Run this on a Mac with an iPhone plugged in and then view a video snap. It will be saved to the current directory. To stop, press Control-C. Requires iFuse. Works without a jailbreak. Clearly not affiliated with Snapchat in any way.

savevid.py

#!/usr/bin/env python

import sys, os
import subprocess
from shutil import copyfile


def main():
	mnt = os.path.expanduser("~/mnt")
	snap = mnt + "/snapchat"
	tmp = snap + "/tmp"
	
	# Create mount path if necessary
	if not os.path.exists(snap):
		os.makedirs(snap)
	
	# Mount Snapchat's sandbox container
	ret = subprocess.call(["ifuse", "--container", "com.toyopagroup.picaboo", snap])
	if ret != 0:
		print("Error mounting Snapchat application directory!")
		return ret
	
	# Wait for mount to succeed
	while not os.path.exists(tmp):
		pass
	
	# Keep scanning Snapchat's tmp dir until we find a .mov file
	try:
		while 1:
			items = os.listdir(tmp)
			for item in items:
				if item.endswith(".mov") and item not in os.listdir("."):
					# Found a .mov file, so copy it to the current directory
					print("Saving %s to %s." % (item, os.getcwd() + "/" + item))
					copyfile(tmp + "/" + item, item)
	except KeyboardInterrupt, e:
		pass
	finally:
		# Clean up our mess
		ret = subprocess.call(["umount", snap])
		if ret != 0:
			print("Error unmounting Snapchat!")
		os.rmdir(snap)
		try:
			os.rmdir(mnt)
		except OSError, e:
			pass
	
	print("")


if __name__ == "__main__":
	ret = main()
	if ret != 0:
		sys.exit(ret)