In the USA, the transition from MPEG-2 to H.264/AVC encoding
was further encouraged by the 2009 official switchover from analog to digital
television (DTV). Worldwide, however, the DTV switchover has yet to happen in
many countries (e.g., Brazil, China, and Russia are not scheduled to switchover
until 2018), and the final country on the current schedule (Cuba) will not join
the DTV “revolution” until 2024. In pre-DTV countries, both SD television and
MPEG-2 encoding technology retain strong holds.
If we apply this lesson about the adoption of new, 2X more powerful,
but also more costly and less proven encoding technology to the new H.265/HEVC
encoders that are now starting to appear commercially, following 2013
finalization of the new 3rd generation MPEG encoding standard, it
seems probable that any significant uptake by broadcasters of new H.265 systems
will be slow to materialize. Just as inexpensive MPEG-2 technology remains in
widespread use today for SD television, despite a 2X bitrate advantage for
H.264/AVC technology, less expensive and better established H.264/AVC
technology is likely to remain the popular choice for use with HD television,
despite its 2X bitrate disadvantage compared to the latest H.265/HEVC encoders.
Judging by the historical lesson of the MPEG-2 to H.264/AVC
transition, the driver for H.265/HEVC technology will not be any mere technical
advantage in bitrate reduction over the decade-older H.264/AVC technology, but
rather the widespread adoption of a new, higher-resolution TV format that
multiplies picture data by a significant number. Fortunately for the new
standard, higher resolution TV formats are already starting to appear.
Relatively inexpensive 4K UHDTV sets, featuring a 3840 x
2160 resolution that multiplies 1920 x 1080 HD formats by a factor of 4, are
already available for purchase, with even larger 8K formats of 7680 x 4320, that multiply HD formats by an
enormous factor of 16, waiting in the wings. When the spread of UHDTV sets to
households reaches critical mass in another few years, followed by the
transition to UHDTV programming over the next few years on the part of
broadcasters, adoption of better encoding technology to cope with the rising
tide of bits generated by UHDTV will become essential. But the transition to UHDTV
will not be quick, let alone immediate. As a result, widespread use of
H.265/HEVC is far more likely to occur towards the end of the current decade
than near its middle.
Although the multiplication of video data due to the rise of
4K programming will make H.265/HEVC encoding technology essential before the
end of the present decade, this latest encoding standard, able to halve the
number of bits needed to generate a picture (compared to H.264/AVC technology),
is obviously not sufficient in itself to cope with a 4X multiplication of bits.
Even postulating another 50% reduction in bits from the introduction of still-to-be-developed
H.266/MPEG-6 technology in 2023 will not help—assuming another 4X increase in
bits during the 2020 decade from a move to 8K programming.
To the contrary, 21 years after the introduction of the
first MPEG-2 standard for broadcast encoding, we appear to be locked into a
losing race, where our best efforts to push encoding technology forward to new
generations increasingly fall behind a growing flood of bits generated by the
market’s appetite for higher and higher resolution pictures. We will consider
this problem in our next blog.
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