Multichannel audio mixdown to stereo

[Edgar Amalyan]

Hi, I extracted a dts-hd ma track from a bluray and converted it to flac to play on Poweramp. The file has 8 channels (7.1) but I hear no speech (center channel) or any of the sounds that should be coming from front left and right channels. I even went back and manually remapped the channels to left, right, center, LFE, surround left, surround right, surround rear left, surround rear right. From my tests Poweramp is not downmixing the channels to stereo. 

 

I'm not sure if downmixing is even a feature, as I don't see an option, or if it is enabled by default, which it should be. Playing the same file in mxplayer works perfectly. 

[andrewilley]

I'm surprised that a 7.1 channel FLAC played at all to be honest, but if it did then yes I guess just the regular channels would get picked. Need to manually downmix it I suspect.

By the way, what software did you use to extract the soundtrack from the BluRays, as I was going to do some myself and was wondering which tool was best?

Andre

[Edgar Amalyan]

I can manually downmix to stereo of course, but with 8 channels you're going to get clipping, even with a professionally mastered 24bit track like on a bluray. The program I use (eac3to) automatically detects clipping and adds a negative gain, which is fine but any good decoder, including Poweramp has clipping protection so you shouldn't need to have multiple files for different devices. I bet I can try different combinations of channel mapping so front left and right play but that's annoying.

*Off topic: I used eac3to for extracting the audio. You need to play around and add arcsoft THT files to decode dtshd ma files, otherwise it just extracts the core. Then if you want just encode the dtshd into flac and mux it back with the video file to get the higher quality audio on android. Pm me if you need help.

Anyway, I guess this is more of a request then a bug to add proper mix down support, can be handy.