request for next version: dts software downmix

malakudi

Vu+ Newbie
Would you consider enabling support for DTS software downmix in next versions of Blackhole? It's an option that is supported in PLI images for VU Duo (Solo doesn't have the CPU performance to achieve this), though it isn't working correctly (lip sync problems) because of the lack of some support in the drivers (something about audio sinks).
 

radoskur

Vu+ Newbie
Have you consider that it can be license problem? Maybe VU have to pay for this funcionality. I hope I am wrong
 

malakudi

Vu+ Newbie
VU will never implement this in the original image, because the open source dts decoder might have patent issues. However, an unofficial image can support this. In DM500HD and DM800se it is already supported. You need the following packages: libdca0 , gst-plugin-dtsdec and most important, libgstdvbaudiosinkext.so (packaged as enigma2-dtsdownmix on some images) . This requires that the DVB driver exports an external audio sink and this is the feature that VU Duo drivers dont' have. If the developer team of Blackhole request this from the VU Duo driver developers, then dts downmix will work in VU Duo. VU Solo doesn't have the FPU performance to do DTS decoding in software.
 

malakudi

Vu+ Newbie
... and most important, libgstdvbaudiosinkext.so (packaged as enigma2-dtsdownmix on some images) . This requires that the DVB driver exports an external audio sink and this is the feature that VU Duo drivers dont' have.
This quote was wrong. I searched this deaper with the help of PLI developers. There is no limitation of VU Duo drivers. This module would work on VU Duo if it wasn't "locked" on DMM hardware via TPM. This module provides the on-the-fly switching between gst-plugin-dtsdec and hardware decoding (that is only pass-through). So someone needs to reverse engineer this module to make it work on VU Duo (no source available), or implement a similar extension from scratch. The problem is that gstreamer caches sink capabilities and you need a way to change the gstreamer graph on-the-fly. PLI team implemented DTS decoding but you need to remove gstreamer cache after each change, so this is not an elegant solution.
 
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