View Full Version : Unhinged PCARS 2 UDP Packet Speculation

12-10-2017, 15:48
Because I'm bored...

Assuming my packet capture tool (http://forum.projectcarsgame.com/showthread.php?51227-Project-CARS-UDP-Packet-Capture) is functioning correctly (a somewhat large assumption), the following packets, identified by size and count, were captured during a 15 minute Ginetta Juniors race (12 laps completed, 20 cars total):

Size: 993 bytes, Count: 21383
Size: 538 bytes, Count: 21541
Size: 784 bytes, Count: 430
Size: 24 bytes, Count: 170

My speculation:
The 538 byte packet is the player car data.
The 993 byte packet is the AI car data, all included in a single packet. I'd have to run a race with a different field size to see if this packet size changes based on the field, or if it's padded to account for a maximum field size (56?).
The 784 byte packet is the player and AI name data. Sent at a lower update rate.
The 24 byte packet is curious; that's not a lot of data and it's sent very infrequently. Weather and/or track updates?

The first two bytes of every PCARS packet was the build version number. That isn't the case for PCARS 2 packets, from my "just try to grab the first two bytes and read an unsigned short" testing. (I didn't go further.)

13-10-2017, 00:39
Some of this is probably wrong. In the course of screwing around I found a bug in the packet capture. ;)

17-10-2017, 13:58
From the old PCARS 3rd Party Apps forum (http://forum.projectcarsgame.com/showthread.php?40113-HowTo-Companion-App-UDP-Streaming/page131)... and given cjorgens's status as both a trusted developer and WMD member, I'd say it's fairly solid information:

The PCARS2 UDP protocol is unfinished which is why there are no officially released specs.

My takeaway: Capturing packets right now for future use would then be pointless, since the spec, once finalized, will be updated with a patch. Again, disappointing, but there's nothing we can do about it right now.