426 lines
12 KiB
Plaintext
426 lines
12 KiB
Plaintext
@chapter Output Devices
|
|
@c man begin 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=@var{OUTDEV}", or you can disable a particular
|
|
input device using the option "--disable-outdev=@var{OUTDEV}".
|
|
|
|
The option "-formats" of the ff* tools will display the list of
|
|
enabled output devices (amongst the muxers).
|
|
|
|
A description of the currently available output devices follows.
|
|
|
|
@section alsa
|
|
|
|
ALSA (Advanced Linux Sound Architecture) output device.
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Play a file on default ALSA device:
|
|
@example
|
|
ffmpeg -i INPUT -f alsa default
|
|
@end example
|
|
|
|
@item
|
|
Play a file on soundcard 1, audio device 7:
|
|
@example
|
|
ffmpeg -i INPUT -f alsa hw:1,7
|
|
@end example
|
|
@end itemize
|
|
|
|
@section caca
|
|
|
|
CACA output device.
|
|
|
|
This output device allows 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
|
|
@code{--enable-libcaca}.
|
|
libcaca is a graphics library that outputs text instead of pixels.
|
|
|
|
For more information about libcaca, check:
|
|
@url{http://caca.zoy.org/wiki/libcaca}
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
|
|
@item window_title
|
|
Set the CACA window title, if not specified default to the filename
|
|
specified for the output device.
|
|
|
|
@item window_size
|
|
Set the CACA window size, can be a string of the form
|
|
@var{width}x@var{height} or a video size abbreviation.
|
|
If not specified it defaults to the size of the input video.
|
|
|
|
@item driver
|
|
Set display driver.
|
|
|
|
@item 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 @code{-list_dither algorithms}.
|
|
|
|
@item antialias
|
|
Set antialias method. Antialiasing smoothens the rendered
|
|
image and avoids the commonly seen staircase effect.
|
|
The accepted values are listed with @code{-list_dither antialiases}.
|
|
|
|
@item charset
|
|
Set which characters are going to be used when rendering text.
|
|
The accepted values are listed with @code{-list_dither charsets}.
|
|
|
|
@item color
|
|
Set color to be used when rendering text.
|
|
The accepted values are listed with @code{-list_dither colors}.
|
|
|
|
@item list_drivers
|
|
If set to @option{true}, print a list of available drivers and exit.
|
|
|
|
@item list_dither
|
|
List available dither options related to the argument.
|
|
The argument must be one of @code{algorithms}, @code{antialiases},
|
|
@code{charsets}, @code{colors}.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
The following command shows the @command{ffmpeg} output is an
|
|
CACA window, forcing its size to 80x25:
|
|
@example
|
|
ffmpeg -i INPUT -vcodec rawvideo -pix_fmt rgb24 -window_size 80x25 -f caca -
|
|
@end example
|
|
|
|
@item
|
|
Show the list of available drivers and exit:
|
|
@example
|
|
ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_drivers true -
|
|
@end example
|
|
|
|
@item
|
|
Show the list of available dither colors and exit:
|
|
@example
|
|
ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_dither colors -
|
|
@end example
|
|
@end itemize
|
|
|
|
@section 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 @code{--extra-cflags}
|
|
and @code{--extra-ldflags}.
|
|
On Windows, you need to run the IDL files through @command{widl}.
|
|
|
|
DeckLink is very picky about the formats it supports. Pixel format is always
|
|
uyvy422, framerate and video size must be determined for your device with
|
|
@command{-list_formats 1}. Audio sample rate is always 48 kHz.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
|
|
@item list_devices
|
|
If set to @option{true}, print a list of devices and exit.
|
|
Defaults to @option{false}.
|
|
|
|
@item list_formats
|
|
If set to @option{true}, print a list of supported formats and exit.
|
|
Defaults to @option{false}.
|
|
|
|
@item preroll
|
|
Amount of time to preroll video in seconds.
|
|
Defaults to @option{0.5}.
|
|
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
|
|
@item
|
|
List output devices:
|
|
@example
|
|
ffmpeg -i test.avi -f decklink -list_devices 1 dummy
|
|
@end example
|
|
|
|
@item
|
|
List supported formats:
|
|
@example
|
|
ffmpeg -i test.avi -f decklink -list_formats 1 'DeckLink Mini Monitor'
|
|
@end example
|
|
|
|
@item
|
|
Play video clip:
|
|
@example
|
|
ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 'DeckLink Mini Monitor'
|
|
@end example
|
|
|
|
@item
|
|
Play video clip with non-standard framerate or video size:
|
|
@example
|
|
ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 -s 720x486 -r 24000/1001 'DeckLink Mini Monitor'
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@section 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
|
|
@file{/dev/fb0}.
|
|
|
|
For more detailed information read the file
|
|
@file{Documentation/fb/framebuffer.txt} included in the Linux source tree.
|
|
|
|
@subsection Options
|
|
@table @option
|
|
|
|
@item xoffset
|
|
@item yoffset
|
|
Set x/y coordinate of top left corner. Default is 0.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
Play a file on framebuffer device @file{/dev/fb0}.
|
|
Required pixel format depends on current framebuffer settings.
|
|
@example
|
|
ffmpeg -re -i INPUT -vcodec rawvideo -pix_fmt bgra -f fbdev /dev/fb0
|
|
@end example
|
|
|
|
See also @url{http://linux-fbdev.sourceforge.net/}, and fbset(1).
|
|
|
|
@section opengl
|
|
OpenGL output device.
|
|
|
|
To enable this output device you need to configure FFmpeg with @code{--enable-opengl}.
|
|
|
|
Device allows 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:
|
|
@code{AV_CTL_MESSAGE_CREATE_WINDOW_BUFFER} - create OpenGL context on current thread.
|
|
@code{AV_CTL_MESSAGE_PREPARE_WINDOW_BUFFER} - make OpenGL context current.
|
|
@code{AV_CTL_MESSAGE_DISPLAY_WINDOW_BUFFER} - swap buffers.
|
|
@code{AV_CTL_MESSAGE_DESTROY_WINDOW_BUFFER} - destroy OpenGL context.
|
|
Application is also required to inform a device about current resolution by sending @code{AV_DEVICE_WINDOW_RESIZED} message.
|
|
|
|
@subsection Options
|
|
@table @option
|
|
|
|
@item background
|
|
Set background color. Black is a default.
|
|
@item no_window
|
|
Disables default SDL window when set to non-zero value.
|
|
Application must provide OpenGL context and both @code{window_size_cb} and @code{window_swap_buffers_cb} callbacks when set.
|
|
@item window_title
|
|
Set the SDL window title, if not specified default to the filename specified for the output device.
|
|
Ignored when @option{no_window} is set.
|
|
|
|
@end table
|
|
|
|
@subsection Examples
|
|
Play a file on SDL window using OpenGL rendering:
|
|
@example
|
|
ffmpeg -i INPUT -f opengl "window title"
|
|
@end example
|
|
|
|
@section oss
|
|
|
|
OSS (Open Sound System) output device.
|
|
|
|
@section pulse
|
|
|
|
PulseAudio output device.
|
|
|
|
To enable this output device you need to configure FFmpeg with @code{--enable-libpulse}.
|
|
|
|
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 set to the specified output name.
|
|
|
|
@item device
|
|
Specify the device to use. Default device is used when not provided.
|
|
List of output devices can be obtained with command @command{pactl list sinks}.
|
|
|
|
@item buffer_size
|
|
@item buffer_duration
|
|
Control the size and duration of the PulseAudio buffer. A small buffer
|
|
gives more control, but requires more frequent updates.
|
|
|
|
@option{buffer_size} specifies size in bytes while
|
|
@option{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.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
Play a file on default device on default server:
|
|
@example
|
|
ffmpeg -i INPUT -f pulse "stream name"
|
|
@end example
|
|
|
|
@section sdl
|
|
|
|
SDL (Simple DirectMedia Layer) output device.
|
|
|
|
This output device allows 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:
|
|
@url{http://www.libsdl.org/}
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
|
|
@item window_title
|
|
Set the SDL window title, if not specified default to the filename
|
|
specified for the output device.
|
|
|
|
@item icon_title
|
|
Set the name of the iconified SDL window, if not specified it is set
|
|
to the same value of @var{window_title}.
|
|
|
|
@item window_size
|
|
Set the SDL window size, can be a string of the form
|
|
@var{width}x@var{height} or a video size abbreviation.
|
|
If not specified it defaults to the size of the input video,
|
|
downscaled according to the aspect ratio.
|
|
|
|
@item window_fullscreen
|
|
Set fullscreen mode when non-zero value is provided.
|
|
Default value is zero.
|
|
@end table
|
|
|
|
@subsection Interactive commands
|
|
|
|
The window created by the device can be controlled through the
|
|
following interactive commands.
|
|
|
|
@table @key
|
|
@item q, ESC
|
|
Quit the device immediately.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
The following command shows the @command{ffmpeg} output is an
|
|
SDL window, forcing its size to the qcif format:
|
|
@example
|
|
ffmpeg -i INPUT -vcodec rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"
|
|
@end example
|
|
|
|
@section sndio
|
|
|
|
sndio audio output device.
|
|
|
|
@section xv
|
|
|
|
XV (XVideo) output device.
|
|
|
|
This output device allows to show a video stream in a X Window System
|
|
window.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
@item 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 @var{hostname}[:@var{number}[.@var{screen_number}]].
|
|
|
|
@var{hostname} specifies the name of the host machine on which the
|
|
display is physically attached. @var{number} specifies the number of
|
|
the display server on that host machine. @var{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, @code{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.
|
|
|
|
@item window_size
|
|
Set the created window size, can be a string of the form
|
|
@var{width}x@var{height} or a video size abbreviation. If not
|
|
specified it defaults to the size of the input video.
|
|
|
|
@item window_x
|
|
@item 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.
|
|
|
|
@item window_title
|
|
Set the window title, if not specified default to the filename
|
|
specified for the output device.
|
|
@end table
|
|
|
|
For more information about XVideo see @url{http://www.x.org/}.
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Decode, display and encode video input with @command{ffmpeg} at the
|
|
same time:
|
|
@example
|
|
ffmpeg -i INPUT OUTPUT -f xv display
|
|
@end example
|
|
|
|
@item
|
|
Decode and display the input video to multiple X11 windows:
|
|
@example
|
|
ffmpeg -i INPUT -f xv normal -vf negate -f xv negated
|
|
@end example
|
|
@end itemize
|
|
|
|
@c man end OUTPUT DEVICES
|