Is 1080p all the same?

[supercooled]

Hi,

I'm seeing movies in 1080P which are 18GB but I also see 1080P movies in DVD9 range (8-9GB). How is that possible?

 

[Andrew Henry]

Length of the movie?

Sound?

Extras?

etc. etc.

 

[JonHimself]

Where are you seeing them? If you're talking about like torrents and whatnot then it's definitely just the fact that the videos are compressed. Someone will be able to explain it better than me. It could have something to do with length of the actual video as well, but it's probably just that the smaller file is compressed more.
To directly answer your question, the 1080p you see at 9gb is probably only considered 1080p because the actual video has 1080 horizontal lines. So in terms of the size of the video (dimensions), yes all 1080p is technically the same. The more you compress it, the worse the quality of those 1080 lines that make up the video, will be.

 

[BoulderBum]

I've actually noticed that about Apple TV "HD". Technically it's 720p, but it's so compressed that it doesn't look all that HD.

I don't blame Apple, mind you. They need to worry a lot about download time until nationwide bandwidth gets a lot better.

 

[skp574]

Yep, it's compression. Generally with Blu-ray/HDDVD rips the video track is compressed (using h264) and the main audio track is untouched. All of the extra features such as additional language tracks are stripped out to try to get it to fit on to a DVD9 disk.

I personally find the 720p and 1080p stuff available on the internet is pretty good quality for me. I haven't watched a Blu-ray of HDDVD movie to compare but I am certainly not disappointed by the quality of the rips out there.

 

[joefinan]

This is the problem with HD - 720P, 1080i, 1080P etc etc means nothing really (when it comes to image quality, at least).

One could compress an HD image to lower quality than VHS and still refer to it as 1080P.

Just look at Sony's range of HD camcorders. They're 1080x1440 (not 1080x1920) and have a data rate the same as MiniDV - so the picture's just compressed to buggery (but still looks ok, I guess) but they can still legally refer to it as 1080 HD.

 

[KershMan]

Here is a good article to look at with bitrates and HDTV http://www.audioholics.com/education/cables/hdmi-1-3-cables-bitrate. The bottom line is you can not get uncompressed HD video, 720p or higher, into your house today over existing networks. I believe commercial cable/satellite compresses HD into something under 20 Mbps. I have Comcast and get a pretty solid 5 Mbps and bursts above 15 Mbps. Since I can watch an HD rental on my AppleTV pretty quickly, I would think Apple has compressed the HD rentals in that range some where.

BluRay is much closer to native and the picture is going to be far superior.

 

[supercooled]

Here is a good article to look at with bitrates and HDTV http://www.audioholics.com/education/cables/hdmi-1-3-cables-bitrate. The bottom line is you can not get uncompressed HD video, 720p or higher, into your house today over existing networks. I believe commercial cable/satellite compresses HD into something under 20 Mbps. I have Comcast and get a pretty solid 5 Mbps and bursts above 15 Mbps. Since I can watch an HD rental on my AppleTV pretty quickly, I would think Apple has compressed the HD rentals in that range some where.

BluRay is much closer to native and the picture is going to be far superior.

The only benchmark I have to judge the stuff I get off the net is the BBC Blue Planet Blu-Ray which is just spectacular even on 720p set. The stuff I get often suffer from running colour blotches in dark scenes but their minimal. I noticed very little difference between AppleTV compressed movies in the 4-5 range to 2-2.5 range so I guess that's what I will be compressing them in.