The Digital Fact Book - Quantel

DDown-resDecreasing the size of video images to fit another format. Typically this reduces an HD formatto an SD format and, as the input images represent over-sampled versions of output,the final quality should be excellent – better than an SD-shot original. Moving from 1080/60Ito 480/60I is down-resing. Technically the process involves: spatial interpolation to reducesize while retaining quality, color correction to compensate for the difference in HD and SDcolor standards and possibly re-framing to fit 16:9 HD onto 4:3 SD. Note that down-resdoes not include any change of frame rate.See also: Down conversion, Format conversion, Standards conversion, Up-res, VersioningDPXSMPTE file format for digital film images (extension .dpx) – ANSI/SMPTE 268M-1994.This uses the same raster formats as Cineon and only differs in its file header.See Cineon fileWebsite: www.cineon.com/ff_draft.php#tvDRAM(1) see RAM(2) Informal measure of Scotch WhiskyDrop-frame timecodeAlteration of timecode to match the 1000/1001 speed offset of NTSC transmissions andmany newer HD video formats used in ‘NTSC’ countries – including the USA, Canada andJapan. 525-line NTSC at a nominal 30 f/s actually runs at 29.97 f/s and 1080-line HD usesthe same frame rate. Even the 24 f/s of film gets modified to 23.97 when applied to TV in‘NTSC’ countries. With timecode locked to the video, it needs to make up 1 in 1001 frames.It does this by counting two extra frames every minute while the video remains continuous.So 10:35:59:29 advances to 10:36:00:02. In addition, at every ten-minute point the jumpis not done. This brings the timecode time almost exactly into step with the video.Timecode that does not use drop-frame is then called non drop-frame time-code.Confusion arises when the wrong one is used!See also: 1000/1001Website: www.dropframetimecode.org70