Inspired by the
difficulties with encoding the recent Shadow of the Beast submission, I decided to run a few tests of my own.
After making 20 excruciatingly slow test encodes on a short (26 second long) sample I realized that doing this alone would be much slower than otherwise.
Since I originally aimed to use a bitrate of 500 kbps I decided to freeze this value and try to optimize quality by tuning other x264 settings. I use SSIM (append
--ssim to your x264 commandline) for quality measurements since it's the
most accurate quality measurement algorithm available to me.
So, here's the challenge.
Get a SSIM value of 0.92+ on the following sample: http://www.sendspace.com/file/slab97 (249 MB).
So far my
best attempt got 0.9151, but I didn't max out a couple of potentially useful parameters due to lack of available waiting time.
Restrictions: use
--fullrange on, don't use
--deldup (for this sample). Target bitrate is
500±5 kbps.
Post your best encodes along with their commandlines, and maybe we can improve something in the current encoding standards! Or maybe you will find some settings in your usual commandlines that decrease the quality in some way.
My current commandline:
--bitrate 500 --ref 16 --no-fast-pskip --bframes 10 --b-adapt 2 --direct auto --deblock -4:-4 --subme 10 --trellis 2 --partitions all --me tesa --merange 64 --aq-strength 2 --no-dct-decimate --ssim --fullrange on --rc-lookahead 250 --qpmin 12 --qblur 0.1 --keyint=1800 --weightb --8x8dct --mixed-refs