AVC and containers

[georgekellerman]

Hi, members of the videohelp board. I'm new here and I have to confess, that I registered to ask something I don't understand. I hope it is OK to debut with a question.

As far as I understand it, MPEG2 not only specifies the MPEG2 video compression, but also two containers, namely MPEG2-Program Stream and MPEG2-Transport Stream. Further there's the MPEG2-PES container which all MPEG2-PS and MPEG2-TS containers consist of. I also know, that when I receive an MPEG2-TS stream from a DVBs source, the PIDs are the keys for the respective MPEG2-PES streams multiplexed into that MPEG2-TS stream. I hope this all is correct.

Now my question is about H.264/AVC: Afaik the MPEG organisation's official container for AVC is the .mp4-container. When I receive a DVB-s2 TV network, does really an .mp4-container hit my satellite dish or are there specific AVC-TS and AVC-PS containers specified? You know, I often read the terms "AVC-TS" and "AVC-PS". Are those official terms or just simply used by people for DVB-s2 environment and BD/HD-DVD environment .mp4-container streams respectively?

Thank you very much in advance.

[Cornucopia]

AVC video compression is aka MPEG4,part 10. As such, it still would be encapsulated/multiplexed in an MP4-type container.

Normally, MPEG1 video compression would go in an MPEG1 System Stream. An MPEG2 video compression would go in an MPEG2 Program or Transport (or PES?) Stream. And an MPEG4 video compression (whether Part1, Part2 or Part10) would go in an MP4 (Program/Transport) Stream.

However, MPEG containers always allow for backward-compatibility of compressions, and usually forward-compatibility (so you can have MPEG1 video in MPEG2/DVD-VOB container, and MPEG2 stream in MPEG1 System Stream, etc).

DVB usually has used MPEG2 Transport streams, but some are moving towards MP4 container streams.

AFAIK, there should be no "AVC-specific" container.

Scott

[georgekellerman]

Thanks Cornucopia!

I see. There's no AVC specific container, there are only MPEG2-PS-, MPEG2-TS- and .mp4-containers. And the terms "AVC-TS" and "AVC-PS" mean AVC video in an MPEG2-TS and MPEG2-PS container respectively...

[georgekellerman]

... Now when it's an .mp4-container DVBs2 broadcast, is it a specific .mp4-container type, namely one specified for the practical situation of broadcasting? Or - unlike it is with MPEG2's PS and TS - is there only one .mp4-container?

Thanks again!

[georgekellerman]

Does anybody know that...

[guns1inger]

I believe a transport stream is agnostic as to the video content, and is not specific to mpeg-2 video.

These pages go back to 2004 discussing extensions to the transport stream design to allow for AVC and H.264 content.

http://forum.doom9.org/archive/index.php/t-85003.html
http://www.dvb.org/news_events/news/archive/dvb_approves_new_guidelin/index.xml

So no, I don't believe the .mp4 container is used for broadcast because it doesn't need to be. The Transport Stream container works in that context.

[georgekellerman]

Yeah, thanks guns1inger. So you don't think there are .mp4-container channels. You know, I just made another thread, asking for posting about it, should someone have found one. Now, after I have read differing views about that, let's wait and see. Personally I believe that there is no .mp4-container broadcast from the satellites, nor are there any plans for such. But who knows...

Anyway, thanks for the links. Those were very helpful. Yeah, MPEG2-TS doesn't care much. AVC in MPEG2-TS is a definite!

Thanks again!