[opendtv] AW: Re: Some results - 1080p @ 60 is Next?
- From: "Hoffmann, Hans" <hoffmann@xxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 4 May 2007 20:58:58 +0200
John,
don't mix up the "demo" with the new subjective testing method using upper
and lower anchor.
In addition, about half the sequences I used were part of the SVT test set
(generated on 65mm film with 50 fps, then scanned to 2160p/50 and
downconverted to 1080p/50, 720p/50 and 1080i/25). Sequences are public
available. The other half came from the HDC1500.
But you are right the method of creating the interlaced signal is always a
problem. This was one of the compromisses I had to take, because I wanted to
have the same content in all three HDTV formats (and repetitive shooting was
a no-go). I simulated basically the field read out method when creating the
1080i/25 from 1080p/50. One could think about much more fancy methods - but
what is practical in CCD cameras today is field read out.
When you view the UNCOMPRESSED images on the matrix displays you have in the
720p/50 case the impact of the spatial upconversion and in the 1080i/25 case
the de-interlacing. In practical terms however it does NOT MATTER what the
results are for uncompressed. The important aspect is how the images are
perceived after emission encoding and presentation in the home. Here we have
the impact of the H.264/AVC encoder (we used the software encoder in coop
with the HHI, because of 1080p/50). You have seen the results.
Does this help?
Best wishes,
Hans
-----Ursprüngliche Nachricht-----
Von: opendtv-bounce@xxxxxxxxxxxxx im Auftrag von John Shutt
Gesendet: Fr 04/05/2007 20:28
An: opendtv@xxxxxxxxxxxxx
Cc:
Betreff: [opendtv] Re: Some results - 1080p @ 60 is Next?
Mark,
I was curious about the specific EBU/IBC tests. From the full
report that
Hans wrote, the EBU created the 1080i25 and 720p50 test clips using
two very
different methods:
"These were shot with the help of SRG-TPC Switzerland and TVN
Germany using
a CCD Camera (type HDC1500) with dual-link output for 1080p/50.
1080p/50
material was used as the source for creating the down-sampled
720p/50 and
1080i/25 content. The 720p/50 down-sampling was performed in
software via
low-pass and sync-window filtering in the DVS server. The 1080i/25
content
was generated via box-filtering (line/pixel averaging) over two
consecutive
frames. Both methods were very close to practical applications in
today's
cameras."
I was wondering if the viewer preference for uncompressed 720p50
upconverted
to 1080p50 in the display, over uncompressed 1080i25 upconverted to
1080p50
(did I say that right this time?) was due to the different methods
that the
EBU used to create the downsampled test material in the first place.
John
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