understanding hd part1

Understanding HD: Frame Rates, Color & Compression

HD Format BreakdownAn HD Format Describes (in no particular order)

ResolutionFrame Rate Bit RateColor SpaceBit DepthColor Model / Color GamutColor Sub-SamplingCompression

HD Format Breakdown

Examples

1920 x 1080 23.98P 10-bit Uncompressed YCbCr 4:2:2

1280 x 720 59.94P 8-bit DVCPROHD (100 Mb/s) YCbCr 4:2:2

Resolutions

Standard HD Resolutions

1920x1080 pixels

1280x720 pixels

2k - 2048 x 1556 pixels

4k - 4096 x 2304 pixels


Resolution Sub-SamplingSub-Sampling to Compress Data

1920 x 1080

1440 x 1080

(HDCAM, HDV, XDCAM HD)

1280 x 1080

(DVCPRO HD)

1280x720

960 x 720 (DVCPRO HD)

Frame Rates

US (NTSC / 60 hz) Frame Rates

59.94i (aka 60i) Interlace Fields per Second

29.97p (aka 30p) Progressive Frames per Second

23.98 (aka 24p) Progressive Frames per Second

24p - true 24 Progressive Frames per Second


Frame Rates

60i US Standard = 59.94i = 29.97i (Confusing I Know)


Odd Field Even Field Odd Field Even Field

60 x Per Second

Frame Rates

30p = 29.97p = 29.97 PsF


First Frame

30 fps

Odd Field Even Field

Third Frame


Second Frame

vOdd Field Even Field

Fourth Frame


60 fps

Frame Rates

Working with 23.98p

2-3 Pull Down to 59.94i

Visually 23.98 & Broadcast Ready

23.98 PsF (Progressive Segmented Frames)

48i Interlaced Fields per Second

Progress feed to recorders


Frame Rates

24P = 23.976p 2:3 Pulldown into 60i


First Frame

24 fps


Third Frame


Second Frame


Fourth Frame


60 fps

Frame Rates

24PA = 23.976p 2:3:3:2 Pulldown into 60i


First Frame

24 fps


Third Frame


Second Frame

vOdd Field Even Field Odd Field Even Field

60 fps

Frame Rates

23.98 PsF (Progressive Segment Frame)


First Frame

24 fps


Third Frame


Second Frame


Fourth Frame


48 fps

Frame Rates

Europe (PAL / 50 hz) Frame Rates

50i Interlaced Fields per Second

25p Progressive Frames per Second

That’s it!


Understanding HD - Frame Rates

Questions?

Understanding Color

How is color made in a digital camera?

What is color depth / bit depth?

What is a color space?

What is a color model?

What is a color gamut?

What is color sub-sampling?

Color: How is it made in camera?

All Digital Sensors are Black & White (Luminance Only)

Color is made in two different ways:

3 Sensors with a Prism

Single Sensor with a Color Mask

Both Produce Red, Green, and Blue Images

3 Sensor Imager

Bayer Mask Sensor

Color: 3 Sensor Color

3 CCD or 3 CMOS Sensors

Color is split by a prism into RGB Images

Used in most small sensor cameras

HVX200 and HPX170 (1/3”)

Panasonic & Sony ENG (2/3”)

3 Sensor Imager

Color: 3 Sensor Color

Color: Single Sensor Color

Single Sensor Color

Each Pixel is filtered for one color

Full RGB images is created by analysis of the color pattern of the sensor

Most popular pattern is the Bayer Mask

Bayer Mask Sensor


Bayer Mask Sensor

Bayer Mask is used on most single sensor cameras

RED One & Epic

Arri Alexa

Sony F3 & FS100

Bayer pattern creates color with filtration

2x2 matrix has 2-green, 1-red, 1-blue

Invented by Dr. Bryce E. Bayer at Kodak


F65 Sensor

Other color patterns are used by different cameras

Sony F35 has a stripped sensor

Sony F65 has a special design

F35 Sensor

Color: The Pixel Image

Defining Color One Pixel at a Time

Each Pixel has its own brightness (luma) and color (chroma) information


I’m a Pixel

Color: The Pixel Image

Luma - Y - is strictly black and white information

Chroma - C - is strictly color information


Bit Depth

Bit Depth AKA Color Depth

Defines the amount of color variation available per color channel per pixel

8-bit & 10-bit are very common.


Bit Depth - 8 Bit

Bit Depth Variations

8-Bit Color

28 = 256 per channel (RGB)

3 Channels x 8 bits = 24 Bits total

16,777,216 colors available


Bit Depth - 10 Bit


10-Bit Color



1,073,741,824 colors available


Bit Depth - 12 Bit


12-Bit Color



68,719,476,736 colors available


Bit Depth - Banding10 bit Image 8-bit Image (no dither)

Bit Depth - Dither8-bit Image (no dither) 8-bit Image (with dither)

What is Color Space?

Color Space is defined by two parameters:

Color Model

Color Gamut (footprint)

Popular Color Spaces

REC 709 / DCI P3

Adobe RGB sRGB

Color Model

A Color Model is a mathematical model describing colors as a set of numerical values (usually in 3 or 4 values)

Examples

RGB

YCbCr / YPbPr

CMYK (used in print)


Color Model

RGB - Red / Green / Blue

R = Red Chroma & Luminance

G = Green Chroma & Luminance

B = Blue Chroma & Luminance


Color Model

Y Cb Cr (digital) / Y Pb Pr (analog)

Removes redundant Y information

Y = Luma only information

Cb = Blue-Difference Chroma information

Cr = Red-Difference Chroma information


Color - The Pixel ImageIn Y Cb Cr - Each pixel contains 1 Y values and 2 Chroma values

In R G B - Each pixel contains 3 Y values & 3 Chroma values

What is Color Gamut?Defining Color the way HUMANS see it

CIE 1931 Color Space

International Commission of Illumination

1931 Study which became CIE RGB

Later Modified to CIE XYZ Color Space

All Color Gamuts are based on limitations of the CIE XYZ Color Space

Color Gamut

ITU-R Recommendation BT.709 (REC709)

Used in HDTV Universally

Defines primaries and limits of what colors can be shown in REC709 video.

The full spectrum is CIE XYZ

REC709 has limited color options (in triangle)

D65 is that white point

Color GamutOther Color Gamuts

ITU-709

F35 (S-Gamut)

Print FilmF65

Visible Color

DCI

Video Gamuts Computer Gamuts

Color Space

Color Space is defined by:

Color Model - RGB, YCbCr, CMYK

Color Gamut - Location of Primaries

Color Sub-Sampling

Color Sub-sampling is a reduction in Color Resolution

Reducing color also reduces data rates, and it is not easily visible to our eyes.

Works in Y Cb Cr

Does not work in RGB


Chroma Sub-Sampling - 4:4:4

YC YC YC YC

YC YC YC YC

Y = LumaC = Chroma

4 Luminance Samples

4 Color Samples

4 Color Samples


Y Y Y Y

Y Y Y YY = Luma

C = Chroma

4 Luminance Samples

2 Color Samples

2 Color Samples

C

C

C

C


Y Y Y Y

Y Y Y YY = Luma

C = Chroma

4 Luminance Samples

1 Color Sample

1 Color Sample

C

C


Y Y Y Y

Y Y Y YY = Luma

C = Chroma

4 Luminance Samples

2 Color Samples

0 Color Sample

C C

Understanding HD - Color

Questions?

Bit Rate

Bit Rate AKA Data Rate

The rate at which video data is transmitted or recorded

Uncompressed video = 1.485 Gb/s (59.94i)

23.98 = 1.19 Gb/s

About 8 Giga Bytes per minute


Bit Rate - Compressed RatesCompressed Data Rates

ProRes 422 HQ - 220 Mb/s

AVC-Intra 100 - 100 Mb/s

DVCPRO HD - 100 Mb/s

XDCAM 422 - 50 Mb/s

XDCAM EX - 35 Mb/s

AVC HD - 24 Mb/s

Bit Rate - Compressed RatesCompressed Data Rates

AJA Data Rate Calculator

Free Online Calculators

Lossless vs Lossy Compression

Lossless = Uncompressed

Lossy = Compressed

Higher Data Rate does not equal Higher Quality

Bit Rate - Compressed RatesDCT (Discrete Cosine Transform) Blocks

An average of frequencies

Used to compress parts of an imageIncreasing Compression

Bit Rate - Compressed RatesDCT Blocks

Used in MPEG2 and MPEG4 (small blocks)

Compression

Compression Types

MPEG-2

DVCPRO HD

HDCAM / HDV

XDCAM HD / 422 / EX

Digital TV & DVD


Compression

Compression Types

MPEG-4

HDCAM SR

AVC-Intra 100 / 50

AVC HD / AVCCAM

H.264 & Other Web Compressions


Compression

Long GOP and I Frame

I-Frame compressions every frame individually

Long GOP (Group of Pictures)

Compresses over 15 frames GOP

I Frames (every 15th frame) are individually compressed

B & P Frames are stored as differences


CompressionLong GOP - 15 Frames

I-Frame P-FrameB-Frame

Compression

Compression Types

Intermediate Formats

ProRess 422 HQ / 422 / LT / Proxy

DNX HD / DNX

CineForm

High bit rate, low compression


Compression

Compression Types

Redcode - Red RAW Compression

JPEG2000 (wavelet based)

Color Channels compressed individually

Four flavors in Red One 28 MB/s (224 mbit/s) 36 MB/s (288 mbit/s), and 42 MB/s (336 mbit/s)


Recording Media

Codec Comparisons in 1080

Apple ProRes 4444 - 1920 x 1080 12 / 10 bit 4:4:4 YCbCr / RGB I-Frame at 330 Mb/s

Apple ProRes 422 HQ - 1920 x 1080 10 bit 4:2:2 YCbCr I-Frame at 220 Mb/s

HDCAM SR - 1920 x 1080 12 / 10 bit 4:2:2 / 4:4:4

YCbCr / RGB I-Frame at 440 Mb/s or 880 Mb/s


AVC-Intra 100 - 1920x1080 10 bit 4:2:2 YCbCr I-Frame at100 Mb/s

XDCAM 422 / Canon XF / NanoFlash - 1920x 1080 8 bit 4:2:2 YCbCr Long GOP at 50 Mb/s

HDCAM - 1440x1080 8 bit 4:2:2 YCbCr I-Frame at 144 Mb/s


XDCAM EX - 1920x1080 8 bit 4:2:0 YCbCr Long GOP at 35 Mb/s

DVCPRO HD - 1280 x 1080 8 bit 4:2:2 YCbCrI-Frame at 100 Mb/s

AVCHD / AVCCAM - 1920x1080 8 bit 4:2:0 YCbCrLong GOP at 24 Mb/s


XDCAM HD - 1440 x 1080 8 bit 4:2:0 YCbCr Long GOP at 35 Mb/s

Canon SLR H.264 - 1920 x 1080 8 bit 4:2:0 YCbCr Long GOP at 40-50 Mb/s

HDV - 1440 x 1080 8 bit 4:2:0 YCbCr Long GOP at 25 Mb/s

Understanding HD - Compression

Questions?

understanding hd part1

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