Scripts for force-syncing movies in BizHawk (particularly N64 movies with different plug-in settings). See http://tasvideos.org/Zinfidel/SyncScripts.html for usage.

net-receive.lua

package.path = package.path .. ';luasocket/lua/?.lua;luasocket/lua/socket/?.lua'
package.cpath = package.cpath .. ';luasocket/?.dll;luasocket/mime/?.dll;luasocket/socket/?.dll'
local socket = require 'socket'

local socClient
local server

local onExitEvent = event.onexit(
	function()
		socClient:close()
		server:close()
		console.log("Client closed.")
	end
	, "Exit Event" );

local function endsWith(str, ending)
	return ending == "" or str:sub(-#ending) == ending
end

local function strChop(str, ending)
	return str:sub(1, -(#ending + 1))
end

-- Pause the client and establish a socket listener.
client.pause()
server = assert(socket.bind("127.0.0.1", 45678), "Socket server failed to bind to ip/port. Script aborted.")
console.write("Waiting on connection...")
emu.yield()

server:settimeout(5)
server:setoption('keepalive', true)

-- Wait for the other instance to connect.
while true do
	local err = nil
	socClient, err = server:accept()

	if not err then
		console.log(" Connected!")
		emu.yield()
		break
	else
		console.write('.')
	end
	emu.yield()
end

socClient:settimeout(10)

console.write("Awaiting a message ...")
while true do
	emu.yield()
	local line, err = socClient:receive()
	if not err then
		if line == "quit" then
			console.log("\nReceived exit message. Exiting now.")
			break;
		elseif endsWith(line, ".State") then
			local frameNum = tonumber(strChop(line, ".State"))
			console.write("\nReceived request for a savestate at frame " .. tostring(frameNum) .. ". Seeking...")
			emu.yield()
			client.seekframe(frameNum)
			savestate.save(line)
			console.log("\nCreated " .. line .. ". Sending to the client.")
			emu.yield()
			socClient:send(line .. "\n")
			console.write("\nAwaiting a message ...")
		else
			console.log("\nUnknown command " .. line .. " received.")
		end
	elseif err == "timeout" then
		console.write('.')
	elseif err == "closed" then
		console.log("\nConnection with client closed. Exiting now.")
		break;
	else
		console.log("\nNo message received. Error: " .. err)
	end
	emu.yield()
end

sync-collect.lua

-- This script is for collecting "sync data" for a game that consists of some sort of canary data
-- that is very likely to indicate a desync happening. Good choices for this kind of data are transformation
-- matrices for models, or manually collected position data like x,y,z,pitch,yaw,roll,etc.

-- Change this to some amount of frames on which data will be flushed. 200 means flush to file every 200 frames.
FLUSH_FRAMES = 200

-- Check if a file exists on the filesystem
local function file_exists(name)
   local f=io.open(name,"r")
   if f~=nil then io.close(f) return true else return false end
end

-- Create a "log.txt" file for the data, but add a number so we don't accidentally overwrite previous results.
local name = "log.txt"
local i = 1
while (file_exists(name)) do
	name = "log" .. tostring(i) .. ".txt"
	i = i + 1
end
LogFile = io.open(name, "w")

-- Flush and close the log file when the script closes.
local onExitEvent = event.onexit(
	function()
		LogFile:close()
		console.log("")
		console.log("Script stopping. Closing log file.")
	end
	, "Exit Event" );


-- Collect sync data
console.write("Flushing to file ")
while true do
	-- Custom data collection for the game goes in here. The example code below is for Star Wars Episode 1: Racer,
	-- it finds the player's position matrix and records each matrix entry as a float to 5 decimals. It writes these
	-- data to a comma-separated line.
	---------------------------------------------------------------------------------------------------------------
	Racedata = 0x118F90
	Statedata = mainmemory.read_u24_be(Racedata+0x84+0x1)

	MatrixStart = Statedata + 0x1C
	for j=0, 15, 1 do
		LogFile:write(string.format("%.5f",mainmemory.readfloat(MatrixStart + 4*j, true)))
		if (j ~= 15) then LogFile:write(',') end
	end
	---------------------------------------------------------------------------------------------------------------
	-- End custom collection code

	-- New line, and if we are at a flush boundary, flush the file.
	LogFile:write('\n')
	if (emu.framecount() % FLUSH_FRAMES) == 0 then
		LogFile:flush()
		console.write('.')
	end

	emu.frameadvance()
end

sync-dump.lua

-- feos, 2017
-- DK64 resync workflow
-- props to thecoreyburton

t = {}            -- array of state names found
count = 0         -- total states found, just for print()
av_paused = false -- pretend we have that info from the emu
offset = 10        -- av delay after stated frame

-- scan the script dir for states and store their names to array
function scandir()
	local popen = io.popen          -- use cmd
	local pfile = popen('dir . /b') -- cmd arguments
	local i = 0
	local index = 0
	local name = ""
	for filename in pfile:lines() do
		i = i + 1
		
		-- skip all but state files
		if filename:find(".State") then
			-- strip frame numbers
			name = string.gsub(filename, ".State", "")
			index = tonumber(name)
			t[index] = filename
			count = count + 1
		end
	end
	pfile:close()
end

scandir()
print("States found: " .. count) -- #t doesn't work for some reason (gaps in the table?)

last_frame = 0
while true do
	if movie.isloaded() then
		-- check if there's a state of "offset" frames back
		local name = t[emu.framecount() - offset]

		-- suspend av and load the state, with a delay
		if name and not av_paused then
			client.pause_av()
			av_paused = true
			savestate.load(name)
			print("Loaded " .. name)
		end

		-- basic report you'd barely see
		if av_paused then
			gui.text(0, 40, "AV paused")
		end

		-- resume av when that frame occurs again
		if t[emu.framecount() - offset] and av_paused then
			client.unpause_av()
			av_paused = false
		end
	end
	emu.frameadvance()
end

sync-savestates.lua

package.path = package.path .. ';luasocket/lua/?.lua;luasocket/lua/socket/?.lua'
package.cpath = package.cpath .. ';luasocket/?.dll;luasocket/mime/?.dll;luasocket/socket/?.dll'
local socket = require 'socket'

local tab = {}                     -- entire parsed file broken into lines
local gap_minimum = 10			   -- Set the minimum number of frames between savestates. This can help prevent thrashing in bad sections.

function ParseFile()
	print("Parsing file...")
	local logfile = io.open("log.txt", "r")

	local char
	repeat
		char = logfile:read("*l")
		table.insert(tab, char)
	until char == nil

	logfile:close()
	print("File parsed! Line count: "..#tab.."\n")
end

-- Customize this function to retrieve your sync data and format it the same way as it appears in log.txt. An example of how
-- to do this for N64 Star Wars Episode 1: Racer, matching the example in sync-collect.lua, is the default implementation. this
-- value will get compared, as a string, to the corresponding line in log.txt to verify sync.
function GetData()
	Racedata = 0x118F90
	Statedata = mainmemory.read_u24_be(Racedata+0x84+0x1)
	SyncData = {}
	MatrixStart = Statedata + 0x1C
	for i=0, 15, 1 do
		table.insert(SyncData, string.format("%.5f",mainmemory.readfloat(MatrixStart + 4*i, true)))
	end

	return table.concat(SyncData, ",")
end

-- Pause the client and establish a tcp connection to the server.
client.pause()
local tcp = assert(socket.connect("127.0.0.1", 45678), "Socket client failed to establish tcp connection with server. Script aborted.")
console.write("Connection to server established!\n")
tcp:settimeout(2)
emu.yield()

ParseFile()

local onExitEvent = event.onexit(
	function()
		console.log("\nScript exiting. Sending quit command to server." );
		tcp:send("quit\n")
	end
	, "OnExit" );

local last_ss = 0

while true do
	local frame = emu.framecount()
	local original = tab[frame+1]
	local yours = GetData()

	gui.pixelText(0, 40, string.format( "%s - original\n%s - yours", original, yours))

	-- mismatch
	if (yours ~= original) and ((frame - last_ss) > gap_minimum) then
		last_ss = frame
		client.pause()

		-- screen and console alarm
		gui.pixelText(0, 40, string.format( "%s - original\n%s - yours\ndesync at frame %d", original, yours, frame), "red")
		print(string.format( "desync at frame %d\n%s\n%s\n", frame, yours, original))
		emu.yield()

		local response = ""
		tcp:send(frame .. ".State\n")
		console.write("Sent packet asking for frame " .. tostring(frame) .. " ...")
		emu.yield()
		while true do
			local line, err, partial = tcp:receive()
			if not err then
				response = line
				console.log("\nReceived message that savestate " .. tostring(frame) .. " is available. Loading ...")
				emu.yield()
				savestate.load(response)
				client.unpause()
				break
			elseif err == "timeout" then
				response = response .. partial
				console.write('.')
			elseif err == "closed" then
				console.log("\nConnection with server closed. Exiting now.")
				break
			else
				console.log("\nUnknown communication error.")
			end

			emu.yield()
		end

	end

	-- so far so good
	emu.frameadvance()
end