XMedia Recode AC3 to AAC loss of channels

[vanix]

Hello,

Does anyone know how to preserve 5.1 audio when going from AC3 to AAC using XMedia Recode and converting from MKV to MP4?

Cheers.

[poisondeathray]

In the audio tab, under channels, select 6

[vanix]

In the audio tab, under channels, select 6

Already tried looking there. Only stereo is available from the dropdown for Apple iPad profile.

[poisondeathray]

Don't use the ipad profile

[vanix]

Don't use the ipad profile

I have tried the custome profile doing copy mode for the video and convert for audio and it takes about 4 times longer for the file to convert. So it seems that I can't have both the 5.1 audio and fast convert. If I want fast encode, I have to go for stereo audio. Why is this?

[rahulcrazy]

1st split audio from video than convert your video and add back 5.1 audio

[poisondeathray]

Or you can try something else. It should be very fast if you are stream copying the video

You can try tencoder, avidemux, ffqueue etc....dozens more

[vanix]

Forget splitting the audio away from the video and then re-merging. Too much hassle. The video should be stream copying as per what I set. What's not clear is why converting audio from 5.1 AC3 to 5.1 AAC is taking so much longer than to 2.0 AAC.

[Keyser]

What's not clear is why converting audio from 5.1 AC3 to 5.1 AAC is taking so much longer than to 2.0 AAC.

Well... because there are 6 channels to encode instead of 2.

[vanix]

Well... because there are 6 channels to encode instead of 2.

Fair enough, but mkvToMP4 handles it in a couple of minutes (though it's not perfect as per my post in its thread), so if it can, what's taking this tool so long? Not sure if it decodes it to WAV and then encodes to AAC under the hood, but it's not great either way.