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SC2Inspector

Project Log

12/28/2011 @ 23:46

Ok, so I've gotten a decent amount done. I was looking at code for an MPQ parser and it looks like the SC2Replay files have a slightly different format. They start with MPQ\x1B then 1024 bytes into the file have another MPQ\x1A which actually starts the normal MPQ file. MPQ1B seems to be a StarCraft II only option for displaying additional metadata without having to read the file.

Using the following data taken from a random SC2Replay:

I was able to determine the following:

Attribute Location (d) Hex Value Interpretation
Id x0-x3 4D 50 51 1B MPQ\x1B
UserDataMaxSize x4-x7 00 02 00 00 512
HeaderOffset x8-x11 00 04 00 1024
UserDataSize x12-x15 3C 00 00 00 60
DataType x16 05 DataType indicated upcomming data is of type Array with keys
NumberOfElements x17 08 Indicates 4 elements in array (VLF)
Index x18 00 Sets index to 0
DataType x19 02 DataType indicated upcomming data is of type Binary Data
NumberOfElements x20 2C Indicates 22 elements in the upcomming array
StarCraftII x21-x42 53 74 61 72 43 72 61 66 74 20 49 49 20 72 65 70 6C 61 79 1B 31 31 A bunch of hex values which resolve to a byte array of ASCII values which end up as “Starcraft II Replay 11”
Index x43 02 Sets index to 1
DataType x44 05 DataType indicated upcomming data is of type Array with keys
NumberOfElements x45 0C Indicates 6 elements in array (VLF)
Index x46 00 Sets index to 0
DataType x47 09 DataType indicated upcomming data is of type VLF
Version x48 02 Major Version
Index x49 02 Sets index to 1
DataType x50 09 DataType indicated upcomming data is of type VLF
Version x51 02 Minor Version
Index x52 04 Sets index to 2
DataType x53 09 DataType indicated upcomming data is of type VLF
Version x54 00 Patch Version
Index x55 06 Sets index to 3
DataType x56 09 DataType indicated upcomming data is of type VLF
Version x57 00 Revision Version
Index x58 08 Sets index to 4
DataType x59 09 DataType indicated upcomming data is of type VLF
Version x60 EA Build Version
Unknown x61-x75 FB 01 0A 09 DA F0 01 04 09 04 06 09 FE 9E 05 FB I'm unsure after this part. Nothing seems to add up correctly.

VLF represents a “Variable Length Format” integer.

Additionally, SC2Replay files have a quirk concerning the way integers are stored. An integer consists of a variable number of bytes in Big Endian order. When parsing an integer, the first i.e. most significant bit of a byte indicates that the succeeding byte is counted towards the integer's value. After parsing all bytes of a number, the least significant bit of the result indicates the sign. Extract this bit and shift the number's value to the right by one. If the bit is set, change the sign to negative, otherwise leave it positive.
Source: http://trac.erichseifert.de/warp/wiki/SC2ReplayFormat#VariableLengthFormat

I've taken the following code from a C# SC2Replay client to do this VLF for me:

private static int ParseVLFNumber(BinaryReader reader) {
	var bytes = 0;
	var first = true;
	var number = 0;
	var multiplier = 1;
	while (true) {
		var i = reader.ReadByte();
		number += (i & 0x7F) * (int)Math.Pow(2, bytes * 7);
		if (first) {
			if ((number & 1) != 0) {
				multiplier = -1;
				number--;
			}
			first = false;
		}
		if ((i & 0x80) == 0) {
			break;
		}
		bytes++;
	}
	return (number / 2) * multiplier;
}

This took almost five hours to decipher with a LOT of help from various sources around the internet. I can't find it anymore but I thought I read somewhere that the game length was supposed to be in the header, but this could be incorrect. I would think the game length would be with the game recording date, players, colors, etc.

Next step is to work on extracting the different files from the ACTUAL MPQ (MPQ\x1A) then parse through the details there.

12/28/2011 @ 18:31

Decided to start on this project. I've added the ViewModelBase and made some changes to App.xaml and App.xaml.cs. Committed r1.

project/sc2inspector.1325142619.txt.gz · Last modified: 2011/12/29 07:10 by smark
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