Only if you can ensure that the programmes show properly on a 4:3 set.
That is - a 4:3 source FILLS the 4:3 set - no black borders on all 4 edges.
Letterbox of a true 16:9 source onto a 4:3 acceptable.
Or put another way, get all broadcasters to use the AFD codes properly!
On freeview thats easily achieved as there is an AFD flag that protects for 4:3 not 16:9 which can be used on 4:3 programs that are letterboxed.
This should have been the standard from the beginning and people should have had:
4:3 auto, that will letterbox widescreen content but centre cuttout 4:3 content that is broadcast in a widescreen frame,
4:3 letterbox, letterboxing all content as it would have been broadcast in a 16:9 frame, but would have the effect of windowboxing any 4:3 content (the black bars ether side of a 14:9 image in a 16:9 frame would be largely hidden in overscan, on a 4:3 set, so thats not an issue),
16:9, always displaying a 16:9 frame, but pillerboxing all 4:3 or 14:9 content (and if thats done at the broadcasters end then there would never be sets with funny shape images on a 16:9 set)
Then all set top boxes have the 16:9 mode set as default, as 4:3 users would more likely notice something was up and set it to 4:3 auto, unless they knew about windowboxing and didnt care about it. Anyway they would most likely refer to the manual that would tell them to try 4:3 auto for funny looking images on a 4:3 set.
Dsat doesnt cope with the protect for 4:3 in a 16:9 frame so the installer (of say Sky, I dont know if an installer would set a freesat box up for people?) would set up the best mode for what TV you had and if you had a large 4:3 TV then it could most likely cope with pillerboxing and if it was very small then it might be better to leave it on a centre cuttout mode.
I do think that the centercutout mode on Dsat should have been a 14:9 mode though so that it compromised because of the not accepting AFD codes properly! cough*sky*cough (its there fault for not sorting the issue out on Dsat!)
Sorry to diverge about Dsat in a freeview post, but the issue is there too although there is less options to sort it there, at least more channels are 720*576 (or 704*576) on Dsat than on freeview!
Noticed this on the D-Day Outside broadcast broadcast - on my TV with 1:1 pixel mapping - there was the pictire had a very narrow black bar left and right (and I think even narrower ones at top & bottom) but they weren't there back on the Studio footage.
Also all SD channels should be broadcast in 16:9 widescreen mode and any 4:3 programs pillerboxed to 16:9 just like on HD channels.
This would mean a redefining of how material is fixed to resolutions, 4:3 will always use the centre 3/4 of the screen (AKA 540 across) and 16:9 will always use the full 720 across!
The trouble with that is historic programmes which were filmed in 4:3 would then lose a third of their horizontal resolution. If you don't like that sort of programme you obviously won't care but a lot of us do.
The trouble with that is historic programmes which were filmed in 4:3 would then lose a third of their horizontal resolution. If you don't like that sort of programme you obviously won't care but a lot of us do.
The BBC already do this. If you record a 4:3 programme from BBC1 or 2 you usually find that it is, in fact, a 16:9 picture with big black vertical stripes (eg. 'Allo, 'Allo or Dad's Army). However, if the AFD is set correctly, my 4:3 set shows this as a full size 4:3 picture. The picture quality is usually adequate, even though - as you point out - some of the horizontal resolution is lost.
The alternative, which I prefer - but lotrjw clearly does not, would be to have whatever the source (16:9, 4:3) described by the full available resolution and have your tv/stb sort out the size on your screen. Some of the channels broadcasting 544x576 do this. (Can't remember whether ITV/4/5 do).
Either way, it relies on the broadcasters setting the correct flags for the source - and they quite often get it wrong. What I don't want to see is black borders on all four sides of the picture, or squashed or elongated pictures.
The trouble with that is historic programmes which were filmed in 4:3 would then lose a third of their horizontal resolution. If you don't like that sort of programme you obviously won't care but a lot of us do.
Most 4:3 programs get shown on channels broadcast in 544*576 res anyway so they are already loosing a third of the full SD resolution!
Also if all channels were forced to be broadcast in 720*576 configuration then the 4:3 programs would only be 544*576 anyway! it would work out!
Also the way the main channels broadcast 4:3 content (which is rare now) is by downscaling off the HD channels (except channel 5 of course!), so 4:3 content is already like the way I have said and the sides get cropped somewhere along the broadcast chain.
If they didnt do that cropping and just left it as is, letting the receiver box do the work instead, then it would be much better. It wouldnt cost more in bandwidth, as it would be black at the sides!
The BBC already do this. If you record a 4:3 programme from BBC1 or 2 you usually find that it is, in fact, a 16:9 picture with big black vertical stripes (eg. 'Allo, 'Allo or Dad's Army). However, if the AFD is set correctly, my 4:3 set shows this as a full size 4:3 picture. The picture quality is usually adequate, even though - as you point out - some of the horizontal resolution is lost.
The alternative, which I prefer - but lotrjw clearly does not, would be to have whatever the source (16:9, 4:3) described by the full available resolution and have your tv/stb sort out the size on your screen. Some of the channels broadcasting 544x576 do this. (Can't remember whether ITV/4/5 do).
Either way, it relies on the broadcasters setting the correct flags for the source - and they quite often get it wrong. What I don't want to see is black borders on all four sides of the picture, or squashed or elongated pictures.
Ah so the cropping does occur at the box with the BBC channels at the least! I usually watch on Dsat and the HD channels at that so I dont see this with the BBC. Im sure in these cases that the 4:3 content, in the central 3/4 of the screen, is 544*576 apx, which, as you say, is adequate for 4:3!
The only time I did see it was when the BBC broadcast their TV copy of the Queens coronation last year on BBC Parliament, I think it was done there, as the program had a section at the beginning that started in 16:9 (that wasnt part of the original broadcast).
I watched it on Dsat though so it was likely it was 720*576 for me, whereas on freeview the BBC broadcast Parliament in 544*576.
If they didnt do that cropping and just left it as is, letting the receiver box do the work instead, then it would be much better. It wouldnt cost more in bandwidth, as it would be black at the sides!
What you are suggesting is what the BBC has always done internally and always broadcast on Freeview. They do it this way so that the pixels are always the same shape. The AFDs indicate which parts of the picture are active, and (additionally) which parts are important.
For DSat, there's an Aspect Ratio Converter driving the encoders which centre-cuts 4x3 material and blows it back up to 720x576.
AFDs work properly on Freesat, but not on Sky boxes, which don't do 14x9.
The implied loss of resolution for 4x3 content was said to be irrelevant. Virtually all UK produced 4x3 programmes were from the analogue/composite era, and at one time all were delivered and/or archived on D3. Even with excellent composite decoding, you couldn't get beyond 600 pixels-worth of information horizontally, so you'd lose a little, but not much, and only on the best sources. Some other countries carried on making 4x3 content into the digital/component era, and cramming this into 528 pixels loses something - but in any case it never makes it look worse than an SD 16x9 source.
What you are suggesting is what the BBC has always done internally and always broadcast on Freeview. They do it this way so that the pixels are always the same shape. The AFDs indicate which parts of the picture are active, and (additionally) which parts are important.
For DSat, there's an Aspect Ratio Converter driving the encoders which centre-cuts 4x3 material and blows it back up to 720x576.
AFDs work properly on Freesat, but not on Sky boxes, which don't do 14x9.
The implied loss of resolution for 4x3 content was said to be irrelevant. Virtually all UK produced 4x3 programmes were from the analogue/composite era, and at one time all were delivered and/or archived on D3. Even with excellent composite decoding, you couldn't get beyond 600 pixels-worth of information horizontally, so you'd lose a little, but not much, and only on the best sources. Some other countries carried on making 4x3 content into the digital/component era, and cramming this into 528 pixels loses something - but in any case it never makes it look worse than an SD 16x9 source.
Cheers,
David.
Thats interesting it confirms what I thought about 4:3 content, the 14:9 issue on Dsat should have been a misnomer though surely?
As if you flag 14:9 in a 16:9 frame then letterbox it into a 4:3 rastered analogue picture, all 4:3 TVs would crop the left and right edges anyway, leaving the viewer with the perception of a full 16:9 image!
OK they might see very thin black bars poking out at the sides from time to time, but not permanent, just a quirk of CRTs where the image moves a bit!
So the BBC (and all other broadcasters for that matter (in the UK)), should have left 4:3 programs pillerboxed to 16:9 and ALWAYS in 720*576 mode, with ether 4:3 protect AFD on 4:3 content and 16:9 protect on 16:9 and 14:9 content!
Ah so the cropping does occur at the box with the BBC channels at the least! I usually watch on Dsat and the HD channels at that so I dont see this with the BBC....
I don't often see this. But when I use a PC dongle to record and then archive (oops - probably shouldn't admit to that) I came across the fact that 4:3 programmes on the BBC turned out to be 16:9 with black borders. When trying to archive to DVD I then had the problem, do I crop it to 4:3? I found it was possible to pass on the equivalent of the correct AFD to a DVD and make it do a centre cut-out on a 4:3 set so it behaves like I want it to. It also displays properly on a 16:9 set (ie. with the black borders shown). So, the short answer is yes usually on the BBC the cropping occurs at the box.
I don't often see this. But when I use a PC dongle to record and then archive (oops - probably shouldn't admit to that) I came across the fact that 4:3 programmes on the BBC turned out to be 16:9 with black borders. When trying to archive to DVD I then had the problem, do I crop it to 4:3? I found it was possible to pass on the equivalent of the correct AFD to a DVD and make it do a centre cut-out on a 4:3 set so it behaves like I want it to. It also displays properly on a 16:9 set (ie. with the black borders shown). So, the short answer is yes usually on the BBC the cropping occurs at the box.
So why would BBC 4:3 programs, when you select 16:9 mode crop to 4:3 still?
Is the AFD on this supposed to be mandatory on freeview boxes then?
In as such that you only see it when using generic DVB decoders and not freeview branded boxes/decoders?
I wonder why the BBC couldn't persuade OFCOM to make this the mandatory way of showing 4:3 content on digital platforms? With the option for the user to overwrite the AFD code and display the full image with pillerboxing on a 16:9 set? in fact display it like that on all 16:9 sets with 16:9 selected!
That would have meant that S T R E T C H Y vision on 16:9 sets would never have happened! except of course when people used to put analogue though a 16:9 set! Oh and DVD players did this too as 4:3 is usually stored using the whole image width!
Thats another thing actually, DVD players should output the 4:3 image as pillerboxed (or at least give the option), when selecting the output for a 16:9 set, just as BluRay players now do!
So why would BBC 4:3 programs, when you select 16:9 mode crop to 4:3 still?
Is the AFD on this supposed to be mandatory on freeview boxes then?
In as such that you only see it when using generic DVB decoders and not freeview branded boxes/decoders?
I wonder why the BBC couldn't persuade OFCOM to make this the mandatory way of showing 4:3 content on digital platforms? With the option for the user to overwrite the AFD code and display the full image with pillerboxing on a 16:9 set? in fact display it like that on all 16:9 sets with 16:9 selected!
The D book tells the broadcasters to get it right with AFD ....
But then confuses things by allowing the set to size the picture by looking for black ...
Most good freeview units do follow AFD and make it difficult to turn off AFD sizing
.
But we soon get into HD and the lack of aspect ratio signalling in HDMI .
The D book tells the broadcasters to get it right with AFD ....
But then confuses things by allowing the set to size the picture by looking for black ...
Most good freeview units do follow AFD and make it difficult to turn off AFD sizing
.
But we soon get into HD and the lack of aspect ratio signalling in HDMI .
As there is a lack of aspect ratio signalling in HDMI it makes it all the more important that the broadcasters send things for 16:9 sets and let the box handle things for 4:3 sets in future!
It looks like the D-book needs a full review, so that all broadcasters send 4:3 (and 14:9) pillerboxed to 16:9 and that they have to use 720*576 resolution on all channels, with the same being done on Dsat and Dcab.
Just a quick question technologist do you know if ITV, C4 and C5 send 4:3 content like the BBC do?
Most good freeview units do follow AFD and make it difficult to turn off AFD sizing.
[MODE="Cloud cuckoo land"]
If only tvs and set top boxes allowed the viewer to defeat the aspect ratios and AFD settings for when the broadcasters get it wrong and we have to correct it. Or for, whatever reason, we want to zoom in on a picture - perhaps to manually crop a 14:9 embedded in a 4:3 as shown on Drama. [/MODE] ;-)
As far as I know the BBC are unique for this, every other broadcaster puts 4:3 pictures in a 4:3 frame (i.e without black bars). At least for SD.
HD is always 16:9 of course.
All I can say to that is roll on HD only emission! Why couldnt the BBC have got the other digital broadcasters to do the same as them? There was enough time for development of digital in the first place, before its launch in 1998 that is, to get these things sorted, so its a shame the system ended up in such a mess!
Well what I do know is that I don't like the BBC's 704x576 as one of my receivers (the Technika HD box) doesn't handle it properly, no doubt there are other receivers that suffer similarly. There are thin black bars at the side and the full picture is slightly compressed horizontally, using the HD channel as a reference. My Youview (HD) receiver handles it properly, the picture matches the HD picture, no distortion.
Well what I do know is that I don't like the BBC's 704x576 as one of my receivers (the Technika HD box) doesn't handle it properly, no doubt there are other receivers that suffer similarly. There are thin black bars at the side and the full picture is slightly compressed horizontally, using the HD channel as a reference.
Surely that's still better than the big thick black lines and distorted picture that 720x576 gave us?
Well what I do know is that I don't like the BBC's 704x576 as one of my receivers (the Technika HD box) doesn't handle it properly, no doubt there are other receivers that suffer similarly. There are thin black bars at the side and the full picture is slightly compressed horizontally, using the HD channel as a reference. My Youview (HD) receiver handles it properly, the picture matches the HD picture, no distortion.
Ah so the cheapo (Sorry Technika HD) box is adding the extra 16 pixels (8 on each side) to the picture to make it up to 720, whereas the Youview box must actually be re-sampling the horizontal resolution first to 720 then to 1920 I presume?
Well what I do know is that I don't like the BBC's 704x576 as one of my receivers (the Technika HD box) doesn't handle it properly, no doubt there are other receivers that suffer similarly. There are thin black bars at the side and the full picture is slightly compressed horizontally, using the HD channel as a reference. My Youview (HD) receiver handles it properly, the picture matches the HD picture, no distortion.
I think it squishes it for 720px too. It always looks slightly out to me, I thought it was the TV I had it connected to.
Ah so the cheapo (Sorry Technika HD) box is adding the extra 16 pixels (8 on each side) to the picture to make it up to 720, whereas the Youview box must actually be re-sampling the horizontal resolution first to 720 then to 1920 I presume?
Comments
On freeview thats easily achieved as there is an AFD flag that protects for 4:3 not 16:9 which can be used on 4:3 programs that are letterboxed.
This should have been the standard from the beginning and people should have had:
4:3 auto, that will letterbox widescreen content but centre cuttout 4:3 content that is broadcast in a widescreen frame,
4:3 letterbox, letterboxing all content as it would have been broadcast in a 16:9 frame, but would have the effect of windowboxing any 4:3 content (the black bars ether side of a 14:9 image in a 16:9 frame would be largely hidden in overscan, on a 4:3 set, so thats not an issue),
16:9, always displaying a 16:9 frame, but pillerboxing all 4:3 or 14:9 content (and if thats done at the broadcasters end then there would never be sets with funny shape images on a 16:9 set)
Then all set top boxes have the 16:9 mode set as default, as 4:3 users would more likely notice something was up and set it to 4:3 auto, unless they knew about windowboxing and didnt care about it. Anyway they would most likely refer to the manual that would tell them to try 4:3 auto for funny looking images on a 4:3 set.
Dsat doesnt cope with the protect for 4:3 in a 16:9 frame so the installer (of say Sky, I dont know if an installer would set a freesat box up for people?) would set up the best mode for what TV you had and if you had a large 4:3 TV then it could most likely cope with pillerboxing and if it was very small then it might be better to leave it on a centre cuttout mode.
I do think that the centercutout mode on Dsat should have been a 14:9 mode though so that it compromised because of the not accepting AFD codes properly! cough*sky*cough (its there fault for not sorting the issue out on Dsat!)
Sorry to diverge about Dsat in a freeview post, but the issue is there too although there is less options to sort it there, at least more channels are 720*576 (or 704*576) on Dsat than on freeview!
Cheers, daveac
The trouble with that is historic programmes which were filmed in 4:3 would then lose a third of their horizontal resolution. If you don't like that sort of programme you obviously won't care but a lot of us do.
The BBC already do this. If you record a 4:3 programme from BBC1 or 2 you usually find that it is, in fact, a 16:9 picture with big black vertical stripes (eg. 'Allo, 'Allo or Dad's Army). However, if the AFD is set correctly, my 4:3 set shows this as a full size 4:3 picture. The picture quality is usually adequate, even though - as you point out - some of the horizontal resolution is lost.
The alternative, which I prefer - but lotrjw clearly does not, would be to have whatever the source (16:9, 4:3) described by the full available resolution and have your tv/stb sort out the size on your screen. Some of the channels broadcasting 544x576 do this. (Can't remember whether ITV/4/5 do).
Either way, it relies on the broadcasters setting the correct flags for the source - and they quite often get it wrong. What I don't want to see is black borders on all four sides of the picture, or squashed or elongated pictures.
Most 4:3 programs get shown on channels broadcast in 544*576 res anyway so they are already loosing a third of the full SD resolution!
Also if all channels were forced to be broadcast in 720*576 configuration then the 4:3 programs would only be 544*576 anyway! it would work out!
Also the way the main channels broadcast 4:3 content (which is rare now) is by downscaling off the HD channels (except channel 5 of course!), so 4:3 content is already like the way I have said and the sides get cropped somewhere along the broadcast chain.
If they didnt do that cropping and just left it as is, letting the receiver box do the work instead, then it would be much better. It wouldnt cost more in bandwidth, as it would be black at the sides!
Ah so the cropping does occur at the box with the BBC channels at the least! I usually watch on Dsat and the HD channels at that so I dont see this with the BBC. Im sure in these cases that the 4:3 content, in the central 3/4 of the screen, is 544*576 apx, which, as you say, is adequate for 4:3!
The only time I did see it was when the BBC broadcast their TV copy of the Queens coronation last year on BBC Parliament, I think it was done there, as the program had a section at the beginning that started in 16:9 (that wasnt part of the original broadcast).
I watched it on Dsat though so it was likely it was 720*576 for me, whereas on freeview the BBC broadcast Parliament in 544*576.
For DSat, there's an Aspect Ratio Converter driving the encoders which centre-cuts 4x3 material and blows it back up to 720x576.
AFDs work properly on Freesat, but not on Sky boxes, which don't do 14x9.
The implied loss of resolution for 4x3 content was said to be irrelevant. Virtually all UK produced 4x3 programmes were from the analogue/composite era, and at one time all were delivered and/or archived on D3. Even with excellent composite decoding, you couldn't get beyond 600 pixels-worth of information horizontally, so you'd lose a little, but not much, and only on the best sources. Some other countries carried on making 4x3 content into the digital/component era, and cramming this into 528 pixels loses something - but in any case it never makes it look worse than an SD 16x9 source.
Cheers,
David.
Thats interesting it confirms what I thought about 4:3 content, the 14:9 issue on Dsat should have been a misnomer though surely?
As if you flag 14:9 in a 16:9 frame then letterbox it into a 4:3 rastered analogue picture, all 4:3 TVs would crop the left and right edges anyway, leaving the viewer with the perception of a full 16:9 image!
OK they might see very thin black bars poking out at the sides from time to time, but not permanent, just a quirk of CRTs where the image moves a bit!
So the BBC (and all other broadcasters for that matter (in the UK)), should have left 4:3 programs pillerboxed to 16:9 and ALWAYS in 720*576 mode, with ether 4:3 protect AFD on 4:3 content and 16:9 protect on 16:9 and 14:9 content!
I don't often see this. But when I use a PC dongle to record and then archive (oops - probably shouldn't admit to that) I came across the fact that 4:3 programmes on the BBC turned out to be 16:9 with black borders. When trying to archive to DVD I then had the problem, do I crop it to 4:3? I found it was possible to pass on the equivalent of the correct AFD to a DVD and make it do a centre cut-out on a 4:3 set so it behaves like I want it to. It also displays properly on a 16:9 set (ie. with the black borders shown). So, the short answer is yes usually on the BBC the cropping occurs at the box.
So why would BBC 4:3 programs, when you select 16:9 mode crop to 4:3 still?
Is the AFD on this supposed to be mandatory on freeview boxes then?
In as such that you only see it when using generic DVB decoders and not freeview branded boxes/decoders?
I wonder why the BBC couldn't persuade OFCOM to make this the mandatory way of showing 4:3 content on digital platforms? With the option for the user to overwrite the AFD code and display the full image with pillerboxing on a 16:9 set? in fact display it like that on all 16:9 sets with 16:9 selected!
That would have meant that S T R E T C H Y vision on 16:9 sets would never have happened! except of course when people used to put analogue though a 16:9 set! Oh and DVD players did this too as 4:3 is usually stored using the whole image width!
Thats another thing actually, DVD players should output the 4:3 image as pillerboxed (or at least give the option), when selecting the output for a 16:9 set, just as BluRay players now do!
The D book tells the broadcasters to get it right with AFD ....
But then confuses things by allowing the set to size the picture by looking for black ...
Most good freeview units do follow AFD and make it difficult to turn off AFD sizing
.
But we soon get into HD and the lack of aspect ratio signalling in HDMI .
As there is a lack of aspect ratio signalling in HDMI it makes it all the more important that the broadcasters send things for 16:9 sets and let the box handle things for 4:3 sets in future!
It looks like the D-book needs a full review, so that all broadcasters send 4:3 (and 14:9) pillerboxed to 16:9 and that they have to use 720*576 resolution on all channels, with the same being done on Dsat and Dcab.
Just a quick question technologist do you know if ITV, C4 and C5 send 4:3 content like the BBC do?
[MODE="Cloud cuckoo land"]
If only tvs and set top boxes allowed the viewer to defeat the aspect ratios and AFD settings for when the broadcasters get it wrong and we have to correct it. Or for, whatever reason, we want to zoom in on a picture - perhaps to manually crop a 14:9 embedded in a 4:3 as shown on Drama. [/MODE] ;-)
The d book "size on black "is most strange and I cannot think of another " leave it to the CE industry" in the whole spec....
But overriding AFD is there and should be
But sky using WSS is an abomination in a digital world
As far as I know the BBC are unique for this, every other broadcaster puts 4:3 pictures in a 4:3 frame (i.e without black bars). At least for SD.
HD is always 16:9 of course.
On Film4 Freeview it is 720x576, 4:3 full frame
On Film4+1 it is 544x576, 4:3 full frame, but with thin black bars left and right.
On Freesat both are 704x576, both 4:3, no black bars.
All I can say to that is roll on HD only emission! Why couldnt the BBC have got the other digital broadcasters to do the same as them? There was enough time for development of digital in the first place, before its launch in 1998 that is, to get these things sorted, so its a shame the system ended up in such a mess!
I see well strangely enough the one on film 4 will have the right resolution for 4:3 roughly! the others I expect have been oversampled for 4:3!
If the Film 4+1 version was fitted within 720*576, as it is and not re-sampled or stretched out to fit the 720 width, that would work out right!
As a side note, is the 704X576 one cropped slightly compared to the 720x576 one?
I don't know, I didn't sample them at the same time.
Ah so the cheapo (Sorry Technika HD) box is adding the extra 16 pixels (8 on each side) to the picture to make it up to 720, whereas the Youview box must actually be re-sampling the horizontal resolution first to 720 then to 1920 I presume?
I think it squishes it for 720px too. It always looks slightly out to me, I thought it was the TV I had it connected to.