(2014-12-15, 02:15)mainerobinson Wrote: (2014-12-12, 23:43)nickr Wrote: Yeah I get a bit confused when we start talking about music formats and passthrough.
An admin over at OpenELEC (lrusak) stated that passthrough only applies to DTS, AC3, DTS-HD, TrueHD, and aac.
Think AAC used to be included in XBMC as a pass through option - but people realised that it was a red herring, as no amps with AAC inputs existed, so it has been removed. (A few amps with WMA were available I believe - but not sure if they are still available and don't remember it being an XBMC pass through option.)
(2014-12-14, 01:48)mainerobinson Wrote: (2014-12-12, 23:43)nickr Wrote: Yeah I get a bit confused when we start talking about music formats and passthrough.
Right. This is all operating at a level somewhere over my head. Glad i'm not alone. What's not clear to me is why I can't just force all audio to passthrough, regardless of format. Must be missing something.
Passthrough is only an option for audio formats where passthrough standards exist. You can't passthrough an audio format if there isn't a SPDIF or HDMI protocol in place to carry it. There are far more audio codecs than there are that have passthrough support - so you can't passthrough all audio formats.
AIUI MP3, MP2, FLAC, ALAC and AAC aren't supported in SPDIF/HDMI for passthrough, whereas AC3, DTS, DTS HD HR/MA and Dolby True HD are (though only the first two via SPDIF). This is presumably because the latter are supported by DVD/Blu-ray, which are the driving forces behind home theatre amps.
Of course MP3, MP2, FLAC, ALAC and AAC can all be decoded losslessly to PCM in XBMC with no quality loss (assuming you can get native sample rate output) whereas many of the passthrough formats HAVE to be passed through as internal decoding isn't always possible.
(2014-12-14, 01:48)mainerobinson Wrote: (2014-12-12, 23:43)nickr Wrote: Yeah I get a bit confused when we start talking about music formats and passthrough.
Right. This is all operating at a level somewhere over my head. Glad i'm not alone. What's not clear to me is why I can't just force all audio to passthrough, regardless of format. Must be missing something.
Passthrough is only an option for audio formats where passthrough standards exist. You can't passthrough an audio format if there isn't a SPDIF or HDMI protocol in place to carry it. There are far more audio codecs than there are that have passthrough support - so you can't passthrough all audio formats.
AIUI MP3, MP2, FLAC, ALAC and AAC aren't supported in SPDIF/HDMI for passthrough, whereas AC3, DTS, DTS HD HR/MA and Dolby True HD are (though only the first two via SPDIF). This is presumably because the latter are supported by DVD/Blu-ray, which are the driving forces behind home theatre amps.
Of course MP3, MP2, FLAC, ALAC and AAC can all be decoded losslessly to PCM in XBMC with no quality loss (assuming you can get native sample rate output) whereas many of the passthrough formats HAVE to be passed through as internal decoding isn't always possible.