[doveman2]

It doesn't seem like the full range is being used for video playback though, as if it was I'd be able to see the bars below 16 when I increase the TV brightness, as I can when playing the files via my TV's USB port. What seems to be happening is that the output is being limited, so perhaps that full range setting that is available on the PC is hidden and defaulted to off on the Pi.

By default video files are limited range and shouldn't encode levels below 16.
You need a flag in the file (like video_full_range_flag for h264) to be able to encode these levels. Does your file have this set?

If you force a DMT mode (with hdmi_group=2) you will get full range by default. CEA modes will get limited range by default.
The full/limited range flag is correctly output by the Pi (in the AV infoframe), and the display should act on that (without requiring setting in menus on display or using hdmi_pixel_encoding on pi)
In our testing, many TV's only support limited range in CEA modes (which you are probably using at 1080p) and only full range in DMT modes (they are manditory, supporting full range with CEA and limited range with DMT is optional).

But I think all this talk is based on a misunderstanding. Full range does not give you more or better colours.
Assuming all parts are the system (the video file flags, the video player, the HDMI settings and the display) agree on whether they are using full or limited then the picture displayed on the display will be identical.

We have done a lot of testing of feeding encoded bars test files through the system, and using a hdmi capture card to confirm that the levels are correct in the full and limited range modes.
That is the only way to confirm that the Pi is outputting the correct signals. We did find in this testing that some TV's do clamp levels below 16, even when we are signalling full range.

I don't know about any encoding flags but as I said, playing the file from my TV's USB socket shows the bars below 16 if I increase the brightness, so clearly it isn't limited range (clipped below/above 16/235). I'm inclined to think that if the TV plays it full range, then the Pi should too. Certainly my TV doesn't clip levels below 16 anyway, at least not in Full mode.

I'm pretty sure the Pi is outputting full range when I use hdmi_pixel_encoding=2 even though I'm not forcing a DMT mode, as there's a noticeable difference in the brightness of the GUI. I'll try setting the mode though.

You seem to be saying that even if I don't set anything in config.txt then the Pi will output a full or limited flag depending on the material being played and that will switch the TV into the right mode. However, as I said I found that without the pixel_encoding=2 setting, my TV in Auto was incorrectly using Full and I had to set it to Normal, otherwise the GUI looks wrong, which means that the TV will stay in Normal mode regardless of any flag the Pi might send when playing video.

I know Full/Limited RGB range is nothing to do with colours. It's probably better described as PC levels (0-255) and Video levels (16-235) and I understand, from threads in AV forums, that outputting at PC levels (to a display that also uses PC levels) allows it to show the WTW (White than White, i.e. above 235) detail, which commercial DVDs often contain. This is just the first thread (discussing Super White mode on the PS3) I came across when googling but there are others on that forum if you want to search more
http://www.avsforum.com/t/967106/calibra...t_14261877

If it has to compress 0-255 levels into 16-235, then you should see more or less the same detail at each end but due to the resulting fewer steps or gradients, then there may be a loss of "smoothness" in the middle. This might not be that noticeable to most people but some people might be more sensitive to it.

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That sounds right, also the test paterns above that doveman2 is running are just to adjust brightness/contrast (assuming all the parts agree on the color range as you said popcornmix) and do not indicate whether limited/full color range is used.

That's not really true as they show if the full 0-255 is being outputted (assuming the TV can also display the full range) or if the output is being clipped to limited 16-235.