Tuesday, January 8, 2013

Bits from LDP-1450 text mode understood better

After capturing yesterday's video, I have examined some of the screenshots in GIMP, and have come up with a pretty strong theory about what each bit means.

Bits 0 and 1 (range 0-3) mean the following:

00: horizontal default size (~26 pixels wide when captured at 720x480)
01: horizontal size * 2
10: horizontal size * 3
11: horizontal size * 4

Bits 2 and 3 are like 0 and 1 but apply to vertical scaling:

00: vertical default size (32 lines tall)
01: vertical size * 2 (64 lines tall)
10: vertical size * 3
11: vertical size * 4

Bit 4, if 1 means display text in a 10x3 grid.  If 0, text is displayed on 1 line and may have a limit of 20 characters (unconfirmed).

Bit 5 means surround letters with a grey border.

Bit 6 apparently has no effect unless bit 5 is also set; if both are set then the text will have a solid grey background (like when the current frame number is displayed).  The grey will be above and to the right of each character, unlike the grey border which is uniformly around each character.  I will need to do further investigation to see if this makes the character offset at all or if it is the grey part that is offset.

Bit 7 (if set) means that the laserdisc video is replaced with a light blue background which is handy for testing this stuff as it makes the letters clearer.

And I also found someone who has the programming manual for the 1450 (and other newer Sony players) and he has tentatively agreed to mail to me.  So I can get a more excellent idea of how the X/Y offsets work plus one other setting that I have (up to this point) completely ignored.

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