[markelliott]

Originally Posted by tghe-retford

Five is running at a resolution of 704x576 according to VLC on my Linux computer, from the Emley Moor transmitter.

Still 544 x 576 from Waltham.

[LoneThistle]

It's still the same here too.

Elsewhere, QUEST seems to be broadcasting at a higher bitrate - same resolution though.

[David Drizen]

Originally Posted by markelliott

It will be because all Mux 2 channels in London use 704 x 576.

Can some one explain all london MUX2 use 704 X 576 and other transmitters use a lower bit rate ? They all have same amount of channels in the MUX so why the difference ??

[markelliott]

Originally Posted by David Drizen

Can some one explain all london MUX2 use 704 X 576 and other transmitters use a lower bit rate ? They all have same amount of channels in the MUX so why the difference ??

Good question David. I would also like to know this.

[lnp]

The quality of the moved Five is shocking. Noticeable within seconds, it's that bad. Looks like literally there has been a straight swap with ITV 4.

Never mind the minimum picture standards required for PSB channels or is that another rule that Ofcon has dropped when it suits them.

[markelliott]

It looks like this has been nothing but a straight swap between Five and ITV3.

It's quite shocking just how bad and blurry the 544 x 576 streams look on Mux 2, especially when compared with the ones on Mux D which use the new encoders. Even more so if you take a look at Channel 4 +1 and E4 on satellite on the same TV and compare them with the ones on DTT, these use the same resolution and nearly the same bit rates and the difference is night and day. I think the hazy pictures are caused by Mux 2 using old encoders which were designed for 720 x 576 and being used at 544 x 576. I might be wrong. Regardless, Five shouldn't be at reduced resolution, as it's one of the main channels!

[clovelly01]

Hi, If feedback to five is required try:

http://about.five.tv/customer-servic...ical-enquiries

[davepusey]

544x576 here on Rowridge, but picture quality is just as good as it was before the move.

[dafydd]

In Wales, S4C moved to Mux 2 on 9/9/9 and the quality of that channel also dropped dramatically. The average bitrate dropped by 500Kbps but the maximum bitrate dropped from 7Mbps to under 4Mbps, which is very noticeably in busy scenes.

Resolution is also 544x576 which I hadn't noticed before, so that may explain the quality drop entirely, rather than any bitrate changes.

I asked S4C about this and their engineers were aware and concerned about it. The MPEG encoding has been tweaked since the 9th and quality has improved slightly but it's still noticeably soft.

Is this a problem that will go away when newer encoders are used? It seems an extremely ill-conceived idea if all the channels considered 'important' are moved to the PSB mux but not so important that picture quality is maintained.

[lnp]

Originally Posted by David Drizen

Can some one explain all london MUX2 use 704 X 576 and other transmitters use a lower bit rate ? They all have same amount of channels in the MUX so why the difference ??

This is a consequence of an experiment ITV did 2 years back transmitting all channels at 704x576 with black borders. Some complaints got ITV to remove the borders and the resolution has stayed the same since.

Full thread http://www.digitalspy.co.uk/forums/s...=624988&page=3

[jzee]

Originally Posted by markelliott

It looks like this has been nothing but a straight swap between Five and ITV3.

It's quite shocking just how bad and blurry the 544 x 576 streams look on Mux 2, especially when compared with the ones on Mux D which use the new encoders. Even more so if you take a look at Channel 4 +1 and E4 on satellite on the same TV and compare them with the ones on DTT, these use the same resolution and nearly the same bit rates and the difference is night and day.

Actually all the C4 channels on sat recently switched to 704 x 576, possibly with new encoders being used so that might explain the superior picture.

[markelliott]

Originally Posted by davepusey

544x576 here on Rowridge, but picture quality is just as good as it was before the move.

How can it be?

[markelliott]

Originally Posted by jzee

Actually all the C4 channels on sat recently switched to 704 x 576, possibly with new encoders being used so that might explain the superior picture.

Thanks mate, I didn't know that as I haven't checked for a while, so my post still stands as this would have been before that happened. I originally noticed the differences in picture quality between Channel 4 +1 and E4 on DTT and satellite over a year ago.

[LoneThistle]

Originally Posted by clovelly01

Hi, If feedback to five is required try:

http://about.five.tv/customer-servic...ical-enquiries

I think I may just do that.

Thank You!

[markelliott]

Originally Posted by lnp

This is a consequence of an experiment ITV did 2 years back transmitting all channels at 704x576 with black borders. Some complaints got ITV to remove the borders and the resolution has stayed the same since.

Full thread http://www.digitalspy.co.uk/forums/s...=624988&page=3

Thanks.

[MartinImber]

Might as well use replay TV then - no logos on it either

[Ray Cathode]

Remember that the movement of channels around the Muxes was a joint BBC/Ofcon idea and ITV was against it.

In particular Ofcon wanted 9 streams on Mux 2 but Arqiva said it couldn't be done.

The general incompetence shown today is mainly due to Ofcon's loony HD scheme although Teletext has come to their rescue. In December when Teletext closes, there will be about 1000kbps released on Mux 2 which will allow higher resolutions for Five and S4C.

Also better encoders will help.

[Ian]

Can anyone do their clever thing to work out what bitrate ITV3 is at now? If it is just a straight swap then that's hilarious - I assumed we'd be cramming a further 9 channels into Mux A or something silly.

[markelliott]

Originally Posted by Ray Cathode

Remember that the movement of channels around the Muxes was a joint BBC/Ofcon idea and ITV was against it.

In particular Ofcon wanted 9 streams on Mux 2 but Arqiva said it couldn't be done.

The general incompetence shown today is mainly due to Ofcon's loony HD scheme although Teletext has come to their rescue. In December when Teletext closes, there will be about 1000kbps released on Mux 2 which will allow higher resolutions for Five and S4C.

Also better encoders will help.

Ray, I thought Ofcom didn't allow the five main channels to use reduced resolution and low bit rates on DTT? The picture on Five right now is disgusting for a main channel.

Like you said, newer and better encoders will of course help, which Mux 2 is in dire need of.

[Tony Richards]

Five here off Crystal Palace is a dreadful picture, much worse than it was.

[Orangemaid]

Can i ask,,Have they moved Five USA,,i cant get it now..,,the screen is or was black and no sound

[Ray Cathode]

Originally Posted by markelliott

Ray, I thought Ofcom didn't allow the five main channels to use reduced resolution and low bit rates on DTT? The picture on Five right now is disgusting for a main channel.

That is correct; ITV1, C4, FIVE & S4C must be broadcast at 720 (or 704) x 576.

I suspect that all that has happened today is a straight swap and all Arqiva will do is make sure that each stream is in the correct place.

Plenty of time to tweak each multiplexer for optimum results over the next week. There are 26 or so for D3&4 alone. I was very surprised that all the commercial teletext services have not started up in Wales where there is now plenty of room.

It looks like there will be a few more retunes this year in DSO areas, because 302 and 305 have been left on BBC B. One of those will replace a C4 channel before December. I can't imagine why it wasn't done today.

FIVE in London is on 704x576 at the moment.

[linkinpark875]

Five's picture quality is miles worse here too.

[chrisy]

Originally Posted by markelliott

I thought Ofcom didn't allow the main five channels to use reduced resolution and low bit rates on DTT?

Correct.

Originally Posted by Charnham

I thought it looked better today actually, but im no expert on this kind of thing

I'm on the same TX as you, and I agree - it looks better than it did. I think Sandy must be broadcasting Five at the correct resolution but have no way of checking.

Originally Posted by dafydd

In Wales, S4C moved to Mux 2 on 9/9/9 and the quality of that channel also dropped dramatically. The average bitrate dropped by 500Kbps but the maximum bitrate dropped from 7Mbps to under 4Mbps, which is very noticeably in busy scenes.

Resolution is also 544x576 which I hadn't noticed before, so that may explain the quality drop entirely, rather than any bitrate changes.

I asked S4C about this and their engineers were aware and concerned about it. The MPEG encoding has been tweaked since the 9th and quality has improved slightly but it's still noticeably soft.

@all
If Five and/or S4C are broadcasting at low resolution, contact Ofcom, with reference to Section 2.1 of the Reference Parameters for Digital Terrestrial Television Transmissions in the United Kingdom (quoted below for reference, along with the Section 3 Terms and Definitions for Qualifying Services)

Originally Posted by ofcom

For Qualifying Services the encoded picture shall have either a full-screen luminance resolution (horizontal x vertical) of 720 x 576 pixels or a non-full-screen luminance resolution of a minimum of 704 x 576 pixels.

Qualifying Services
These are: Channel 3, Channel 4, Channel 5, S4C Digital

If the quality is generally poor (low bitrate, bad sound etc) it is worth mentioning that too. Ofcom's predecessor - the ITC - made ITV increase the bitrate of ITV1 on DTT three times due to complaints about the quality of picture during football broadcasts!

Sound encoding is mentioned in the document but as a recommendation only.

[LoneThistle]

Originally Posted by Ian

Can anyone do their clever thing to work out what bitrate ITV3 is at now? If it is just a straight swap then that's hilarious - I assumed we'd be cramming a further 9 channels into Mux A or something silly.

General
Overall bit rate : 1 884 Kbps
Video
Format : MPEG Video
Format version : Version 2
Bit rate mode : Variable
Bit rate : 1 561 Kbps
Nominal bit rate : 15.0 Mbps
Width : 544 pixels
Height : 576 pixels
Audio #1
Format : MPEG Audio
Format profile : Layer 2
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s) : 2 channels