This document describes the use of the three Raspberry Pi
camera applications as of July 2013.
There are three applications provided: raspistill, raspivid
and raspistillyuv. Both raspistill and raspistillyuv
are very similar and are intended for capturing images, while
raspivid is for capturing video.
All the applications are command-line driven, written to take
advantage of the mmal API which runs over OpenMAX. The
mmal API provides an easier to use system than that presented
by OpenMAX. Note that mmal is a Broadcom specific API used
only on Videocore 4 systems.
The applications use up to four OpenMAX(mmal) components -
camera, preview, encoder and null_sink. All applications
use the camera component: raspistill uses the Image
Encode component, raspivid uses the Video Encode
component, and raspistillyuv does not use an encoder, and
sends its YUV or RGB output direct from camera component to
file.
The preview display is optional, but can be used full screen or
directed to a specific rectangular area on the display. If preview
is disabled, the null_sink component is used to 'absorb' the
preview frames. It is necessary for the camera to produce
preview frames even if not required for display, as they are used
for calculating exposure and white balance settings.
In addition it is possible to omit the filename option, in which
case the preview is displayed but no file is written, or to redirect
all output to stdout. Command line help is available by typing just
the application name in on the command line.
This document describes the use of the three Raspberry Pi
camera applications as of July 2013.
There are three applications provided: raspistill, raspivid
and raspistillyuv. Both raspistill and raspistillyuv
are very similar and are intended for capturing images, while
raspivid is for capturing video.
All the applications are command-line driven, written to take
advantage of the mmal API which runs over OpenMAX. The
mmal API provides an easier to use system than that presented
by OpenMAX. Note that mmal is a Broadcom specific API used
only on Videocore 4 systems.
The applications use up to four OpenMAX(mmal) components -
camera, preview, encoder and null_sink. All applications
use the camera component: raspistill uses the Image
Encode component, raspivid uses the Video Encode
component, and raspistillyuv does not use an encoder, and
sends its YUV or RGB output direct from camera component to
file.
The preview display is optional, but can be used full screen or
directed to a specific rectangular area on the display. If preview
is disabled, the null_sink component is used to 'absorb' the
preview frames. It is necessary for the camera to produce
preview frames even if not required for display, as they are used
for calculating exposure and white balance settings.
In addition it is possible to omit the filename option, in which
case the preview is displayed but no file is written, or to redirect
all output to stdout. Command line help is available by typing just
the application name in on the command line.
การแปล กรุณารอสักครู่..
