codecs in Constant 2009
documentary is and can be, to the production tools and
content management systems media makers use, to a legal status of
media that reflects an understanding that culture is something which
is shared, down to the technical details of the formats and codecs
carrying the media in a way that facilitates sharing, instead of complicating it.
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Mutual Motions
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Whether we operate a computer with the help of a command line interface, or by using butt
d wireless networks both use
signal processing, but for different reasons. Although they seem quite
disparate from each other in terms of how we embody them, they
actually sometimes use the same DSP algorithms. (In other work, I
have discussed video codecs. 3
3
The case of video codecs
In the foreground of the UMPC vision, stand images, video images in particular, and
to a lesser extent, sounds. They form a congested mass, created by media and information networks. People in electronic media cultures constantly encounter images in
YouTube.com, Yahoo video, etc.). A powerful media-technological imagining of
video moving everywhere, every which way, has taken root.
The growth of video material culture is associated with a key dynamic: the proliferation
of software and hardware codecs. Codecs generate linear transforms of images and
sound. Transformed images move through communication networks much more quickly
than uncompressed audiovisual materials. Without codecs, an hour of raw digital video
would need 165 CD-ROMs or take roughly 24 hours to move across a standard computer
network (10Mbit/sec ethernet). Instead of 165 CDs, we take a single DVD on which a
film has been encoded by a codec. We play it on a DVD player that also has a codec,
usually implemented in hardware. Instead of 32Mbyte/sec, between 1-10 MByte/sec
streams from the DVD into the player and then onto the television screen.
The economic and technical value of codecs can hardly be overstated. DVD, the transmission formats for satellite and cable digital television (DVB and ATSC), HDTV
as well as many internet streaming formats such as RealMedia and Windows Media,
third generation mobile phones and voice-over-ip (VoIP), all depend on video and audio codecs. They form a primary technical component of contemporary audiovisual
culture.
Physically, codecs take many forms, in software and hardware. Today, codecs nestle in
set-top boxes, mobile phones, video cameras and webcams, personal computers, media
players and other gizmos. Codecs perform encoding and decoding on a digital data
stream or signal, mainly in the interest of finding what is different in a signal and what
is mere repetition. They scale, reorder, decompose and reconstitute perceptible images
and sounds. They only mo
is performance of difference and repetition of video comes at
a cost. Enormous complication must be compressed in the codec itself.
Much is at stake in this logistics from the perspective of cultural studies of technology
and media. On the one hand, codecs analyse, compress and transmit images that
fascinate, bore, fixate, horrify and entertain billions of spectators. Many of these
videos are repetitive or cliched. There are many re-runs of old television series or
Hollywood classics. YouTube.com, a vi
online and broadcast media. A video beheading lies
at the outer limit of the ordinary visual pleasures and excitations attached to video
cultures. Would that beheading, a corporeal event that takes video material culture to
its limits, occur without codecs and networked media?
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its purpose is to receive and transmit information wirelessly, and
that it accommodates a variety of wireless communication standards
(WiMAX, HSPA, 802.16m, etc). In this context, much of the terminolog
ve movement or constitutive difference that is
interiorised. We can trace this interiorisation in the DSP used in
wireless networks. I do not have time to show how this happens
in detail, but hopefully one example of DSP that occurs but in the
video codecs and wireless networks will illustrate how this happens
in practice.
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Late in the encoding process, and much earlier in the decoding
process in contemporary wireless networks, a fairly generic computational algorithm comes int
out the impossibility of realtime
calculation was important to make during the 1990s, it seems well-established now.
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would select the most important or relevant components. This is precisely what happens in video and sound codecs such as MPEG and
MP3.
The ffT treats sounds and images as complicated superimpositions of waveforms. The envelope of a signal becomes something that
contains many simple signals. It is interesting that wireless networks
tend to use this process in re
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