[mythtv-users] HD reference files?
beww at beww.org
Tue Mar 6 01:45:57 UTC 2007
On Mar 5, 2007, at 6:00 PM, David Murphy wrote:
> As hardware requirements for HD/SD playback are a constant theme I was
> wondering if there are any HD reference files that are freely
> on the net? I know there are plenty of movie trailers etc but what I
> had in mind was a small set of like 10-15 second clips at the various
> common formats 1080i/p, 720p, 480p etc.
> It would be nice if these clips were perhaps the most complex and
> demanding scenes possible, designed to push decoding requirements as
> high as possible. Mythtv users could then download a small test set of
> files, dump them on their hardware and see how a given hardware config
> handles a common reference.
There are several "worst case" videos used in broadcast, including
the tulips waving in the wind, the merry-go-round, the slow-speed
chopper rotors etc. Some of them are on the Radio Shack 44-1250 test
DVD but as they are already MPEG-2 they are for testing decoder
setups, to test encoders you'd have to have a source of "perfect"
baseband video, not cheap for HD.
If you used an HD signal from cable, satellite or OTA you would have
at least 2 sets of encoder/decoders and possibly more, as some
broadcasters actually use MPEG for transport and backhaul.
CBS transports as MPEG, decodes at the affiliate station to get
baseband so they can switch it, then re-encodes to MPEG. Fox uses a
different method, they have a device that lets them insert
commercials and the like directly into the MPEG stream, more
expensive gear but it saves a decode/encode step.
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