Xvid inside DivxNetworks MP4

[Neo Neko]

MP4 is one of the up commig formats for the future. And DivxNetworks has delivered one of the first general use muxers and players.

PROBLEM: Their Muxer only wants to mux content created with Divx5 or higher.

SOLUTION: The Muxer appears to be looking at the fourCC and stream headder to check before conversion. If it does not see "divx" and "DIVX" respectively it is a no go. If you set the Xvid codec to output with a fourCC of DIVX this only half solves things. There is a program in the downloads section. AviC I believe. http://www.doom9.org/Soft21/Editing/AviC.zip Last time I used it was back in the early days of Divx3 when SMR and Angelpotion codecs were common. Get it and set it to work on your Xvid AVI. The first field should contain "divx" and the second field "DIVX". Once this is done the DivxNetworks MP4 util will gladdly process it only stopping to take notice that there are no B frames. After that the content plays back in The Playa just as if it was DivxNetworks Divx sans B frames. Gotta love that ISO.

Neways did not know if it would be usefull to anyone else. Just thought I would post it just in case. Cause for many of you like myself Xvid is still your codec of choice. But MP4 should be prety awesome here in the future.

[rui]

I already tried, following a tip Nic gave me here: http://forum.doom9.org/showthread.php?s=&threadid=19208&pagenumber=2

But i would advise everybody to use Avic program created by Nic instead of the one that is in doom9's site, because Nic's has 6 KB, and doom9's has 133 KB. ;)

But until there is some way of muxing audio with the mp4 file, this isn't much usefull. Still, it's the future, right?

[Nic]

Im really looking forward to it, as I wrote the AAC (MPEG-4 Audio) DirectShow filter a while back (I'd got several emails from Andrea at DivXNetworks asking for the source code(!!!)) & I'd love to start using that, so we can have Psytel AAC in our movies :)

Cheers,
-Nic

[Koepi]

HU?

Nic, why isn't that finsihed yesterday? ;)

Gogogo!
That would be soooo damn useful :)

Regards,
Koepi

[Nic]

The damn problem is there is no MP4 DirectShow parser, thats what we need, and thats too big a project for what I have time for....(And I doubt DivXNetworks will release it) :(

Its pretty much semi finished.....if we ever get close to using the MP4 format properly, maybe I should have it in the XviD CVS :)

-Nic

ps
"pretty much semi finished"....I like that line, im going to say that at least once to my boss today :)

[Neo Neko]

Originally posted by rui
I already tried, following a tip Nic gave me here: http://forum.doom9.org/showthread.php?s=&threadid=19208&pagenumber=2

But i would advise everybody to use Avic program created by Nic instead of the one that is in doom9's site, because Nic's has 6 KB, and doom9's has 133 KB. ;)

But until there is some way of muxing audio with the mp4 file, this isn't much usefull. Still, it's the future, right?

If there is MP3 audio in your AVI it will be in the MP4 as well. The only time you would have problems creating MP4 with sound at this point id if you have the codec output directly to MP4. Also I have heard through someone else that they have added AAC audio to DivxNetworks MP4 with the MPEG4IP tools. Only problem is there are not many players that can handle the AAC and MP4 at the moment.

[morello12]

Just curious Nic, but does the Mpeg-4 (mp4) ISO spec allow for ac3 audio? Or just Mp3 and AAC?

[Neo Neko]

I doubt it supports AC3. Why should it when it uses a superior format like AAC. Dolby is very tight lipped so there is serious question about AC3 getting inside any other formats.

[rui]

Originally posted by Neo Neko


If there is MP3 audio in your AVI it will be in the MP4 as well. The only time you would have problems creating MP4 with sound at this point id if you have the codec output directly to MP4. Also I have heard through someone else that they have added AAC audio to DivxNetworks MP4 with the MPEG4IP tools. Only problem is there are not many players that can handle the AAC and MP4 at the moment.

Good point! Simple, yet i overlooked it ;)

Right now i am at work, where i have a comp without sound card, but when at home i will try to convert a xvid avi (after changing the fourcc) with sound, to .mp4, and see how it goes.
Just to be clear, if all goes well i will, in future, be able to play this converted mp4 file in some exterior hardware with mp4 decoding capabilities, right? Sound and all, right?

[Neo Neko]

That is the aim. And so long as no one goes Microsoft that should be the result. MSMPEG4 or Divx3 files will not be compatable with the future.

[soujir0u]

Hmm... So does AAC have 5.1 channel audio also so that we can transcode AC3 to AAC without downmixing it? Also, will the quality degrade after transcoding?

[Nic]

Because I have to be quick:

1) Im pretty sure MPEG-4 should not allow MPEG-1/2 Layer 3 audio in it, but you can put it in (it just isn't in the iso spec, only aac, twinvq & CELP are)

2) AAC is far superior to AC3 and so therefore yes, it can easily do 5.1 :D

-Nic

[Neo Neko]

No MPEG1 or 2 audio in the new MPEG streams NIC? Really? I mean they are MPEG after all. Hrm........

[Nic]

Yup, of course you can put them in there (as people are doing :) )

I asked Ivan about it at hydroaudio not so long ago, he also confirmed what I thought...

CELP = voice
TwinVQ (aka VQF) < 6kbps
AAC > 6kbps

& thats all the audio profiles listed....But because of Dolby's tight control over AAC, It wouldn't surprise me if alot of players supported MP3....

Cheers,
-Nic

ps
Also, MPEG-2 contains AAC, actually Psytel AAC pretty much only makes MPEG-2 AAC LC (Low Complexity) (although you can make it produce
an MPEG-4 stream, AAC LC differs only very slightly between MPEG-2 & MPEG-4.
...MPEG-4 AAC introduces other tools, PNS (Perceptual Noise Shaping, good for low bitrates) & LTP (Long Term Prediction..I think Nokia helped develop that)

....Hmmmm The audio scene, full of acronyms :)

[Neo Neko]

Originally posted by Nic

CELP = voice
TwinVQ (aka VQF) < 6kbps
AAC > 6kbps

Is your 4 broken Nic? 6Kbps?

[-h]

Is your 4 broken Nic? 6Kbps?

6

:)

-h

[soujir0u]

6 kbps as in kilobytes? So = 48 kilobits?

[-h]

6 kilobits per second, as in 750 bytes.

-h

[Neo Neko]

6 kilo-bits per second is quite low! 6 kilo-bytes per second is insanely high. What aplication would 6Kbps have except for low quality voice. Doubt it would be good for music much.