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...and ManyMORE...

VDO on-demand e-Learning

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My Late Experience from

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Agenda

VDO Fundamental

Properties of VDO Digital

VDO Formats

Digital VDO Production

Record

CaptureEdit

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Properties of VDO

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Analog VDO

• Motion VDO was originally created and stored in analog form.

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Digital VDO

• A means of reproducing the continuous VDO waveform as a stream of digital numbers.

Benefit: immune to various

distortion attributed to analog

such as noise...

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Interlacing• Interlacing was originally conceived as a way

to achieve good visual quality within a limitations of a narrow bandwidth.

odd field even field

open wiki to embrace the explanation!!

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Progressive Scanning(non-interlaced scanning)

• A method of representing moving images on a display screen, in which every pixel is represented in each frame.

• Computer monitors use a progressive scan.

• The standard refresh rate for a flicker-free display is a vertical scan rate of 75 Hz or higher.

• It’s used to project movies in theaters.

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Notein digital TV terminology:

interlaced scan is denoted by a lowercase i

progressive scan is denoted by a lowercase p

frame rate: (60i, 24p)resolution: (1080i, 720p)

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Flicker Rate

• Flicker fusion rate is the human eye’s ability to notice flicker within rapid pulses of light.

• Flicker will be observed if a light pulses on and off below 72 pulses per second (pps).

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Frame Rate

• Frame frequency is a measure of how quickly an image device can produce unique consecutive images called frames. (expressed in frames per second - fps)

• Typically, the human eye can interpret motion at 10 fps, but this rate causes a flicker effect that’s distract.

• Increasing the frame rate reduces flickering.

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Frame Rate

• Movies - 14 fps

• Television:

• NTSC - 29.97 fps

• HDTV - 60 fps

• VDO games (frame rate is very important):

• action-oriented games - 20-30 fps

• 3D-heavy games - 90-100 fps

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Aspect Ratios

• The ratio of the width of the image to its height (w:h)

• motion-picture - 1.85:1 and 2.35:1

• tv screens - 1.33:1 (aka 4:3)

• HDTV - 1.78:1 (aka 16:9)

16:9 4:3 letterbox

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Compression• VDO is huge - one sec of analog VDO

stored in an uncompressed digital format takes up 1 MB of disk space

• thus, 5-min VDO ~ 300 MB

• not practical

• VDO compression is a MUST

• VDO contains many spatial and temporal redundancies

• Codecs are needed for creating and viewing

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Digital VDO Formats

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AVI

• Most common AV data on Windows

• Can be saved in a variety of compression schemes - full frames (uncompressed), Radius’s Cinepak, Intel Video, and Indeo.

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MOV

• Quicktime Movie was developed by Apple Computer

• MPEG-4

• Qt 7 use H.264

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MPG

• The compressed VDO file format for standard DVD using the MPEG-2 encoding standard

• A large file can be transferred to MPEG with little loss of quality while dropping the bit rate a great deal

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• The MPEG group develops the standards for encoding VDO and audio

• MPEG standards:

• MPEG-1: used as VCD standard (MP3 is the popular compression)

• MPEG-2: use in many things such as DVD, digital satellite TV and so on

• MPEG-4: support 3D content, low bit-rate encoding, support for Digital Right Management

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• WMV

• a part of Windows Media framework

• used for streaming VDO over the internet

• uses MPEG-4 standard

• RM

• a multimedia container with RealVideo and RealAudio codecs in a single file

• is used to stream AV over the internet

Others

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VDO Production

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Equipments

• Digital tapeless (D)

• HDV (D)

• DV (formerly DVC)

• 8mm (A)

• VHS (A)

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Connecting Recorder to Computer

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Coaxial

• VDO and audio signals are both carries in one cable

• Poorest transfer

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A/V• Use RCA connectors

• Yellow is (composite) video

• Red is right audio & White is left audio

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S-Video

• Separate video - transmit VDO signals over a cable by dividing the VDO info into 2 separate signals: color (chrominance) and brightness (luminance)

• Sharper than composite VDO

• must be used in conjunction with audio cables

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USB

• USB 2.0 are common

• 480 Mbps

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FireWire

• Developed by Apple Computer

• IEEE-1394 standard

• 400 Mbps

• higher transfer rates are available (800, 1600, and up to 3100 Mbps)

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Transferring from Recorder to Computer• Calculate disk space (uncompressed):

• (pixel width) x (pixel height) x (color bit depth) x (fps) x (duration in secs) / 8,000,000

• say, 3-min VDO @ 15 fps, 24-bit depth, 320x240 pixels will take:

• (320) x (240) x (24) x (15) x (180) / 8,000,000 = 622 MB

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VDO Editing

• Editing:

• cut and paste sections

• add special effects

• add transitions

• add titles

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