As far back as I can remember on this site this aspect has been discussed, early 1999 at least and if E Martineze is still a reader here you may be interested in my lastest 16:9 finding when testing the CCE version 2.5 encoder in SVCD:

If you make sure you set a 16:9 project, capture in Premiere 6 and do not deliberately letterbox the output (use 16:9 pixel ratios out) then the image from a Pioneer 535 DVD player will automatically letterbox on a 4:3 TV. What a bonus for the 16:9 er's! Wonder what happens in DVD?

Whether this happens in VCD I do not know, but certainly this happened in SVCD. It does not happen with my Philips 725 DVD player, the Hollywood Plus or with my software players but.........

Just another of those "all DVD players are not born equal" it seems.

-- Ross McL (rmclennan@esc.net.au), September 02, 2001

Answers

The thing, I'm told, is in the MPEG stream. One can author a VCD with a MPEG-1 stream that contains true 16:9 video, but when viewed on a 4:3 TV it will still always look wrong with images squeezed horizontally, even if that TV can and is set to automatically detect 16:9 video. You HAVE to manually set the TV to widescreen mode. After a little research, and armed with an oscilloscops, I found out that any video source (typically a DVD player, a satellite receiver, or a camcorder) that is set to widescreen mode and has an S-video output, when a true 16:9 video program is present, +5V is superimposed on the C-line of the Y/C (S-video). When the appropriate 4:3 display device detects this it squeezes the picture vertically; otherwise for all other conventional 4:3 programs the C-line centers on 0V, picture stays the same no squeezing is done. Unlike MPEG-1, MPEG-2 has flags that can be set in the encoder to tell the decoder whether or not the stream is 16:9. This, together with what setup setting (letterbox or widescreen) was chosen on the DVD player determines the output. If letterbox is chosen, and the MPEG-2 stream is 16:9, the player re- composes the 16:9 video and adds black bars on top and bottom (with a view to using a conventional, non 16:9-detecting TV). This is called in-player letterboxing; some DVD players do it better than others, in the artifacts (or lack of them) that get introduced in the picture. If widescreen is chosen, and the stream is 16:9, the C-line signal is made to ride atop +5V (which the 16:9 capable TV detects and treats the video appropriately). Since 16:9 is one characteristic of MPEG-2, TMPGenc has appropriate settings to add flags to the stream automatically in the encoding, and SVCDs created thus are treated appropriately by (at least in my experience) Pioneer DVD players, which automatically performs in-player letterboxing (what you saw), or tell a 16:9 TV (or a 16:9-capable 4:3 TV) to behave accordingly through conditions on the C-line of the S-video out (which also explains why auto-16:9 is not possible on the composite video output).

-- Mehmet Tekdemir (turk690@yahoo.com), September 03, 2001.

Thank you very much for that explanation, very much appreciated, just an outstanding experience when it occurs after trying for so long for what seemed impossible to achieve. However, in firther testing I could not repeat it with LSX or TMPGEnc so I guess its nothing to get wildly excited about afterall as it is specific it seems.

Thanks

-- Ross McL (rmclennan@esc.net.au), September 03, 2001.