Introduction of New VNC codec

[Adam Tkac]

Hitachi Systems & Services, Ltd. napsal(a):
> Dear VNC developer.
>
>
>                   Introduction of
>   "ZYWRLE":Enhanced VNC codec for Motion picture
>
>
> 1. Introduction
>  The lossy codec based on Wavelet transform is frequently
> used in compression of natural image, motion picture and
> audio stream.
>  But it isn't almost used in Remote Desktop protocol like
> VNC because classical lossless run-length codec like ZRLE
> has high performance in peculiar image which has big mono
> color region like desktop image. The lack of lossy codec
> cause low performance of motion picture in VNC.
>  We introduce new codec "ZYWRLE(ZLib YUV Wavelet Run Length
> Encoding)" which applied wavelet transform partially and
> is based on ZRLE. In this new codec, network traffic reduced
> to 15%-50% traffic of ZRLE when we play motion picture. 
>
>
> 2. Highlight of Evalution of ZYWRLE
>
>                Result of ZYWRLE for motion picture
> +-------+-------------------+------------------+------------------+
> |quality|  Raw tile(Mbytes) |   Total(Mbytes)  |Raw tile|PSNR(RGB)|
> |       |  Out | Raw  |rate | Comp.|  Raw |rate| rate(%)|   (dB)  |
> +-------+------+------+-----+------+------+----+--------+---------+
> | ZRLE  |125.8 |125.8 |100  |117.1 |392.2 |29.8|  32.1  |   INF.  |
> |  Hi   | 53.85|167.58| 32.1| 52.10|370.96|14.0|  45.1  |  28.025 |
> | Mid   | 31.83|264.05| 12.1| 20.56|378.50| 5.4|  69.7  |  23.980 |
> +-------+------+------+-----+------+------+----+--------+---------+
>
> * Comp. rate of ZRLE(about 30%) goes to 15%(Hi-quality)/5%(Mid-quality)! 
>
>
> 3. Reference Implementation(C source code/patch for VNC Servers)
>   * Core Codec of ZYWRLE
>       http://mobile.hitachi-system.co.jp/publications/ZYWRLE/zywrletemplate.c
>   * Patch for Ultr "at" VNC V1.0.2
>       http://mobile.hitachi-system.co.jp/publications/ZYWRLE/UltraVNC-102-ZYWRLE-diff.txt
>   * Patch for LibVNCServer 0.8.2
>       http://mobile.hitachi-system.co.jp/publications/ZYWRLE/LibVNCServer-0.8.2-ZYWRLE-diff.txt
>
> I think that Any VNC server can be applied ZYWRLE easlilly using one of these patch. 
>
>
> 4. License of ZYWRLE
>  Though ZYWRLE is our intellectual property and was developed for
> our micro-VNC, We Hitachi Systems & Services, Ltd. decided make it
> open source. You can use it with no fee for commercial and/or 
> non-commercial purpose. The above reference implementation are released
> under our BSD-like license. More detail, see top of zywrletemplate.c. 
>
>
> 5. More detail
>  See our ZYWRLE page(http://mobile.hitachi-system.co.jp/publications/ZYWRLE/)
>
> We are glad if your VNC server supports ZYWRLE.
>
> Thank you.
>
> ---
> Noriaki Yamazaki
> Administrator of micro-VNC
>
> Research & Developement center
> Hitachi Systems & Services, Ltd.
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>   
This idea looks very nice. I'm going to implement this new encoding in 
Fedora's VNCServer for future performance tests.

Regards, Adam