Dimming problem every time subtitles appear on 32PFL9705

[Adamo]

Hi Freddy!

I've tried your test image with my 32pfl9705H/12 (fw ver 0.140.36.00): same problem for me...

I hope that Philips will solve this issue.

Regards,
Adamo

[mdiehl]

hi,

same problem here with your new test image.
32PFL9705K/02.

markus

[durtro]

Have the same problem in a 32PFL9705H/12. Most sources with subtitles exhibit this annoying effect and those are a big portion because in Portugal almost everything is subtitled besides kids programs and national ones.

Because of that, many times I disable the dynamic backlight or else I see the picture "flashing" with the subtitles.

[DerShortyy]

I can confirm this "bug" on my 32pfl9705k/02. Although i do not watch movies with subtitles very often... but i tested the files you guys uploaded here... i you are forced to watch with subtitles i can understand that it is anoying...
Best regards

[durtro]

This is the same examples I posted in another Freddy's thread. He asked me to post them in this thread also.

There are two little videos showing the problem at http://homeo11.durtro.operaunite.com...aring/content/

The first one is the mouse pointer effect when it appears over the still frame and also the video toolbar effect when it appears at the bottom.

The second one is the video itself during a little segment where the effect is clearly visible with at least one subtitle.

Those are directly hosted by my computer and should be available every time I have opera up and running.

[Freddy]

Thanks durtro,

as I said, especially your first video (MOV00585.MPG) clearly shows the bug we're dealing with here.

Please Philips, look at his video's and/or use my video and picture tests to see the problem yourself. And please, find a solution for, what I think is, the last big picture quality bug! I had hoped for a solution in the last four firmware updates already, but unfortunately... it is still there in 140.39!...

[Freddy]

Hello again,

today I made a new test picture, showing this bug even more clearly than ever before!... (What smiley to use here?... ... ... or... )

https://lh3.googleusercontent.com/-F...arkFlowers.jpg

If you, Philips... and everyone else of course... could maybe take a look at it again, this time with firmware 140.40!?...
Just watch the picture and turn the sound on and/or off... and watch the problem show itself!...

The appearance of the volume indicator in the upper left corner SHOULD NOT influence the ENTIRE picture!...

Please Philips... fix this bug, please!...

Thanks again in advance!

Freddy

[durtro]

Hello again,

today I made a new test picture, showing this bug even more clearly than ever before!... (What smiley to use here?... ... ... or... )

https://lh3.googleusercontent.com/-F...arkFlowers.jpg

If you, Philips... and everyone else of course... could maybe take a look at it again, this time with firmware 140.40!?...
Just watch the picture and turn the sound on and/or off... and watch the problem show itself!...

The appearance of the volume indicator in the upper left corner SHOULD NOT influence the ENTIRE picture!...

Please Philips... fix this bug, please!...

Thanks again in advance!

Freddy

I've seen worse. Like in "MOV00605.MPG" in http://admin.homeo11.durtro.operauni...aring/content/. The all image flashes quite visibly when the mouse appears. By the way, in most of this situations the image needs to be fullscreen for the effect to be fully visible. In movie aspect ratios the problem is passable since I put my subtitles on the lower black border and the effect does not affect the outside movie frame, however, in anime, tv series and most other content the effect is a constant. More than 50% of the content I see is affected by this which makes the dynamic backlight useless.

[Adamo]

Hello again,

today I made a new test picture, showing this bug even more clearly than ever before!... (What smiley to use here?... ... ... or... )

https://lh3.googleusercontent.com/-F...arkFlowers.jpg

If you, Philips... and everyone else of course... could maybe take a look at it again, this time with firmware 140.40!?...
Just watch the picture and turn the sound on and/or off... and watch the problem show itself!...

The appearance of the volume indicator in the upper left corner SHOULD NOT influence the ENTIRE picture!...

Please Philips... fix this bug, please!...

Thanks again in advance!

Freddy

Hi Freddy,

I've tried your test picture and I can see the dimming bug as you described.
My TV is 32pfl9705H and fw is 140.40.

I hope that Philips will solve this bug.

Thank you,
Adamo

[Freddy]

Hello again,

I finally figured out how (part of) the Dynamic Backlight feature works and, even more importantly, why it is causing this subtitle dimming bug. If I do make any mistakes, please feel free to correct me Philips!... Really, please do!...


First of all, the LED Pro Dynamic Backlight function works in three ways:

- it adjusts the intensities of the LED segments according to how bright that part of the picture should be, of course;
- but it also corrects for overly strong intensity differences between neighboring segments, to lessen the halo effect;

- on top of that it uses, what we know as, the Perfect Contrast function (even if you have it disabled), to correct for strong brightness differences within a single segment.


In most cases this works wonders!... Really!

But... the problem is, that this "secret" part of the Perfect Contrast function isn't used gradually when needed, but in the same big steps as we can set it: seemingly Off/Minimum/Medium/Maximum.


Now back to the problem at hand. When you're looking at a rather dim picture, all the LED segments are in their lower states. No correction for neighboring differences is needed and the "secret" Perfect Contrast function is in one of its higher states, to make sure you can still see enough now that the LEDs are dimmed so much.
But then something bright appears, like subtitles. The LED segments behind the subtitles are being intensified, of course. The difference between these bright segments and all the other still dimmed segments is now so big, that the correction part takes care of this in such a way that actually all LED segments are getting just a little bit more intense than before.

This is where I originally thought things went wrong but, even though I don't think the correction should be this drastic, in fact it is still not causing the actual fault. Things go bad in the next step...

Due to the fact that all the segments are made just a little bit more intense, some, or even all of them, go over that edge where the "secret" Perfect Contrast function is working in one of its higher states. So suddenly the "secret" Perfect Contrast in these segments drops from, say Maximum to Medium. Now that is something you will notice!...


So to finalize this long story... things could be improved drastically, if the internal, so called "secret", Perfect Contrast part of the Dynamic Backlight function would be regulated in much smaller steps than is being done right now. Philips!?... Got a job for me!?...

[LocDim]

Hi

I have the same problem with the subtitles and dimming on my new 58pfl9956. The local dimming/brightening system seems to work way to aggressively. If what you are saying is correct, this seems to happen on only a few models. I wonder why ? Is this a Philips quality control problem ?

[petasis]

What is the setting for local dimming in your setup? Can you try with the typical setting?

[Freddy]

I have the same problem with the subtitles and dimming on my new 58pfl9956.

I agree with you that this is kinda disappointing... Thanks for letting us know the problem is still there in even the latest models. But... I would try to contact Philips (one of the guys here maybe), point them to this thread and see what they say. The fact that the problem has not been solved yet for even the new series, makes it a current one... again! Philips!?...

[petasis]

I don't remember the exact number the problem got introduced, but the first 9705 firmwares didn't have this problem (a small change in a part of the picture affecting the whole picture).

[Freddy]

I don't remember the exact number the problem got introduced, but the first 9705 firmwares didn't have this problem (a small change in a part of the picture affecting the whole picture).

Are you sure about that?...

Because I know for a fact that the problem is there with firmware 140.25 and all versions after that. Older ones I'm not sure about, so I would be interested to know what you seem to remember about this.