Image Processing Reference
In-Depth Information
Of the first three, each is covered in a chapter of its own following this one, while
Flash is covered in Chapter 25 together with some other alternatives.
Open Standards
The trend seems to be for players to move toward the support of open-standards content
formats. If this continues, they will lose some hold on the customer base since the propri-
etary lock-in is no longer in force. This is good news for the service providers, because they
can deploy the best products for the task at hand—for example, Windows Media produc-
tion tools running on Intel hardware or QuickTime tools running on Mac OS X feeding
content to a Helix or Darwin server running on Linux or Solaris. In the long term, the mar-
ket should find its own level, based on the suitability and quality of the tools, if the cus-
tomer is allowed to choose the most fit-for-purpose products and integrate them into a
systematic workflow.
The open-standards support is good for consumers because they are able to use the
player of their choice. It would be ludicrous to mandate that consumers must watch a par-
ticular TV channel on one manufacturer's TV. The parallels are very similar, and many
online video providers are forcing users to make exactly that choice. Proprietary formats
are not well enough supported by the competing players, so there is an opportunity to
solve that problem by using open standards.
There are some robust, emerging open standards for multimedia and some very
advanced video coding technologies available as open standards. Let's examine how that
might look from the standpoint of the three major companies and the Linux operating sys-
tem with prior de facto standards that might be threatened.
The most encouraging possibility is that all three dominant players and those whose
market share is minuscule by comparison appear to be willing to embrace the open stan-
dards. It is anticipated that the H.264 standard will be supported widely. If that happens,
you will have a better chance of reaching viewers on all platforms regardless of the player
or platform they choose.
Postprocessing in the Player
De-blocking filters are the most common postprocessing operation that the player applies
to the decoded output. This is designed to hide the edges of the macroblocks when
extreme compression ratios are used.
Some codecs just allow the player to apply de-blocking blindly and whenever they
feel like it. There is no finesse to this approach because it is just a blurring operation.
More recent and advanced codec designs insert de-blocking hints into the file to
assist with the de-blocking process at the decoding stage. The hints are worked out based
on the errors and residuals in the encoded input.
In addition to de-blocking, some decoders support a de-ringing or de-fringing of
edge artifacts. These get introduced by the DCT transform. They may be there in the first
place because too much sharpening was applied when the video was scanned on
the Telecine unit. Refer to the chapters on video formats and quality issues, as well as the
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