patse t a t a Video Sata

1
?pa?t?se?? ???t??? ??a ???t??? ?a? Video S?µata

• ?e? ?p???e? d?af??? st?? apa?t?se?? d??t??? ?s??
  af??? t? ???ta?? µet?d?s? ?a? t?? ??????f?s?.
  Ost?s?, st?? e???af?? apa?te?ta? µe?a??te??
  p?st?t?ta ?a? e????st?? a???µ?? ?a???.
• S?µa?t???? pa????? ed? e??a? ? ?a??st???s? t??
  µet?d?s??. (St?? ???ta??? ep????????e? µp??e? ?a
  ???e? a?e?t? ??p??a ?a??st???s?, ??? ?µ?? ?a?
  st?? a????ep?d?ast???? Interactive)

2
?????p??? a?t????? ???? ?a? ?????a?

• ?? a????p??? aft? d?a sa? ??a? d?af???st??
  ?pe?t??????ta? t?? e?a??a???
• ?? a????p??? µ?t? d?a sa? ??a? ????????t??
  f??t?????ta? t?? e?a??a???.

3
Sf??µata ?at? t? S?µp?es?
4
????t?ta ????

• ???ef????? p???t?ta
• ??d???p???s? G.711. ????? ????? 3.4 kHz.
• ?? f?sµa t?? a????p???? ?µ???a? µp??e? ?a e?ta?e?
  se e???? 10 kHz.
• CD ???t??? p???t?ta 20 kHz µ???f?????
• Sound Studio ????t?ta ??p??s?a t?? p??????µe???

5
?pa?t?se?? ???t??? ??a ?s?µp?esta S?µata

• ???ef????? ????t?ta 64 Kbps
• ?? a?a?????? s?µa de??µat???pte?ta? 8000/s ?a?
  ???e de??µa ??d???p??e?ta? µe 8 bits.
• CD p???t?ta ste?e?f????? 1.4 Mbps
• ?e??µat?????a sta 44.1 kHz µe 16 bits/sample X 2
  ??a t? ste?eof???a d??e? 1411.2 ?bps.

6
?pa?t?se?? ???t??? ??a S?µp?esµ??a S?µata

• ???ef????? p???t?ta 32, 16 a??µ? ?a? 4 Kbps, µe
  t? ?at?????? ??d???p???s?.
• CD p???t?ta 192 ste?e?f????? 64 mono
• ???f??e? te?????? ??d???p???s?? ep?t?e?a? t?
  µet?d?s? se t?t??e? ?aµ???? ta??t?te?
• ?a??de??µa ? efa?µ??? MUSICAM se te??????
  ep?p?d?? MPEG

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???e? ?pa?t?se??

• Delay Jitter se interactive efa?µ??? 0.1 µe 0.5s
  (one way), e?? ? ????? round trip delay ??a real
  time ?/?a? virtual reality p??pe? ?a e??a?
  µ????te?? t?? 100ms.
• G?a ??a PC ?a? ??a CD p???t?ta ? transit delay
  variation de? p??pe? ?a ?pe?ßa??e? ta 100ms. G?a
  efa?µ???? p???µ?s?? ?a p??pe? ?a ??µa??eta? 20 µe
  30ms.

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... ???e? ?pa?t?se??

• ? ????t???t?ta t?? buffer st?? pa?a??pt? ?e?
  e??a? apa?a?t?t? ?a e??a? ?d?a?te?a µe????, a??µ?
  ?a? ?? t? offset delay a????eta? se de??de?
  de?te???epta.
• Intermedia Synchronization (p?. Audio ?a? Motion
  Video)
• Error Rates ??t? ap? 10-2 ??a t??ef?????
  p???t?ta, 10-3 ??a CD p???t?ta ?a? as?µp?esta
  s?µata ?a? 10-4 ??a s?µp?esµ??a

10
Motion Video

• ???te p???t?te?
• High Definition Television (HDTV)
• Studio-Quality digital television
• Current broadcast-quality television
• VCR-quality television
• Low-speed videoconferencing quality

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HDTV ?
digital high definition television

• ????t???? pa??µet???
• Frames per second
• image resolution (picture elements per frame
  - pixels, pixel depth)
• image alteration (a?????s? e????a?)
  ?fe???µe?? st? s?µp?es?

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S??d?asµ?? ??a t?? HDTV

• High resolution/high frame rate (1920 x 1080/60
  fps), 1920pixels/line ?a? 1080lines/frame
• High resolution/conventional frame rate (1920 x
  1080/30 fps) ?? PAL ?a? SECAM ????? 25 fps e?? t?
  NTSC 30 fps
• Improved resolution/conventional frame rate (1280
  x 720/30 or 24 fps)
• Aspect Ratio 169 a?t? t?? s?µe????? 43

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????t?ta HDTV

• ?e t?? pa?ap??? ??? e?????µe ??a t?p? high
  resolution/high-frame-rate, d??ad? 1920 pixels
  a?? ??aµµ? ?a? 1080 ??aµµ?? st? frame, p??
  pa???s?????ta? µe ???µ? 60 frames t? de?te???ept?
• ??e???eta? ?a ?a????s???? ep?s?? ta standards t??
  ???? ?a??? ?a? ? µ??? ????-e????a?.

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Interlacing

• Interlaced HDTV ?????e? t? frame se d?? ped?a,
  ?a???a ap? ta ?p??a a?t?st???e? se d?af??et????
  (??t?e?-pe??tt??) ??aµµ?? t?? ??????. ?ts?
  ?e?t????e? ? s?µßat??? TV.
• Progressive scan ??e? ??a ped?? a?? frame. ??
  pe??ss?te?e? ????e? ?p?????st?? d???e???? ?ts?.
  G?a t? ?d?? bit rate t? progressive scan e??a?
  ?a??te??.

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Studio quality digital television

• Digital Video Effects (DVE)
• 525 lines ?a? 858 samples/line (NTSC) ? 625 lines
  ?a? 864 samples/line (PAL-SECAM) all to
  luminance
• 30 ? 25 frames per second
• interlaced scan
• 8 bit 3components/pixel 24 bit per pixel

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Studio quality ITU-R 601 TV
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Sampling Freq. Stud qual.TVLuminance signal only
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Broadcast quality TV

• Digital TV cameras with sophisticated editing
  functions
• Modern TV sets, ?aµß????? t? a?a?????? s?µa ?a?
  t? µetat??p??? se ??f?a?? µe p????? ße?t??se??
  ?a? ?pt??? eff?

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VCR quality TV

• H ??a???t??? ??a??t?ta e??a? pe??p?? ? µ?s? ap?
  t?? PAL ? SECAM broadcast quality TV

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Videoconference quality

• Low speed at 128 Kbps d??ad? 2 ??aµµ?? ßas????
  ISDN ?????. (??e? ?a? 384Kbps)
• ? ??a???t??? ??a??t?ta e??a? t? t? 1/4 t?? TV
  studio quality
• Common Intermetiate Format (CIF) ITU-TS standard
  called H.261 µe 352 pixels ?a? 288 lines per
  frame
• ?? Frame Rate e??a? 5 µe 10 fps

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Delay jitter for real time video

• Lip synchronization ??a HDTV ?a? VCR
• Variation of Network Transit Delay
• ?e???? 50 ms ??a HDTV
• 100 ms ??a broadcast quality
• 400 ms ??a videoconference quality

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Error Rates

• Intervals between affected frames ??a?t?ta? ap?
  t? Bit Error Rate (BER) ?a? t? p???t?ta t??
  ep????????a? p.?.
• VidConf Qual. (100 Kbps) 1 sec ??a BER 10-5 ?a?
  3 ??e? ??a BER 10-9
• HDTV 240 ?a??asµ??a bits/sec ??a BER 10-5 ?a?
  1min ??a BER 10-9

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??t?µet?p?s? ?a??? µet?d?s??

• Forward Error Correction (FEC). ?e t? µet?d?s?
  ep?p??s?et?? bits e?????? ??a non-grouped errors,
  µp????µe ?a e??????µe ?a? ?a d?????s??µe ???? st?
  µet?d?s?.

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Artifacts ?a? a?t???pt?t?? ?a???

• ??a?t?ta? p.?. ?? t? ????? bit e??a? se Least
  Significant Bit ?a? st? ??d???p???s? ???µat??,
  ??te p?? ?a ???e? a?t???pt?.
• ???t?? ?e???e? s?µp??se?? ?a ep?f????? ?a?
  µe?a??te?e? p??a??t?te? ??????.

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?p?????? ?a??? (Error concealment)

• ?? Data blocks ?a???? ? ??f???? ß?ad?te?a,
  ?p?????? te?????? ??a epa?????s?. (Extrapolating
  ? interpolating t?? ap??es???t?? blocks.) ???ad?
  a????e???µe ta pa?ap??s?a ?a? a?ap?????µe ta
  ?aµ??a ded?µ??a.

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?p?d?as? t?? s?µp?es?? st?? ?????t???t?ta (Burst.
Ratio 10 p??? 1)
28
Images as Data Files Uncompressed

• Medium size image (640 X 480) 900 Kbytes
  uncompressed. 640 pixels 480 lines 24 bits color.
  ?ta? ???s?µ?p???s??µe 4 bits color, t?te
  apa?t???ta? 150 Kbytes
• Large computer screen image (1280 X1024) 4
  Mbytes uncompressed. Color 24 bits

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Compressed Images

• Medium size (640 X 480) 36 Kbytes
• Large size image (1280 X 1024) 160 KBytes

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Transmission Time for images
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Transmission and overall transfer delay
32
???e? apa?t?se??

• Multicasting ( audio-video d?a??µ??, cooperative
  work, seµ?????a, µa??µata ?t?.)
• Cashing ?a? mirroring

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Burstiness ratio
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Holding time
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Response time