SIDE (IRT 3930) Loeng 10/2011 Võrguteenused Teema - teenused Avo Ots telekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst. avots@lr.ttu.ee Teenused 361
Lairibaühendus Teenused 362
Traffic Classes Traffic class Characteristics Example application Conversational Preserve time relation between information entities of the stream. Conversational pattern (stringent and low delay) Streaming Interactive Background Preserve time relation between information entities of the stream. Request-response pattern. Preserve payload content. Destination is not expecting the data within a certain time. Preserve payload content. Speech Video calls Real-time streaming video Web browsing E-mail File downloading Demanding Delay Jitter Demanding Bit rate Jitter Tolerant Delay and bit rate can vary Integrity Easiest Delay and bit rate can vary Integrity Teenused 363
QoS Pakettvõrkudes liikluse korralduse (traffic engineering) mõiste garanteeritud teenuse kvaliteet (QoS, Quality of Service) tähendab tõenäosuslikku hinnangut, et sidevõrk jälgib liikluslepet. Paljudel juhtudel kasutatakse QoS tõenäosusena, et pakett läbib võrku saatjast vastuvõtjani oma ettemääratud ajavahemiku jooksul. Teenused 364
Teenusekvaliteedi aspektid (2) QoS Teenuse Kättesaadavus (Accessibility) Teenuse Püsivus (Retainability) Teenuse Terviklikus (Integrity) QoS parameetrid QoS parameetrid QoS parameetrid Teenused 365
Teenused 366
Värvuse kodeerimineyuv Y is luminance UV are chrominance YUV from RGB Y =.299R +.587G +.114B U = 0.492 (B - Y) V = 0.877 (R - Y) U-V plane at Y=0.5 Y U V Teenused Source: wikipedia 367
Videovoo digitaliseerimine Komponentide ribalaius kuni 6 MHz Diskreetimissagedus f d = 13.5 MHz f d = 864 f h NTSC (Põhja-Ameerika) f d = 858 f h PAL (Euroopa) Kvanteerimine 8 bitti => 13.5* 8 =108 Mbps Standard ITU-R BT.601 => 720 pildipunkti reas 4 : 2 : 2 => 216 Mbps Teenused 368
Analoogvideo digitaalseks Digivideo standard ITU-R BT.601 standardi järgi on kaadri suurus 720x576 (PAL jaoks). Ei tarvitse olla 720 pikselit reas. Video digitaliseerimiseks võetav pikselite arv ei pea vastama kuvamise seadme pikselite arvule PAL formaadis saab digivideot esitada erinevatel kaadri suurustel 720x480 või 720x576. Teenused 369
Digivideo vormingud ITU-R-601 720x480 4:2:2 CIF 360x288 4:2:0 4:3 HDTV 1440x1152 4:2:2, 4:2:0 9:16 HDTV 1920x1080 4:2:2, 4:2:0 4CIF, 16CIF, QCIF Teenused 370
HDTV Digital Television Broadcast (DTB) Võrreldes analoog-standard TV-ga 2 korda ja 2 korda (read <-> veerud) Resolutsioon (eristusvõime) 1920x1080 (1080p) Standard HDTV Kaadrisagedus: 50 (60) kaadrit sekundis Teenused 371
Videovoo digitaliseerimine Komponentide ribalaius kuni 6 MHz Diskreetimissagedus f d = 13.5 MHz f d = 864 f h NTSC (Põhja-Ameerika) f d = 858 f h PAL (Euroopa) Kvanteerimine 8 bitti => 13.5* 8 =108 Mbps Standard ITU-R BT.601 => 720 pildipunkti reas 4 : 2 : 2 => 216 Mbps Teenused 372
Digivideo vormingud ITU-R-601 720x480 4:2:2 CIF 360x288 4:2:0 4:3 HDTV 1440x1152 4:2:2, 4:2:0 9:16 HDTV 1920x1080 4:2:2, 4:2:0 4CIF, 16CIF, QCIF Teenused 373
Kahemõõtmeline kujutis Teenused 374
Ruumiline aeg 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 Teenused 375
Ruumiline sagedus 0.5 0.7 0.2 0.05 0.6 0.5 0.07 0 0.1 0.08 0.01 0 0.01 0 0 0 Teenused 376
Muutuva pikkusega koodid A B C D E F p=0.40 p=0.20 p=0.14 p=0.10 p=0.06 p=0.05 0 111 101 100 1100 1101011 Teenused 377
JPEG Joint Photographic Experts Group Teenused 378
JPEG Compression 8x8 blocks Source Image B G R DCT-based encoding Image Preparation FDCT Quantizer Entropy Encoder Compressed image data Table Table Teenused 379
DCT Basis Functions Increasing frequency Increasing frequency Teenused 380
Makroblokk (8 * 8) 124 125 122 120 122 119 117 118 121 121 120 119 119 120 120 118 126 124 123 122 121 121 120 120 124 124 125 125 126 125 124 124 127 127 128 129 130 128 127 125 143 142 143 142 140 139 139 139 150 148 152 152 152 152 150 151 156 159 158 155 158 158 157 156-4 -3-6 -8-6 -9-11 -10-7 -7-8 -9-9 -8-8 -10-2 -4-5 -6-7 -7-8 -8-3 -4-3 -3-2 -3-4 -4-1 -1 0 1 2 0-1 -3 15 14 15 14 12 11 11 11 22 20 24 24 24 24 22 23 28 31 30 27 30 30 29 28 Teenused 381
Koosinusteisendatud, 39.88 6.56-2.24 1.22-0.37-1.08 0.79 1.13-102.43 4.56 2.26 1.12 0.35-0.63-1.05-0.48 37.77 1.31 1.77 0.25-1.50-2.21-0.10 0.23-5.67 2.24-1.32-0.81 1.41 0.22-0.13 0.17-3.37-0.74-1.75 0.77-0.62-2.65-1.30 0.76 5.98-0.13-0.45-0.77 1.99-0.26 1.46 0.00 DC AC AC AC AC AC AC AC AC AC AC AC AC AC AC 3.97 5.52 2.39-0.55-0.051-0.84-0.52-0.13-3.43 0.51-1.07 0.87 0.96 0.09 0.33 0.01 Teenused 382
JPEG 2000 Original (TIF 116KB) JPEG (8:1, 14KB) JPEG-2000 (8:1, 14KB) Teenused 383
JPEG 2000 Features Improved compression efficiency (vs. JPEG) Highly scalable embedded data streams Progressive lossy to lossless compression within a single data stream Arbitrarily crop images in the compressed domain Selectively enhance quality of spatial regions of interest Support for very large images Teenused 384
Motion Picture Expert Group (MPEG) General Information about MPEG Began in 1988; Part of Same ISO as JPEG MPEG-1/Video MPEG/Audio MP3 MPEG-2 MPEG-4 MPEG-7 MPEG-21 Teenused 385
MPEG Video Processing Intra frames (same as JPEG) typically about 12 frames between I frames Predictive frames encode from previous I or P reference frame Bi-directional frames encode from previous and future I or P frames I B B P B B P B B P B B I Teenused 386
Heuristics I, P, or B Frames change of scenes should generate I frame limit B and P frames between I frames B frames are computationally intense Type Size Compress I 18K 7:1 P 6K 20:1 B 2.5K 50:1 Avg 4.8K 27:1 Teenused 387
MPEG Audio Encoding Characteristics Precision 16 bits Sampling frequency: 32KHz, 44.1 KHz, 48 KHz 3 compression layers: Layer 1, Layer 2, Layer 3 (MP3) Layer 3: 32-320 kbps, target 64 kbps Layer 2: 32-384 kbps, target 128 kbps Layer 1: 32-448 kbps, target 192 kbps Teenused 388
MPEG Audio Encoding Steps Teenused 389
MPEG 4 Teenused 390
MPEG 4 etapid Teenused 391
MPEG-4 lahendusi MPEG-4 on objektipõhine Panoraamkujutised ülisuure pakkimistihedusega 1000:1 Teenused 392
Encoder Teenused 393
IPTV CPE (Access-Switch) 100 Mbit FOC 12 Mbit DSL DVB-C + IP 100 Mbit TP 100 Mbit TP Scartkaabel Settop Box POTS ISDN VOIP PC TV Telefon 4-8 Mbit MPEG-2 1.5-3.0 Mbit MPEG-4 AVC 8-12 Mbit HDTV MPEG-4 AVC Teenused 394
Multipleks Audio Programm 1 Video PTS/DTS Programm 2 Audio Video Programm 3 PTS/DTS Audio Video MUX Transpordivoog Transport stream PTS/DTS PAT PMT NIT Teenused 395
Lainelevi Teenused 396
Keerukas modulatsioon võimsus aeg sagedus Teenused 397
DVB-T raadiokanali moodustamine Teenused 398
Kõnekvaliteedi kategooriad Teenused 399
Lõpulingid (10) http://www.chiariglione.org/mpeg/ http://en.wikipedia.org/wiki/yuv http://www.iec.ch/ http://www.itu.int/rec/r-rec-bt.601/en http://www.ebu.ch/ http://en.wikipedia.org/wiki/video_codec http://www.cs.rit.edu/~ncs/color/a_spectr.html Teenused 400