HD Broadcasting

I find the differences between SD and HD very easy to see.

The text at the bottom of the screen is unreadable on SD, whereas it’s clear and easy to see on the HD channels.

6 Likes

I think some confusion arises when upconverted shows are seen. Anyone watching local Nine News in Queensland across several hours each day would probably be wondering about the benefits of HD given the quality is comparable to a VHS tape.

4 Likes

But fortunately in the case of QLD, it’s one of the few occasions that this would arise.

Other posts in the Nine News threads have indicated Nine News Brisbane will go HD soon anyhow,

1 Like

As time goes by I’m sure there will be fewer up conversions on all channels. Hopefully they also ditch the 4:3 aspect movies from the library.

1 Like

Which is why the slow return of ABC HD was so bad. Here was an opportunity to show the biggest group of doubters (older demos) that HD is superior and all it showed for weeks was upconverted content. At least it’s all in the past and ABC HD looks magnificent now.

2 Likes

44 posts were merged into an existing topic: Seven HD

I hope they don’t. The Wizard of Oz, Casablanca and other classic movies were filmed in 4:3 as they were made before widescreen was around, but they are available in high definition.

1 Like

I wonder if they will ever crop those 4:3 movies to make them widescreen?

Hopefully not, they did this with Seinfeld and I didn’t like it as I knew I wasn’t seeing the full picture.

1 Like

I’ve been looking at the bit rates on the various multiplexes and I believe that the networks can fit in more HD broadcasts now without shutting down any legacy MPEG2 format.

My thinking is that a 720p HD MPEG4 broadcast would be suitable for a multichannel. Looking into the numbers, 720p needs fewer bits to be transmitted per second plus more importantly the progressive stream apparently compresses better. I think that a 2.5 - 2.8 Mbps 720p stream would provide a quality HD channel.

So if we took Nine’s multiplex in Brisbane tonight 9HD in 1080i is running at 3.26 Mbps.

The other channels are
9SD 4.0
9Go 3.3
9Gem 3.3
9Life 3.8

So all that needs to happen is 0.625 - 0.7 reduction in bit rate for each channel to give 2.5 - 2.8.

In the case of SBS, SBS HD is currently running 7.5 (MPEG2) so they could replace that with 3 x 720p HD channels without having to adjust the bit rates for any of the SD channels.

2 Likes

Are broadcasting encoders really good enough these days that you can broadcast three 720p MPEG2-HD channels on a multiplex at 2.5-3.0mbps without it becoming all pixelated/blurry every five seconds?

1 Like

They would be 720p MPEG 4 - 9HD is currently running at 3.2 1080i whithout too many complaints so I think it is realistic.

3 Likes

As I understand it, networks can accommodate 23 M/bits per second of data on each channel.
The streams you’ve listed there add up to approx 17.7 M/bits.
Can see you where the other 5.3 has gone?

Some small amounts of data might be taken up by closed captions and EPG info, but as I don’t think there’s any error correction used in DVB-T, there’s no slideshows (both of which accounts for space in DAB+ Radio), and there’s no EPG channel anymore.

1 Like

Some of it will be used by the audio channels aswell.

2 Likes

The various audio channels add up to approx 3.7 and Extra is 1.8 for video

1 Like

I’ve noticed that too, Nine SD via WIN at times looks terrible, but funny enough Seven SD & other channels looks okay.

1 Like

Good news so far on the 7HD front for Sydney (and I’m guessing Bris and Perth as well)…

In that my EPG is still showing 7HD will remain as the main channel for most of next week (at least).

So will be good to see Seven’s big guns eg. MKR in HD for the first time in these parts :grinning:

2 Likes

Are you saying 7HD is still there after the tennis has finished? When does the AFL season begin again?

March 23

Didn’t Seven switch back early last time so that the pre-season matches were shown on 7bogan HD? :smiling_imp:

Seven’s HD channel wasn’t in MPEG4 this time last year…

1 Like