The H.264 Codec - A Practical Guide to Video and Audio Compression - page 238

tools were provided for the encoder to use when compressing the content. These tools are
designed to cover those situations where the tools available in MPEG-2 were at their
design limits for performance, thus creating a need for new tools.

13.2.2 Digital TV

The MPEG-2 codec is most often used for digital TV services; the H.264 codecs could be
deployed to achieve better quality at the same bit rate or the same quality at a lower bit
rate. Comparative side-by-side tests have shown that H.264 offers superior quality to
MPEG-2 at less than half the bit rate. A very good-quality domestic TV service could be
delivered at around 2 Mbps or better. This area is advancing technologically very quickly.
Bulldog is now offering a 4-Mbps broadband service to UK homes and there is speculation
that domestic services as high as 22 Mbps might be possible.

13.2.3 Main Features of H.264

Here are the main selling points of this codec:

High quality

●

Ultra efficient

●

File size is efficient

●

Scalable from 3G to HDTV and D-cinema

●

Delivers full HD playback on contemporary hardware

●

Open standard-ratified

●

Cross-industry support for interoperability

●

Elected as a standard for next-generation DVD, set-top boxes, and computing

●

The resulting codec delivers video at very low bit rates for devices ranging from
mobile phones to high-definition TV and D-cinema formats. The mobile format is repre-
sented by 3GPP 176 × 144 at a bit rate of 64 Kbps. High-def format would be 1920 × 1080

scanned progressively at a bit rate of about 8 Mbps or better.

13.3 What's in a Name?

The ITU and the ISO MPEG working groups combined to form the Joint Video Team so
the codec is sometimes called JVT . Because it is ratified as an ISO standard, it is called
ISO_IEC_14496-10 but this is hard to remember. The ISO 14496 standard describes MPEG-
4 so this codec is sometimes called MPEG-4 part-10. The MPEG working group calls it
Advanced Video Coding to distinguish it from MPEG-4 part 2, which is called the MPEG-
4 visual standard. So the term AVC is used quite often.
Finally, the ITU recommendations are all coded with an H prefix so it is known as H.264.
In order to distinguish the incomplete working status of the standard before it was ratified,
the ITU replaces the last digit with a letter, so you may encounter the terminology H.26L .