RTÉ TWO HD - What A Waste!

Capt'n Midnight

mike65 wrote: »

Are we stuck with the dismal SD resolution until MUX 2 is fired up then?

Pretty much unless you can break the laws of physics.

All new device approvals from (jan ?) 2013 will require a T2 tuner. This gets you maybe another ~30% of bits. But no use for the foreseeable future since most people don't have them. (That's the lovely thing about standards - so many to choose from)


The other problem is the rate adaptive compression. In digital TV you send fewer key frames and more partial frames with only the changes. In theory most of the time big changes aren't happening on all channels at the same time so you can give each channel more bandwidth when it needs it because it will need less when only someone lips are moving.

In theory you could spend a lot of time compressing say a movie so that you get a better trade off between bitrate and quality than encoding it live. But to do that you would need to guarantee a fixed amount of bandwidth for the movie. AND you would not be able to improve quality when there was spare capacity on other channels.

At that stage you are heading for fairly impressive stuff, like having a movie compressed in advance (spend lots of time on a render farm for quality) at a variety of bitrates (to fit available bandwidth) and when showing the movie you send the best quality packets for the available bandwidth.

But it's a question of complexity vs. ease of use.
And I'm not even sure if a render farm would give that much of an improvement compared to on-the fly compression given the diminishing returns of lossy compression.



Also it's a pretty safe bet that if offered a discount for using a lower bitrate or lower priority during high demand that TV3/3e would say yes. It costs RTE €1.5m a year for all their channels on Saorsat, By not going on it TV3 are probably saving less than Tubberty pays in income tax.

The Cush

STB wrote: »

Even so the average quality of the broadcast output on the stat mux is 1200KB/s on RTE2HD compared to 300KB/S on the SD channels.

lawhec wrote: »

Those figures don't look right, they should be both at least 4-5 times those values.

I'd hate to see a 1440x1080 1080i HD programme running on an average bit rate of 1.2Mbps :eek:

Average 2 Mbps for the SD channels and 6 Mbps for RTÉ2 HD according to RTÉ. If you remember the thread that covered the first true HD programme on RTÉ2 HD, the Magners League Final, it was posted that at times during the match the bitrate was over 9 Mbps.

RTÉ plans to use statistical multiplexing. As part of a statistical multiplexed pool the
HD service will use an average bit rate of c. 6.3 Mbps, RTÉ News Now will use an
average bit rate of c. 2.2 Mbps, RTÉjr and RTÉ Plus will share the same spectrum,
requiring an average bit rate of c. 2.2 Mbps and RTÉ Aertel Digital will require 1.0
Mbps of capacity.

STB

lawhec wrote: »

Those figures don't look right, they should be both at least 4-5 times those values.

I'd hate to see a 1440x1080 1080i HD programme running on an average bit rate of 1.2Mbps :eek:
..........blah.

Re-read the values......

1KB/s = *kbps ?

The Cush

STB wrote: »

Re-read the values......

1KB/s = *kbps ?

1KB/s = 8kbps.

Didn't notice that in your op, I've only ever seen DTT mux capacity referred to in Mbps.

The 1200KB/s (9.6 Mbps) avg bitrate you mention for RTÉ2 HD appears to be a bit high when looking at RTÉ's published figures. During the Magners League final when the reported bitrate averaged 8.5 Mbps (1062.5 KB/s) the RTÉjr/RTÉ1+1 stream was off-air and would have had about 2 Mbps available for that particular event.

This from RTÉ

Statistical multiplexing will be used for all video services, audio and data services are fixed bit rate.

It is planned to use the following bit rates as part of a statistical multiplexed pool.

High Definition Video (HD)
1 Minimum of 2.0 Mbps
2 Maximum of 9.0 Mbps
3 Weighting 90%
4 Resolution 1440 x 1080i
5 Expected average bit rate 6.0 Mbps

Standard Definition Video (SD)
• Minimum of 1.0 Mbps
• Maximum of 8.0 Mbps
• Weighting 90%
• Resolution 544 x 576
• Expected average bit rate 2.0 Mbps

lawhec

STB wrote: »

Re-read the values......

1KB/s = *kbps ?

Touché

lawhec

The Cush wrote: »

I've only ever seen DTT mux capacity referred to in Mbps.

Same here, that or Kbps

STB

The Cush wrote: »

1KB/s = 8kbps.

Didn't notice that in your op, I've only ever seen DTT mux capacity referred to in Mbps.

The 1200KB/s (9.6 Mbps) avg bitrate you mention for RTÉ2 HD appears to be a bit high when looking at RTÉ's published figures. During the Magners League final when the reported bitrate averaged 8.5 Mbps (1062.5 KB/s) the RTÉjr/RTÉ1+1 stream was off-air and would have had about 2 Mbps available for that particular event.

This from RTÉ

I wasn't talking about Mux capacity, but Mux capacity depends on coding/mod parameters and bit rates.

The figures I mentioned earlier in the thread are the individual bit rates at one snapshot in time.

During the Champions league Man City VS Real Madrid game broadcast RTE2HD peaked at 1287KB/s (10.2Mb) so the reality is that during HD broadcasts the statistical muxing effect on other stations on the multiplex is quite evident and certainly more than the max quoted by you above which is from the DCENR Consultation document on RTE's new service proposal from November 2010.

Even during Non HD broadcasts RTE2HD is outputing bit rates that are 2.5-3 times that of the SD stations.

When the second Mux kicks off we should see higher picture quality on the SD stations if the stations are evenly distributed. My pain point initially was that RTE2HD is given bit rate preference on the Mux regardless of the output being HD or upscaled. This has the visual impact for most punters that it is something special.

The Cush

STB wrote: »

I wasn't talking about Mux capacity, but Mux capacity depends on coding/mod parameters and bit rates.

The figures I mentioned earlier in the thread are the individual bit rates at one snapshot in time.

Whether individual bit rate or capacity all I was saying is I've never see it described in KB/s.

STB wrote: »

During the Champions league Man City VS Real Madrid game broadcast RTE2HD peaked at 1287KB/s (10.2Mb) so the reality is that during HD broadcasts the statistical muxing effect on other stations on the multiplex is quite evident and certainly more than the max quoted by you above which is from the DCENR Consultation document on RTE's new service proposal from November 2010.

In the consultation document, from prior to the public launch of Saorview and RTÉ2 HD, they were described as the expected bitrates. Post consultation/Saorview launch/RTÉ2 HD launch we see actual bitrates.

How does the Saorview RTÉ2 HD 10.2 Mbps peak bitrate compare with UPC and Sky for the same event?

STB wrote: »

When the second Mux kicks off we should see higher picture quality on the SD stations if the stations are evenly distributed. My pain point initially was that RTE2HD is given bit rate preference on the Mux regardless of the output being HD or upscaled. This has the visual impact for most punters that it is something special.

As you say the picture quality of the upscaled content on RTÉ2 is very good compared to the SD channels, hopefully the other 3 main channels will go upscaled/full HD in the coming months.

Better picture quality on the SD channels when the second mux launches provided they don't cram in too many services, an article last month did mention a third PSB mux if required.

Elfinknight

lertsnim wrote: »

BBC HD and BBC One HD require no package of any kind

I know. What i was trying to explain that with sky, you don't need to pay the extra charge sky have for hd to view them. Sorry for being unclear.