DVL-Digest 1112 - Postings: Index Saturation vs De-saturation of color before recording to DVt Saturation vs De-saturation of color before recording toDVta tv instead of field monitor - (2) Saturation vs De-saturation of color before recording to DVt - "Perry Mitchell" There are several possible areas of interest in Michael's hypothesis. 1) The DV system ideally stores picture information. Information is defined as that which is 'unpredictable'. A field full of a single color is thus the minimum information, a field full of random noise would be the maximum. 2) A color=black is no different information than a color=max saturation. 3) In practice with real pictures, the higher the saturation, the more levels will be present and thus the more information will be present. 4) In the first analysis, the DV system records component color; so the color levels should not effect the luminance quality. 5) In the second analysis, the DV system works on a 'bit budget', so ideally all the information data space not used for recording color can be used to record luminance. The reality would depend upon the actual pictures and the design of the DV codec engine. My best guess is that a typical result for limited saturation adjustment would maybe be an apparent loss of smooth graduation on color information with higher saturation. Completely removing color may have a more dramatic effect on luminance quality. It's an interesting area and worthy of some tests Perry Mitchell Video Consultant http://www.perrybits.co.uk Saturation vs De-saturation of color before recording toDVta - "Perry Mitchell" From: Ross Jones >But does it make it easier on the DV compression chips since there >is less info to process. Hopefully some of the people on the list >who understand codecs etc can share some thoughts. Where's Adam Wilt when you need him? I don't understand codecs, but here are my thoughts: In my fading memory of the DV codec specs I'm pretty sure there wasn't a dynamic allocation of compression resources between the color (U/V) and luminance (Y) sampling, but since most of us are viewing this material in the analog realm, there are fewer artefacts when the color information is limited. However, a reduction of color information in the Y sample may allow the DCT algorithm to use more resources on the luminance data. tv instead of field monitor - "Perry Mitchell" From: Crittenden, Jan Clive, Using a TV to tell you whether you have the right colors etc. is like using a glass for a stethoscope. It will tell you that your hear is beating but not much else. A TV is built with the objective to show the prettiest picture from the worst video. A production monitor is designed to tell you what is real, and whether you are recording garbage. Two completely different ideas, but I can assure you that you want to know whether you are recording garbage. Save your money until you can afford a production monitor. tv instead of field monitor - "Perry Mitchell" From: Crittenden, Jan The producer may look at it on a TV but the Engineer that airs it or the duplicator that is going to duplicate it will look at it on a production monitor. Errors in TV only get worse. Production monitors can be found on Ebay as well as companies like the Broadcast Store. It doesn't have to have SMPTE Phosphor, it just has to be a diagnostic tool with Blue Gun Only, pulse/cross and underscan, so that you can make a judgment call. Now Perry may discount that but even with the small stroke of reality that I put into the mix, a real tool is much better than the TV which is virtually no better than the LCD that was giving you fits in the first place. (diese posts stammen von der DV-L Mailingliste - THX to Adam Wilt and Perry Mitchell :-) [up] |
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