Multi-channel audio + MP4

General discussions about TV Mosaic application.
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DaveH
Posts: 21
Joined: Fri Mar 30, 2018 9:00 am

Multi-channel audio + MP4

Post by DaveH » Sun Jun 03, 2018 4:40 pm

This is not specifically related to TVMosaic, but I have a question about multi-channel audio converting to MP4 format.

When I record a program with multi-channel audio, I can play it back on my Apple TV and decode the audio properly for my home cinema amplifier. I assume the audio is just passed through from the transport stream file?

When I convert the program to MP4 using SendTo, why does the audio come out as stereo only? Why is it not preserved as multi-channel?

Oberon
Posts: 1288
Joined: Thu Jan 26, 2017 8:45 am

Re: Multi-channel audio + MP4

Post by Oberon » Sun Jun 03, 2018 5:27 pm

There is a check box under sendto target properties if to convert audio to aac. It is checked by default.

DaveH
Posts: 21
Joined: Fri Mar 30, 2018 9:00 am

Re: Multi-channel audio + MP4

Post by DaveH » Sun Jun 03, 2018 7:06 pm

When converting audio to AAC, it still mixes to stereo. The other channels are removed.

Oberon
Posts: 1288
Joined: Thu Jan 26, 2017 8:45 am

Re: Multi-channel audio + MP4

Post by Oberon » Sun Jun 03, 2018 7:08 pm

DaveH wrote:
Sun Jun 03, 2018 7:06 pm
When converting audio to AAC, it still mixes to stereo. The other channels are removed.
That is what I mean. You need to uncheck the box to preserve audio in original format.

DaveH
Posts: 21
Joined: Fri Mar 30, 2018 9:00 am

Re: Multi-channel audio + MP4

Post by DaveH » Mon Jun 04, 2018 6:03 pm

OK, now I am even more confused. :?

If I uncheck the box, the audio doesn't work at all (it's DVB-T2, LATM container?)

It looks like there are only two channels of audio in the original source, but my amplifier gets 5.1 channels.

Oberon
Posts: 1288
Joined: Thu Jan 26, 2017 8:45 am

Re: Multi-channel audio + MP4

Post by Oberon » Tue Jun 05, 2018 7:27 am

Your recordings are very unfortunate in this sense. They happen to have aac-latm audio, which ffmpeg cannot transfer as is into mp4 container.
So for now your only option is to have audio converted to AAC stereo.

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