[M4IF Technotes] Downloadable standard MPEG test sequences

[Kris Huber]

Ben,
>Another issue I have with the current test sequences is almost no
>real-world apps can read the .yuv format, and there aren't any tools I know
>of that can do a native colorspace conversion between .yuv and .mov or
.avi.
We have "ifdefs" in the code that dump and read these formats for internal
conformance testing of our MPEG-4 products and to create/use m4if interop
raw bitstreams as needed and to test using the MPEG4 conformance bitstreams
as part of self-certification.  I suppose if conformance testing were being
done by an external organization we could make this capability available in
a more user-friendly way.  Apparently that capability is quite important to
you?
As for conversion out of raw .yuv, I know the .avi and .mov are quite
flexible formats.  Although I'm less familiar with them than I should be, my
guess is that it's possible to convert from raw .yuv to either one without
doing a redundant color conversion.  I think it would depend on if anyone
has registered a format for "raw YUV" for .mov and .avi.  The problem with
that is that not all YUV's are equal, some having come from RGB through
somewhat different processes.  In a raw YUV format you are on your own to
know the color space and image resolution via external means.  There are no
headers.  Some formats have one or more color spaces associated with them,
although in actual usage the data in those formats are not always indicated
or obeyed strictly.  In the MPEG-4 visual object (VO) header the color space
information can be encoded.  Currently that information includes 6 choices
of color primaries systems, 8 choices of opto-electronic transfer
characteristic and 5 choices of colorspace conversion matrix (the one used
to go from RGB to YCbCr), but there is ample reserved space to add more
choices in the future as a need arises.  You can find more on the specific
choices that are currently available near the end of subclause 6.3.2 of the
video spec (ISO/IEC 14496-2:2001).
Best regards,
Kris
-----Original Message-----
Date: Wed, 10 Jul 2023 18:42:38 -0700
Subject: Re: [M4IF Technotes] Downloadable standard MPEG test sequences
From: Ben Waggoner <ben   interframemedia.com>
To: Rob Koenen <rkoenen   intertrust.com>, M4if <technotes   lists.m4if.org>
CC: "Klaus Diepold (TU Munchen) (E-mail)" <kldi   ei.tum.de>
Rob,
    Excellent news on a standard set of images with clear rights.
    Another issue I have with the current test sequences is almost no
real-world apps can read the .yuv format, and there aren't any tools I know
of that can do a native colorspace conversion between .yuv and .mov or .avi.
Ben Waggoner <http://www.benwaggoner.com>
Compressed Video Consulting, Training, and Encoding
Cleaner Tutorial:   http://www.saferseas.com/navseries/adclean.html
My Book:            http://www.benwaggoner.com/books.htm
Compression Books:  http://www.benwaggoner.com/bookshelf.htm
Compression classes at Stanford, July 15-19 and August 12-16:
http://www.digitalmediaacademy.org/courses/videocompress.html
on 7/10/02 5:15 PM, Rob Koenen at rkoenen   intertrust.com wrote:
> This is a problem and it has always been one.
> 
> Test sequences belong to companies, not to MPEG, and there
> was never a clear way of getting a hold of them, and it
> is even murkier for which purpose they can be used within
> constraints imposed by their owners a long time ago.
> 
> To alleviate this problem, M4IF is working with the Technical
> University in Munich, who are taking the initiative to shoot, and
> make generally available for use in MPEG and M4IF, a series of
> representative test sequences.
> 
> This will not help you for now, though.
> 
> If anyone on this list can help Ben get his hands on the sequences
> often used in MPEG, then please speak up.