I have a tvOS app that receives AAC 5.1 audio stream over the network and I am using AudioToolbox to decode (mFormatID = kAudioFormatMPEGAAC) to 5.1 channels. But I only hear 2 channels (Stereo) outputs on my 5.1 surround system (which is connected to the TV using an Audio Optical cable).
I am not sure why PCM multi-channel is not outputting from AppleTV. Am I missing anything?
I have a tvOS app
Are you programming an app? Then consider visiting the developer forums.
Setting manually to Dolby Digital 5.1 did not help. I think it says it could be re-encoded to DD 5.1 or Stereo.
DD 5.1 and Stereo are fallback; that is how it is supposed to work.
So it might not do re-encoding. I am not sure how to force to re-encode.
I think it re-encodes everything, possibly with exception of what already matches the set output format.
If I want to play 5.1 AAC audio, what should be set up if not optical cables?
AAC 5.1 would be converted to Dolby Digital 5.1, with the Dolby Digital 5.1 output setting. There is no untouched passthrough, AAC or otherwise. Either uncompressed PCM Multichannel (over HDMI), re-encoded Dolby Digital 5.1, or downmixed Stereo (PCM 2.0). Those are device settings, not app settings.
I have a tvOS app
Are you programming an app? Then consider visiting the developer forums.
Setting manually to Dolby Digital 5.1 did not help. I think it says it could be re-encoded to DD 5.1 or Stereo.
DD 5.1 and Stereo are fallback; that is how it is supposed to work.
So it might not do re-encoding. I am not sure how to force to re-encode.
I think it re-encodes everything, possibly with exception of what already matches the set output format.
If I want to play 5.1 AAC audio, what should be set up if not optical cables?
AAC 5.1 would be converted to Dolby Digital 5.1, with the Dolby Digital 5.1 output setting. There is no untouched passthrough, AAC or otherwise. Either uncompressed PCM Multichannel (over HDMI), re-encoded Dolby Digital 5.1, or downmixed Stereo (PCM 2.0). Those are device settings, not app settings.
Setting manually to Dolby Digital 5.1 did not help. I think it says it could be re-encoded to DD 5.1 or Stereo. So it might not do re-encoding. I am not sure how to force to re-encode.
If I want to play 5.1 AAC audio, what should be set up if not optical cables? Thanks!
Yeah, I am programming a tvOS app.
I have asked this question in the developer forum as you suggested,
https://developer.apple.com/forums/thread/681948
Thanks!
PCM Multichannel is not compatible with optical cables (bandwidth limitations). Set the audio format in Apple TV Settings to Dolby Digital 5.1 or Stereo, as those are compatible with optical cables.
Playing AAC multichannel (5.1 surround) audio stream on Apple TV
