[x264-devel] I444 support

[James Gardiner]

Hi,
I have been monitoring this list for quite some time now.  A long time
ago I mentioned that I was interested in high 4:2:2 and High 4:4:4
support.  Peter List recently mentioned that H.264 was not suitable for
hi quality encoding with low compression.  I would like to ask a few
specific question to the list regarding this and its opinion.

Firstly, I work with digital Media Playback systems specifically for
cinema.  Currently MPEG2 and H.264 codec are very popular for
distribution on these devices.  To give you some general positioning
here.
A low compressed MPEG2 stream is generally considered to be of much
better quality on screen then FILM.  Ie 1920x1080 is, in most cases, a
much better picture then a Film that has been duplicated 3 to 5 times
from a master (film).  Film does not duplicate well at all.

MPEG2 and H.264, however, have a very limited colour space, and trained
eyes, like mine, can see this stand out.  Generally, however, 99% of
movies goers do not know the difference.  Still, it is the main big
drawback in e-Cinema (Compared to DCI d-cinema).

Now, DCI or D-cinema uses JPEG2000 and a very constraining DRM system.
It is expected that all cinemas will have a DCI player and a OPEN
player. (Due to security issues with DCI and also because many
films/advertising may also be distributed in NON-DCI formats in the
future.).  As such, this open player really needs to stand up to better
colour depth.
JPEG2000 is an option, however, as a INTRA frame compression, movies in
this format as HUGE.  Moving this data around will be very troublesome
and expensive to a cinema owner.  As such, using a better compressor for
smaller files which can archive no perceivable difference on screen is a
technology this industry should be very interested in.  (Once it exists)

H.264 at Profile High-4:2:2-10bit colour should do the job. This is
mainly because, most DI (Digital editing of films) is done at this same
colour space and depth.

So, I have been monitoring this list for a LONG time waiting to see what
you guys get up to.

However, the comments about use of H.264 and JPEG2000 has encourage me
to stand up for once and ask a question.

Considering what I have described above and what Peter List has said. Is
H.264 worth using for the picture I have painted above?  Will not a IBP
type compression always get far better picture quality per byte then a
INTRA compression.  Considering this is a distribution format, will not
the picture on screen be as good as a JPEG2000 stream?


Thanks,
James