set.
For more information about XVideo see <http://www.x.org/>.
Examples
• Decode, display and encode video input with ffmpeg at the same time:
ffmpeg -i INPUT OUTPUT -f xv display
• Decode and display the input video to multiple X11 windows:
ffmpeg -i INPUT -f xv normal -vf negate -f xv negated
SEE ALSO
ffmpeg(1), ffplay(1), ffprobe(1), libavdevice(3)
AUTHORS
The FFmpeg developers.
For details about the authorship, see the Git history of the project
(https://git.ffmpeg.org/ffmpeg), e.g. by typing the command git log in
the FFmpeg source directory, or browsing the online repository at
<https://git.ffmpeg.org/ffmpeg>.
Maintainers for the specific components are listed in the file
MAINTAINERS in the source code tree.
FFMPEG-DEVICES(1)
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