19360 Business Center Drive
Northridge, CA 91324 www.ITSamerica.com
October 26, 2011 Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 1

NTSC Analog Video
NTSC video -color bar test pattern
October 26, 2011 Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 2

At the SDI source
SDI Digital Video
At the end of a 100 meter cable
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 3

Making stills move
 Frame Rate (pictures per second)
• Set to give the illusion of smooth motion; beyond persistence of vision frequency.
• Rates above 16 images/second yield smooth motion
• 24 fps is used in film; 25 in the EC (PAL) and 30 in the USA (NTSC)
 Illumination Rate (most often 2x frame rate)
• Flicker fusion is the frequency that pulsing light looks steady
• Illumination rate is pushed high enough to achieve flicker fusion
• Film generally uses 48 Hz flicker rate, interlace TV scanning is 2x the frame rate.
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 4

 Number of Pixels is Only a part of the resolution story
 Shades of gray (steps, pixel depth)
Pixels
Few pixels
Many shades
October 26, 2011
Many pixels
Few shades
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 5

Many pixels
Many shades
Pixels
Specifying resolution Covers
 Pixel elements
 Shades of gray PER COLOR = number of colors
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 6

Pixel Depth; Color Depth; Colors
2 bits = 4 colors
4 bits = 16 colors
8 bits = 256 colors
According to http://en.wikipedia.org/wiki/Color , humans can distinguish up to 10 million colors
24 bits = 16 million colors
Pictures from http://en.wikipedia.org/wiki/Color_depth
Transitioning From NTSC to SDI Digital Video
October 26, 2011
Copyright ITS 2011
Sheet 7

Pixels & Bit Count & Data Rate
 Bit rate
 pixel count X sampling & encoding method
 Sampling:
• The eye is more sensitive to intensity changes than color changes
• Subsampling is delivering fewer color samples than luma samples for a group of pixels
• 4:2:2 Subsampling = color at ½ luma rate

Image quality indistinguishable from sampling both at the same frequency
 Sampling resolution is typically (TV) 10 bits per channel
• Channels are Y (luma), Cr (red component), Cb (blue component)
• Green derived from Y –Cr & -Cb (similar to analog video)
 Sampling Frequency generally 74.xx MHz for HD
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 8

Quick Idea About Subsampling
4:2:2 subsampling causes two luma samples to share one pair (Cr and Cb) of color samples
Active Video SDI
Data Stream
Cr
0-1
Color Sample
Y
0
Sample Pair
Cb
0-1
Y
1
Sample Pair
Pixel 0 Pixel 1
Cr
2-3
Color Sample
Y
2
Sample Pair
Pixel 2
Cb
2-3
Pixel 3
Y
3
Sample Pair
Graphic from “Chrominance Subsampling in Digital Images”, by Douglas Kerr
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 9

Pixels & Bit Count & Data Rate
 Each pixel = a Y (luma) sample
 Vertical blanking space adds lines; e.g. 45 in 1080
• 1080 lines, plus blanking = 1125 lines/frame
 Horizontal blanking space adds samples; e.g. 280 Y samples per line in 1080/60
• 1920 visible pixels + 280 Y H blanking samples = 2200 pixels/line
 Each pixel in 4:2:2 sampling is 20 bits deep
• 10 bits of luma (Y) and 1 of the color components (Cr or Cb) @ 10 bits = 20 bits
 Interlace Video delivers ½ the image in one field and the other half in a second field
• Frame rate = ½ field rate (e.g. 1080i/30)
 Progressive Video delivers a complete frame per scan
• Frame rate = field rate (e.g. 1080p/60)
• Frames may repeated at field rate (e.g. 1080p/30)
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 10

Pixels & Bit Count & Data Rate
BIT RATE = Resolution x sample depth x Fields/Frame X Frame Rate
For 1080p/60 = (1125 lines x 2200 pixels) x (20 bits/pixel) x 1 Field/Frame x 60 fps
= (49,500,000 bits/image) x 1 x 60 fps
= 2,970,000,000 bits/second
For 1080i/30
(60Hz field rate)
=(1125 x 2200/2) x 20 bits/pixel x 60 fields/sec
= 24,750,000/field x 60 = 1,485,000,000 bits/sec
For 720p/60 ={(720+30) x (1280+370)} x 20 bits/pixel x 30 fps x 2
=24,750,000/image x 60 = 1,485,000,000 bits/sec
Bit rate examples assume 4:2:2 subsampling IAW SMPT 259M
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 11

October 26, 2011
Electronics
Two 32 Bit RISC Processors @ 100 MHz
Custom 43K CE FPGA to substitutes image samples, sample x sample in real time
Custom 25K CE FPGA design to manage ITS substitution engine, specify text and graphic overlays, colors and housekeeping functions
3 GHz Data I/O Pathway with equalizers & drivers
One 8 bit Z80 Microprocessor running at 4 MHz
Custom 320 CE Gate Array to hold text bit maps and manage overlay timing
20 MHz Video amp and coax driver
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 12

Transport
How do you get raw video (SDI) from source to destination?
 Analog NTSC
• any channel with a 6 MHz bandwidth will work
 SD-SDI
• Requires a channel capable of passing 143 MHz data rate
 HD-SDI
• Requires 1.5 GHz channel for 720p/1080i and 3 GHz for 1080p
Choices
 Direct Connect (copper)
• SMPTE Specs SDI be capable of operating to 100-200 meters of 75 Ω Coax (e.g Belden
1694A)
• These do require line equalizers and drivers; Reclocking is generally needed to properly decode
• Short runs can use Cat 6A/Cat 7 copper cable for short runs (10 m); CAT 5 and standard
CAT 6 will not work
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 13

Transport
Choices (cont.)
 Ethernet
• At 1G Ethernet, ED-SDI can work
• At 1 G Ethernet, 720p/1080i will not work
• 10G Fiber Only full duplex only
• 100G Fiber Only, full duplex, still evolving
 Fiber
• 10GBASE-ER single-mode fiber supports transport @ 10.3 Gbit/sec up to 30-40 Km
• Next level down “-LR” can support this rate up to 220 meters
 Radio
• Where would the band and bandwidth exist?
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 14

The Compression Beast
 Alternative to whole new infrastructures
 Typical Compression Ratios that maintain excellent image quality
• H.263 and MPEG-2 ; 30:1
• MJPG 2000; 20:1 to 40:1
• H.264/MEG-4 part 10; 50:1
 Compression Issues
• Interframe prediction (MPEG) vs. image compression (M-JPG)
• MPEG is motion sensitive
• M-JPG can generate “rings” at the harsh image edges
• Trade off between image quality and frame rate/Frame dropping
• Latency
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 15

The Compression Beast
MPEG Coding
 Computationally Intensive
 More flexibility between image quality and frame rate tradeoff
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 16

The Compression Beast
MJPEG Coding
 Less computationally intensive due to the lack of prediction
 Less bit efficient, will force tradeoff between frame rate sooner, image ringing
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 17

The Compression Beast
Latency
∑ decode (sdi-image stream) + compression + xmit latency + buffer time + decompress
+ decode for display
SDI Source Decode Compress xmit
Display Decompress Buffer Receive
 Compression
• Many factors including image content, motion between frames, hardware speed
 Buffer Time
• Decompression requires a complete data set and enough buffered data to ensure every frame is reconstructed at the full expected frame rate



4-5 frames of data may be needed up to 20 depending compression parameters
(MPEG)
83-300 ms seconds to complete a buffer @t 100 MB Ethernet @30:1 compression,
720p/1080i
74 ms to complete a buffer using MJPEG2000 @ 2-3 frames; @ 20:1 compression
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 18

Bit Rates
SMPTE
Standard
259M
344M
292M
424M
Video Type
SD-SDI
ED-SDI
HD-SDI
3G-SDI
Example
Formats
480i, 576i
480p, 576p
720p,
1080i
1080p
Bit Rates
(Mbits/s)
270
360
143
177
540
1485
1470
2970
2940
Bit Rates
MJP2000
(Mbits/s)
@10:1
27
36
14
18
54
148
147
297
294
Bit Rates
MPEG-2
(Mbits/s)
@ 30:1
9
12
4.8
5.9
18
49.5
99
Bit Rates
MJP2000
(Mbits/s)
@40:1
6.8
9
3.6
4.4
13.5
37
74
Bit Rates
H.264
(Mbits/s)
@50:1
5.4
7.2
2.9
3.5
10.8
29.7
59.4
1 Stream
Video over
Ethernet
10 Base T
100Base T
100Base T
1000 Base T
October 26, 2011 Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 19

The Compression Beast
Accuracy of time stamps at the destination (
) is unpredictable do to wide variation in latency
 Transport mechanism
 Encoding/Decoding mechanism
 Amount of pre-image regen buffering
Camera control more difficult due to image latency
Conclusion?
 Time stamping must be at the source of the SDI digital video stream
• Transport necessities will not impact time stamping accuracy
 Manage transport bandwidth to minimize latency
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 20

The Compression Beast
 Degree of compression needed
• Video content
• Hardware CODEC speeds
• Transport bandwidth
 Fine detail may be smeared or lost to macroblocks
 Overlay text may be smeared or unreadable
 Size of characters chosen for time stamping and other critical data at record time may not be appropriate displays at analysis and playback time
 Time stamp and store critical information in SDI metadata stream at the source
• Ancillary Packet Format (metadata) per SMPTE 291M and related specifications
• Survives compression losslessly
• Decoder can overlay at display time
• Parameters of overlay can be adjusted to suit the display
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 21

HD Video Spec Checklist
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 22

HD Video Spec Checklist
Use SDI video sources
 Must be SMPTE compliant
 Digital equivalent of the raw video
 Must preserve meta data
Use recording devices that preserve metadata
 Metadata decoders can then place critical data on the video at playback
Design your system such that
 Specify a system that stamps at a finite instance in the video (e.g. vertical sync)
 Time stamps and other time to image critical data is impressed into the SDI video stream and meta data at the source
• Eliminates any latency sources
Genlock your video sources
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 23

HD Video Spec Checklist
 SMPTE standard is accurate to the second, but only records frame number thereafter
• Use equipment that time stamps at a finite point in the SDI stream (e.g. vertical sync)
• Use equipment that captures time in fractions of a second
 e.g. 6980G-HD captures to 100 µS precision
Use Equipment with interoperable metadata encoding
 STANAG 4609 is a possible method
• Is in use in several NATO and US programs
• Provides a non-proprietary format for encoding accurate time and other critical data
• Builds on and compliant with SMPTE 291M and related specifications
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 24

Handy Reference Material
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 25

Comparing Analog to Digital Video
Attribute
Raw Video
Sync
Blanking
Active Video
Frame/Field Rate
October 26, 2011
Analog Video SDI Digital Video
Complex AM, FM and phase modulated signal requiring 6 MHz bandwidth
Serial encoded bit stream at bit rates from 140 Mbits/s to 3000 Mbits/sec
Pedestal and color burst sync areas scaled generally below the black level
A predetermined voltage level in the video signal
An AM signal with overlaid phase modulated color information
RS 170 60Hz /30 Hz Field/Frame
RS170A (NTSC) 59.94 (60/1.001)
CCIR 50Hz /25Hz field/frame
Progressive and Interlaced
A reserved bit pattern defined by
SMPTE in the SDI stream
Fixed format data blocks before and after the active video data set
A stream of video samples the number of which and format varies with resolution, sampling scheme and color depth
26
Many from 24.975 to 60 Hz and beyond
Progressive and Interlaced
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 26

Comparing Analog to Digital Video
Attribute
Visible Scan Lines
Resolution/Line
Color Sampling
Analog Video
NTSC 480/frame
PAL 576/frame
This depends on the source and signal quality but ranges to the equivalent of
300 to 720 pixels
Continuous time domain signal, intensity swings are limited by the available 1.5 MHz bandwidth
SDI Digital Video
480 SD
576 (PAL) SD
720 HD
1080 HD
SD 720 pixels
HD 1280 and 1920 pixels
YUV encoding samples intensity every pixel and color differently depending on the encoding chosen. 4:2:2 is most frequently used
27
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 27

Pixels & Bit Count, Data Rates, Resolutions & Specs
SDTV
HDTV
Active lines per frame
Total lines per frame
Active
Luma samples per
Line
Luma
Samples in
Blanking
Area
Total
Luma
Samples
(Pixels)
Aspect Frame Rate
Ratio (Hz)
SMPTE
SDI
Bit Format
Digitizing
Specification
Bit Rate
(MBit/Sec)
SDTV I
HDTV
HDTV
(PAL)
HDTV
P
P
I
HDTV
(PAL)
I
HDTV P
480 525 720 190
720 750 1280 370
720 750 1280 700
1080 1125 1920 280
1080 1125 1920 720
1080 1125 1920 280
910 4:3 29.97
1650 16:9
60 or
60/1.001
1980 16:9 50
2200 16:9
30 or
30/1.001
2640 16:9 25
259M ITU-R BT.601
143.18
292M ITU-R BT.709
1485.0
292M ITU-R BT.709
1485.0
292M ITU-R BT.709
1485.0
292M ITU-R BT.709
1485.0
2200 16:9 60 424M ITU-R BT.709
2970.0
October 26, 2011
Transitioning From NTSC to SDI Digital Video
Copyright ITS 2011
Sheet 28