CVD::ServerPushJpegBuffer< C > Class Template Reference
[Video buffers]

#include <serverpushjpegbuffer.h>

Inheritance diagram for CVD::ServerPushJpegBuffer< C >:

Detailed Description

template<class C>
class CVD::ServerPushJpegBuffer< C >

Play a server push stream as a video stream.

This is a standard used by a number of HTTP based security cameras. The format is as follows:

 --ImageSeparator\n
 Content-Type: image/jpeg\r\n
 Content-Length: 123456789\r\n
 \r\n
 <123456789 bytes of JPEG go here>\r\n

This exact format is from the InVision IQEye series of cameras. Other cameras have a different image separator, and do not miss the carriage return.

The buffer reads a number of frames from the stream on initiation (by default 10), in order to flush the camera's inbuilt buffer. With some cameras, changing the video size does not flush the buffer, so the first few frames will be of the incorrect size. After flushing the buffer, the size of the first frame is taken to be the size of the video stream. If spurious frames arrive of a different size later, these will be ignored.

WARNING: error checking is currently very minimal. The result of failure will probably result in an exception being thrown from the JPEG loader.

Parameters:

T The pixel type of the frames to provide (usually CVD::Rgb<CVD::byte> or CVD::byte. If the image files are of a different type, they will be automatically converted (see Image loading and saving, and format conversion).

Definition at line 36 of file serverpushjpegbuffer.h.


Public Member Functions
	S (std::istream &i, bool warnings_=0, int eat_frames=0)
virtual ImageRef	size ()
LocalVideoFrame< C > *	get_frame ()
void	put_frame (VideoFrame< C > *f)
bool	frame_pending ()
void	seek_to (double)
double	frame_rate ()

Member Function Documentation

template<class C>

CVD::ServerPushJpegBuffer< C >::S	(	std::istream &	i,
		bool	warnings_ = `0`,
		int	eat_frames = `0`
	)			`[inline]`

Construct a ServerPushJpegBuffer from an istream.

The istream

Parameters:

	i	The stream to use for video.
	warnings	Whether to print warnings if mis-sized frames arrive.
	eat_frames	Number of frames to discard on initialization.