SC434L_DVCC-Tutorial 1 Intro. and DV Formats

Transcription

1 SC434L_DVCC-Tuorial 1 Inro. and DV Formas Dr H.R. Wu Associae Professor Audiovisual Informaion Processing and Digial Communicaions Monash niversiy hp:// hrw@csse.monash.edu.au and Compuer Engineering Nanyang Technological niversiy ashrwu@nu.edu.sg

2 DVCC_Tuorial-1 Quesion T1.1 iven he gamma correced and normalized ri-simulus analog signals R,, and B, and ransformaion o give analog componen YVsignal as shown in equaions (T1.1-1 o T1.1-3), 2 Y 0.299R B (T1.1-1) B Y (T1.1-2) 2.03 R Y (T1.1-3) V 1.14 a.) express he above relaionship beween YV and RB coordinaes in marix noion; b.) derive he inverse ransform for conversion of YV o componen RB signals. NOTE: 1. R,, B here are gamma correced normalized and RB1 corresponds o reference whie C of uniy luminance. 2. If R,, B are in he rang of (0-1) vol, Y is also in he rang (0-1 vol). 3. The conversion formulaion applies o boh PAL and NTSC.

3 Soluion T1.1: a.) Sep 1: To find ransform/conversion marix in he form of Sep 2: From Eqs (T1.1-1 o T1.1-3), eliminae variable Y from Eqs (2 and 3), i.e., from Eq (2), from Eq (3), DVCC_Tuorial-1 Y??? R??? V??? B Y 0.299R B B Y 2.03 R Y V 1.14 B Y B (0.299R B) R B R Y R (0.299R B) V R B (T1.1-1) (T1.1-2) (T1.1-3) (T1.1-4) (T1.1-5) 3

4 DVCC_Tuorial-1 Soluion T1.1: b.) Sep 3: Combine Eqs (T1.1-1, 4 and 5) and pu hem in a marix form, resuling in: 4 Y R V B b.) Sep 1: To find ransform/conversion marix in he form of A (T1.1-6) End of Q (T1.1 a.) R??? Y??? B??? V B Sep 2: -1 Mehod 1: calculae inverse marix of A, since BA Malab command: >>A[ ; ; ] >> Binv(A)

5 Soluion T1.1: b.) Sep 2 (con.): Mehod 2: From Eqs (T1.1-1 o 3) R Y V DVCC_Tuorial-1 1 Y R B B Y ( ) (T1.1-7) (T1.1-8) (T1.1-9) 5 Sep 3: subsiue Eqs. (T1.1-7 and 9) ino Eq. (T1.1-8) and eliminae R and B in Eq.(T1.1-8), 1 ( Y 0.299( Y V) 0.114( Y ) ) Y V (T1.1-10) Sep 4: Combine Eqs (T1.1-7, 10 and 9) and pu hem in a marix form, resuling in: R Y B V (T1.1-11) End of Q (T1.1 b.)

6 DVCC_Tuorial-1 Quesion T1.2 Considering ransmission of he IT-R 601 digial video wih he YCC (4:2:2) d b r forma, 8-bi per componen and a resoluion of 720 x 576 pixels per frame a 25 frames per second, a.) calculae minimum compression raio required o ransmi he video over a 10 Mbps cable modem; and b.) repea a.) for IT-R 601 digial video wih YCC d b r (4:2:0) forma. Soluion T1.2: a.) Sep 1: calculae he raw daa rae required by he digial video wih (4:2:2) forma. Toal bi rae 25 frames/s x ( ) x576 componen pixels/frame x 8 bis per componen pixel 166 Mbps (T1.2-1) Sep 2: Calculae he minimum compression raio required by Minimum compression raio Toal bi rae / Available bandwidh 166 Mbps / 10 Mbps :2:2 forma

7 Quesion T1.2 DVCC_Tuorial-1 Considering ransmission of he IT-R 601 digial video wih he (4:2:2) forma, d b r 8-bi per componen and a resoluion of 720 x 576 pixels per frame a 25 frames per second, a.) calculae minimum compression raio required o ransmi he video over a 10 Mbps cable modem; and b.) repea a.) for IT-R 601 digial video wih YCC(4:2:0) forma. d b r Soluion T1.2: b.) Sep 1: calculae he raw daa rae required by he digial video wih (4:2:0) forma. Toal bi rae 25 frames/s x 720 x576 componen pixels/frame x 8 bis per componen pixel + 25 frames/s x ( ) x288 componen pixels/frame x 8 bis per componen pixel Mbps (T1.2-1) Sep 2: Calculae he minimum compression raio required by Minimum compression raio Toal bi rae / Available bandwidh Mbps / 10 Mbps 12.4 YCC 7 4:2:0 forma

8 2.2. Pixel Represenaion The eye is sensiive o hree colour componens. Colour can be represened by Red, reen and Blue componens (RB). For analog signals: Transform ino a more efficien represenaion: Y V 8 NOTE: Y 0.299R B B Y 2.03 R Y V 1.14 (2.2-1) (2.2-2) (2.2-3) 1. R,, B here are gamma correced normalized and RB1 corresponds o reference whie C of uniy luminance. 2. If R,, B are in he rang of (0-1) vol, Y is also in he rang (0-1 vol). 3. The conversion formulaion applies o boh PAL and NTSC. 4. The marix form is given as follows.

9 2.2. Pixel Represenaion amma correced and normalized R,,B o Y V conversion in marix form: 9 Y R V B And he inverse is given by (2.2-4) R Y B V (2.2-5)

10 2.2. Pixel Represenaion For digial componen signal (CCIR Rec 601, now IT-R 601), 8-bi digial variables are used; however: 1. Full digial range is no used o give working margins for coding and filering. 2. RB o YCC d b r conversion is given by 10 Yd 219Y ( B Y) C b ( R Y) C r (2.2-6) (2.2-7) (2.2-8) where digial luminance, Yd, has a rang of (16-235) wih 220 levels saring a 16, and digial chrominance difference signals, Cb and Cr, have a range of (16-240) wih 225 levels cenered a 128.

11 2.2. Pixel Represenaion Defining 8-bi digial RB signals as Rd255R, d255 and Bd255B, IT-R 601 colour ransformaion from RddBd o YCC d b rand inverse are given in marix form by: and Yd Rd 16 C b d C r B d 128 Rd Yd 16 d Cb 128 B d Cr 128 (2.2-9) (2.2-10) 11 (a) Red (b) reen (c) Blue (d) Y (e) Cb (f) Cr