Michael W. Marcellin Regents Professor Department of Electrical and Computer Engineering University of Arizona Tucson, AZ 85721 [email protected] www.SPACL.ece.arizona.edu +1-520-621-6190 Digital Cinema2 Digital Cinema Specifications  Digital Cinema Initiatives, LLC (DCI)  Founded by seven Hollywood studios in March 2002  Disney  Fox  MGM  Paramount  Sony Pictures Entertainment  Universal  Warner Bros.  DCI mission:  “DCI's primary purpose is to establish and document voluntary specifications for an open architecture for digital cinema that ensures a uniform and high level of technical performance, reliability and quality control. DCI will also facilitate the development of business plans and strategies to help spur deployment of digital cinema systems in movie theaters.”3 ECE160 Spring 2011 Lecture 11 DCI (cont.)  System requirements and specifications  Completed July 2005  Available at www.dcimovies.com  Specifies requirements for Digital Cinema  File format  Color space  Resolution  Compression  Encryption  Etc4 ECE160 Spring 2011 Lecture 11 SMPTE DC28  DC28 is a Technology Committee of SMPTE  Society of Motion Pictures and Television Engineers  Standardizing Digital Cinema  Creating necessary detailed documents  Ensure interoperability  Content creators/distributors  Projector and server manufacturers  Four study groups  DC28.10 – Mastering  DC28.20 – Distribution  DC28.30 – Exhibition  DC28.40 – Stereoscopic5 ECE160 Spring 2011 Lecture 11 Why Digital Cinema?  Many viewings conducted at Digital Cinema Lab  Side by side butterfly viewing of digital vs. answer prints  Digital quality comparable to answer prints  Digital 2K slightly softer, 4K slightly sharper  Significantly better than distribution prints  Distribution prints suffer generational loss  Digital does not suffer from spatial jitter  Film grain less visible (some say this is a negative)  Digital is “cool”6 ECE160 Spring 2011 Lecture 11 Why Digital Cinema? (cont.)  Workflow issues  Many motion pictures use “digital intermediate” in post-production  Processing done digitally, then (currently) film out  Distribution cost  Film distribution costs roughly $1200 per screen  Initially, savings may finance roll out  Single inventory  Stereoscopic movies  Digital projectors can display 48 frames per second  Polarized glasses  Shuttered glasses7 ECE160 Spring 2011 Lecture 11 Projectors  Two resolutions specified  2K – 2048 x 1080  4K – 4096 x 2160  Some studios believe 2K is sufficient  Others believe 4K is necessary  Motivated by distinction over home theatre  Two technologies  DLP (Texas Instruments) – mature products exist  Christie  Barco  NEC  LCOS (Sony, NTT) – products for small screens currently exist  Both are micro-display “reflective” technologies8 ECE160 Spring 2011 Lecture 11 Image Data  Two max frame sizes  2K (2048 x 1080) – 24 or 48 frames per second  4K (4096 x 2160) – 24 frames per second  Max not required in both dimensions  Accommodates different aspect ratios  4096 x 1714 – 2.39  3996 x 2160 – 1.85  Pixels are square  12 bits per pixel per component  X’Y’Z’ color space  Allows for future wide gamut projectors  Expands code space9 ECE160 Spring 2011 Lecture 11 Audio Data  Uncompressed 24 bits per sample (PCM)  48 Kbps  96 Kbps  16 tracks – 8 specified  Far left screen  Far right screen  Center screen  Screen low frequency effect subwoofer  Left wall surround  Right wall surround  Mid left to center screen  Mid right to center screen10 ECE160 Spring 2011 Lecture 11 Security  Compressed image frames individually encrypted  AES – 128 bit key  Preferred system has media block in projector  Decryption and decompression occurs in media block  If media block outside projector, link encryption must be used  Audio encryption optional  Biggest current piracy problem is camcorder  Forensic watermarking will be employed  Watermark insertion in real time at media block  Watermark specific to location and time (accurate to 15 minutes)  Watermark must appear in every five minute segment11 ECE160 Spring 2011 Lecture 11 Distribution  Image frames compressed via JPEG2000  Compressed image, (uncompressed) audio, captioning, subtitling wrapped via MXF  MXF = SMPTE standard file format  Organized as “reels”  Packing list  Playlist  Digital signature  Distribution is store-and-forward (no streaming)  Physical media delivery in short to medium term12 ECE160 Spring 2011 Lecture 11 JPEG2000  The latest International Standard for image compression  Selected by DCI for distribution of motion pictures13 ECE160 Spring 2011 Lecture 11 JPEG2000 Compression14 ECE160 Spring 2011 Lecture 11 Component Transform: Improves Compression Efficiency  Three components – no subsampling  Typically RGB  X’Y’Z’ for digital cinema (12 bits)  Applied independently to each color pixel  Most energy is in resulting Y component  Cz and Cx are highly compressible  Improves compression efficiency  2:1 rate improvement for same quality15 ECE160 Spring 2011 Lecture 11 Wavelet Transform: Enables Resolution Scalability  The filtering perspective 1-D Forward Wavelet Transform 1-D Inverse Wavelet Transform 0h 1h ][0ny][1ny][kx0g 1g ][kx2 2 2 216 ECE160 Spring 2011 Lecture 11 Wavelet Transform High pass and low pass filters Down sample Repeat as required17 ECE160 Spring 2011 Lecture 11 Down Sampling 128x128 image Downsampled to 16x1618 ECE160 Spring 2011 Lecture 11 Wavelet Transform  Low pass and high pass in both x and y followed by down sampling by 219 ECE160 Spring 2011 Lecture 11 2D Transform: An Example20 ECE160 Spring 2011 Lecture 11 Wavelet Transform Example: Two Levels (Three Resolutions) Note: High frequencies scaled for display21 ECE160 Spring 2011 Lecture 11 Codeblocks and Precincts: Enable Spatial Random Access and Low Memory22 ECE160 Spring 2011 Lecture 11 Bitplane Coding: Enables Quality Scalability and Precise Rate Control  Bitplane coding applied independently to each codeblock  Each bitplane coded in three “coding passes”  Each