awalls at radix
Oct 18, 2008, 5:45 PM
Post #1 of 1
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Program to compute SAV/EAV RP codes
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Attached is a small program that computes all the possible ITU-R BT.656
and VESA VIP 2 SAV/EAV Raster reference/Protection (RP) codes and dumps
out a reference table.
And just to comment on the comment in ivtv-streams.c:
"Other code pairs that I found are: 0x250E6249/0x13545454 and 0x25256262/0x38137F54.
However, I have no idea what these values are for."
The first code set looks like attempts to pick off very specific VBI
lines at the end of the VBI:
0x25 [.active raw VBI video in last line of vblank of the odd field ] 0x13
0x0E [.active raw "VBI" video when in last vert active line in the odd field] 0x54 (nonsense)
0x62 [.active raw VBI video in last line of vblank of the even field ] 0x54
0x49 [.active raw "VBI" video when in vert active line in the even field ] 0x54 (maybe OK)
The second code set actually makes much more sense:
0x25 [active raw VBI video in vblank of the odd field ] 0x38
0x25 [.active raw VBI video in last line of vblank of the odd field ] 0x13
0x62 [active raw VBI video in vblank of the even field ] 0x7f
0x62 [.active raw VBI video in last line of vblank of the even field] 0x54
For the CX25840 digitizer it may be better to use the codes
0x20206060/0x30107050 for raw VBI than the ones in use now. Of course
I've wondered when the T bit would toggle since it has to toggle in the
EAV RP before the active video display which should also be the last
line of VBI. In that case, maybe 0x20206060/0x309070A0 would be the
right codes.
-Andy
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rpcodes.c
