Why mpeg-2 rather than mpeg-4 avc for HD movies?

[travisbicks]

I apologise for the likely naivety of the following questions.

I’ve learnt that some high definition films on HDDVD and BluRay discs are encoded in a modified mpeg-2 format and I’m wondering what the advantage of this is over encoding them in an mpge4 avc format such as VC-1 or H264?

I believe that the compression of mpeg-4 is much more efficient, so is there a quality advantage that mpeg 2 still has that makes it worth using?

[foxyshadis]

Price and availability. AVC and VC1 authoring studios are a little more expensive, and most of the big suppliers had their MPEG2 encoders ready for HD long before the other codecs. (Sony, in particular, pushed hard to get bluray studios to use its lousy MPEG2 suite, though they now have all 3.) Buying a new system when the old one was just purchased 6 months ago doesn't make sense, even when the new ones look better.

[travisbicks]

Thanks!

So, as the continued use of mpeg-2 is due to short term economic factors, am I right to suppose it will become obsolete and replaced by mpeg-4 avc eventually?

[bond]

Thanks!

So, as the continued use of mpeg-2 is due to short term economic factors, am I right to suppose it will become obsolete and replaced by mpeg-4 avc eventually?no, mpeg-2 is one of the most widely used formats and will be widely supported for a very long time to come

[JoeShrubbery]

no, mpeg-2 is one of the most widely used formats and will be widely supported for a very long time to come

Exactly. Support for PLAYBACK will be supported and that will continue for the foreseeable future (it's embedded in the standards for all current disc and broadcast HD standards, and will thus survive at least as long as those standards are in use), but in realistic usage for encoding new content? Once those authoring suites without AVC support are looking long in the tooth even to penny-pinching studio execs you're just not gonna see the big studios releasing stuff on disc in mpeg-2, if only to be able to cram more extras on certain big-title releases that people are expecting and demand long checklists of extras on.

[CZroe]

It helps to be able to provide all of the DVD release's extras over to the HD movie without having to recreate them. No reason for HD discs to have less content and therefore less reason to buy them just because it's harder to remake all that content.

Also, HDTV broadcast content (ATSC) is already encoded as MPEG2, so encoding that to AVC or VC-1 would be pointless unless they want to fit more episodes on discs or have access to higher-quality source material (film).