Raspberry Pi A, User Manual, Page: 258 / 314

P A R T I V
H A R D W A R E H A C K I N G
242
The filename after the output (
-o
) option can be anything you want it to be, with the preced-
ing commands merely using example filenames. When writing the filename, always be sure
to add the extension appropriate to your file type:
.jpg
for JPEG images,
.png
for Portable
Network Graphics,
.bmp
for bitmap images and
.gif
for the Graphics Interchange Format.
For a full description of all options available to
raspistill
, turn to Appendix B, “Camera
Module Quick Reference”. Alternatively, type the following command to see a list of options:
raspistill --help
Recording Video
Just as there is a dedicated application for capturing still images through the Raspberry Pi
Camera Module, there is another for capturing video:
raspivid
. Using
raspivid
is very
similar to using
raspistill
, but there are several differences you’ll need to know before
forging ahead.
The most important difference between
raspivid
and
raspistill
is in the
-t
option: in
raspistill
, the
-t
option provided the time-out for the preview before the image was
captured; in
raspivid
, the
-t
option provides a limit for the overall length of the recorded
video. If a value of
0
is given, the video will record forever—rapidly filling your SD card or
external storage device.
As with
raspistill
, the default for the
-t
option is five seconds. So, to check the camera
is working and record a short video, you can simply type the command’s name along with the
-o
(output) option and a filename:
raspivid -o defaultvideo.h264
This records a five-second video and saves it as in a format known as h.264 . Unlike
raspistill
, there is no option to save the file in a different format:
raspivid
uses the
hardware acceleration available in the Pi’s BCM2835 processor to do the recording, and only
h.264 is supported as a capture format.
If you play the video back, you’ll find that there’s no sound. Unfortunately, the Raspberry Pi
does not include a microphone input. Although it’s possible to record audio by connecting
certain USB microphones or sound cards, this will need to be captured using separate soft-
ware and combined with the video file later using a video editing package.