[opendtv] AVC for ATSC M/H
- From: Ron Economos <w6rz@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Thu, 14 Aug 2008 01:44:13 -0700
Found this on the JVT website.
http://ftp3.itu.ch/av-arch/jvt-site/2008_07_Hannover/AgendaWithNotesAB_d5.doc
http://ftp3.itu.ch/av-arch/jvt-site/2008_07_Hannover/JVT-AB016.zip
Ron
Liason Statment from ATSC:
The ATSC reported that it is developing specifications for a new service
to deliver video to mobile and handheld devices, known as ATSC M/H. A
tentative decision has reportedly been made to employ AVC coding,
Baseline Profile at level 1.3, with one picture format of 416 by 240
luma samples (WQVGA), with frame rates from 12.0 to 30 fps. These
choices were made based on input from device manufacturers who indicate
they can support early market entry of a large number of receiving devices.
Broadcasters have reportedly expressed interest in transmitting higher
resolution (up to wide SDTV) pictures over ATSC M/H. A tentative
decision has also reportedly been made that higher resolution may be
handled by use of SVC.
However, concerns have reportedly been expressed that by restricting the
video tools that may be used (e.g. no 'B' frames), and relying on SVC as
a path to higher resolution, some inefficiency may be designed in that
could lead to a long term under-utilization of precious data bandwidth.
Before decisions are final, broadcasters would reportedly like to better
understand the consequences to eventual bit rate possibilities.
ATSC would welcome any information that MPEG could provide to them as to
the possible increased efficiency (compared to Baseline Profile, Level
1.3, 416x240 pixel image format constrained for SVC) that could be
obtained by choosing a set of AVC tools that would give us more
efficient coding (e.g. use of 'B' frames, weighted prediction, directly
coding wide SDTV vs using SVC, etc.).
ATSC would like to reference a specific MPEG AVC Profile in the M/H
specification. If a set of AVC tools that do not fit within an existing
AVC Profile are the best solution for the M/H application, they ask if
MPEG would consider defining a new Profile that ATSC could reference in
its standards. If such a new profile option would be considered, they
ask in what time frame this work could be completed.
Response from JVT:
Remark: It was suggested that the context of the intent was that picture
aspect ratio would always be approximately 16:9, always have
approximately square luma samples, and always be "progressive" scan.
Further, it was suggested that the desire would be to have
standardization completed in WG 11 and ATSC by the end of 2009, and to
have devices actually deployed by that time. It was suggested that the
total bit rate for the low-res and SD video might be about 0.5 Mbits/s.
Basic aspects of contribution:
- Interest in greater coding efficiency than Baseline
- Initial focus on 390-macroblock pictures, with longer term
interest in SD
- Some interest in SVC
Suggestion: Respond saying:
The use of the High profile may be appropriate. Our understanding is
that very low cost, low power decoder implementations of the High
profile are already available in the marketplace. For example, we have
located product announcements for High profile decoding such as:
- an implementation for 1920x1080p60 decoding that uses 160 mW,
- an implementation quoting 1080p using 120 mW,
- a reference to 3.5G and 4G mobile implementations of high bit
rate High profile 1080p decoding in 2009-2011,
- an announcement referring to HD decoding using 45mW,
Further such information should be discoverable with somewhat more
study. Note that support for 1920x1080p60 would include support for a
sample processing speed ratio that is higher by a factor of more than 40
relative to the requirements for 416x240x30.
Regarding compression capability, some information that we have received
suggests that about a 40-60% bit rate savings for use of High profile
rather than Baseline profile might be expected for material such as the
416x240 use that they describe (e.g., per JVT-N014 of Jan 2005, and we
note that encoding technology for use of High profile features has
advanced substantially further since that time).
If the High profile does not meet the needs of your application, we are
prepared to collaborate further with you to study the subject and take
appropriate action as necessary. Although we suggest that no new
profile specification should be needed, in the event that this initial
assessment is incorrect, the ISO/IEC approval process (and typical
parallel ITU-T approval processing) for a new profile specification
would ordinarily take 1-1.5 years after the decision to create a new
profile and the determination of the detailed requirements of the
profile design.
Selection of the High profile for lower resolution use would not
preclude the use of scalable video coding (SVC) with this lower
resolution video as the base layer, as the AVC specification includes a
Scalable High profile that is specified to operated in that fashion.
We encourage further study and communication regarding the detailed
application requirements, such as bit rates, image sizes, frame rates,
etc. for the combined usage scenarios for the SD delivery in conjunction
with WQVGA over ATSC M/H.
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