The document discusses multimedia systems and provides an overview of video fundamentals including properties of video, digital video formats, compression, production, and editing. It covers topics such as analog versus digital video, frame rates, aspect ratios, common file formats like AVI, MOV, MPG, and video equipment for capturing, transferring, and editing digital video.
22. Digital VDO
• A means of reproducing the continuous VDO
waveform as a stream of digital numbers.
23. Digital VDO
• A means of reproducing the continuous VDO
waveform as a stream of digital numbers.
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24. open wiki to
Interlacing embrace the
explanation!!
• Interlacing was originally conceived as a way to
achieve good visual quality within a limitations
of a narrow bandwidth.
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25. 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.
26. Note
in 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)
27. 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.
28. 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
29. 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
30. 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
33. Temporal Compression
• Make key frames, say every 6 frames and do the
spatial compression on these frames.
• Between key frames, each one of them will be
replaced by a difference frame.
36. 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.
37. MOV
• Quicktime Movie was developed by Apple
Computer
• MPEG-4
• Qt 7 (and later) use H.264
38. 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
39. • 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
40. Others
• 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
45. Coaxial
• VDO and audio signals are both carries in one
cable
• Poorest transfer
46. A/V
• Use RCA connectors
• Yellow is (composite) video
• Red is right audio & White is left audio
47. 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
50. FireWire
• Developed by Apple
Computer
• IEEE-1394 standard
• 400 Mbps
• higher transfer rates are
available (800, 1600, and
up to 3100 Mbps)
51. 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
52. VDO Editing
• Editing:
• cut and paste sections
• add special effects
• add transitions
• add titles