MP4 Audio Options

[phase]

I remember in previous versions that it wasn't possible to pass-through AC3 when the target file was an MP4 container because it didn't officially support AC3. Now, some years later and pleased to find that I can pass-through AC3 to an MP4 container, I notice that in MKV one can also pass through DTS and choose for MP3 target audio. Why are these latter two options not possible for an MP4 container?

For one thing, I know that MP3 audio (or more specifically MPEG 1 Layer 3) is "supported" in an MP4 container, but what I miss is DTS pass through option, so I can preserve all original audio tracks in MP4 to pass through to a digital amplifier, be it AC3 or DTS audio. Perhaps it's a design choice to limit the creation of non-universally supported files (then again, which implementation conforms 100% to specs?), but why not offer users the option/choice to pass through DTS as well if so desired. I for one, 99% of the time, am only concerned about recoding MPEG2 video streams and keep the audio tracks, because my amplifier doesn't eat multi-channel AAC or MP3 (I am sure others would be inclined to agree), but it does talk AC3 and DTS...

The reason why I can't (or refuse) to use MKV to do this, is because my set-up is mostly Apple and well, MP4 is natively supported which allows for integration that I can not get using MKV on practically stock systems.

[rhester]

There is no standard (yet) for DTS-in-MP4.

Rodney

[TedJ]

You probably could shoehorn DTS into mp4 by flagging it as a private stream, but I can't think of a single player that it would work with.

[eddyg]

I've tried fooling the atv into passing through the dts by marking it as ac3. However no luck. I guess there is something about packet sizes or interpretation going on. Or I stuffed it up. Hard to tell which.

Cheers Ed

[dynaflash]

I've tried fooling the atv into passing through the dts by marking it as ac3. However no luck. I guess there is something about packet sizes or interpretation going on. Or I stuffed it up. Hard to tell which.

Cheers Ed

Did the same here ... no joy. Oh well can't say we didn't try.

[Ritsuka]

Actually there are some official specs for dts inside mp4/isomedia, but they aren't public, and I don't know any player supporting it.