No surprise that the BBC thought police are quickly clamping down on any discussion about picture quality and bitrates on the BBC Blog... :rolleyes:
If bit rates and resolution make no difference as the BBC would have us believe - and as they remind us, on which the Trust made a judgement - then why is it necessary to increase it for this trial?
You can't just say "because it is 3D", because I can (and do) watch 3D material at lower resolutions and lower bitrates (for example some of the downloadable PC 3D content). If 3D can work on a Nintendo DS, it can sure as heck work using the current BBC HD transmissions.
Ergo, the only reason that resolution and bitrates are being increased is because they do make a difference.
Bitrates need to be increased so that artifacts are reduced, as artifacts can quickly destroy the 3D illusion. So, why are artifacts acceptable in 2D when they are just as visible to many people, when the bitrate could be increased to reduce them?
Similarly, if the 3D horizontal resolution is being increased by a 3rd (720 > 960), in order to improve picture quality, then why isn't 2D horizontal resolution being increased by a 3rd too? (1440 > 1920).
There seems to be little logic in the BBC's arguements.
Everyone's jumping on the bandwagon - ITV is reported as testing on 11973 V 27500 2/3 in 3D! The channel ID is 7480 with the name 'Test Service' showing. It is encoded but apparently there are times when it is fta. ITV have already produced an episode of Coronation Street in 3D. It is believed that the channel is being offered initially to Virgin when it launches although other platforms will presumably follow.
Ideally 3D requires both an increase in resolution and in bandwidth.
Resolution increase to make it more HD - otherwise it will only be SD.
Bandwidth increase to reduce artifacts - artifacts quickly kill the 3D illusion if both frames don't match correctly because one contains different artifacts to the other as a result of compression.
I don't buy the latter argument. I can see why people think it should be true, but I've watched the 3D demos on 23.5 degrees East - these have easily visible artefacts in some footage, but these artefacts don't look substantially better or worse in 3D than they would in 2D IMO.
If anything, the artefacts (and low resolution - all side-by-side 3D is half the resolution of HD) are less noticeable in full 3D mode than when watching the same broadcast, left-eye-only signal stretched to full screen, in 2D mode. The 3D-ness gives you something else to notice
I suspect, like the Royal Wedding, they're just going to do the best they can for this showcase event. Then normal service will be resumed!
Interesting, isn't it? It's "our" BBC - but they'll happily close down entire forums to stop people having their say. They desperately tried to make the BBC Four forum "a place to think" - but when all anyone would post was "get rid of the DOG, then we'll talk about the programmes", they scrapped them. Now on the "internet blog", whenever people invite the BBC to join the future of full HD broadcasting, they're slapped down.
Sky broadcasts full HD. Sky is now removing DOGs. Where Sky leads, the BBC follows - but it usually takes them a few years. :rolleyes:
I know some people in the BBC agree with what's posted on DS and share "our" frustration. Sadly they don't get to make the decisions.
Still, at least it's VBR, and not that ~9Mbps CBR crap from the other year. If DVB-S2 means they're thinking of launching all their other channels in HD too, that might almost make up for 1440. I'm not usually one to favour quantity over quality, but having everything simulcast in HD would be good, and if it's two channels in 1920 or 4-5 channels in 1440, then (when most programmes are HD) the latter makes more sense. Problem is, I suspect 5 channels in 1920 at decent bitrates would easily be possible, on satellite at least!
I don't buy the latter argument. I can see why people think it should be true, but I've watched the 3D demos on 23.5 degrees East - these have easily visible artefacts in some footage, but these artefacts don't look substantially better or worse in 3D than they would in 2D IMO.
The demo and talk I saw by Sony at BVE was highlighting that unless the two frames are very 'consistent' that the illusion breaks up. If one frame has coarse grained blocks in it due to compression, but the other frame hasn't in the same area, then the 3D will fail in that part of the picture. It may be that it only happens at extremes though.
(accurate alignment and focusing of the two frames is more critical)
Hence why I understood Sky 3D broadcasts at a higher bitrate than Sky 2D - and not because the resolution is higher for 3D, unlike the BBC.
The macro blocks do line up, and sit in the field of the TV screen (i.e. not offset between views, so not in front of or behind the TV) - but I'm saying this because I know it to be true, not because I saw it (if you see what I mean).
I guess it depends on the content. My subjective impression was that it looked "crunchy" - rather like BBC One SD coping with flashing lights and movement on Strictly, for example.
Might just be my eyes! As you say, Sky have chosen to increase the bitrates. The thing is, any artefact is double horizontal size, so you need great care to avoid gibbs/ringing because it'll be doubly obvious. That's at the top end of the quality spectrum, while visible macroblocking is really at the bottom.
the only thing I'll add to this debate.. is that I think my license fee could have been spent on something else rather than 3D technology which doesn't work for me and a lot of other people.. no matter what - it's still looks flat and 2D.. I'll stick with a conventional 2D TV for now.. if I want to be part of experience I'll go and sit on centre court and heckle Andy Murray.. 3D is just a fad, I hope it dies sooner rather than later..
Just wondering: how does a 3D TV detect a side-by-side 3D broadcast, given that the frame rate is the same as a standard 2D broadcast?
With Sky 3D you need to manually switch the 3D TV into the correct mode, as the Sky box doesn't send out the necessary HDMI CEC signal to autoswitch the TV. (whereas a bluray 3D player would)
With Sky 3D you need to manually switch the 3D TV into the correct mode, as the Sky box doesn't send out the necessary HDMI CEC signal to autoswitch the TV. (whereas a bluray 3D player would)
The capability is built into the latest hdmi spec (1.4) without this it's down to the user to manually tell the display it's a 3D signal.
The platform must have switched the BBC HD channel to 1920 x 1080 because I observed a side by side 3D test card plus a short video sequence at 11:56am. Sadly I cannot confirm technically.
The platform must have switched the BBC HD channel to 1920 x 1080 because I observed a side by side 3D test card plus a short video sequence at 11:56am. Sadly I cannot confirm technically.
The latest snapshot of the BBC HD transponder output here http://www.digitalbitrate.com/dbr.php?link=0&mux=10847&pid=6940&live=69¬e=0&lang=en shows ITV1 HD video 22%, BBC One HD 24%, BBC HD 24% and null packets 21% (the rest is audio & text). Peak demand over the past 6 hours has seen 37Mbps consumed out of 40Mbps available. So no significant increase in BBC HD's bitrate with its increased resolution. The above website has detected 1440 x 1080 resolution tonight.
@Ray Cathode: I don't know what time that website scanned BBC HD, but last night's Springwatch and Case Histories were 1920, and so was the preview loop at 3 am and at around 9 am.
On bitrates, Vidoeredo gives the following for the Monty Don clip on the preview loop:
1440: 6075 frames, actual video bitrate: 9.58 Mbps
1920: 6075 frames, actual video bitrate: 11.71 Mbps
Haven't actually watched anything closely to compare yet, but I thought bits of Springwatch looked very good indeed last night.
@Ray Cathode: I don't know what time that website scanned BBC HD, but last night's Springwatch and Case Histories were 1920, and so was the preview loop at 3 am and at around 9 am.
On bitrates, Vidoeredo gives the following for the Monty Don clip on the preview loop:
1440: 6075 frames, actual video bitrate: 9.58 Mbps
1920: 6075 frames, actual video bitrate: 11.71 Mbps
Haven't actually watched anything closely to compare yet, but I thought bits of Springwatch looked very good indeed last night.
Hardly a massive increase in bitrate for the extra gain of resolution. It would be wishful thinking if the beeb left BBC HD at 1920!
Hardly a massive increase in bitrate for the extra gain of resolution. It would be wishful thinking if the beeb left BBC HD at 1920!
Depends on how many more bits and pieces of 3D they may want to experiment with! As they have got increased bandwidth with their move to DVB-S2 I am going to continue to hope!!!
The latest snapshot of the BBC HD transponder output here http://www.digitalbitrate.com/dbr.php?link=0&mux=10847&pid=6940&live=69¬e=0&lang=en shows ITV1 HD video 22%, BBC One HD 24%, BBC HD 24% and null packets 21% (the rest is audio & text). Peak demand over the past 6 hours has seen 37Mbps consumed out of 40Mbps available. So no significant increase in BBC HD's bitrate with its increased resolution.
That graph tells a lot:
BBC HD seemed to do their still picture trick on the 25th May, but nothing too its place (just lots more null packets)
Before the change to DVB-S2, the VBR encoder / stat mux was occasionally throttled (look at the flat top to the bitrate graph - it used all that was available, and presumably it wanted to use more, but couldn't).
Most recently, the 1920 broadcasts, along with all the others, have made use of the extra bitrate available in DVB-S2 mode.
Generally BBC One HD uses far more than ITV1 HD.
BBC HD seemed to do their still picture trick on the 25th May, but nothing too its place (just lots more null packets)
Before the change to DVB-S2, the VBR encoder / stat mux was occasionally throttled (look at the flat top to the bitrate graph - it used all that was available, and presumably it wanted to use more, but couldn't).
Most recently, the 1920 broadcasts, along with all the others, have made use of the extra bitrate available in DVB-S2 mode.
Generally BBC One HD uses far more than ITV1 HD.
Cheers,
David.
It's possible that on 25th Royal Wedding day, their plans did not work out!
Comments
http://3dradar.techradar.com/3d-tech/depth-wimbledon-3d-behind-scenes-23-05-2011
Somehow I can't see iplayers HD 720p service coping
If bit rates and resolution make no difference as the BBC would have us believe - and as they remind us, on which the Trust made a judgement - then why is it necessary to increase it for this trial?
You can't just say "because it is 3D", because I can (and do) watch 3D material at lower resolutions and lower bitrates (for example some of the downloadable PC 3D content). If 3D can work on a Nintendo DS, it can sure as heck work using the current BBC HD transmissions.
Ergo, the only reason that resolution and bitrates are being increased is because they do make a difference.
Bitrates need to be increased so that artifacts are reduced, as artifacts can quickly destroy the 3D illusion. So, why are artifacts acceptable in 2D when they are just as visible to many people, when the bitrate could be increased to reduce them?
Similarly, if the 3D horizontal resolution is being increased by a 3rd (720 > 960), in order to improve picture quality, then why isn't 2D horizontal resolution being increased by a 3rd too? (1440 > 1920).
There seems to be little logic in the BBC's arguements.
If anything, the artefacts (and low resolution - all side-by-side 3D is half the resolution of HD) are less noticeable in full 3D mode than when watching the same broadcast, left-eye-only signal stretched to full screen, in 2D mode. The 3D-ness gives you something else to notice
I suspect, like the Royal Wedding, they're just going to do the best they can for this showcase event. Then normal service will be resumed!
Cheers,
David.
from http://www.bbc.co.uk/blogs/bbcinternet/2011/06/gearing_up_to_deliver_wimbledo.html?postId=109303558#comment_109303558
Interesting, isn't it? It's "our" BBC - but they'll happily close down entire forums to stop people having their say. They desperately tried to make the BBC Four forum "a place to think" - but when all anyone would post was "get rid of the DOG, then we'll talk about the programmes", they scrapped them. Now on the "internet blog", whenever people invite the BBC to join the future of full HD broadcasting, they're slapped down.
Sky broadcasts full HD. Sky is now removing DOGs. Where Sky leads, the BBC follows - but it usually takes them a few years. :rolleyes:
I know some people in the BBC agree with what's posted on DS and share "our" frustration. Sadly they don't get to make the decisions.
Still, at least it's VBR, and not that ~9Mbps CBR crap from the other year. If DVB-S2 means they're thinking of launching all their other channels in HD too, that might almost make up for 1440. I'm not usually one to favour quantity over quality, but having everything simulcast in HD would be good, and if it's two channels in 1920 or 4-5 channels in 1440, then (when most programmes are HD) the latter makes more sense. Problem is, I suspect 5 channels in 1920 at decent bitrates would easily be possible, on satellite at least!
Cheers,
David.
The demo and talk I saw by Sony at BVE was highlighting that unless the two frames are very 'consistent' that the illusion breaks up. If one frame has coarse grained blocks in it due to compression, but the other frame hasn't in the same area, then the 3D will fail in that part of the picture. It may be that it only happens at extremes though.
(accurate alignment and focusing of the two frames is more critical)
Hence why I understood Sky 3D broadcasts at a higher bitrate than Sky 2D - and not because the resolution is higher for 3D, unlike the BBC.
I guess it depends on the content. My subjective impression was that it looked "crunchy" - rather like BBC One SD coping with flashing lights and movement on Strictly, for example.
Might just be my eyes! As you say, Sky have chosen to increase the bitrates. The thing is, any artefact is double horizontal size, so you need great care to avoid gibbs/ringing because it'll be doubly obvious. That's at the top end of the quality spectrum, while visible macroblocking is really at the bottom.
Cheers,
David.
With Sky 3D you need to manually switch the 3D TV into the correct mode, as the Sky box doesn't send out the necessary HDMI CEC signal to autoswitch the TV. (whereas a bluray 3D player would)
The capability is built into the latest hdmi spec (1.4) without this it's down to the user to manually tell the display it's a 3D signal.
http://en.wikipedia.org/wiki/HDMI
Basically if you have a 1,4 source connected to a 1.4 display with a 1.4 cable it's automatic.
Yep, 1920 x 1080 now on tennis.
http://www.mediafire.com/i/?8vd5mr0wr4697w1
you do realise it is only temporary, and the BBC plan to revert back after Wimbledon.
Unless they change their plans, which I wouldn't be confident of yet.
On bitrates, Vidoeredo gives the following for the Monty Don clip on the preview loop:
1440: 6075 frames, actual video bitrate: 9.58 Mbps
1920: 6075 frames, actual video bitrate: 11.71 Mbps
Haven't actually watched anything closely to compare yet,
Hardly a massive increase in bitrate for the extra gain of resolution. It would be wishful thinking if the beeb left BBC HD at 1920!
That graph tells a lot:
BBC HD seemed to do their still picture trick on the 25th May, but nothing too its place (just lots more null packets)
Before the change to DVB-S2, the VBR encoder / stat mux was occasionally throttled (look at the flat top to the bitrate graph - it used all that was available, and presumably it wanted to use more, but couldn't).
Most recently, the 1920 broadcasts, along with all the others, have made use of the extra bitrate available in DVB-S2 mode.
Generally BBC One HD uses far more than ITV1 HD.
Cheers,
David.
It's possible that on 25th Royal Wedding day, their plans did not work out!
Also BBC HD bitrate seems to be ever increasing!