capturing yuv instead of rgb

[poescp]

does anyone know of cheap capture cards that capture in yuv color format.
i have a ADS pyro 1384 firewire capture card and when i capture video from my sony trv80 dv cam the video is rgb. i do not know if the capture card is a rgb capture card or the source material from my sony trv80 cam can only records rgb (how would i find out if my cam is recording rgb or yuv, there is nothing in the manual).

please could someone advise

[edDV]

does anyone know of cheap capture cards that capture in yuv color format.
i have a ADS pyro 1384 firewire capture card and when i capture video from my sony trv80 dv cam the video is rgb. i do not know if the capture card is a rgb capture card or the source material from my sony trv80 cam can only records rgb (how would i find out if my cam is recording rgb or yuv, there is nothing in the manual)...

The TRV 80 is outputting YUV in the form of DV format (YCbCr). Internally, the CCD optically captures RGB off a single CCD using optical separation techniques.

Typical single CCD DV camera (this one shows wide mode):



The RGB is processed into YUV DV format and sent over the IEEE-1394 connection to a DV-AVI file where the data is stored as YCbCr (4:1:1 sampled 720x480i/576i 29.97/25 fps with 16bit 48KHz uncompressed PCM stereo audio).

Up to that point, you have 8 bit YUV. Broadcast oriented software works in YUV from there. Computer graphics based software often converts everything to 0-255 8 bit RGB (with losses). More sophisticated software can work in YUV/RGB spaces with near lossless conversion from one to the other. Find correct formulas at http://www.fourcc.org/

[poescp]

great reply, wow!!! so would i need a yuv capture card and if so which cheap capture card would do? because as you say it is yuv material, but when i capture the material via my capture cards via scenalyzer the material when checked via avisynth is rgb and not yuv.

otherwise the graphics software i use is yuv compliant = avisynth, procoder express, premiere pro 2.0

the thing is that i want the best possible color or should i stick to rgb?

[edDV]

great reply, wow!!! so would i need a yuv capture card and if so which cheap capture card would do? because as you say it is yuv material, but when i capture the material via my capture cards via scenalyzer the material when checked via avisynth is rgb and not yuv.

otherwise the graphics software i use is yuv compliant = avisynth, procoder express, premiere pro 2.0

the thing is that i want the best possible color or should i stick to rgb?

Here's the deal.

Sources are all YUV (e.g. camcorder, VCR, cable box, capture cards, ...). RGB sources typically are limited to computer graphics and animation.

Editors can be internally YUV (e.g. Premiere Pro) or RGB (e.g. Premiere and Vegas).
YUV to RGB to YUV can be lossy or near lossless depending on formulas used.

Most destination targets are YUV (e.g. DVD, NTSC VCR, PAL VCR, MPeg2, MPeg4, etc.)
Display adapters convert YUV to RGB for display.

So it is best to keep the entire path YUV unless a special filter needs to be used. Conversion to RGB and back can be done correctly but often isn't. Compare the waveform display for the outgoing signal to the return waveform from the filter (with nominal settings). They should be the same until the filter is applied.

YUV and RGB are two ways to represent color space. YUV space is used for video for many reasons. Computers mostly use RGB, print uses CMYK, the human eye uses rods and cones. Rods see Y. Cones divide into R,G and B sensitivity.

http://www.faqs.org/faqs/graphics/colorspace-faq/
http://www.poynton.com/Poynton-color.html
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

[edDV]

Part 2. Where RGB is usefull.

So we as consumers only get video in variations of YUV. That is fine because YUV is designed to match human vision.

When machines have to "view" or process the image, they prefer wideband RGB. High end movie special effects are best done in full bandwidth RGB. Film scanners and HDCAM SR movie cameras output and store RGB data. Effects are done in RGB and then everything is converted to YUV for editing and release. This RGB -> YUV conversion tosses all the colorspace and bandwidth that is irrelevant to human vision. Full monochrome resolution is saved as Y. U and V are bandwidth reduced to match cone vision response. This is not a reversable process.

Broadcast television production and transmission (including HDTV) work entirely in YUV space. Broadcast and consumer cameras output in YUV. All distribution is in YUV.

[count_jackula]

edDV Wrote;

The RGB is processed into YUV DV format and sent over the IEEE-1394 connection to a DV-AVI file where the data is stored as YCbCr (4:1:1 sampled 720x480i/576i 29.97/25 fps with 16bit 48KHz uncompressed PCM stereo audio).

DV for PAL has chroma sampling of 4:2:0
[/quote]

[edDV]

edDV Wrote;

The RGB is processed into YUV DV format and sent over the IEEE-1394 connection to a DV-AVI file where the data is stored as YCbCr (4:1:1 sampled 720x480i/576i 29.97/25 fps with 16bit 48KHz uncompressed PCM stereo audio).

DV for PAL has chroma sampling of 4:2:0

True. Consumer PAL DV and DVCAM use 4:2:0. PAL DVCPro uses 4:1:1 (for better multi-greneration performance).