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View Full Version : Apple Lossless audio in .m4v video container




Mr Dobey
Aug 17, 2011, 04:51 PM
As of now Apple Lossless Audio is not supported with video in a .m4v/.mp4 container. Both the developers of MP4 Tools and Subler say ALAC is not sported yet.

Main Goal:
Transcode Blue Ray DTS-HD Master Audio or TrueHD Audio to Apple Lossless.

This way one could losslessly transcode a complete Blue Ray to a .m4v container playable by iTunes/Quicktime X.

Obviously a full transcode is already available with MakeMKV. But again natively DTS-HD Master Audio and TrueHD are not supported in the .m4v container.

eAC3to (Win) can already transcode DTS-HD Master Audio/TrueHD to FLAC, which then can be transcoded to Apple Lossless (Mac). But no Muxer that I am aware of can mux Apple Lossless and raw H.264 together.

If possible I would see an Applescript to would chain together the following:

Blue Ray > MakeMKV > demux (MP4Tools 3) > ALAC transcoder > mux (H.264 & ALAC).

I'm sure it would be plausible to create a Mac app in the near future that could transcode like eAC3to or at least get Wine support rolling. And of course VC-1 Blue Rays would be off limits from the get go.



osohardy
Aug 17, 2011, 07:15 PM
handbrake nightly build can add dts-hd as passthru in mp4 apparently, but virtually nothing will play it (you need very recent ffmpeg). I don't know what if any player on mac OS X would fit that bill but at least a start. It would be a nice compromise to at least have a decoder/encoder mac side like eac3to so if you have to re-encode to ac3 for apple tv you could do it from the lossless track.

Mr Dobey
Aug 18, 2011, 01:55 AM
I was unaware of handbrake achieving DTS-HD in .mp4, thank you for sharing!
That's at least one step further.

Do you happen to know any of the handbrake developers? I'd be interested to know their knowledge on the subject.

osohardy
Aug 18, 2011, 12:51 PM
no i don't know them, I was just browsing the forum for related topics and saw mention of it, I think in the devices section.

Mr Dobey
Aug 18, 2011, 01:22 PM
I'm trying to figure out if adding ALAC is technically possible right now or is quicktime the one holding us back. According to Wikipedia (http://en.wikipedia.org/wiki/Comparison_of_container_formats) it is. Though I've never come across a .mp4 file that already has ALAC in it.