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Capture Devices, Video Encoding Standards and post-production techniques
B.Sc. (Hons) Multimedia Computing
Media Technologies
Video Capture and Editing
Agenda
Devices Connectivity Compression / Decompression (CODECS) Export formats
MPEG-4 Cinipac Sorenson Spark
Deployment Support for Legacy Formats
B.Sc. (Hons) Multimedia Computing
Media Technologies
Capture Devices
PCI Card (PC) FireWire port on Mac( Developed by Apple) & PC USB Port Video Camera Web Camera
Connectivity
SCART Plugs and Sockets
Phono Leads (RCA)
Video in
Audio in left
Audio in right
Connectivity
S-VHS
Video (Yellow)
Audio Right (Red)
Audio Left (White)
The Serial Digital Interface ‘Firewire’ Originally developed by Apple as the IEE1394 Serial
Digital Interface Referred to as FireWire Simple and highly efficient method of not only
transferring digital signals between devices Most Camcorders have DVout which can be
connected to computer Firewire Port via appropriate lead
Two connector sizes, four pin - Camcorder, and six pin - computer
The Serial Digital Interface ‘Firewire’
Connection between computer and camcorder enables users to control the camcorder playback
Where suitably equipped DV-in camcorders are present - recording functions using the on-screen controls of the appropriate program
Compression & Decompression ‘CODECS’
Need CODEC (Compression-Decompression; more recently, Coder-Decoder) on system to play movie or extract compressed data to load into an editing application (Premiere, etc).
Some CODECS not well-supported across platforms MPEG-X (X=1,2,3,4 etc.) is best for multimedia Sorenson via Flash CS4 best solution for Flash-
based work
What is a CODEC? (adapted from Wikipedia)
Video is basically a three-dimensional array of colour pixels. Two dimensions serve as spatial (horizontal and vertical) directions of the moving pictures, and one dimension represents the time domain. A data frame is a set of all pixels that correspond to a single time moment. Basically, a frame is the same as a still picture.
Video data contains spatial and temporal redundancy. Similarities can thus be encoded by merely registering differences within a frame (spatial), and/or between frames (temporal). Spatial encoding is performed by taking advantage of the fact that the human eye is unable to distinguish small differences in color as easily as it can perceive changes in brightness, so that very similar areas of color can be "averaged out" in a similar way to jpeg images. With temporal compression only the changes from one frame to the next are encoded as often a large number of the pixels will be the same on a series of frames.
Lossy compression results in far higher compression ratios at an acceptable level of quality.
What is a CODEC? (2) One of the most powerful techniques for compressing video is interframe
compression. Interframe compression uses one or more earlier or later frames in a sequence to compress the current frame, while intraframe compression uses only the current frame, which is effectively image compression.
The most commonly used method works by comparing each frame in the video with the previous one. If the frame contains areas where nothing has moved, the system simply issues a short command that copies that part of the previous frame, bit-for-bit, into the next one. If sections of the frame move in a simple manner, the compressor emits a (slightly longer) command that tells the decompresser to shift, rotate, lighten, or darken the copy — a longer command, but still much shorter than intraframe compression. Interframe compression works well for programs that will simply be played back by the viewer, but can cause problems if the video sequence needs to be edited.
Since interframe compression copies data from one frame to another, if the original frame is simply cut out (or lost in transmission), the following frames cannot be reconstructed properly. Some video formats, such as DV, compress each frame independently using intraframe compression. Making 'cuts' in intraframe-compressed video is almost as easy as editing uncompressed video — one finds the beginning and ending of each frame, and simply copies bit-for-bit each frame that one wants to keep, and discards the frames one doesn't want.
CODECsFurther reading about CODECs...http://www.animemusicvideos.org/guides/avtech/video3.htmhttp://videoproductiontips.com/video-production/digital-video-file-formats-explained/
Export Formats
Cinepac (Radius) MPEG Sorenson Spark Video for Windows (Indeo) File types:
avi (Windows) mpg. (MPEG) Mov (Quicktime)
Common video file formats(‘Container’ formats) AVI - "Audio Video Interlace" - Introduced in 1992 by Microsoft, supports
multiple steaming audio and video feeds. MOV - QuickTime Movie File - Released in 1991, popular Apple format
that supports live streaming. RM - "RealMedia" - Multimedia format by RealNetworks which is mostly
used to watch streaming content over the web. 3GP - Mobile Phone Format - Developed by the Third Generation
Partnership Project (3GPP), it is a format used for recording and viewing on most modern cell phones.
WMV - "Windows Media Video" - Approved in 2006, WMV is a codec that has seen wide-scale adoption in not only streaming web content, but physical media such as HD DVD and Blu-ray discs as well.
MPG/MPEG - Developed by the "Moving Pictures Experts Group," this format has gone through several revisions - the first of which being MPEG-1, a compression standard that is the most widely used in the world.
MP4 - "MPEG-4 Part 14" - Based on Apple's MOV container, this format allows for subtitles as well as some MPEG features
Sorensen Spark (Wikipedia)
As Apple began to move away from proprietary codecs with its embrace of MPEG-4, Sorenson Media next licensed a new video codec to Macromedia (later Adobe) as Sorenson Spark (Sorenson H.263), released with Macromedia Flash 6/MX on March 4, 2002.
Sorenson Spark is the required video compression format for Flash Player 6 and 7. Macromedia later tried to find a better video codec. Starting with Flash Player 8 (released in September 2005), the preferred video codec is VP6.
The Sorenson Spark can be still used in the Adobe Flash CS4 Professional (2008) Flash Video .FLV files as one of three video compression formats (alongside H.264 and On2 VP6). Sorenson Spark is an older codec but it is also a widely available and compatible one, when used in Flash Video.
Sorensen Spark is considered an incomplete implementation of H.263.
The complete standard is known as H.264.
Global Uptake of H.264 Brazil’s terrestrial broadcast service uses H.264/AVC in ISDB-T Colombia announced in August 2008 the adoption of the DVB-T broadcasting standard. Czech Republic O2, one of DVB-T providers is broadcasting HD versions of TV channels CT1 and
Nova experimentally in H.264/AVC. France's prime minister announced the selection of H.264/AVC as a requirement for receivers of
HDTV and pay TV channels for digital terrestrial broadcast television services (referred to as "TNT") in France in late 2004.
Lithuania, Estonia, Latvia and Slovenia are expected to use H.264/AVC for all terrestrial digital television services.
Hong Kong’s leading broadcaster, TVB, selected H.264 in for new digital services there, including HDTV service, in the China DMB-T/H system environment, starting from the end of 2007. Asia Television Limited has joined this decision and uses H.264 for its new digital services too (both broadcasters use MPEG-2 to encode the digital simulcast of the existing analogue channels.)
Hungary's DVB-T service, MinDigTV, uses H.264 for encoding both SD and HD transmissions, including simulcasts of analogue channels.
Japan's Mobile-segment terrestrial broadcast services of ISDB-T uses the H.264/AVC codec, including major broadcasters such as NHK and Fuji Television.
Korea's Digital Multimedia Broadcast (DMB) service will use H.264/AVC. Poland will test DVB-T transmissions (as of 2007) working reliably for several years) use MPEG-2,
but commercial run scheduled after 2010 will be MPEG-4 only. Portugal's DVB-T service from Portugal Telecom will use H.264 for encoding both SD and HD
transmissions starting in 2009. New Zealand's Freeview service launched its DVB-T transmissions in March 2008 using
H.264/AVC. Norway's NTV use H.264/AVC for its national DVB-T broadcasting started October 2007 in
central southern areas of Norway. Norway are among the first to use MPEG-4/AVC exclusively in all its terrestrial television broadcasts, finished by November 2008. The analogue transponders will be switched off in 2009.
Singapore's first over-the-air HDTV channel, MediaCorp HD5, uses H.264/AVC.
Deployment
Compromises required to bring resource requirements of video within capabilities of delivery medium ( e.g networks) and low-end machines
Reduce frame size - down sample to quarter frame size - i.e. 320x240 pixels
Reduce sample rate (12 or 15 fps is OK for smoothmotion, flicker not a problem on computer
Reduce colour depth
Support for Legacy Formats
Betamax Video 8 VHS
Director Final Cut
Video Transfer Interface Devices
Post Production Techniques
B.Sc. (Hons) Multimedia Computing
Media Technologies
Video Editing
Agenda
Typical applications Post production process Popular effects Examples Software applications
B.Sc. (Hons) Multimedia Computing
Media Technologies
Typical Applications
Broadcasting (sports, light entertainment) Marketing (TV Ads) Film Industry Transfer from different formats Recovery / renovating of archive material
Post Production Process Apply after footage is recorded and edited
(sequence) Apply effects ( adjust, modify, transform) Transfer it to something you audience can see -
whether it's a DVD, the Web, or even a VHS tape. Resource intensive Time consuming Sometimes the hardest part Professional equipment ( High Definition (HD) Video)
very expensive £10 000 +
Post Production Effects Adjustment / correction
Brightness Contrast Colour Balance Volume (gain, reverb, etc)
Blur / Sharpen Stylize ( emboss, texturize) 3D (depth of field, compositing) Perspective ( skew, scale, stretch) Transitions (wipes, fades, etc) Text ( titles, path text)
B.Sc. (Hons) Multimedia Computing
Media Technologies
Post Production:Adjustment
Original (left) and with variations of Brightness & Contrast applied (centre and right)
Brightness and Contrast effect
Post Production: Adjustment
Original (left) and with variations of Color Balance applied (centre and right)
Colour Balance effect
Post Production:Blur & Sharpen
Original (left) and with variations of Directional Blur applied (centre and right)
Directional Blur effect
Original (left) and with variations of Channel Blur applied (centre and right)
Channel Blur effect
Post Production:Blur & Sharpen
Post Production: Distortion
Original (left) and with variations of Corner Pin applied (center and right)
Corner Pin effect
Post Production: Noise
Original Layer (left), Noise HLS (center), and two applications of Noise HLS with low Saturation values (right)
HLS Noise effect
Post Production:Keying
Original (left) and background layer (centre) are combined using Color Difference Key (right).
Colour Key effect
Post Production: Image Control
Original (left) and with variations of Change Color applied (centre and right)
Change Colour effect
Post Production: Paint
Two strokes in different colors painted on the robot's antenna, using three variations of Vector Paint
Vector Paint effect
Post Production: Stylize
Original (left), a layer used to create texture (center), and the texture applied to background layer (right)
Texturize effect
Post Production: Transition
Original (left) and with variations of Block Dissolve applied (centre and right)
Block Dissolve effect
Post Production:Perspective
Original (left) and with variations of Basic 3D applied (centre and right)
Basic 3D effect
Post Production: 3D
Original (left) and with variations of Depth of Field applied (centre and right)
Depth of Field effect
Post Production: 3D
Original (left), with applied using the near alien as the ID Selection (centre), and composited over a new background (right)
ID Matte effect
Post Production: 3D
Original (left), Gradient Layer (centre), and with Fog 3D applied (right)
Fog effect
Post Production:Text
Original (left) and with variations of Path Text applied (centre and right)
Path Text effect
References
B.Sc. (Hons) Multimedia Computing
Media Technologies
Digital Multimedia 3rd EditionChapman N. Chapman J. Wiley. 2010
http://www.cinepak.com/ http://www.mpeg.org/ http://www.sorenson.com/ http://www.adobe.com http://www.digitalpostproduction.com
