16:9 to 4:3 Converter?

[raditechman]

The only solution that might work is to feed the Sky box video out to a computer with a video input. If it has not got one USB video capture devices are quite cheap. The Sky box needs to be set to 16:9 with no cropping.
On the computer use the program VLC media player to capture and display the video. There should be enough options in the VLC menus with zoom, crop, aspect ratio, geometry etc to get a 4:3 output. You then need a video out from the computer or if it has only VGA a VGA to video adaptor, then feed the video into a modulator to get RF output!
Could work, but is it worth all that trouble?

John

[peter_scott]

Sorry to keep harping on about this method of supplying signals to 405 line (or 625 line or 240 line or 819 line etc) sets. But as in John's description VLC player and a suitable modulator is a very simply, low cost way that is proven to work.

http://www.nostalgiatech.co.uk/Baird%20240%20lines.htm

Peter

[ntscuser]

Originally Posted by Focus Diode

Can't speak for Sky but certainly with Freeview boxes and DVDs it's possible to adjust the aspect ratio. 16:9 transmissions come through elongated, the reverse is of course true attempting to view 4:3 at 16:9.

More and more Freeview channels force letterboxing even when pan & scan is selected, the BBC is particularly annoying in that respect. Oddly enough the one thing they don't letterbox is the hidden testcard on Red Button Ch.250 which I could really use!

My 'trick' is to download shows from the internet in a higher resolution than I need then zoom them to fill the screen. That way there is no apparent loss of vertical resolution and the bits at the side I couldn't care less about. For some reason I'm not able to do this with live broadcasts.

[regentone001]

I have just found a setting on my tivo box, ZOOM, it gets rid of the cut offs at the sides but keeps the aspect ratio correct.

[llama]

I think I have solved this for my installation (4:3 projector + 2 PVRs) but I'll need to do more tests. I found that unplugging the HDMI feed to the plasma TV and using the "yellow" phono socket output on my Humax FreeSat PVR it is possible to select 4:3 in the settings menu. I'll need to do more tests (and unfortunately I don't think I can do this on the BT YouView box) but it looks like it works with live, PVR recordings and iPlayer. I even went to the bother of recording a programme (see below) onto a DVD so I have a reference source.

A useful source of a decent size circle for geometry tests is "Something Special" from the Cbeebies channel. When the child taps the presenter's tablet one of the circles on it swells to fill most of the screen.
Graham

[Andrew2]

Originally Posted by regentone001

I have just found a setting on my tivo box, ZOOM, it gets rid of the cut offs at the sides but keeps the aspect ratio correct.

But won't that lose strips from the top & bottom? When you zoom a 4:3 picture to fill a 16:9 screen, something has to give!

[kan_turk]

There is no such thing as 'lossless' aspect ratio conversion - the various formats, 4:3, 14:9, 15:9, 16:9 etc are simply not compatible and the user has to decide on the 'least worst' solution for their application - trading off picture cut-off against 'black bars' - the broadcasters solution in the day was 14:9 giving, argueably, modest picture cut-off & not too obtrusive black bars

[dseymo1]

Originally Posted by ntscuser

More and more Freeview channels force letterboxing even when pan & scan is selected, the BBC is particularly annoying in that respect.

Presumably, pan & scan requires intervention on the broadcaster's part to follow the action. I don't know whether that's done manually or via some sort of computer algorithm, but it's understandable that they don't want the trouble of doing it for what must by now be a small audience.

[ntscuser]

I should have said "centre cut" rather than "pan & scan" as it's a bit less involved.

[llama]

I think I've completed my tests and really what I need is a 16:9 to 4:3 converter!

I'd like to be able to feed the BT box into the projector so on the odd occasion I want to rent a film I have the option of viewing it on the projector. Whether the HDMI lead is plugged in or not, the only picture format setting I can find just has "unsupported format" which I take it to mean no format changes are possible. I've tried recording from the yellow phono socket and I just get tall people. Playing the recorded DVD on a Sony player gives tall people for all video settings whether I choose 16:9, 4:3 letterbox or 4:3 pan-and-scan. Doesn't seem right but nothing seems to affect it.

A hardware device would do the conversion I'm sure. In my case I'd be happy with the sides cut off so a pair of line stores could be used to store the incoming line then immediately read out the middle section so as to fill the available 58uS with those pixels. Two line-stores would be needed so one can be filling as the other empties. I think creating a letterbox within the 4:3 would require a framestore.

I wonder if I could get a "stretch" lens to go in front of the projector lens...
Graham

[Brigham]

Are you wanting to display the centre portion of a 16:9 picture on a 4:3 set?
If so, then ZOOM is the setting you need.
Problem is, you need to be able to control the amount of ZOOM, so that you can 'zoom-in' until the top and bottom edges of the picture just fill the mask.
At this point, you have the full height of the scene, and have lost the minimum of the width.
This is how they used to transmit 'widescreen' films in 4:3 days. They would 'squash' the picture while the opening credits were running, then switch to just the middle 4:3 section for the action.
On extreme widescreen, such as CINERAMA, a TK operator would physically shift the transmitted portion of the picture left and right, to centralize the action.
(This is the job I wanted to do, as a kid).

[llama]

Hi Brigham. Yes, your first sentence is correct - the set in question in my case being a 4:3 projector. It doesn't have a zoom setting. An old-fashioned "height" control on it would be ideal.

Neither my 2 DVD recorders (Philips and Panasonic) nor my Sony DVD player have a display setting that makes any difference. They give a nice description of what 16:9, 4:3 letterbox and 4:3 pan-scan should do but don't actually make any difference. I'm sure they've all got a frame-store or two in 'em as part of the encoding/decoding but won't make it available to me!

Funny how my Humax FreeSat machine manages to do it.
Any ideas on settings for recording or playback would be great.
Graham

[Grubhead]

Could you post a picture of the connections of the projector?
Because it must be something to do with the way your DVD players are connected, that will not allow them to use the picture format options.

[llama]

Thanks for the interest. You've got me thinking about the connections to the DVD and PVR machines. I wonder if the notorious SCART pin 8 might provide a clue. So far I'm just using the yellow RCA to the same on the projector. I've used a SCART to RCA adaptor at the machines and but I don't think that interferes with pin 8 in any way.
The projector photo doesn't really show much. Apart from loop-through VGAs there's just the 3 RCAs.

Hmm - just seen on Wiki that pin 8 is a signal from the source so I guess it wouldn't like being forced one way or another.

Graham

[Grubhead]

I think that passing it via the yellow RCA socket is removing the widescreen adjustments for the conversion. Below that RCA looks like a S-Vhs socket. Is there anyway you can pass the video signals via that? Do any of your DVD players have an S-Vhs?

[dglcomp]

Some projectors do support RGB of the format given out by SCART but via the VGA connector(s), my Mitsubishi XL9U certainly does. So that may be another option for devices that support it, or for devices that have HDMI out just use a cheap HDMI-VGA adaptor, I do just that and with the PVR/BLU-RAY set to 4:3 letterbox the pictures come out just fine.

Video compatibility: NTSC / NTSC4.43 / PAL (including PAL-M, N) / SECAM / PAL-60, Component Video: 480i/p (525i/p), 576i/p (625i/p),720p (750p 60Hz), 1080i (1125i 50/60Hz), [1080i (1250i 50Hz),720p (750p 50Hz) is not available], SCART (RGB+1V sync)

[llama]

Possibly using VGA might work but it wouldn't be a sustainable option for domestic reasons...
Quite reasonable objections, actually!
My feed to the projector is a single coax. It goes via the loft and that has given me an idea - point a video camera at a CRT TV in the dark in the loft. I think a flat panel TV up there would introduce video processing delay and muck up the lip-sync. Sounds a bit daft/surreal but it would certainly convert rented BT Vision films into the letterbox that would give me all the visual info without any geometry errors.

This afternoon I tried a Fresnel lens over the front of the projector lens in the hope that I could bend it slightly and if carefully done could provide the anamorphic effect needed. It didn't work - I think the lens had much too much magnification so the image was small on the screen and beyond the focus range of the projector's lens. I don't suppose a very low magnification Fresnel lens is available.

Maybe electronics is the way to go. (Or bite the bullet and get a more recent projector).
Graham

[raditechman]

To do it optically you need an anamorphic lens in front of the projectors lens. Cinemas once had to use them for CinemaScope 35mm films and others which had a horizontally squeezed image. I have an ex-cinema one in my collection. It is a Varamorth and you can adjust the amount of stretch.
Nowadays with digital replacing film the stretch can be done electronically or optically.
You can still buy anamorphic lenses but they are not cheap.

John