04 digital video
TRANSCRIPT
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04 Video
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2 Video
Video
Technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion
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3 Video
Evolution
Developed for CRT television systems Formats: VHS DVD Blu Ray 3D Internet: Real Video, YouTube
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4 Video
Analogical Video Standards
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5 Video
Digital Video
Works by using a digital video signal Introduced by Sony in 1986 (Digital Betacam) QuickTime (Apple): 1991 Progressive increase in quality
MPEG-1, MPEG-2 (DVB-T, DVD), DV Tapes, HDTV, MPEG-4 Non-linear editing systems deployed cheaply and widely on Desktop Computers Internet broadcasting. Video on Demand
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6 Video
Digital Video Standards
Spain, SD MPEG-2, HD MPEG-4/H.264
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7 Video
Frames per second (fps) Interlacing Resolution Aspect Ratio Color Space Bit-rate
Main Parameters of Video
PAL (576i50)
25 fps 720 x 576
4:3 Color YUV
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8 Video
Frames per second
Frame rate: number of still pictures per unit of time of video Standards
DVB-T : 25 fps
Cinema (35 mm): 24 fps
HFR : 48 fps
Internet Files 12 15 fps
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9 Video
Resolution
Measured in pixels DVB-T SD / DVD : 720x576
DVB-T HD : 1280x720, 1920x1080
Full HD TV / Blu-Ray : 1920x1080
4K Ultra HD TV : 3840x2160
8K Ultra HD TV : 7680x4320
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10 Video
Interlacing
Progressive Scan Systems Each refresh period updates all of the scan lines
DVB-T HD (Spain) 720p 1080p
Blu-Ray 1080p
Interlaced Systems Designed to avoid the limitations of a narrow bandwidth
The horizontal scan lines are partitioned into two fields (odd and even)
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11 Video
Aspect Ratio
Ratio between the width and height of a frame Old TV : 4/3 (1.33:1)
HDTV : 16/9 (1.77:1)
Cinema in Blu-Ray : 2.40:1 (1920x800)
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12 Video
Color Space and Color Depth
Color Space YCbCr (YUV)
Y: Luminance (brightness)
CbCr: Chrominance (color)
Color Depth Number of bits stored for each pixel (bits per pixel)
More bits for Luminance
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13 Video
A color image and YCbCr components
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14 Video
Bit rate
Number of bits stored per unit of time VCD 1.15 Mbits/s
DVD 9.8 Mbits/s
Blu-ray 36 Mbits/s and more
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15 Video
Bit rate
The Adventures of Baron Munchausen Video Bitrate: 25.98Mbits/s Case Blu-ray, 2008 Aspect ratio: 1.85:1
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16 Video
Bit rate
Bit rate 150 Mbps, 4K 3840x2160 Effective Pixels 8,300,000 Recording time 50 min, 64GB
UHDTV
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17 Video
Video Compression
Motivation: high bit rate of uncompressed video The majority of video compression algorithms use lossy compression. There is a trade-off between video quality and system requirements.
Home cinema, Portable video, etc
Highly compressed video may present visible or distracting artifacts.
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18 Video
Video Compression Formats
Examples of video compression formats (specifications):
MPEG-2 : DVD Video, Blu-ray, DVB-T MPEG-4 Part 2 : Quicktime, DivX, Xvid Theora : free software, VLC, Mplayer, FFmpeg H.264/MPEG-4 AVC : Blu-ray, Vimeo, YouTube,
HDTV
RealVideo : RealMedia, suitable as a streaming media format
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19 Video
Video CODEC
Device or software that enables compression and/or decompression of digital video using a specific video compression format MPEG-4 Part 2 Divx Pro by DivX Inc.
Xvid free/open source OpenDivX project FFmpeg included in libavcodec (codec library)
H.264/MPEG-4 AVC
X264 GPL implementation QuickTime H.264 by Apple DivX Pro
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20 Video
File Formats
Multimedia Container Can store different data types (audio, video, subtitles, information, etc.)
For video AVI, FLV, MKV, MP4, OGG
Format Selection Based on: popularity, overhead, support for codecs, advanced content , support of streaming media HTML5 Support!
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21 Video
HTML5 Video Support
Currently, there are 3 supported video formats for the tag: MP4, WebM, and Ogg MP4: MPEG 4 file, H264 video codec, AAC audio codec Ogg: Ogg file, Theora video codec, Vorbis audio codec WebM: WebM file, VP8 video codec, Vorbis audio codec
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22 Video
Video Formats and Browser Support
Browser MP4 WebM Ogg
Internet Explorer 9+ YES NO NO
Chrome 6+ YES YES YES
Firefox 3.6+ NO YES YES
Safari 5+ YES NO NO
Opera 10.6+ NO YES YES
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23 Video
Methods for stereoscopic video creation Two channels using polarized glasses (passive stereo)
One channel with two overlaid color coded layers (anaglyph)
One channel with alternating left/right frames + LCD shutter glasses (active stereo)
Auto stereoscopic displays
3D Vdeo
04 VideoVideoEvolutionAnalogical Video Standards Digital Video Digital Video Standards Main Parameters of Video Frames per secondResolutionInterlacingAspect RatioColor Space and Color DepthA color image and YCbCr componentsBit rateBit rateBit rateVideo Compression Video Compression FormatsVideo CODEC File FormatsHTML5 Video SupportVideo Formats and Browser Support3D Vdeo