Friday 30 August 2013

TV Calibration Challenges

It would have been easier if I had an expensive spectrum analyser or independent TV calibration hardware to make sure the TV is set up correctly in the first instance but oh well...

I have the following sources, all via HDMI directly into the Panasonic P65VT65:

1. SkyHD
2. XBMC on Acer Revo on XBMCBuntu
4. Blu-Ray player (in future this will share the HDMI TV input with the CCTV via a HDMI switcher as the TV has only 3 HDMI inputs)

CCTV, I'm not going to worry about at all.  
Blu-Ray player I'll do when I get it (though it could help me calibrate the TV as it could act as the reference source).

The SkyHD box is a problem as I can't load test images on it.  Sky used to send out a test card (replicating the old BBC test card but updated with Myleene Klass):

They do not send it out any longer it seems.

BBC themselves used to broadcast a specific HD test card:

They too have stopped.  

So the only thing I can do is calibrate Sky by eye, not the most perfect or elegant solution.  I've set this to THX Cinema mode (very happy with this mode in general) and tweaked the contrast and brightness a little.

XBMC on Acer
There are a few things that complicate this.  As I'm running XBMC on a Linux PC (XBMCbuntu) I have to take in to consideration the graphics card (Nvidia) and drivers and software on top i.e. Linux and XBMC.  Each of these could have an effect.  The largest impact by far is by Xorg/X11 (providing the GUI) and the Nvidia setup. 

The default output for X is a monitor.  The values used for RGB is 0-255 (0 = perfect black, 255 - perfect white).  The issue comes when you use a TV as a display with source which is not created with 0-255 in mind...i.e. movies...they use 16-235 (16 = perfect black, 235 = perfect white).  Why don't they use the full range?   The shooting and digitisation process is not perfect so some head room and foot room is given, maybe to accommodate a filter overshoot for example.

So I made sure that my XBMC setup was outputting 16-235.  After a lot of research the solution was a simple addition to my xorg.conf:
Option "ColorRange""Limited"

In fact the XBMC devs have recognised this:
Video calibration...
See #Video calibration...
  Future Gotham feature: Use limited color range (16-235)  
Use limited color range instead of full color range (0-255). Limited range should be used if your display is a regular HDMI TV, while full color range should be used if your display is a PC monitor.

So now that my basic XBMC setup was done I went through the calibration steps from AVSForum guys: As I have the THX blue filter glasses, I was able to get the skin tones done too.

I recognise that this is not all there is to calibration and different sources will still produce different issues but this is enough for me at least.

So now I have a calibrated picture for both Sky HD and my XBMC setup...problem is when I go to other peoples homes, I am instantly distracted by the tendency of their TV's to oversaturate and use too much brightness!

Future Possibilities
I have a Canon 5D Mark III....I'm wondering whether I can use the capabilities of the camera somehow as an accurate spectrum analyser i.e. I take a picture of an RGB 128,128,128 (gray), output it on to the TV, measure with camera again, tweak until the picture is close to RGB 128,128, that with multiple colours and grays etc.

London Street Games - The Threadneedle Files - Update

We came third, gutted.

It was ours to lose as we got the vital clue first.  All props to Asra (my sister-in-law) who took the time to figure out how the clue related to the final destination we had to reach.  We were apparently minutes behind.  Great day though and definitely worth doing.

Thursday 22 August 2013

Panasonic TX-P65VT65 has arrived!

TV has arrived and is sitting on top of a table temporarily.  It will be hoisted on to the wall in the next week or so.

The picture is superb, the images very life like and full of detail.  

Haven’t gotten round to doing my own custom calibration yet (have ordered the THX blue glasses, so when they arrive I’ll be spending many, many hours tweaking the picture!). I have tried the custom calibration settings used by the AV Forum reviewer, but found the THX mode marginally more to my liking; there is a THX mode for bright rooms, but I personally didn't like the slightly brighter, less punchy images. 

Sound is pretty impressive for a Panasonic TV.  My previous model was pretty awful.  The fan is noticeable at night when watching very quiet sources, but not enough to throw my toys out of the pram over.

It is incongruous to have a TV with reference quality picture and then provide a pen aimed at children to write on the surface; the person who thought that was a good idea needs to re-evaluate whether she/he should carry on working in the high-end TV market!  It certainly feels wrong to be touching the surface of your new reference quality TV, even with a soft tip.

I haven’t got any 3D sources so haven't played much with 3D, but the 2D to 3D conversion kinda works.  Still unlikely that I’ll be watching 3D so might just sell the glasses on ebay!

The Smart TV features are plenty, but I'll hardly be using them...apart from Youtube and Skype.  The camera is nice, but I really wish it would pop back in automatically when not using an app that can use it.

Overall very happy with the TV and can't wait till it's on the wall.

Tuesday 20 August 2013

London Street Games - The Threadneedle Files

Just got the mission briefing!...

Classification: Top Secret - Need to Know only

SITUATION REPORT 24th August 2013

Further to the discovery of a mole inside the London network, we have been alerted to a situation which puts our national security in extreme jeopardy. The double agent has stolen top secret information regarding Treasury bank accounts, including access codes to national vaults inside the Bank of England. Our intelligence informs us that the traitor intends to hand over the encoded documents to enemy agents via a 'dead letter drop' at a secret location in the City of London. This handover is due to occur within the week, we believe it is set to happen late on Saturday 24th August.


Monday 19 August 2013

Panasonic TX-P65VT65

Have decided to buy the P65VT65  over the P60WT65 or the Samsung F8500, or any 4K TVs.

The reasoning behind these...

Against the P60WT65:

  • WT65 does not have a camera built in for Skype (not earth shattering to be honest but is a nice touch)
  • From several reviews the picture quality is not leaps superior than the VT65 (but is marginally better)
  • Doesn't come in 65 inch for UK (not a huge difference but the 65 will be a perfect fit for the living room)

Against the Samsung F8500:

  • Is better if you like brighter picture but not if you prefer (slightly) better picture quality
  • I am used to owning Panasonic

Against 4K TVs:

  • Amazing if you are going to be close to the TV but otherwise the picture quality does not compare to the above TVs
  • The stupendously expensive price is not worth it as there is very little content currently.  I can't see a huge amount of content in the near future either...look how long HD is taking to be ubiquitous 
Any of these TVs would be amazing to own. Which has superior picture quality is, arguably, not discernible by most humans, and then only when they are side by side.

Note to self: don't tell the kids the TV comes with a pen you can draw on the TV with!