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Feature #1

closed

Svideo sync line support

Added by admin over 7 years ago. Updated over 7 years ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Start date:
04/04/2017
Due date:
% Done:

0%

Estimated time:

Description

Doesn't look too hard to change. In the svideo component they do this for luma:

luma = (84*R+164*G+32*B + 58880)/512 (i.e. 115-255 on dac)
luma (sync) = 0 (i.e. 0 on dac during sync periods)
So never using 1-114 on dac...

So... we need to remove the sync stuff from the component (this is done with sync pin instead) then change it to:
luma = (153*R+300*G+58*B)/512 (i.e. 0-255 on dac)
luma(sync) = 0 AND use the sync pin...

Which is an easy change I think. Also we get more luma resolution since we are using values 0-255 on the dac instead of 115-255:-)

(luma = 0.299*R+0.587*G+0.114*B + syncLevel)


Related issues 1 (0 open1 closed)

Is duplicate of Feature #14: Svideo core for first prototypeClosedfoft04/24/2017

Actions
Actions #1

Updated by foft over 7 years ago

A comment

Actions #2

Updated by foft over 7 years ago

  • Status changed from New to Resolved

Implemented in test core, probably will need some debugging...

Actions #3

Updated by sadosp over 7 years ago

admin wrote:

Doesn't look too hard to change. In the svideo component they do this for luma:

luma = (84*R+164*G+32*B + 58880)/512 (i.e. 115-255 on dac)
luma (sync) = 0 (i.e. 0 on dac during sync periods)
So never using 1-114 on dac...

So... we need to remove the sync stuff from the component (this is done with sync pin instead) then change it to:
luma = (153*R+300*G+58*B)/512 (i.e. 0-255 on dac)
luma(sync) = 0 AND use the sync pin...

Which is an easy change I think. Also we get more luma resolution since we are using values 0-255 on the dac instead of 115-255:-)

(luma = 0.299*R+0.587*G+0.114*B + syncLevel)

\
In all the cases we need to connect the sync pin of dac on a I/O of fpga?

Actions #4

Updated by foft over 7 years ago

Received the board and gave this a go. svideo and composite look nice and bright now. However saturation is too low, need to work out how to boost this without too much impact to brightness.

Also need to work out why its just black and white on Panos' TV!

Actions #5

Updated by foft over 7 years ago

  • Status changed from Resolved to Closed

Being handled in issue 14

Actions #6

Updated by foft over 7 years ago

  • Is duplicate of Feature #14: Svideo core for first prototype added
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