AC3 in MP4!

[bond]

will nerodigital devices now not need to support aac anymore? what about multichannel aac?

why does nero not simply use .mov? because the extension .mp4 is more funkier? and why dont you use .mpg with avc and ac3 like hddvd does?

[bond]

Originally Posted by JohnV

Skipping the re-encoding of the audio to AAC will also speed up the overall encoding process.
The AC3 support for NeroDigital MP4 will come before the summer.

yeah, saving 7 minutes is a good thing for skipping interoperability

edit: JohnV, you shouldnt forward every nonsense request you hear on boards to your developers and bosses

[JohnV]

Originally Posted by bond

will nerodigital devices now not need to support aac anymore? what about multichannel aac?

Sure they need. Multichannel AC3 is just added for flexibility for the 2 highest AVC profiles.

why does nero not simply use .mov? because the extension .mp4 is more funkier? and why dont you use .mpg with avc and ac3 like hddvd does.

Nero Digital uses .mp4, it has been set long ago. But it's possible that our encoding software will include larger scale encoding support for different purposes in the future..

[JohnV]

Originally Posted by bond

yeah, saving 7 minutes is a good thing for skipping interoperability

edit: JohnV, you shouldnt forward every nonsense request you hear on boards to your developers and bosses

Any speed up is a good thing, especially if you want to include multiple audio streams, though our next AAC encoder version should be 20-25% faster.

Sorry bond but you are wrong, this was not my idea nor my forwarding, but it is a very good idea, since many people want to preserve the original AC3 track of HDTV tv-streams and use AVC (very clear trend out there), don't have to use mkv, and future hardware supporting these specific 2 high profile ND-AVC profiles will play it.. You can always keep interoperability by using AAC if you want, this is just added flexibility and choise for users. And notice that this AC3 option will be available only for the 2 highest Nero Digital AVC-profiles, not for Nero Digital ASP or "lower" AVC-profiles.

Hopefully also Haali, MPC's and VLC's etc. splitters will add support for this new addition when it comes out.

[sillKotscha]

Originally Posted by JohnV

[...] it is a very good idea, since many people want to preserve the original AC3 track of HDTV tv-streams and use AVC (very clear trend out there) [...] You can always keep interoperability by using AAC if you want, this is just added flexibility and choise for users. [...]

and this is why I always wondered about the whole discussion why AC3 shouldn't be added to mp4... it is a question of private choice - from a technical point of view this might_be nonsense... but it seems to be a way to go for a huge company like Ahead... if SAP's will support it and (future) sales figures entitle to do so... hm, why not

[SeeMoreDigital]

Like Bond, I was not keen about the idea of incorporationd AC3 into MP4.

However, since owning a few MP4 capable hardware devices (two with NeroDigital support), it's become clear to me that the majority of end-users are totally baffeled as to why their surround sound amplifiers can't accuratlely decode the (6Ch AAC) audio element of Recode2 generated streams.

When you try to explain to them that surround sound amplifiers don't actually include AAC decoder chip-sets, only DolbyDigital/AC3 and DTS decoder chip-sets. And that in order to hear 6Ch AAC audio streams correctly, they'll have to use their players/amplifiers 6Ch analouge connections instead (if indeed they have them, most devices don't), most end-users response is: "no thanks, I'll stick with using .AVI" or "I think I'll wait for MKV to be supported in stand-alones".... Which is not good

More-over, now neither of the new high-def disc formats include AAC audio within their specifications, there's no urgency for surround sound amplifier manufacturers to include support for AAC decoding in their chip-sets.... Which is a great shame!

Personally I love using AAC audio. All my audio CD's are backed up to this format.... But amplifier manufacturers don't seem very enthusiastic about it. Hopefully their minds will be changed as and when the specifications for DAB 2 (radio) are sorted.


Cheers

[Sharktooth]

ah... i smell EVOs...

[bond]

if i would have an avc and ac3 stream i would place them in .mpg/.evo, cause it will have a bigger change to be handled on hardware players than a strange .mp4 with ac3 audio...

[JohnV]

Originally Posted by bond

if i would have an avc and ac3 stream i would place them in .mpg/.evo, cause it will have a bigger change to be handled on hardware players than a strange .mp4 with ac3 audio...

The point here is Nero Digital uses .mp4 and was set long ago, not what you would do. But if you need something else, I think remuxing shouldn't be impossible..

[ChronoCross]

I think the problem is AC3 in mp4 is not part of the spec for mp4. So now special workarounds in every demuxer has to be made.

[sillKotscha]

specs are nice for the vast majority of hardware producers ... but ahead/ nero build their own units thus are able to play their own content... if the user/ buyer is satisfied with the result - TRUE 5.1 digital sound without analogue loop ways - the user is the last one who cares about specs

[Sharktooth]

well, i wouldnt call them "workarounds" but support for AC3 private streams.
Private streams are also in the specs, so it's not completely out of specs...
It's just a "private" solution but since there are tons of ac3 decoders it would suffice to implement private streams parsing in the splitter and "connect" the ac3 decoder when necessary.

[SeeMoreDigital]

Yep... that's right..

Unlike with situation with the .AVI container, it's not like "private streams" in .MP4 are an out-and-out hack

The placing of VOBsubs subtitles within MP4 as a "private stream" has, by all accounts, proved to be a very useful implementation. As it makes use of the original subtitle decoder engine, installed within all MPEG-4/DVD players.

Placing AC3 within MP4 as a private stream and have it use the original AC3 (or even DTS) decoder engine, installed within all MPEG-4/DVD players seems a very logical step forward.... And far more understandable for end-users.

[SeeMoreDigital]

I guess these last few posts would be better placed in this thread: -

http://forum.doom9.org/showthread.php?t=23084

[Mtz]

Ok, if this posts will be moved I'll post also my opinion: Nero was "forced" by some manufacturers of standalone player chipsets to support AC3 in their MP4. I think they made a good decision.

enjoy,
Mtz

[foxyshadis]

Perhaps, instead of flouting the standards, what's really happening is a forced evolution of the format, hopefully on a sponsored standards track. Although my first instinct is to agree with bond, it almost seems that AC3, Vobsub, and MPEG-2 were deliberately kept out of the mp4 format to keep it from competing with DVD/HD. If others follow nero's private standards, it isn't so bad, provided they tell us how to mux compliantly.

[SeeMoreDigital]

Originally Posted by foxyshadis

... it almost seems that AC3, Vobsub, and MPEG-2 were deliberately kept out of the mp4 format to keep it from competing with DVD/HD.

As far as I know, MPEG-2 and MPEG-1 video along with MP2 and MP3 audio is in the ISO 14496 specification.

[easy2Bcheesy]

Originally Posted by JohnV

Nero Digital Information Thread
updated 5th February 2007

Coming updates from Nero:
-HD-DVD, Blu Ray BDMV and AVCHD authoring support in NeroVision

This is pretty earth-shattering stuff. Any idea of any kind of timescale on this? Will we be able to encode our own content into AVC for these formats?

[bond]

what we need are official specs for placing ac3 in mp4, everything else is just private stuff having no chance to get "big" somewhen

[JohnV]

Originally Posted by bond

what we need are official specs for placing ac3 in mp4, everything else is just private stuff having no chance to get "big" somewhen

Sure it would be nice if it became official in MPEG4. But if that won't happen, this is better than no support. At least we'll now see support in both hardware and software for AC3 in MP4.