Anecdotally I've noticed that higher quality videos, whether be a 1080p HD video on the TV or a BluRay rip on a computer, the volume seems to be lower than a standard quality video. I've noticed this since at 100% volume of several really high quality video's its still difficult to hear while 100% volume of lower quality videos is deafeningly loud.
Why is this? Is there a technical reason? Is it assumed that high quality videos will be played on high quality speakers which go louder?