Audio transcoding


Hi, apologies if I've missed it, but is it possible for the app and / or the dvr service to send DD ac3 instead of 5.1 PCM as the sound output?

I'd like to use the optical input of my AV receiver.

Kind regards,



What app and device are you using?

5.1 PCM should work with any receiver as well.


Yes, multi channel PCM isn't an issue, but you have to use HDMI as the cable, an when I do that, I get issues with CEC doing annoying things... so to get around this, I use optical, but optical cannot transport 5.1 PCM and it ends up stereo.

So, if you could transcode to video / ac3 instead, all good :slight_smile:


Strange. I use 5.1 PCM over optical without issue on my Apple TV 4K. What device are you running Channels on?


It's not possible to transmit uncompressed multi channel over optical, not enough bandwidth...


Are you using the android tv app or tvOS app?


Hi, I'm using android, nvidia shield... but this makes no difference really.

I'm assuming that the stream being sent from my linux server is the transcoded stream, which contains decoded (hence uncompressed) audio, and that will never go down the optical, and is always reduced to PCM 2.0


The stream comes directly from the hdhomerun to the android tv and is converted by the audio driver being used. There is a setting on the android audio driver to send the raw compressed audio, but we have that option disabled due to problems on FireTV devices. We can try to re-enable it for the shield.


I've tried a few apps, and most are sending out 5.1 pcm, but i tried emby today and they are kicking out ac3. But its not as good as channels


Similar thing happens in plex if a movie as 5.1 aac. It gets decoded to pcm and them if I use optical, stereo.

In this case, I transcoded 'said' movie to have an ac3 stream using ffmpeg