I was just musing on the subject of 16:9 aspect ratio as opposed of course to 4:3. Since digital modulator/encoders are permitted to use 16:9, I wondered whether there are any analogue cameras (i.e. composite video out) which deliver 16:9 aspect ratio. If anyone knows any could they please let us all know?
73's
Laurence 2E0DTX
Widescreen DATV
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This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.
Thank you
Re: Widescreen DATV
If they were tube cameras it could be done by simply turning the height control down, if it had enough range, registration for a 3 tube colour camera might be a bit more of a problem.
At work we used to mod the monitors we used by turning the height down, by this time the cameras were chip so were either 4:3, 16:9 or some were switchable. Chip cameras can't be modified in this way. An anthropomorphic lens would do it or a digital effects unit?
Brian
At work we used to mod the monitors we used by turning the height down, by this time the cameras were chip so were either 4:3, 16:9 or some were switchable. Chip cameras can't be modified in this way. An anthropomorphic lens would do it or a digital effects unit?
Brian
Re: Widescreen DATV
There is no reason 16:9 can't be used - after all the uk's been widescreen on broadcast channels for many years.
The majority of video sources available to the amateur are widescreen capable these days.
As Brian mentions you can use an anamorphic lens ahead of the camera or some form of
digital manipulation - or just have a switchable camera
It would also be dependent on how the receivers are set up at the repeater - some see the format descriptor
and put a letterboxed 16:9 on a 4:3 raster. It could also be set to make 4:3 centre cut-out - or also to ignore the afd and pass it through
unchanged.
And then what descriptor would the repeater send and how would the receiver respond
Problem is we have so much of a mixed economy of signals whatever is proposed will be "wrong" for someone.
Even when the broadcasters were in that situation they didn't get it right. Sometimes things went through the aspect
ratio correctors twice so you either had stuff twice as wide or twice as tall.
What was more worrying is many people at the sending end couldn't identify what was wrong.
Ian
The majority of video sources available to the amateur are widescreen capable these days.
As Brian mentions you can use an anamorphic lens ahead of the camera or some form of
digital manipulation - or just have a switchable camera
It would also be dependent on how the receivers are set up at the repeater - some see the format descriptor
and put a letterboxed 16:9 on a 4:3 raster. It could also be set to make 4:3 centre cut-out - or also to ignore the afd and pass it through
unchanged.
And then what descriptor would the repeater send and how would the receiver respond
Problem is we have so much of a mixed economy of signals whatever is proposed will be "wrong" for someone.
Even when the broadcasters were in that situation they didn't get it right. Sometimes things went through the aspect
ratio correctors twice so you either had stuff twice as wide or twice as tall.
What was more worrying is many people at the sending end couldn't identify what was wrong.
Ian
Re: Widescreen DATV
Most domestic camcorders are wide screen and they give an analogue video PAL output.
This output can often be switched to a variety of wide screen modes.
The mode that the BBC and ITV used to transmit on analogue is called compressed, I think.
This is the mode that makes people look skinny on a normal 4:3 monitor.
So if you feed this signal either direct or via a repeater into a wide screen monitor it will display 16:9 correctly.
This assumes that you have got the monitor set to wide screen.
Most cameras put a signal in the vertical blanking interval that will often automatically switch the monitor to wide screen.
Obviously this is still a 625 line picture, there are very few repeaters that will relay an HD picture.
For an example, some of the pictures shown on GB3BH on Wednesday evening are wide screen.
To get the BATC streaming pages to show in wide screen, click on the full screen button on the right just below the picture.
This will give you a wide screen picture if you are using a wide screen computer monitor.
Dave.
This output can often be switched to a variety of wide screen modes.
The mode that the BBC and ITV used to transmit on analogue is called compressed, I think.
This is the mode that makes people look skinny on a normal 4:3 monitor.
So if you feed this signal either direct or via a repeater into a wide screen monitor it will display 16:9 correctly.
This assumes that you have got the monitor set to wide screen.
Most cameras put a signal in the vertical blanking interval that will often automatically switch the monitor to wide screen.
Obviously this is still a 625 line picture, there are very few repeaters that will relay an HD picture.
For an example, some of the pictures shown on GB3BH on Wednesday evening are wide screen.
To get the BATC streaming pages to show in wide screen, click on the full screen button on the right just below the picture.
This will give you a wide screen picture if you are using a wide screen computer monitor.
Dave.
Re: Widescreen DATV
OK Thanks Dave, and everyone else too!
I was thinking in the context of the DTX1, which will detect the wide screen signalling (WSS) in the VBI if the input has it there. It's just does anyone make a simple SD Video camera which has 16:9 aspect ratio as native, and preferably with WSS in the video out?
I don't know of any. which is dangerous, because it gives me the urge to design one from the ground up
Cheers
Laurence
I was thinking in the context of the DTX1, which will detect the wide screen signalling (WSS) in the VBI if the input has it there. It's just does anyone make a simple SD Video camera which has 16:9 aspect ratio as native, and preferably with WSS in the video out?
I don't know of any. which is dangerous, because it gives me the urge to design one from the ground up
Cheers
Laurence
Re: Widescreen DATV
Re: Widescreen DATV
Postby 2E0DTX » Sun Dec 15, 2013 7:42 pm
OK Thanks Dave, and everyone else too!
I was thinking in the context of the DTX1, which will detect the wide screen signalling (WSS) in the VBI if the input has it there. It's just does anyone make a simple SD Video camera which has 16:9 aspect ratio as native, and preferably with WSS in the video out?
I don't know of any. which is dangerous, because it gives me the urge to design one from the ground up
Cheers
Laurence
That sounds time consuming Laurence
Postby 2E0DTX » Sun Dec 15, 2013 7:42 pm
OK Thanks Dave, and everyone else too!
I was thinking in the context of the DTX1, which will detect the wide screen signalling (WSS) in the VBI if the input has it there. It's just does anyone make a simple SD Video camera which has 16:9 aspect ratio as native, and preferably with WSS in the video out?
I don't know of any. which is dangerous, because it gives me the urge to design one from the ground up
Cheers
Laurence
That sounds time consuming Laurence
Re: Widescreen DATV
Hi Mark;
Wouldn't be too daunting as design jobs go. The micro-controller that set up the sensor could stuff the WSS bits onto the VBI (it's only like teletext but a lot slower) with very little trouble. The knack is finding a 16:9 sensor that has SD composite out, since it's far more likely they will present as BT656 or similar but as HD e.g. 720p minimum.
I can't help but think there must be a sensor out there that could be pressed into service, although the manufacturer's aren't usually interested in offering design support or even silicon if the volumes are low..
Perhaps I should give up before I waste too much time on this especially if the rest of the chain can't handle it. It was, after all, just another musing on a rainy day
73's
Laurence
Wouldn't be too daunting as design jobs go. The micro-controller that set up the sensor could stuff the WSS bits onto the VBI (it's only like teletext but a lot slower) with very little trouble. The knack is finding a 16:9 sensor that has SD composite out, since it's far more likely they will present as BT656 or similar but as HD e.g. 720p minimum.
I can't help but think there must be a sensor out there that could be pressed into service, although the manufacturer's aren't usually interested in offering design support or even silicon if the volumes are low..
Perhaps I should give up before I waste too much time on this especially if the rest of the chain can't handle it. It was, after all, just another musing on a rainy day
73's
Laurence
Re: Widescreen DATV
Sounds like an excercise to me Laurence! One still has to get lens to match etc. You can get PAL cameras of EBAY these days for £10 !! Mate bought one this week for his van - reversing camera in metal enclosure with IR leds & sealed against the elements. 12v in - video out & quite good picture surprisingly. £10 ... 
Didn't have WS though
Didn't have WS though