multichannel wav/ flac -> no passthrough possible?!
#16
(2014-05-19, 06:57)606u Wrote:
(2014-05-17, 06:44)nickr Wrote: wav is not DTS! nor is flac!
I believe what thread's starter asks is about this:

You can record an audio-CD with RAW 1,411.2 kbit/s DTS instead of RAW 1,411.2 kbit/s PCM, and, if signal is transferred 1:1, in digital, your receiver will (most likely) pickup DTS stream and will decode it; hence, you get 5.1 audio from a "standard" CD-audio. You can also treat RAW DTS data as RAW PCM (even if it is not) and apply FLAC compression.
Embedding a DTS stream within a WAV file is a clever hack, but a hack nevertheless, not guaranteed to work - only if the entire playback chain passes it through bit perfect will the receiver see a DTS stream. Otherwise you just have white noise.

The player (omxplayer / paplayer etc) and the new audio engine in Gotham would have to pass the data through unaltered. Any change at all and it will fail. For example, because XBMC thinks it is sending a raw PCM stream if you adjust the volume within XBMC (+/- buttons) to anything other than 100% the data is no longer bit perfect.

If you use the Volume amplification setting (within the Audio OSD controls) the data is no longer bit perfect. If sample rate conversion is enabled in the new audio engine settings it is no longer bit perfect, etc...

You could try this, but it still may not work:

* Make sure volume is set to 100% in XBMC.

* Make sure volume amplification is set to zero.

* In system settings enable expert settings and go into the audio output section and try different settings for "Output configuration", the default is optimized, you might find "Fixed" and a sampling rate of 44.1Khz works to prevent resampling which would otherwise prevent a bit perfect transfer of PCM data.

Good luck, but don't expect it to work.

The only way it could ever be reliable is if the player itself had support added to detect a DTS/AC3 stream within a PCM container and switch into a "PCM passthrough" mode where it sends the data to the receiver as unaltered bit perfect PCM. (Disabling resampling, volume adjustment etc)
Kodi 18.3 - Mid 2007 Mac Mini, 4GB, 2TB HD, Windows 7 SP1
Kodi 18.3 - Vero4k, Raspberry Pi 2. OSMC.
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RE: multichannel wav/ flac -> no passthrough possible?! - by DBMandrake - 2014-05-20, 17:45


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