HDTV compression damaging video quality?

[jswilli1]

I found this article on Yahoo news and found it interesting. I did not know about the compression techniques that the Satellite and Cable companies used for HDTV broadcasts. It appears the only "TRUE" HDTV experience is through uncompressed Blu-ray movies.


http://news.yahoo.com/s/pcworld/1448...76Ou65xi0DW7oF

[musicman1999]

Bluray movies are compressed.Uncompressed video files would not fit on a bluray.


bill

[sptrout]

All digital video formats are compressed, even OTA. Digital video just requires to much bandwidth not to be compressed. Also remember that most digital audio formats are compressed in nearly everything from your friendly cell phone, to CDs & DVDs. It is only recently that we are now finally able to decode uncompressed audio in formats such as DVD-A, SACD, HD-DVD, and Blu-ray.

The real issue is how much video compression is used. The service providers are not going to jump up and confess that they are over compressing their video; they leave it up to the end user to figure it out. They really hope that the home user does not know/see the difference, and most viewers probably do not realize that some of the artifacts that they are seeing are do to over compression and other problems.

[JJ]

Originally Posted by musicman1999

Bluray movies are compressed.Uncompressed video files would not fit on a bluray.


bill

Uncompressed is 4K and all that good stuff. Blu-ray is still compressed, he is right. But less so than DVD, obviously.

And "HD" broadcasts on TV...HA! They should be called Medium Definition. They are better than regular, but by no means do I consider them High. There are more technical details to it, but I'll leave it up to someone with a more complete knowledge of the subject to answer that.

[Bobby Henderson]

"4K" doesn't have anything to do with compression of HD.

The 4K format is merely a high resolution setting used for digital intermediates of very few movies. Most current movies have their CGI and digital intermediates rendered at only 2K.

Uncompressed 1080p HD material runs at a bit rate of approximately 1.5 billion bits per second. That data rate is much higher than the 40 million bit per second "limit" applied to 1080p video on Blu-ray (I've seen video on some discs surpass that 40 Mb/s rate -Juno is a recent example).

Cable and satellite companies use more severe levels of data compression on HD video. The level of severity may also depend on the HD channel. A premium channel like HBO|HD will play at higher bit rates than less popular cable channels.

HD video hosted on Internet web sites may have levels of data compression more severe than HD from any other source. Just look at what Apple has been doing with the HD movies they're renting out at $6 for a 24 hour viewing window.


Right now, Blu-ray represent the very best viewing format for HD content in the home. No other home delivery method is any better than that. To do any better than Blu-ray, you have to watch a 2K digital cinema file that runs at 7 times the bit rate of Blu-ray. Or you have to gain access somehow to watch the original master file.