Telecine control

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Three principal types of high definition telecine machines are in common use today. The Spirit and Spirit2 devices are manufactured by Thomson-Grass Valley. The C-Reality is manufactured by Cintel International. Control of these machines is performed by means of ethernet packets. The machines constantly broadcast their current status which an external controller is expected to monitor constantly. The external controller can change the state of the telecine machine by issuing a command sequence encoded in an ethernet packet.

While the C-Reality has its own ethernet protocol, the Spirit protocol is by far the most common command protocol in use. In fact, C-Reality has implemented the Spirit protocol as well as its own native ethernet protocol. The Spirit2 is a newer telecine machine and does not yet enjoy the same market penetration as the older Spirit. The Spirit2 has a different ethernet protocol.

Contents 1 Basic Packet Structure 2 Spirit Protocol 3 Spirit2 Protocol 4 References

[edit] Basic Packet Structure

Spirit and Spirit2 status and commands are encoded in ethernet packets. The header of the packet is 20 bytes. The header is organized as follows:

bytes 00-05: Destination address
bytes 06-11: Source address
bytes 12-13: Packet type
bytes 14-15: Packet length
byte 16  : User command
bytes 17-18: Data length
byte 19  : Source command

The data, which can be either a status report from the telecine or a command sequence to the telecine, begins at byte 20. This is an ethernet Type II frame.

[edit] Spirit Protocol

The address of the external controller is always 0x00, 0x05, 0x00, 0x1F, 0xBB, 0x00. The address of the film deck controller of the telecine is always 0x00, 0x02, 0x00, 0x1F, 0xBB, 0x00.

When receiving status reports from the Spirit, the destination address is that of the external controller. The source address is that of the film deck controller. The packet type is always 0x81, 0x55. The packet length is variable. The user command is 0x3E. The data length is variable. The source command will be 0x40.

When issuing a play command to the Spirit, the destination address will be that of the film deck controller. The source address will be that of the external controller. The packet type is 0x81, 0x55. The packet length is 0x01, 0x00. The user command is 0x43. The data length is 64. The source command is 0x00.

When issuing the stop command, the user command is 0x41.

[edit] Spirit2 Protocol

The addresses of the external controller and the film deck controller appear to be variable. More observation is needed to confirm.

The status reports in the Spirit2 protocol are the same as in the Spirit protocol.

When issuing a play command to the Spirit2, the packet type is 0x08, 0x00. The packet length is 0x45, 0x00. The user command is 0x00. The data length and source command bytes are used for a counting mechanism: each command increments the count. Byte 51 carries the play instruction, 0x43.

The stop command is 0x0E at byte 51.

[edit] References

This article may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. (September 2007)

  1. ^ Ethernet Prototype Circuit Board. Smithsonian National Museum of American History. Retrieved on 2007-09-02.
  2. ^ LAN MAN Standards Committee of the IEEE Computer Society (20 March 1997). IEEE Std 802.3x-1997 and IEEE Std 802.3y-1997. The Institute of Electrical and Electronics Engineers, Inc., pp. 28–31.