[x265] Who washed my video? x264 vs x265 'placebo' comparison

[Tom Vaughan]

Hi Niccolò,
Thanks for sharing.

Does the MKV contain video that was ripped straight from the Blu-ray Disc?
The video in the MKV is only 14 Mbps... I would have expected a higher bit
rate (and more detail) if this was not re-encoded.  It would be best to
start with the highest quality source possible.

Notice that prova.h264 is twice the size (12 MB) of prova.h265 (6 MB).  This
explains some of the difference in quality.  It's hard to hit a bit rate
target with such a short clip.  You may need to use CRF, experimenting with
different values until you get close.  I think that your test method is
valid, and the results are very interesting, but you have to make sure that
you end up with identical bit rates.

To be fair, we want to compare encoded frames to the original incoming
frames.  We don't want to consider "more compression artifacts" to be "more
detail".  There are definitely some areas where your x264 encode preserved
more detail, such as in the waves on the water, or the green areas in the
landscape.  I noticed that even at half the bit rate, the x265 encode
provides much more accurate edge definition of objects in motion and far
lower noise than the x264 encode.  Notice how you can see the individual
feathers in the close-up shots of the birds flying.

The x265 development team is working to port and adapt the remaining x264
algorithms that haven't been ported (like psycho-visual optimizations), and
we continue to test and improve the algorithms already implemented (adaptive
quantization, etc.).   We appreciate feedback like this.  We would also like
to hear any suggestions from developers or other video experts on how we can
improve our algorithms to achieve the best possible visual quality under all
circumstances.

Thanks!
Tom


-----Original Message-----
From: x265-devel [mailto:x265-devel-bounces at videolan.org] On Behalf Of
Niccolò Belli
Sent: Sunday, February 23, 2014 12:33 PM
To: x265-devel at videolan.org
Cc: x264-devel at videolan.org
Subject: [x265] Who washed my video? x264 vs x265 'placebo' comparison

Hi,
I did a quick x264 vs x265 comparison in my blog, hopefully someone will be
intersted watching it:
http://www.linuxsystems.it/2014/02/washed-video-x264-vs-x265-placebo-comparison/

Cheers,
Niccolò
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