Live Video on Dashboard

[writchie]

On Friday of the Florida Regional Team 2152 was prohibited from using its Dashboard ostensibly because the live video would provide an unfair advantage over other teams.

We were not able to pursuade the Chief Referee that the live video was legal as long as it was passed through the user data. The language of Update #5 was considered ambiguous because it did not say yes. Q&A questions that do not say "yes" or "no" seem to remain ambiguous, especially where a simple yes or no before the explanation is omitted.

The Chief Referee did graciously agree to contact FIRST headquarters Friday night for clarification and present the following letter:

To: FIRST Officials to whom it may concern.
Subject: Team 2152 Dashboard Video

Team 2152 has a custom dashboard and Software in the MDC that transfers
live video from the Axis 206 camera and packs compressed images in the
user data portion of the MDC to Dashboard data frames.

We are not being permitted to use this live video at the Florida Regional.

The Q&A contains a specific question from FRC2104 on 1/11/2009.
The GDC response was:

"It is technically possible to capture an image obtained by an
on-board camera, pass it through the Mobile Device Controller,
transmit it back to the Driver Station, and display it on a dashboard
display. However, limitations on the data transfer rate provided by
the wireless communication system may provide a practical limit
on the effectiveness of the implementation"

We did not, an do not, interpret this as "No". We took, and
continue to take the response to mean: "You can if you want,
but we (the GDC) don't think it will be effective"

Team 2152 took this as a challenge, and solved the technical
issues to make it effective. The video subsystem was implemented
by using highly compressed video and packing video frames within
the 984 byte per packet user data stream that the rules allow.
Our dashboard software (written in Python) runs on a standard
PC (as permitted), connected to the DS as permitted,
receives the permitted user data bytes, unpacks video, and expands the
video from 160x120 to 320x240 for display on the Dashboard;
providing our pilots with a live view, along with other Telemetry.

No Rule, Q&A answer, or Update, can be cited that prohibits us from using
the 984 bytes user data in the Dashboard packets for live video.
There are rules that prohibit using additional data transport, e.g. that
used by the Camera to PC video relay (which uses different ports)
but this is not what we are doing. We are transfering images collected
from the camera over the local link, and using the same 984 bytes of
user data that all cRIO's transmit to the DS for forwarding over
UDP to the dashboard.

The Inspection checklist prohibits unauthorized wireless communication
devices. We are using all KoP of items in the authorized configuration.
The axis camera is sending data over the LOCAL ethernet port,
in the same manner as when this is used for tracking. The cRIO is
sending the exact same datastream to the DS, except that the
984 bytes of user data (which is ALWAYS transmitted) now
includes our compressed data stream.

Our laptop PC is legally connected only to the DS and uses
only the specified UDP port and IP address.

There is no RULE specifically prohibiting live video!

Team 2152 believes that we should be allowed to compete
using our innovate live dashboard video solution, which
provides 25 frame per second live view.

Respectively,

Team 2152

On Saturday morning, the Chief Referee profusely apologized and advised us that we could use our live video dashboard as long as we could demonstrate that the data was coming through the user data portion of the MDC to DS frames.

As 2152 was doing well at the time (4/2), we made the decision not to make any changes to the cRIO software for the 3 remaining qualifiers.

We are providing this information for the possible benefit of teams at future regionals and the championship. If you have similar capabilities, you should be prepared to bring them to the attention of the inspectors on Thursday and make sure that you are able to demonstrate to them that your live video uses the user data transport and not some other path. Wireshark is a good tool for doing this. I thought the FMS was blocking all other ports but this may not be the actual case.

2152 intends to post the live camera code and dashboard source in the next few days so other teams may take advantage of this capability if they wish.