From 38ff1bd2613556adf5f9f85c2120578e3fa883ad Mon Sep 17 00:00:00 2001
From: Jordan Cristiano <jordan.cristi@gmail.com>
Date: Thu, 2 Jul 2015 23:01:26 -0400
Subject: [PATCH] Started documenting the dem format

---
 docs/DemFormat.md | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 docs/DemFormat.md

diff --git a/docs/DemFormat.md b/docs/DemFormat.md
new file mode 100644
index 0000000..c1f8cd0
--- /dev/null
+++ b/docs/DemFormat.md
@@ -0,0 +1,50 @@
+Source Engine DEM format
+=======
+
+This document applies to the version of TF2 as of July 1, 2015.
+
+### DEM Format
+The Source Engine DEM format at a high level:
+
+[Demo Header]  
+[Command Header][Command Packet]  
+[Command Header][Command Packet]  
+...  
+[Command Header = dem_stop]  
+~fin
+
+### Demo Header
+| Type | Name | Description | Example |
+|------|------|-------------|---------|
+| char[8] | Demo File Stamp | Demo file identifier. | "HL2DEMO" |
+| int32 | Demo Protocol | Demo protocol version. | 3 |
+| int32 | Network Protocol | Network protocol version. | 24 |
+| char[260] | Server Name | Name of the server that recorded this demo. | "Team Fortress" |
+| char[260] | Client Name | Name of the client that recorded this demo. | "SourceTV Demo" |
+| char[260] | Map Name | Name of the map where this demo was recorded. | "cp_granary" |
+| char[260] | Game Directory | Game directory relative to hl2.exe | "tf" |
+| float32 | Playback Time | Length of the demo in seconds. | 9.05999947 |
+| int32 | Playback Ticks | Length of the demo in ticks. | 604 |
+| int32 | Playback Frames | Length of the demo in frames. | 151 |
+| int32 | Signon Length | Length of the signon data in bytes. | 640166 |
+
+Note: Examples are from a short demo recording, hence the 9 second playback time.
+
+### Command Header
+| Type | Name | Description |
+|------|------|-------------|
+| int8 | Command Type | Type of the next command packet. |
+| int32 | Tick | Game tick of the next command packet. |
+
+### Command Type
+| Type | Value | Description |
+|------|-------|-------------|
+| dem_signon | 1 | Signon packet. Same format as a network packet. |
+| dem_packet | 2 | Network packet. |
+| dem_synctick | 3 | Signals the client to sync clock to demo tick. |
+| dem_consolecmd | 4 | Console command. |
+| dem_usercmd | 5 | User input command. |
+| dem_datatables | 6 | Network data tables. |
+| dem_stop | 7 | Signals the end of demo messages. |
+| dem_stringtables | 8 | Stringtables. |
+