= Subjective Viewing =

== Preparing material for subjective viewing ==

=== Video data ===
Please provide a directory per proposal or reference containing:
 - decoded 8bit yuv files, using the naming convention of the original material on
   the uni-hannover ftp site.  Eg, "BQMall_832x480_60.yuv".
   [[BR]]
   This will allow scripts to automatically determine the display parameters.

 - if the same sequence at multiple QPs is to be tested, place video files in
   directories called qpNN.

 - this data should be copied to {{{Z:\XXX\SomeUsefulIdentifierEgCE11}}} on the playout computer.

 - please avoid using spaces in file or directory names.

For example, assuming two proposals, "REF" and "DUT" we should see the following:
{{{
$ ls -R REF/
REF/qp22/BQMall_832x480_60.yuv
REF/qp22/ParkScene_1920x1080_24.yuv
...
REF/qp27/BQMall_832x480_60.yuv
REF/qp27/ParkScene_1920x1080_24.yuv
...

$ ls -R DUT/
DUT/qp22/BQMall_832x480_60.yuv
DUT/qp22/ParkScene_1920x1080_24.yuv
...
DUT/qp27/BQMall_832x480_60.yuv
DUT/qp27/ParkScene_1920x1080_24.yuv
...
}}}

=== Preparing a playlist ===
We have a script that will create a playlist in the correct form to do a randomized
A-B-A-B viewing.  It requires an input file to list the sequences that are of interest
and the order in which to evaluate them:

 1. Create a textfile that names the order you wish to view the test points.  Eg,
{{{
$ cat order.txt
qp22/BQMall_832x480_60.yuv
qp27/BQMall_832x480_60.yuv
...
qp22/ParkScene_1920x1080_24.yuv
qp27/ParkScene_1920x1080_24.yuv
...
}}}
    Note the lack of any "DUT" or "REF" prefix.
 1. Run [[http://ftp.kw.bbc.co.uk/davidf/jctvc/gen-playlist-shuffled.pl|gen-playlist-shuffled.pl]] to generate a playlist:
    [[BR]]
{{{
$ gen-playlist-shuffled.pl /path/to/REF /path/to/DUT order.txt > out.plst
}}}
    NB, the path given to REF and DUT should be fully qualified.
 1. For a subjective test with multiple viewing sessions, it is advisable to generate
    multiple copies of the playlist, one for each viewing session.  Each viewing session
    is then randomized differently.
    [[BR]]
    For example,
{{{
$ for N in 1 2 3 4 5 6; do
     gen-playlist-shuffled.pl /path/to/REF /path/to/DUT order.txt > session$N.plst
  done
}}}

=== Running the test ===
Launch the [[http://ftp.kw.bbc.co.uk/davidf/videoplayer/|videoplayer]] using:
{{{
$ /path/to/videoplayer --vt.readahead=128 --vdu-fps=60 --quit --full --osdstate=2 $ANYOPTIONS_IVE_MISSED out.plst
}}}

The player will quit automatically when it reaches the end of the playlist.

//DF: this could be made simpler if we create a small script and associate the .plst
file extension with it.  Then people only have to double click on the correct playlist//

== Notes on test configuration ==
 - The [[http://ftp.kw.bbc.co.uk/davidf/jctvc/gen-playlist-shuffled.pl|gen-playlist-shuffled.pl]] script
   will produce an A-B-A-B stimulus, with A and B randomized for each test point.
   [[BR]]
   eg, for BQMall @ qp22, it might be REF-DUT-REF-DUT, but for qp27 it might be DUT-REF-DUT-REF.

 - If the test involves multiple proposals, an A-B-C-D-E-..Z-A-B-C-D-E-..Z stimulus can be generated
   by providing multiple directories.  The stimulus order for each test point is randomized.
   Eg, {{{ gen-playlist-shuffled.pl REF DUT1 DUT2 DUT3 DUT4 order.txt }}}
   [[BR]]
   //DF: this seems kind of pointless, surely it should be A-A-B-B-C-C-D-D-E-E-...Z-Z, which is what we've done before//

== Notes on black & white level ==
By default, the videoplayer outputs R'G'B' at 16-235, however on a
computer monitor, this will look wrong.  The following options will set
the output range to 0-255: {{{ --out-black=0 --out-range=256 }}}

Alternatively, one can interactively toggle between the two to see the
difference by using the 'n' and 'b' keys.

//DF: what range has the monitor been configured for?