ATSC ADOPTS STANDARD FOR ADVANCED VIDEO CODING

Video compression, which reduces the bandwidth required to transport a digital video signal, was one of the key technologies that enabled the development of digital television (DTV). The state-of-the-art for video coding technology in the early 1990s was MPEG-2, and this became a fundamental part of the Advanced Television Systems Committee (ATSC) standard, as well as DTV standards in other parts of the world. The vast majority of DTV receivers worldwide, including many millions in the United States, now decode MPEG-2 video.

Due to "Moore's Law," the processing speed and memory capacity of hardware devices for video encoding and decoding has advanced greatly since MPEG-2 was developed. This has enabled increasingly sophisticated compression algorithms to be developed that take advantage of the increased hardware power now available at ever-lower price points. These new video encoding/decoding (codec) systems provide significant improvements in coding efficiency compared to MPEG-2 and can result in equivalent or better quality at lower bit rates. However, none of the new advanced codecs are backward-compatible with MPEG-2, which creates a challenge for their introduction into existing broadcast systems.

One of the new codecs that is receiving wide acceptance in deployment of new video services is Advanced Video Coding (AVC) and last week the ATSC published a standard to enable the use of AVC for ATSC DTV. One of the reasons for adding AVC to ATSC is that several countries that still have to decide on the DTV transmission standard to be adopted have asked for advanced codec capability, and this is needed for ATSC to be competitive with alternative systems under consideration. In the United States, AVC is unlikely to be used in the near future for regular DTV broadcasting because the large installed base of MPEG-2 integrated receivers and set-top boxes in this country would be unable to decode such programming. As mentioned in the ATSC press release (see below), standards for new mobile/handheld (M/H) and non-real-time (NRT) services are now being developed in ATSC that, by their nature, would require new receiver devices. These are obvious candidates to take advantage of the improved efficiency of AVC. In fact, a high-efficiency advanced codec is virtually essential for the M/H standard in order to preserve adequate DTV channel bandwidth for existing MPEG-2 services.

In their press release on AVC, for the first time in public, the ATSC refers to "ATSC 2.0." This concept for next generation services for fixed receivers is part of the ATSC long-term strategic plan for the future of DTV. ATSC 2.0 is currently in the development stage in the ATSC Planning Committee, chaired by NAB Science & Technology staff member Graham Jones, and is a separate effort from the mobile/handheld standard now in preparation. Various new capabilities are envisioned for ATSC 2.0, which is expected to trigger a new generation of receivers potentially including AVC.

"WASHINGTON, September 2008 - The Advanced Television Systems Committee, Inc. has approved and published A/72 which details the methodology to utilize Advanced Video Coding (AVC) within an ATSC DTV transmission. AVC, which was developed by the ITU-T Video Coding Experts Group together with the ISO/IEC Moving Picture Experts Group, is also known as H.264 and MPEG-4 Part 10. The A/72 Standard defines constraints with respect to AVC, compression format restraints, low delay and still picture modes, and bit stream specifications. In addition it specifies how CEA-708 closed captions are to be carried in an AVC bit stream. The new standard is in two parts, Part 1 is titled "Video System and Characteristics of AVC in the ATSC Digital Television System," and "Part 2" AVC Video Transport Subsystem Characteristics."

"AVC compression provides increased efficiency and flexibility", said ATSC President Mark Richer. "The new standard will be especially important for those countries which have not yet implemented digital television. AVC will also be used with standards in development such as ATSC-M/H for mobile and handheld applications and ATSC-NRT for non-real-time delivery of programming."

The Advanced Television Systems Committee is an international, non-profit organization developing voluntary standards for digital television. The ATSC member organizations represent the broadcast, broadcast equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. ATSC creates and fosters implementation of voluntary Standards and Recommended Practices to advance terrestrial digital television broadcasting, and to facilitate interoperability with other media.

ATSC-M/H is being developed to support a variety of services including free (advertiser-supported) television and interactive services delivered in real-time, subscription-based TV, and non-real-time content download for playback at a later time. The standard may also be used for transmission of new data broadcasting services such as real-time navigation data for in-vehicle use.

ATSC-NRT addresses the new reality that consumers are increasingly in control and want information and entertainment content, when and where they want it. By leveraging the low cost of storage in receivers, broadcasters utilizing the ATSC-NRT Standard will be able download content to a new generation of products.

ATSC-2.0 will define a complete suite of "Next Generation" services for the conventional fixed DTV receiver viewing environment."

The A/72 standard is available for download at: http://www.atsc.org/standards/a72.php.

http://naob-advocacy.informz.net/naob-advocacy/archives/archive_150694.html

A non issue for the US - ATSC 1.0 will be the way forward for a very long time.

Yep - whilst AVC makes sense for those countries migrating from digital OTA MPEG2 SD to HD, like the UK, Sweden etc., or in territories where pay-TV via OTA is standard (much of Europe) where a new set top box or TV will be needed for HD anyway (or provided by the pay-TV provider), it makes little commercial sense for the US, where OTA is already HD and almost universally FTA.

Presumably ATSC are adding AVC/H264 to the standard in a hope that it will be adopted in other territories, just as DVB-T and DVB-T2 supports H264 (and is already on the air with AVC/H264 in SD and/or HD in some countries - such as Sweden, New Zealand, Norway etc.)

A non issue for the US - ATSC 1.0 will be the way forward for a very long time.

What's your definition of a long time? I can see ATSC 2.0 being proposed as a new standard in about five years. It could start with dual broadcasts with the broadcasters doing both ATSC 1.0 and 2.0.

What's your definition of a long time? I can see ATSC 2.0 being proposed as a new standard in about five years. It could start with dual broadcasts with the broadcasters doing both ATSC 1.0 and 2.0.

There simply won't be enough room to repeat a dual broadcast conversion in the future, since we are losing 52-69 and 2-6 are of very limited utility for DTV. Considering that very few OTA viewers had converted to DTV in the preceding 9 years, it was probably a waste of energy anyway. To this day, most believe DTV isn't here yet!

What's your definition of a long time? I can see ATSC 2.0 being proposed as a new standard in about five years. It could start with dual broadcasts with the broadcasters doing both ATSC 1.0 and 2.0.

But where is the spectrum for dual broadcasting going to come from? Hasn't the post-analogue-switch-off free-spectrum been auctioned off?

(In the UK - we're shifting from 6 x DVB-T SD MPEG2 muxes to 5 x DVB-T SD MPEG2 muxes and 1 DVB-T2 HD H264 mux - but this may compromise SD MPEG2 quality yet further, even though the remaining 5 DVB-T muxes will be running in new configurations to deliver the same payload as previously delivered with 6...)

AVC is at least 50% more efficient than Mpeg-2 so in theory could squeeze both one HD Mpeg-2 HD stream anlong with one AVC HD stream into one channel. I believe even after the analog cut off and the reclaiming of broadcast bandwidth their should still be enough space in most areas for broadcasters to use the AVC technology on a temporary (perhaps reduced power) basis. This will be an issue for the FCC to look at.

Great, so we get to look forward to 2 primary bitstarved subchannels for a long period to accomodate a new codec which does not exist in hardware on pretty much any of the 30-40% of US viewers who bought a HDTV between 1998-2010?

Who's looking forward to ~8-9 mbps broadcasts of 1080i mpeg2 :eek:?
(OK-maybe they would do 11.5 mpeg2 & 7.5 avc?)

AVC is at least 50% more efficient than Mpeg-2 so in theory could squeeze both one HD Mpeg-2 HD stream anlong with one AVC HD stream into one channel. I believe even after the analog cut off and the reclaiming of broadcast bandwidth their should still be enough space in most areas for broadcasters to use the AVC technology on a temporary (perhaps reduced power) basis. This will be an issue for the FCC to look at.

Current AVC encoders seem to require at least 8Mbs, and ideally nearer 10-11Mbs, to deliver decent quality 1080i content. (The Thomson Mustang-based stuff being shown at IBC were very watchable at 11Mbs on the DVB-T2 demo)

MPEG2 encoders require significantly more.

The UK is planning to squeeze three (possibly eventually four) H264 1080i streams into one 36Mbs DVB-T2 multiplex.

Trying to get an HD MPEG2 and an HD H264 stream into a single 19Mbs ATSC channel is going to be pretty tough on both streams in quality terms. You really need 15Mbs+ to deliver decent quality 1080i content in MPEG2 AIUI - even H264 won't deliver watchable HD in the 4Mbs that is left.

With decent encoders and a following wind you MIGHT get two watchable H264 HD 1080i streams into a 19Mbs ATSC stream.

What COULD be possible - is for a station to broadcast in SD MPEG2 at around 2-5Mbs, and then use the rest of the payload to carry H264 HD. (Would this make sense for digital stations that don't have any intention of going HD?)

Current AVC encoders seem to require at least 8Mbs, and ideally nearer 10-11Mbs, to deliver decent quality 1080i content. (The Thomson Mustang-based stuff being shown at IBC were very watchable at 11Mbs on the DVB-T2 demo)

MPEG2 encoders require significantly more.

The UK is planning to squeeze three (possibly eventually four) H264 1080i streams into one 36Mbs DVB-T2 multiplex.

Trying to get an HD MPEG2 and an HD H264 stream into a single 19Mbs ATSC channel is going to be pretty tough on both streams in quality terms. You really need 15Mbs+ to deliver decent quality 1080i content in MPEG2 AIUI - even H264 won't deliver watchable HD in the 4Mbs that is left.

With decent encoders and a following wind you MIGHT get two watchable H264 HD 1080i streams into a 19Mbs ATSC stream.

What COULD be possible - is for a station to broadcast in SD MPEG2 at around 2-5Mbs, and then use the rest of the payload to carry H264 HD. (Would this make sense for digital stations that don't have any intention of going HD?)

.
Currently in the Washington, DC area you have one station WJLA HD -ABC (720p) with two SD channels. Also you have WETA HD -PBS (1080i) with three SD channels and WRC HD - NBC (1080i) with two SD channels. I somehow get the feeling that some broadcasters really don't care about HD quality but jist want to get as many channels on the air as possible. Until the public gets vocal about this we will see more channels do the same thing.

In another thread their is the issue of cable companies squeesing three HD channles into on QAM, also with a loss of HD quality.

What COULD be possible - is for a station to broadcast in SD MPEG2 at around 2-5Mbs, and then use the rest of the payload to carry H264 HD.

Hi there

Is this wild idea backwards compatible with all existing ATSC tuners?
Will the transport demux ignore and not choke on the non-MPEG data stream?

Regards

The ATSC spec always included provisions for carrying data. Some crappy receivers (Voom come to mind) didn't handle the streams correctly, but anything standards-compliant should be able to ignore extra data.

ATSC M/H has a better chance of being adopted in the next 5 years than this ATSC 2.0. I would think for the typical station getting more eyeballs is key and using some portion of their BW (2-3Mbs) for portable devices makes more sense than trying to reinvent the wheel with H264. Also, without a mandate from the FCC it'll never happen. The inertia from the status quo is so huge it'll never happen without a huge shove. I mean there's still people today saying that the analog shutdown should be postponed/canceled. :rolleyes:

ATSC M/H has a better chance of being adopted in the next 5 years than this ATSC 2.0. I would think for the typical station getting more eyeballs is key and using some portion of their BW (2-3Mbs) for portable devices makes more sense than trying to reinvent the wheel with H264. Also, without a mandate from the FCC it'll never happen. The inertia from the status quo is so huge it'll never happen without a huge shove. I mean there's still people today saying that the analog shutdown should be postponed/canceled. :rolleyes:

Maybe ATSC 2.0 with AVC would go well with ATSC M/H, for the mobile stream. Can't you mix them?

- Tom

Hi there

Is this wild idea backwards compatible with all existing ATSC tuners?
Will the transport demux ignore and not choke on the non-MPEG data stream?

Regards

DVB receivers don't seem to have any problems. When the BBC and ITV/C4/Five ran their HD test stream OTA in 2006, most SD receivers saw the MPEG audio, but ignored the H264 video and AC3 audio. The same is true for the main SVT HD service in Sweden OTA.

Similarly DVB-S receivers are fine with a transponder carrying both H264 and MPEG2 video - BBC HD in H264 is broadcast in the same transport stream as BBC One CI and BBC One East (W) in SD MPEG2.

Some cheaper receivers with poor implementations may have issues - but I'd have thought they were fine.

Wasn't USDTV a similar situation?

Maybe ATSC 2.0 with AVC would go well with ATSC M/H, for the mobile stream. Can't you mix them?

- Tom

I'd have assumed so - wouldn't AVC be better than MPEG2 at the low data rates used for mobile TV?

ISTR that the Japanese ISDB-T system uses HD MPEG2 for their main HD service (which was a surprise - I'd have expected AVC - but maybe it is a compatibility issue with their satellite and cable services?) but low-res AVC for their 1-seg mobile TV offering?

I'd have assumed so - wouldn't AVC be better than MPEG2 at the low data rates used for mobile TV?

ISTR that the Japanese ISDB-T system uses HD MPEG2 for their main HD service (which was a surprise - I'd have expected AVC - but maybe it is a compatibility issue with their satellite and cable services?) but low-res AVC for their 1-seg mobile TV offering?

ISDB-T in Japan uses MPEG2 because it was launched way before AVC was available, just like ATSC. ISDB-T in Brazil that was launched this year uses AVC.
Also ATSC is about to adopt VC1 as another video codec under A/73 standard.

ISDB-T in Japan uses MPEG2 because it was launched way before AVC was available, just like ATSC. ISDB-T in Brazil that was launched this year uses AVC.
Also ATSC is about to adopt VC1 as another video codec under A/73 standard.

Yep - my mistake. I was under the impression that ISDB-T in Japan had launched a bit more recently than 2003 - when MPEG2 was still the only realistic codec choice for HD.

Nobody launching a new TV service these days would chose MPEG2 unless there was a very important reason to. AIUI almost all new DVB-T countries are launching with H264/AVC.