[vdr] Compressing VDR recordings without losing quality.

VDR User user.vdr at gmail.com
Sat Oct 30 21:16:13 CEST 2010


On Sat, Oct 30, 2010 at 10:03 AM, Niko Mikkilä <nm at phnet.fi> wrote:
> Tradeoffs
>
> As Lars Bläser pointed out earlier, all this processing and encoding
> comes at a high price in CPU time and energy consumption. Whether it's
> worth it depends on your purposes, so make your own calculations. If you
> only want a bitrate reduction for storage reasons, CPU time alone may
> cost more than the required disk space -- unless it gets cold outside
> and you are heating with electricity...
>
> Efficient encoding still requires lots of manual work because there are
> no reliable automatic detection schemes for recognizing different types
> of sources: interlaced, telecined, field-blended and phase-shifted.
> Personally I'd like a scheme where the encoder frontend would adapt to
> source type changes on the fly and encode the video with a variable
> framerate, but this is not always desirable.

Unfortunately it will always require a lot of manual work, and more
importantly knowledge of encoder settings and how they affect the end
result.  It would be great to have an app which is capable of properly
detecting the requirements of each frame and selecting the best way to
process it but that's extremely complex and it will never be perfect,
which is why you don't see such software.  It doesn't help that many
editors and broadcasters completely trash their source material.  I've
delt with video that made me want to slap the person(s) who processed
it and I'm guessing I'm not the only one here who can say that.  ;)

We can get into a huge discussion about the different filters and
methods available but I don't think this thread or mailing list is the
right place for that so I'll just say that there are few filters that
are 'best' to use across the board.  For the best results you have to
identify the needs of the source and choose filters that are able to
deal with it with the highest quality.  Not all interlaced source is
the same.  Not all telecined source is the same.  Etc, etc..

I'd also like to stress to the OP that the time investment, encoding
time for TB's worth of sources and energy usage may be far less
attractive then simply buying additional storage space.  Especially
when you consider good 1TB drives can be had for around $50-$70USD
these days.  Reencoding all that stuff would be the last option on my
list to be honest but that's only my opinion.



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