Dear VNC developers,
I am extending the RFB protocol and would like to do it in a manner that is
most beneficial for the community at large. The impetus for the changes are
as follows:
* Minimize bandwidth usage, and maximize performance on low speed connections.
* Minimize the load and complexity on a RFB proxy/mirror server application.
My experiments with 8 bit color depth have shown that applying bzip2
compression to an entire raw encoded full frame buffer update will save
roughly 30% size over TightVNC's encoding scheme. This is significant for my
application.
Here is the proposed change:
1) Add a pseudo encoding type such as:
#define rfbEncodingProxyFmt 9
2) Modify the FramebufferUpdate like so:
/*-----------------------------------------------------------------------------
* FramebufferUpdate - a block of rectangles to be copied to the framebuffer.
*
* This message consists of a header giving the number of rectangles of pixel
* data followed by the rectangles themselves. The header is padded so that
* together with the type byte it is an exact multiple of 4 bytes (to help
* with alignment of 32-bit pixels):
*
* JDR addition - if rfbEncodingProxyFmt is enabled, then:
* 1) The 'pad' byte is followed by an unsigned long which is the block size
* of the remaining frame buffer update. This makes it easy to proxy or
* broadcast.
* 2) If the first bit of 'pad' is set, then the remaining frame update is
* bzip2 compressed.
*/
typedef struct _rfbFramebufferUpdateMsg {
CARD8 type; /* always rfbFramebufferUpdate */
CARD8 pad; /* JDR - Used if rfbEncodingProxyFmt is enabled! */
/* CARD32 blkSz; <-- Exists if rfbEncodingProxyFmt is enabled! */
/* If rfbEncodingProxyFmt is enabled and the 0th bit of 'pad' is set,
* the remainder of the update is bzip2 compressed
*/
CARD16 nRects;
/* followed by nRects rectangles */
} rfbFramebufferUpdateMsg;
--
=============================================================
John D. Robertson, Computer / Engineering Consultant
Robertson & Robertson Consultants, Inc.
3637 West Georgia Rd.
Pelzer, SC 29669
Phone: (864) 243-2436
Fax: (864) 243-3023
Email: [EMAIL PROTECTED]
WWW: http://www.rrci.com
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