Mailing List Archive: colour adjustment

colour adjustment

Mar 21, 2003, 11:25 PM

Post #1 of 4 (1602 views)

A sad story about a moron/word of warning/feature request...

This evening I played with the colour adjustment buttons. On my system,
the changes did not occur real time, but were delayed several seconds.
Therefore since I didn't see the change, I kept pushing the button and
then pushed other buttons. Eventually after I decided that the colour
controls weren't working and stopped pushing buttons, all my changes
took place at once - and I was left with a pitch black screen with blue
undertones.

I tried for about a half hour to correct the colour/contrast/brightness,
but without the changes taking place in real time and without a slider
control to see where I was, I just couldn't get the picture to look
right. I'm probably just a moron, but I'm telling you I tried and
couldn't get it. (especially complicating the matter was that the
settings are per channel based, a good thing, but the channel I was
watching had the basketball game on.)

There probably is an easier way, but to solve my problem, I re-ran setup
to clear the db, and then re-ran mythfilldatabase. (mythfilldatabase
--xawchannels was unrecognized for some reason)

So for those that don't have a colour balance problem, don't touch the
buttons. :)

For those in the know, please let me know of an easier way to fix this,
if there is one.

It would be really great if there was a slider or some indicator of
change from the baseline (such as +5/-5). An ability to reset may also
work.

-rac

Re: colour adjustment [ In reply to ]

bjm at lvcm

Mar 22, 2003, 2:26 AM

Post #2 of 4 (1564 views)

Permalink

Ryan A. Carris wrote:
> A sad story about a moron/word of warning/feature request...
>
> This evening I played with the colour adjustment buttons. On my system,
> the changes did not occur real time, but were delayed several seconds.
> Therefore since I didn't see the change, I kept pushing the button and
> then pushed other buttons. Eventually after I decided that the colour
> controls weren't working and stopped pushing buttons, all my changes
> took place at once - and I was left with a pitch black screen with blue
> undertones.
>
> I tried for about a half hour to correct the colour/contrast/brightness,
> but without the changes taking place in real time and without a slider
> control to see where I was, I just couldn't get the picture to look
> right. I'm probably just a moron, but I'm telling you I tried and
> couldn't get it. (especially complicating the matter was that the
> settings are per channel based, a good thing, but the channel I was
> watching had the basketball game on.)
>
> There probably is an easier way, but to solve my problem, I re-ran setup
> to clear the db, and then re-ran mythfilldatabase. (mythfilldatabase
> --xawchannels was unrecognized for some reason)
>
> So for those that don't have a colour balance problem, don't touch the
> buttons. :)
>
> For those in the know, please let me know of an easier way to fix this,
> if there is one.

Ryan, I'm not exactly sure how to react to this sad tale
other than to start by saying that I certainly understand
your plight. The simple "+" and "-" displayed on the screen
are of little or no use in this situation and this has been
a problem for weeks...

> It would be really great if there was a slider or some indicator of
> change from the baseline (such as +5/-5). An ability to reset may also
> work.
>
> -rac

...but this is exactly what I took care of YESTERDAY! 8-).

Check out the current CVS. Each of contrast, brightness and
color have sliders that shows the percentage just like the
volume control.

If you want to get your color back to 50% for all channels,
you could do this:

mysql> update channel set colour=32768;

What I found recently is that, for each of the cards I
tried, white is out of proportion compared to medium tones.
I had thought this might be a gamma problem but lowering
the contrast on the capture card made the images much more
life-like:

mysql> update channel set contrast=28000;

Hope this helps,

-- bjm

----------------------------------------------------------------------------
Changes committed by bjm on Thu Mar 20 21:50:26 2003

Modified Files:
in MC/libs/libmythtv:
channel.cpp remoteencoder.cpp remoteencoder.h tv_play.cpp
tv_rec.cpp tv_rec.h
in MC/programs/mythbackend:
encoderlink.cpp encoderlink.h mainserver.cpp
Log Message:
Contrast, brightness and color OSD sliders just like the volume control.

----------------------------------------------------------------------------

Re: colour adjustment [ In reply to ]

rac at racarris

Mar 22, 2003, 9:05 AM

Post #3 of 4 (1572 views)

Permalink

Bruce Markey wrote:
> Ryan, I'm not exactly sure how to react to this sad tale
> other than to start by saying that I certainly understand
> your plight. The simple "+" and "-" displayed on the screen
> are of little or no use in this situation and this has been
> a problem for weeks...

it sounds like you already have fixed it. -great, thanks.

>> It would be really great if there was a slider or some indicator of
>> change from the baseline (such as +5/-5). An ability to reset may also
>> work.
>> -rac
>
> ...but this is exactly what I took care of YESTERDAY! 8-).
> Check out the current CVS. Each of contrast, brightness and
> color have sliders that shows the percentage just like the
> volume control.

excellent!

> If you want to get your color back to 50% for all channels,
> you could do this:
>
> mysql> update channel set colour=32768;
>
> What I found recently is that, for each of the cards I
> tried, white is out of proportion compared to medium tones.
> I had thought this might be a gamma problem but lowering
> the contrast on the capture card made the images much more
> life-like:
>
> mysql> update channel set contrast=28000;
>
> -- bjm

I'll play with these sometime. I also notice that the white is out of
proportion a bit. Is there a page/link that tells me a little more about
these numbers? Is it linear between 0 and 65536, with 32768 half way
and 28000 less than half? Also, I noticed last night that Xaw allows
changes to the Hue, but Myth doesn't appear to. Is there a reason, or
am I incorrect? Also, is the default 50% for all channels or something
else?

-rac

Re: colour adjustment [ In reply to ]

bjm at lvcm

Mar 22, 2003, 2:54 PM

Post #4 of 4 (1575 views)

Permalink

Ryan A. Carris wrote:
...
> I'll play with these sometime. I also notice that the white is out of
> proportion a bit. Is there a page/link that tells me a little more about
> these numbers? Is it linear between 0 and 65536, with 32768 half way
> and 28000 less than half?

Right. The interface take a 16bit unsigned int. The number
is divided by 655 to present it as a percentage so 28000
is about 42%. For some channels, I may need to go as low as
35% to get a good image.

> ...Also, I noticed last night that Xaw allows
> changes to the Hue, but Myth doesn't appear to. Is there a reason, or
> am I incorrect?

When Chris Liscio contributed the code to control these, he
didn't expect to muck with hue. I kind of think the tint will
always be close to the middle and exposing it would have likely
exposed people to sad stories your's from yesterday. And what
would the keys be? ";" and ":"? I'm starting to think there
should be one key for "controls" that repeated presses rotate
through contrast, brightness, etc. then one pair of keys for
increase and decrease. I thought about adding hue on Thursday
but I'd rather have a "controls" key mechanism first.

> Also, is the default 50% for all channels or something else?

AFAIK all of these settings default to 32768 (50%) unless an
application specifically modifies them.

-- bjm

http://gossamer-threads.com/perl/mailarc/gforum.cgi?post=5091;search_string=;guest=268733&t=search_engine#5091