Questions about MP4

[Tanshu]

I usually encode my backups to XviD with AC3 audio in Matroska Container with chapter information and subs in VobSub format.
I was thinking of changing to the MP4 container, but there are a few things which I was wondering (mostly regarding the audio).
Firstly, I want to create a spec compliant file, therefore I do not want to add hacks for unsupported files or chapter infrmation.

Secondly, I will have to convert the audio to AAC, I could not get a difinitive answer on this as there are conflicting reports. but will there be significant quality loss converting from AC3 to AAC?

Thirdly, should I go for HE-AAC or normal AAC?

Fourthly, And which audio encoder to use? I think that for HE-AAC, Nero is pretty much the only choice and iTunes/Quicktime for normal AAC.

Fifthly, Can I later demux the contents of the container so that I can get the original files back?


I am thinking of creating a menu for this and also OCR all the vobsubs . So, this is going to take a bit of effort. But the whole thing hinges on the quality drop in the AC3 to AAC conversion.


Update
After a lot of searching, I have come to believe that there are currently no tools which can encode subtitles and chapters into an MP4 file in 100% spec compliant way. They basically use the Nero hack. Am I correct in this assumption?

Thanx in advance for your help guys.

[pogo stick]

Originally posted by Tanshu
Secondly, I will have to convert the audio to AAC, I could not get a difinitive answer on this as there are conflicting reports. but will there be significant quality loss converting from AC3 to AAC?
Converting audio is almost always lossy process objectivity.
But if you do everything right then you then losses will be controllable. I am not sure that everyone will be able to tell which audio is AC3 and which is AAC at the same file size.
Originally posted by Tanshu
Thirdly, should I go for HE-AAC or normal AAC?
Fourthly, And which audio encoder to use? I think that for HE-AAC, Nero is pretty much the only choice and iTunes/Quicktime for normal AAC.
HE-AAC very good for saving space and for multichannel.
Usually 6ch HE-AAC takes about half of 6ch AC3 file size (of course it depends on bitrates).
LC-AAC is for higher bitrates.
I use Nero encoder for AAC. They announced improved new version.
Originally posted by Tanshu
Fifthly, Can I later demux the contents of the container so that I can get the original files back?
Yes, it's no problem as far as I know.
Originally posted by Tanshu
After a lot of searching, I have come to believe that there are currently no tools which can encode subtitles and chapters into an MP4 file in 100% spec compliant way. They basically use the Nero hack. Am I correct in this assumption?
Nero's way for subtitles and chapters doesn't break compatibility.
MP4 will be spec compliant, but system players will not be able to use subtitles and chapters info.
Chapters can be used by 3ivx splitter. See this (http://forum.doom9.org/showthread.php?threadid=69703).
And I think Nero will make it possible to use chapter in mp4 in their hardware players.
There is no way to use subtitles inside mp4 without Nero ShowTime.
But 3ivx announced new version of their soft. Maybe they will do something for subtitles and chapters.
And they promised MP4 editing tool!
I can't wait! :)

[Tanshu]

Thanx pogo
I do not mind a high bitrate for the audio as was planning going to use the AC3 file. So, you suggest that LC AAC is a better option for high bitrate. It is a 6ch 448k audio, so would 288k AAC be ok?
Is there any tool which can perform sort of a compressibility check on the audio to determine the bitrate needed?

Also, another method I was thinking of was to mux all the information in a Matroska file for the moment and later transcode it to MP4 when more tools are out to work with.

I am sort of a newbie in video encoding. I just managed to move up from DivX to XviD and AVI to Matroska. I saw the whole thing and it seems pretty complex to create and use an MP4 file (as there are too many combinations or decoders with their specific benifits and problems) also, I only use MPC and it do not want to use Nero to watch my backups.

But still, AAC is matroska should be a good idea as it will keep the size down.

Edit: wrote the wrong bitrate

[stephanV]

Originally posted by Tanshu
Also, another method I was thinking of was to mux all the information in a Matroska file for the moment and later transcode it to MP4 when more tools are out to work with.

for me personally (i have to be more careful now :rolleyes: ), that seems to be the wisest thing to do. you can always recode your AC3 audio later on if you decide to switch to MP4, although AAC audio can go in matroska.

from a practical point of view there is and will be very little difference between matroska and MP4 if your only watching your files on your computer. matroska might actually be favorable there as it is less limiting for more different stream types (yes, i know about private streams in MP4). on hardware players MP4 is favorable over Matroska.

also the tools available today are quite limiting, and apart from the 3ivx-muxer, i (personally) wouldnt trust them to crate my MP4-files yet.


And they promised MP4 editing tool!

hmmm... well, lets wait and see :devil:

[Tanshu]

Thanx StephenV four your vote of confidence.

I have finally decided to do just that. I find Matroska to be a very nice container, it is just that I MP4 seems to be on its way to being the dominant container in the future and thus thought it would future proof the encodes a bit. I don't really watch my backups on standalones. Also, the Menu system was attracting me. But Matroska is also going to implement it :)

So, the menu will be for some other day.

[stephanV]

and anyways, for MPEG4 audio and video streams Matroska is (or will be) completely interchangeable with MP4. so the most important part seems to be covered :)

[Tanshu]

Yeah.

[SeeMoreDigital]

Tanshu,

The first place you need to look for more information about the MP4 container is here (http://forum.doom9.org/showthread.php?s=&threadid=62723), in bonds excellent information

If I were you I would just hang on a little, at least until Kiss release their new HD player, which promises some of the features you want. And will be the first player to implement them in hardware!

With regard to 6Ch AAC audio. AAC-HE offers a CBR option of 96kbps max but there's also VBR option which can take the bitrate much higher. When encoding more than 2Channels VBR is the only way to go.

AAC-LC on the other hand offers much higher bitrates, up to 448kbps for Nero.

With regard to Chapters and Subtitles goes, Nero use their own method. So it's too early to tell if they will be adopted in hardware!


Cheers

[Tanshu]

Actually SeeMore, That is a very helpful thread which I had looked at the tread several times, but it does not have details about AAC files (HE, or LC, the target bitrate, etc; I know it is not supposed to have it as it is about the container and not the audio coded).

I just reread the whole article and found this about the the Subtitles.

The format is still very young and therefore no implementations exist at the moment

I somehow missed it earlier, so I agree it was my fault.

Also, I don't think it states if the standard method of chapter marking is possible, though it too states the Nero method along with the information that it is not totally spec compiant (in the sense that it will be interpreted by all decoders and not just be ignored). Thus I just wanted to confirm what I had interpreted (Just in case there were any new programs which could do this)

[SeeMoreDigital]

Kiss and Nero have buddied together so there's every reason to assume that Nero's 'software' player features might be incorporated into the Kiss 'hardware' players.

But as I said, we'll have to wait and see what happens when the new Kiss players arrive!

For more information about AAC, why not have a look here (http://forum.doom9.org/showthread.php?s=&threadid=68300#post424070).

There are many of us on the forum who want answers to the same questions as you :)


Cheers

[Tanshu]

SeeMore,
After looking at this link you gave me again (I swear I read thru the whole thing once befor), I found more info. It told me the bitrate to strive for.

Earlier I had searched Doom9 and HydrogenAudio and looked at atleast few dozen pages (but in a few hours I got so tired maybe I missed this stuff).

Also, just one thing, is HE-AAC recommended for high bitrates, cos the Mpeg4ip site on sf says that it is designed for low bitrates while doom9 recommends it for high bitrate as well. I wanna encode a 448k 5.1 AC3 in a transparent way. In LC-AAC, it should be 320k, right? Just wanna make sure.

Thanx.

[SeeMoreDigital]

Originally posted by Tanshu
SeeMore,
After looking at this link you gave me again (I swear I read thru the whole thing once befor), I found more info. It told me the bitrate to strive for. :) I know what you mean!

But remember Doom9 is like no other site. There are a lot of enthusiasts, developers, software writers etc on this forum. So the information posted is constantly being updated.

When bond is on form you'll find Mpeg4 and MP4 information updated by the hour. You may even find your posts split or moved... There's just no stopping him.

That said, he's rather quiet today, so we can all talk about him while the heat is off :D

Originally posted by Tanshu
Also, just one thing, is HE-AAC recommended for high bitrates, cos the Mpeg4ip site on sf says that it is designed for low bitrates while doom9 recommends it for high bitrate as well. I wanna encode a 448k 5.1 AC3 in a transparent way. In LC-AAC, it should be 320k, right? Just wanna make sure. To be honest I don't know!

We've been discussing the possiblities of generating multi-channel audio blind tests but they a much more complcated affairs to implement than the current 2 channel ones.

Some time ago Sagittaire, bond and I generated some low-bitrate VBR(around 128kbps) AAC-HE and WMA9 test files from the same AC3 source. All sounded very good.


Cheers

[Tanshu]

But remember Doom9 is like no other site. There are a lot of enthusiasts, developers, software writers etc on this forum. So the information posted is constantly being updated.

I know, I have been here since I found GK (which was in .26 i think or maybe even less), so I know that this is the place for enthusiasts and developers (I lurked a loooong time as guest before signing up). The project Helix , Matroska team and not to forget my favourite XviD team.

I am aware of Bond's reputation. His posts started a flame war on HydrogenAudio. I am not kidding, but I really did search and research on the topic extensively cos I know how irritating it can be to answer questions whose answer can be found in a few seconds with a little searching.

Back to topic, so u reckon tht HE-AAC with about 256k should more than do the trick or is it overkill? I want to keep it just a tad bit above wht is needed, to be safe. I know the sound quality is a very subjective thing, but still just give me your opinion. :) After reading a lot that such things r subjective, I need a concrete answer :p

[Tuning]

Originally posted by Tanshu
.. is HE-AAC recommended for high bitrates, cos the Mpeg4ip site on sf says that it is designed for low bitrates while doom9 recommends it for high bitrate as well. I wanna encode a 448k 5.1 AC3 in a transparent way. In LC-AAC, it should be 320k, right? Just wanna make sure.


HE-AAC cant be used at higher bitrates, as the encoder itself bouce back to LC mode automatically. The max bitrate for HE-AAC is 128kbps for aiff source and 96kbps for wav source( stereo ) files. And max VBR preset is "streaming" for HE-AAC.

And for 5.1 files higher bitrates are required as there is more than 2 channel. If that what you are talking?

btw, I cant see where He-AAC is recommended for higher bitrates. Could you point it?

[SeeMoreDigital]

Originally posted by Tanshu
Back to topic, so u reckon tht HE-AAC with about 256k should more than do the trick or is it overkill? I want to keep it just a tad bit above wht is needed, to be safe. I know the sound quality is a very subjective thing, but still just give me your opinion. :) After reading a lot that such things r subjective, I need a concrete answer :p Would-that-you-could-but-you-can't encode AAC-HE at these bitrates, only AAC-LC (well, not that I know of).

Nero current maximum VBR setting is: 'Streaming::Medium'. And as it's VBR, the final bitrate will depend on the content.


Cheers

[Tanshu]

Turning,


this (http://forum.doom9.org/showthread.php?s=&threadid=68300#post424391) is where I got it

Answer no. 13. I says tht HE-AAC is good for 5.1, so I guessed it could scale to higher frequencies than 128k.

[Tanshu]

SeeMore,
Turning got that but thanks. So, 320k LC-AAC it is. You have been a great help.

[Tuning]

Originally posted by Tanshu
Answer no. 13. I says tht HE-AAC is good for 5.1, so I guessed it could scale to higher frequencies than 128k.




Thanks Tanshu.

I think you got confused with that answer. The answer points that your total bitrate for 5.1 channels will be around 320 kbps. and that statement is only applicable to LC AAC.

For HE-AAC the maximum VBR preset for both stereo and multichannel files is " Streaming" profile.

And what the answer tells about bitrate is that if you choose 64kbps (say) in preset then the overall bitrate for 5.1 will be equvalent to 2.5 times 64. and its generated automatically, you dont have to set in encoder. You need to set it as 64 kbps only.

So in case of Nero if you set 96 kbps VBR then overall 5.1 bitrate will be 2.5 x 96 == 240kbps file.

So to make a quality encode you could choose the normal rule, i.e how far HE-AAC is available for stereo and set it accordingly. To find out overall 5.1 bitrate use the equation 2.5 times the bitrate.

hence the FAQ says the 128 kbps equvalent is equal to 320 kbps LC AAC.

Hope that helps...



13. How are bitrates divided among channels in 5.1 LC and 5.1 HE AAC? What bitrate should be used for 5.1 AAC to be equvalent in bits/channel to 128kbps?

For the bits/channel to be the same, one must add 2x(bitrate per stereo)(FL,FR,RL & RR)+ 1x(mono bitrate(Centre))+ a small additional bitrate for lfe. Therefore the total bitrate should be about 2.5-3x as much as stereo to achieve the same bits/channel. So to achieve the datarate equivalent to 128kbps stereo: 128kbps*2.5=320 kbps. 320kbps is a good quality bitrate for LC AAC. However due to the efficiency and channel coupling of AAC, one can encode HE-AAC at 128kbps and still have decent quality and 5.1 channels.

[Tanshu]

hence the FAQ says the 128 kbps mp3 equvalent is equal to 320 kbps LC AAC

I got everything else you said, but I think you mistyped this. r u sure it is 128 kbps mp3? or that 128kbps per channel is equal to 320k per 5.1 AAC?

[Tuning]

Yep, it was a typo....I always add mp3 after 128kbps :p :D ( Addicted to foobar :mad: )

The actual info was about datarate. Sorry. will edit that.

[Tanshu]

k thanx. No worries. :D
Same here foobar is the best.

[SeeMoreDigital]

Hi Tanshu,

Are you okay now with all this information. Or are there any issues you are still confused with?


Cheers

[pogo stick]

Originally posted by SeeMoreDigital
But remember Doom9 is like no other site. There are a lot of enthusiasts, developers, software writers etc on this forum. So the information posted is constantly being updated.
When bond is on form you'll find Mpeg4 and MP4 information updated by the hour.
Well, not by hour, but very often. I checked. See my new signature. :)
Originally posted by Tuning
And what the answer tells about bitrate is that if you choose 64kbps (say) in preset then the overall bitrate for 5.1 will be equvalent to 2.5 times 64. and its generated automatically, you dont have to set in encoder. You need to set it as 64 kbps only.
Are you sure about this?
Do your mean that CBR bitrate amount in Nero encoder is amount for one channel? This is strange to me. But I don't use CBR, so I can not tell for sure.

But I can tell about VBR HE-AAC. Usually I encode with "streaming" preset. And for 5.1 bitrate is almost always higher then 128kbps. I think, it was changed and AAC FAQ 14 is little outdated. For two 5.1 files I encoded today it was about 200kbps.

And using HE-AAC with bitrates higher then "streaming" is practically possible, but theoretically questionable. E-Male's bsn.dll mod (http://forum.doom9.org/showthread.php?threadid=77361) can do that. But there must be reason why it was disabled by Nero.

[SeeMoreDigital]

Hi pogo stick,

I wonder wher bond is today. These sorts of questions are useually right up his street?

It's not like him to miss a "mass-de-bate" :D


Cheers

[bond]

Originally posted by Tanshu
Firstly, I want to create a spec compliant file, therefore I do not want to add hacks for unsupported files or chapter infrmation.placing chapters in mp4 is not a hack
the mpeg-4 standard allows the user to place any private info, like tags or chapters, in the user data atom (udta) in mp4. players which dont understand these infos stored there will simply ignore it
it doesnt break any compatiblity! its spec compliant

Secondly, I will have to convert the audio to AAC, I could not get a difinitive answer on this as there are conflicting reports. but will there be significant quality loss converting from AC3 to AAC?these is always a quality loss if you convert from any a/v format to another, not matter if you convert from ac3 to aac, vorbis, mp3 or whatever
still as rjamorims listening tests showed using itunes aac at 192kbps should be transparent for as good as everyone existing (i am not really able to hear a difference between an original cd source and itunes aac at 128kbps)

so would 288k AAC be ok?more than ok

Also, another method I was thinking of was to mux all the information in a Matroska file for the moment and later transcode it to MP4 when more tools are out to work with.there are more tools existing able to handle mp4 than matroska!
still mp4 lacks a nice and free editing tool (only proprieatary tools exist for this)

Fourthly, And which audio encoder to use? I think that for HE-AAC, Nero is pretty much the only choice and iTunes/Quicktime for normal AAC.aac codecs at 128kbps:
http://www.rjamorim.com/test/aac128v2/plot12z.png

Fifthly, Can I later demux the contents of the container so that I can get the original files back? of course, there exists already a whole bunch of tools able to do that

Update
After a lot of searching, I have come to believe that there are currently no tools which can encode subtitles and chapters into an MP4 file in 100% spec compliant way. They basically use the Nero hack. Am I correct in this assumption?again placing vobsubs and chapters in mp4 is not a hack
a hack is placing a stream into a container, the container could not store technically normally

mp4 has no problems storing vobsubs and chapters, storing these streams will also break NO mp4 tool, as the mpeg-4 standard exactly defines how to place private tracks/infos in mp4

I saw the whole thing and it seems pretty complex to create and use an MP4 file (as there are too many combinations or decoders with their specific benifits and problems)thats not correct! there are not "too many specific combinations or decoders with their specific benefits and problems"? can you be more specific? i dont know these issues ;)

the only issue i am aware of is that you can not mux packed bitstreams with the mp4ui tool without getting a not spec compliant mp4 file

I only use MPC and it do not want to use Nero to watch my backups.plz read my faq!
there are maybe more than 20 different players existing which are able to play mp4 files (not counting dshow based player like wmp9, mpc, bsplayer aso... which can also play them)!
you are in no way limited to use nero for watching mp4 files!

[Tanshu]

Thanx for the detailed answers Bond.

I used the wrong term when I said 'hack' I do understand that all these methods do not actually break compatibilty with any software or hardware methods, but it is really not the way that subtitles and chapter information is to be stored (that is not how the design team intended this information to be stored). What I mean is that all the players should be able to use the information and not ignore it. I know it sounds a bit strange as these methods are not against the specification, but I am sort of strange that way. :p On the other hand The implementation in Matroska is as it has been designed.

I had already seen the tests rjamorim had done and thus made the choice of iTunes for LC-AAC and Nero for HE-AAC and the slide you have shown also confirms that. By only choice I meant in the terma of quality and not the availability of encoders.

Thanx for the info on muxers. I guess one can mux an MP4 file right now with the extra files and upgrade it later when better tools come out. But the thing is that MMG is just so convenient. I will look for MP4 muxers and if there is any which is just as easy to use, I will use it instead of MMG. Cos if i have to do the whole thing twice, I don't want to put in a lot of effort twice.

As far as the filters are concerned, I must be mistaken. But I read a lot of posts on how to get the correct combination of filters and splitters. I have never used graphedit and am not too technically inclined so thought maybe that there are problems.

I guess for me the root of the problem is choice. For Matroska, there is one good muxer, I don't need a directshow splitter as i use the inbuilt one in MPC, VSFilter does the subtitles and AC3Filter the audio. So, I had grown accustomed to just finding one tool. :D

As far as the Nero comment is there, I think I read somewhere that currently it is the only player which can display subtitles, so put that in.


Guess it is time to start learning again. ::)


Edit: Had left out part about playing in Nero

[bond]

Originally posted by Tanshu
I used the wrong term when I said 'hack' I do understand that all these methods do not actually break compatibilty with any software or hardware methods, but it is really not the way that subtitles and chapter information is to be stored (that is not how the design team intended this information to be stored).hm its exactly the way the design team intended this information to be stored!

they knew that things will come up they have not thought about when specifing mp4, so they thought: "lets give them the udta atom, where they can place everything we didnt specify"

What I mean is that all the players should be able to use the information and not ignore it.its not so easy, you can not expect that every player existing can handle everything able to be done in mp4
the container is simply too powerful so that i doubt that there will be a tool existing sometime which will handle everything which is possible in it

so its the decision of the player manufacturer which info to handle and which not

Thanx for the info on muxers. I guess one can mux an MP4 file right now with the extra files and upgrade it later when better tools come out.hm what do you mean? the files created by existing mp4 creators are spec compliant, no need to be upgraded or so in the future

As far as the filters are concerned, I must be mistaken. But I read a lot of posts on how to get the correct combination of filters and splitters. I have never used graphedit and am not too technically inclined so thought maybe that there are problems.hm there must have been a misunderstanding

as i wrote in my faq for playing any file (matroska, avi, mp4...) in directshow you need two things:
1) a parser/splitter filter (which analyses the file and passes the streams to the decoders)
2) decoder filters (which decode the audio/video streams)

in my opinion the best splitter/parser is the one coming with 3ivx
3ivx also comes with a mpeg-4 video decoder and an aac audio decoder, which is all you need

if you want to use other decoders (like ffdshow or coreaac) you can do this too with 3ivx, but there is no need to

[Tanshu]

ok, so the udta is the official spec. Information from various sources made me believe that the current chapter and subtitles storage was first used by nero and now also supported by 3ivx. This makes the upgradation thing useless. :D

Thanx for the info on the splitter combination.

[bond]

Originally posted by Tanshu
ok, so the udta is the official spec.yes

Information from various sources made me believe that the current chapter and subtitles storage was first used by nero and now also supported by 3ivx. This makes the upgradation thing useless.thats also correct
as i said you cant expect every player to support every feature. like not every player existing will handle subtitles, now if 3ivx says they will support it its good for us and good for them as more people will use their stuff and not neros ;)

[Tuning]

Originally posted by pogo stick

But I can tell about VBR HE-AAC. Usually I encode with "streaming" preset. And for 5.1 bitrate is almost always higher then 128kbps. I think, it was changed and AAC FAQ 14 is little outdated. For two 5.1 files I encoded today it was about 200kbps.


Yep, it is an approximation to multichannel overall bitrate. The info was taken from HA.org and was told by Ivan ( Ahead Developer ). The exact equation can be found in AAC faq Q# 13. And again CBR in AAC is not actually a perfect constant bitrate encoding. It varies around 1-2 kbps from selected value.

And about Q #14, the info is getting outdated as Ahead is developing more and more sophisticated AAC encoders. You can see the improvements in new versions already. ;). (Getting higher bitrates than expected)

[hans-jürgen]

Originally posted by Tuning
And about Q #14, the info is getting outdated as Ahead is developing more and more sophisticated AAC encoders. You can see the improvements in new versions already. ;). (Getting higher bitrates than expected) Usually improvements in lossy audio compression (and lossless, too) are considered to lower the bitrates, not raise them - except on HA, maybe...:rolleyes:

[Tanshu]

I checked and with the E-Male's bsn mod I produced 5.1 HE-AAC at 220k. I think that it is an acceptable bitrate since I chose the Transcoding quality.
But I am concerned about one thing. HE-AAC recreates the frequencies removed by SBR with very little information. This means that the original information is being discarded. So, this should mean that at high bitrates (where the codec maxes out), this will produce lower quality output. Right?

[hans-jürgen]

Originally posted by Tanshu
But I am concerned about one thing. HE-AAC recreates the frequencies removed by SBR with very little information. This means that the original information is being discarded. So, this should mean that at high bitrates (where the codec maxes out), this will produce lower quality output. Right? Again: HE AAC is meant for lower quality files, LC is the profile for higher and highest quality in AAC. 220 kbps/6ch is already an average bitrate that could be achieved with the LC profile, e.g. with FAAC at -q 70. The advantage of the Low Complexity Profile is that the future hardware 5.1 AAC decoders in DVD players like Kiss will be able to decode this without problems while they would discard the SBR part of any HE AAC file, i.e. sounding like crap then.

[Tanshu]

K, got it that HE-AAC at high bitrates is a bad idea. Now to wait for iTunes to come out with a VBR encoder or Nero to get better than the iTunes.

[Phobos]

i have done a couple of encodes of multichannel HE-AAC audio. I find that streaming (the highest HE-AAC afaik) is good enough for a movie. You are still looking at it, not listening to artifacts (whcih are very difficult to notice with he-aac at streaming :) ) I've been a hydrogenaudio member for a while, and the trend there is also lower bitrate, more quality, but its just people there wont give that much quality for lower bitrate. Myself i find the LC-AAC transparent preset indistinguishable from cd, and HE-AAC streaming as the best you can get for a low filesize. In short, for a movie go for he-aac, for a music concert go for the internet preset or transparent if you are an audiophile (and if you want to loose that much video quality lol)

The "problem" (not quite) with mp4 is that there is still a lot of development going around for it. Ill state what i know for now:

- Video part is practicaly complete, XviD 1.0 gives top notch quality at as low as .18 bits/pixel ->IMHO played on a TV!!!<-
- Audio part is almost complete, there is still to be released (in a couple of weeks!!! hoorra!!) HE-AAC+PS which still lowers HE-AAC bitrate with the same quality. I remember a graph show in hydrogenaudio (which i couldnt find) where 56kb/s HE-AAC+PS had almost the same score as 64kb/s (streaming preset FYI)HE-AAC
- Container part has still quite some work left. The container is finished but not enought tools atm. There isnt a noob or lazy way to create bifs subtitles or non-nero chapters, hopefuly the 3ivx mp4 edit tool will fix this, anybody knows an estimated release date??

-Hardware part is the worst (as always), the new phillips player supports mp4, but not even lc-aac audio and i doubt it supports subtitles/chapters, so i guess mp4 is locked into the pc until good hd-dvd players come out (2 years???)

The lack of support of aac audio of the player is moot since phillips released lc-aac audio capable cd players about 3 years ago, like the exp503(which i own).

pls post your comments on my conclusions