BBO BlinkenArea > Blinkenarea > BlinkenlightsProtokolle > BlinkenlightsProtocols > ExtendedBlinkenlightsProtocolEnglish BlinkenArea webs:
BlinkenArea | Main | TWiki | Sandbox | (Recycle Bin)
Blinkenarea . { Changes | Index | Search }

BlinkenArea.ExtendedBlinkenlightsProtocolEnglish
144 pixels ought to be enough for anybody


Home
Ziele
BlinkenArea
BlinkenLights

News
Presse
Links
Forum
MailList
Join

Audio,Video
Projekte
Protokolle
Dateiformate
Troia
bluebox

WTH
ICMP
CBCamp
CCCamp
CCCongress
EasterHack

Stats
Users
SiteMap
TWikiDoku
SiteTools
Translate
WebChanges

Impressum
Imprint

Datenschutzerklärung
Privacy Policy

RSS and Mail notification
powered by: [Powered by Eventphone]

EBLP - extended Blinkenlights protocol deutsch

The extended Blinkenlights protocol is used to transmit grayscale Blinkenlights streams using UDP packets. Simply, a UDP packet is sent for every new frame:

+-----------------------+
| magic                 |
| 0xFE 0xED   0xBE 0xEF |
+-----------------------+
| frame number          |
| 0x00 0x00   0x00 0x00 |
+-----------+-----------+
| width     | height    |
| 0x00 0x12 | 0x00 0x08 |
+-----------+-----------+
| pixels                |
| 0xFF 0xCC   0x99 0x66 |
| 0x33 0x00   0x00 0x00 |
| ...                   |
| 0x00 0x00   0x00 0x00 |
+-----------------------+
  • magic: fixed value
  • frame number: number of the frame, incremented with every frame, use is optional
  • width: the width of the image in pixels
  • height: the height of the image in pixels
  • pixels: the value of the width * height pixels
    • 0x00 for off, 0xFF for on, other values for grayscales
    • from left to right, then from top to bottom (i.e. top left pixel first, pixel right to it next, ...)
  • all values are in network byte order - big endian - highbyte first

The dynamic extension can be used to request a EBLP stream dynamically. A request packet is sent periodically (e.g. every 10s) to the UDP port of the server. The server then replys with a EBLP stream sent from this port to the source port of the request packet. After no request packet has been received for a longer time (e.g. 30s), the stream is no longer sent.

The format of the request packet is as follows:

+-----------------------+
| magic                 |
| 0xDE 0xAD   0xBE 0xCD |
+-----------------------+
| command               |
| 'R'  'E'    'F'  'R'  |
| 'E'  'S'    'H'  '2'  |
| '5'  '6'              |
+-----------------------+
  • magic: fixed value
  • command: fixed value

It is also possible to tell the server that the stream is no longer needed. This happens by sending a close packet instead of a request packet:

+-----------------------+
| magic                 |
| 0xDE 0xAD   0xBE 0xCD |
+-----------------------+
| command               |
| 'C'  'L'    'O'  'S'  |
| 'E'  '2'    '5'  '6'  |
+-----------------------+
  • magic: fixed value
  • command: fixed value

The UDP port should be configurable at server and client side. The standard port is UDP 2323.

-- StefanSchuermans - 06 Jun 2004


EOF

Topic ExtendedBlinkenlightsProtocolEnglish . { Edit | Attach | Ref-By | Printable | Diffs | r1.2 | > | r1.1 | More }
Revision r1.2 - 06 Jun 2004 - 20:52 - StefanSchuermans
Parents: BlinkenlightsProtokolle > BlinkenlightsProtocols