Can we put ac3 in mp4 without the use of a private stream?

[Zep]

When i demux a .ts i get ac3 and i do not want to convert to aac. i want to use the ac3 as is in my mp4 but it appears the only way STILL is via private stream/media object. I'm ok with that except most players/decoders do not look at the private streams when they find no audio in the standard location and standard audio tags.

Has anyone been able to get this to work in such a way as to not be such a hack? (well a hack for now anyway. I hope that changes in the near future)

Thoughts?

yes i could use .mkv but that has pros and cons also

thanks

[GodofaGap]

AC3 storage is not standardized for MP4 and it won't be, so what you want is not possible.

This question is asked at least 1 time per month...

[Zep]

Originally Posted by GodofaGap

AC3 storage is not standardized for MP4 and it won't be, so what you want is not possible.

This question is asked at least 1 time per month...

yes i read a few of the older threads but most were off base since i put ac3 in mp4 all the time in OSX via private stream and it works fine with players and decoders that are smart enough to look at the private stream and read the header info and see that it is an audio file etc... mp4 was designed to support media objects of all types and not just the standard out of the box basic ones.

Anyway, I wanted to know if the windows side has caught up and it appears it has not

However i see on sourceforge a few of the projects they added ac3 private stream support so things are looking up in the windows camp.
A hack yup but so is most of the video/audio stuff being used like h264 in avi and VBR mp3 in avi and on and on...

thanks for you input!

[derek ss7]

can any one tell me why recorded tv programs to disk on my sony RDR HX900 dvd recorder will not play on my pc or any other dvd player they never reconise the disk, i know the disks are ok. is there any software out there that can help. thanks

[SeeMoreDigital]

Originally Posted by Zep

yes i read a few of the older threads but most were off base since i put ac3 in mp4 all the time in OSX via private stream and it works fine with players and decoders that are smart enough to look at the private stream and read the header info and see that it is an audio file etc...

Interesting

Could you provide me with a sample please (with MPEG-4 SP video)?


Cheers

[bond]

Zep, i guess what you have is a mov file with the wrong extension, and not mp4...

again, it makes no sense to place ac3 in mp4. if you think that the technology used in mp4 is so great (eg better than mkv or mpg) use mov for storing ac3...

[GodofaGap]

Originally Posted by Zep

A hack yup but so is most of the video/audio stuff being used like h264 in avi and VBR mp3 in avi and on and on...

I don't care if it's a hack or not (and I don't think the other things you mentioned are necessarily hacks either), but you asked if there was a way without private streams I believe. Since the mp4 specs do not specify how to store AC3 specifically ( ), it is not possible. I didn't want to pass on a moral judgement if you should use AC3 in MP4 or not.

Can I ask you what tool you are using to make these files?

[SeeMoreDigital]

Originally Posted by bond

Zep, i guess what you have is a mov file with the wrong extension, and not mp4...

again, it makes no sense to place ac3 in mp4. if you think that the technology used in mp4 is so great (eg better than mkv or mpg) use mov for storing ac3...

I must admit I can't see how AC3 can be placed within MP4, hence my request for a sample...

That said, with regard to placing AC3 within MOV, I'm not sure whether this is possible, given that QuickTime player does not support AC3!


Cheers

[Kurtnoise]

Originally Posted by GodofaGap

Can I ask you what tool you are using to make these files?

Open a vob including ac3 streams into Avidemux, choose x264 for video compressor and Audio Copy in the drop list then save your file into mp4.

This kind of file is playable with MPC but like Bond and others said that makes no sense.

[Drachir]

The way avidemux place ac3 in MP4 is wrong, there is no mp4a box/atom. In MP4 files the elementary stream type is identified through the objectTypeIndication number. For unregistered elementary streams types you have to use a private objectTypeIndication number. Take a look here for registered numbers: http://www.mp4ra.org/object.html

If you want know how to place elementary streams into MP4 take a look at the nhml import/extract from MP4Box.

[popper]

Originally Posted by SeeMoreDigital

I must admit I can't see how AC3 can be placed within MP4, hence my request for a sample...

That said, with regard to placing AC3 within MOV, I'm not sure whether this is possible, given that QuickTime player does not support AC3!


Cheers

the BBC HD are using AVC and AC3 in their .ts ,does that count?, or am i missing somethng.

the BBC_HDTrial.ts file over on the DS thread for instance.

[GodofaGap]

what does ts have to do with MOV or MP4?

[woah!]

maybe because the .ts files have H264 (MP4) video and AC3 audio so i think its a valid question.

[foxyshadis]

No, .ts and .mp4 have nothing to do with each other, they're entirely different containers and can hold entirely different formats. H.264 is MPEG-4, not MP4, though it can be stored in MP4.

The entire reasoning behind MP4 is that it will only contain MPEG-4 streams, vastly simplifying implementation requirements, and that enough other formats exist to satisfy the need for non-MPEG-4 streams when it arises. (3gpp goes beyond this to specify a few other voice formats its own version can use.) Non-standard streams will most likely restrict playability on hardware devices. Please stop turning mp4 into the new avi.

[bond]

for how to mux ac3 into .mp4:

open quicktime and merge your ac3 stream into a .mov file. after that rename the .mov to .mp4 and you will get a spec compliant ac3-in-mp4 file as any other method outputting ac3-in-mp4 would give you too

/cynism


edit: imho the best container for merging ac3 and avc is .mpg program stream (not .ts), as
1) there are official/widely accepted specs for storing avc and ac3 in .mpg
2) hddvd uses exactly the same (ac3 + avc in .mpg), so ac3+avc in .mpg has a big chance of hardware compatibility (imho bigger than .mp4, not to speak of .mkv)
3) ac3 should not be placed in .mp4

[SeeMoreDigital]

Originally Posted by bond

for how to mux ac3 into .mp4:

open quicktime and merge your ac3 stream into a .mov file. after that rename the .mov to .mp4 and you will get a spec compliant ac3-in-mp4 file as any other method outputting ac3-in-mp4 would give you too

/cynism

Well I have QT7 Pro installed and as far as I can see it does not support AC3 at all. Whether it be muxed into VOB or MPG, or even as an elementary stream...

All you get is QT7 saying this: -




Cheers

[bond]

well i wasnt really serious anyways

[SeeMoreDigital]

Originally Posted by bond

well i wasnt really serious anyways

I guess what we could do with now are some muxing tools that will allow us to place MPEG-4 Part10 (and Part2 - for good measure) with AC3 audio into the .MPG container...

Any takers?

[bond]

my best bet would be ffmpeg

[SeeMoreDigital]

I guess muxing with FFmpeg will be a "command-line" affair?

I just tried muxing MPEG-4 with AC3 into .MPG, .TS and .PS using AVIdeMux 2.2.0 Rev 1984.... It was a no go!


Bummer!