Samsung 850 HDMI Format

clockworks

Novice Member
I've got my 850 connected to my Samsung LE40R51 using HDMI, set to 720p. In the setup menu, there are 4 options for video format:

RGB - Normal
RGB - Expand
YCbCr (4:4:4)
YCbCr (4:2:2)

What's the difference, and what's the best one to use? The manual is worse than useless.
 

andyjack

Novice Member
I've just got my 850 am using HDMI, set to 720p. In the setup menu, there are 4 options for video format:

RGB - Normal
RGB - Expand
YCbCr (4:4:4)
YCbCr (4:2:2)

i use RGB - Expand

I agree the manual is worse than useless but that looks the best setting to me.
:thumbsup:
 

unique

Moderator
clockworks said:
I've got my 850 connected to my Samsung LE40R51 using HDMI, set to 720p. In the setup menu, there are 4 options for video format:

RGB - Normal
RGB - Expand
YCbCr (4:4:4)
YCbCr (4:2:2)

What's the difference, and what's the best one to use? The manual is worse than useless.
i use RGB expand as the manual says its the full range HMDI output - the ycbcr says limited range


http://www.answers.com/topic/ycbcr-sampling

YCbCr (4:4:4)
ach of the three channels has the same sample rate, so each single pixel in the resulting image gets three full words (usually 8 or 10 bits long) of information, resulting in 3 bytes per pixel for 8-bit quantization when not using compression.

Mapping:

The bitstream

Y0 U0 V0 Y1 U1 V1 Y2 U2 V2 Y3 U3 V3
will map to the following four pixels:

[Y0 U0 V0] [Y1 U1 V1] [Y2 U2 V2] [Y3 U3 V3]
This is the best color sampling ratio (it yields a perfect representation of each pixel's color), and is used as an intermediate format in high-end film scanners and cinematic postproduction. Note that 4:4:4 may (and often indeed does, as in some modes of HDCAM SR) also mean that the three values are all color values in the RGB color space, which must always be sampled at the same frequency.


YCbCr (4:2:2)
Each of the two color-difference channels has half the sample rate of the brightness channel, so horizontal color resolution is only half that of 4:4:4. For uncompressed video and 8-bit quantization, each macropixel of two neighbouring pixels uses 4 bytes of memory.

Mapping:

The bitstream

Y0 U0 Y1 V1 Y2 U2 Y3 V3
will map to the following four pixels:

[Y0 U0 V1] [Y1 U0 V1] [Y2 U2 V3] [Y3 U2 V3]
This is still a very good quality, and most higher-end digital video formats use this ratio:
 

clockworks

Novice Member
Thats the way I read the manual - RGB expand seems to have the highest range.

It all looks a bit complicated, though.
Presumably, the DVD is encoded using one of these formats - which one, and are all commercial DVDs encoded the same way?
Presumably the DVD player will decode the video data, then attempt to re-encode it to one of these 4 formats, and pass it out of the HDMI socket.
Then, the TV will strip out the 3 different signals, and convert them to digital values for each pixel on the screen.

Do the electronics in the TV have any bearing on the best format to use? Is it a processing speed thing - more colour data=harder to process=more artifacts?

I'd have thought that HDMI, as a "digital interface", would just take the raw data from the DVD. It'd be nice if the TV told the DVD player what format it could handle (plug & play), leaving all these user adjustments to the analogue connections.
 

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