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Post-Production Output. Post-Production. Retouching Image processing Compositing Editing Timing Transitions Music and sound effects Titles and credits Render/save in desired formats. Retouching. Image Processing. Color correction Sharpening, blurring Depth of field Day-for-night
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Post-Production • Retouching • Image processing • Compositing • Editing • Timing • Transitions • Music and sound effects • Titles and credits • Render/save in desired formats
Image Processing • Color correction • Sharpening, blurring • Depth of field • Day-for-night • NTSC Colors • Various other effects
Compositing • Traditional matting techniques • Mattes painted on glass or film • Special camera with projector could combine two video sequences • Computerized compositing • Two video sources • Alpha channel: specifies transparency • “Traveling matte:” moving alpha channel • E.g. “garbage matte” to remove wires, scaffolding, lights, microphones, etc. • Blue screen: blue background is made transparent
Editing • We’ll use Windows Movie Maker (or whatever you have handy) • Demo • Remember: be sure you have the rights to the music and images you use if you want to show beyond fair use (personal or educational use) • Can you find a friend to compose and perform music, sound effects? • Free sources of music and sound effects on the internet • Sound effect CDs
Titles and Credits • Credit where credit is due • Before or after • Opening sequence for your production group
Output • Resolution • Frames per second • Interlace • Common formats • NTSC • Composite, S-video, component (Y, R-Y, B-Y) • D1-resolution: 720x486 • PAL, SECAM • DV: 525 lines, 5:1 compression, 25 Mbps, 0.9 • HDTV (various formats, codecs, bit rates)
Digital Video • JPEG: ISO Joint Picture Experts Group • JPEG standard issued in 1992, approved 1994 • MPEG: ISO Motion Picture Experts Group • H.261 – MPEG-1 (early 1990s) • MPEG-1 audio layer 3 = MP3 • H.262 – MPEG-2 video, 1994 (used in DVDs) • H.263 – MPEG-4 part 2 ASP, 1996 • H.264 – MPEG-4 part 10 AVC, 2003 • H.265 – planned for about 2010
JPEG • Convert 8x8-pixel blocks to the frequency domain with a Discrete Cosine Transform (DCT) for each color channel • Coefficient quantization • Perceptual filtering • Downsampling color • Entropy coding • Compression ratios: 6-1, 20-1, 100-1
MPEG (H.261) • Intended for video at CD data rates • 1.5 Mbps • 352x240 video • Based on JPEG • Extensions for video • I-frame: Intra frame (key frame) • P-frame: Predictive • B-frame: Bi-predictive
MPEG-2 (H.262) • Used in DVDs • DVDs typically use about 5 Mbps for D1 video • VOB container format (Video OBject) • Common data rates for HD, over the air • 19.7 Mbps, 8.9 GB/hr • For cable, may be as low as 13, or even 10 Mbps
MPEG-4 ASP (H.263) • MPEG-4 has 21 profiles including Simple, Advanced Simple, Main, Core, Advanced Real Time Simple, etc. • ASP: “Advanced simple profile” (1996) • Optimized for low-bitrate use, e.g. Internet • Many implementations of H.263 exist • DivX • XVid • Like MPEG-2, with support for Interlacing, B-frames, motion compensation • Not much advantage over MPEG-2
MPEG-4 AVC (H.264) • “Advanced Video Coding” (2003) • Good-quality video at lower bit rates (similar quality at half the bit rate of H.263) • 2-3 times more computationally intensive • Features • Multi-frame prediction • Better motion compensation • Multiple motion vectors per multiblock • Variable block size • Weighted prediction • Logarithmic quantization • Better entropy coding • Etc, etc etc
MPEG-4 • Advanced audio codecs • MPEG 4 part 3, Advanced Audio Codec (AAC): major improvement over MPEG-2’s AC3 • Container • VOB replaced with a new container format based on Apple’s QuickTime • [Microsoft tried to scrabbling together its own container format and get it in the standard, but QuickTime is proven, having been in continuous support and use since 1991]
H.264 support • Many profiles, levels of support • Patented technologies, depending on your country • Implementations • HD-DVD and Blu-Ray • Apple – iTunes, iPod, Apple TV (different profiles) • Adobe – in Flash player • Youtube • ATSC (HDTV) in US • Digital video broadcast in Europe • Satellite broadcast • Etc, etc
Microsoft • “Embrace and extend” vs. standardization • Microsoft defined VC-1 video compressor, based on H.263, but modified in incompatible ways (Windows Media 9). This is the video compression format they push • MS is fighting against standardization on H.264, despite its superiority • E.g. MS-supported HD-DVD uses (used) VC-1
Apple • Uses ISO standards where possible • .mp4: video and audio • .m4a: just audio, aka AAC • .m4b: audio book • .m4p: protected audio, AAC with their own FairPlay DRM
DivX, XviD • Microsoft’s new ADF container format (used with Windows Media V3 and VC-1) was an “embrace and extend” variant of H.263, intended to be proprietary • “hackers” took the MS codec, VC-1, and used older AVI container format to make “DivX ;-)” • DivX the company – used it, varied it • Now fully H.263-compliant • XviD: free and open source variant.
HDTV • Blu-Ray: 25 GB per layer, H.264 most often, though VC-1 is supported • HD-DVD: 15 GB per layer, VC-1 (Windows Media 9) most often, though H.264 is supported • Blu-Ray invited Microsoft to support it, but MS insisted on support for WinCE-based HDi for interactive content. • Blu-Ray was already using BDi, from HP, based on Java. 3-month test: no switch. • “Microsoft was livid” (Peter Burrows of BusinessWeek). • MS announced exclusive support for HD-DVD. • Reportedly, Toshiba was ready to drop HD-DVD and join Blu-Ray but they get a big cash infusion from someone… • To run WinCE/HDi menus, Toshiba needed P4 processor, 1GB ram, 256GB flash, etc -- $674 parts cost originally
Blu-Ray vs. HD-DVD • Nov. 2006, MS offered USB-based HD-DVD for Xbox 360, sold 155,000 in 8 mo. • Sony included Blu-Ray in PS3 – sold 6.2 million. • Recently, Warner defected from HD-DVD to Blu-Ray • Fox may follow • The format war is over • HD-DVDs on fire sale ($130, with 5 movies)
Your output • For Wednesday: Use MS’s highest quality standard format: seems to be “High-quality Video (Large)” • Don’t use DivX, XviD, H.264, etc. • For stereo, left and right videos seems best • Turn in your final project • Same format as before – would be fine • I may also be able to use some other formats • Class DVD • I’ll make a class DVD. • You pick up later, in my office • Who wants one?