DV25 Codec

[Loki]

I am aware that the colour space on the DV25 codec is 4:1:1. Am I correct to assume that the Luma channel provides nice accurate B&W reproduction?

Since there is no resolution compression on the B&W data, I assume I am getting a pixel for pixel representation of what was captured by the CCD? Or does the DV codec apply compression to even this data?

I am just wondering if shooting in B&W in camera produces better images than making the footage B&W in post.

is the compression on the Lumanince channel as lossy as the chroma?

anyone have any insight into this?

 

[Barry_Green]

Re: DV25 Codec

DV25 is 4:1:1 for NTSC; in PAL it's 4:2:0.

The chroma decimation is not actually a part of the codec, as I understand it; it's pre-processing before the codec gets ahold of it. Luminance is sampled in a full 720x480 grid, but chrominance is sampled at 160x480 (in NTSC).

The entire frame gets compressed at 5:1. So the 720x480 luminance is compressed. Obviously the luminance compression is less than the chroma, because the chroma gets decimated to 1/4 its size before the overall compression gets applied, whereas the luminance stays in the original 720x480 grid before compression.