Will I notice a big difference from sd to hd itunes tv shows?
Will I notice a big difference from sd to hd itunes tv shows on a ipod 4th generation 16gb?
iPod touch, iOS 6.1.3
Yes but how much you will notice is up to how picky you are. The 4G iPod/iPhone 4 was the first small device (the iPad 1 came out about six months before) was the first to support HD (720p).