After few days of research and testing, there are some new information about playback MQA files on CoreELEC:
Good message: CoreELEC is full capable of playing MQA content with full quality. But external DAC with full MQA support is necessary for right full working .
Why? CoreELEC (KODI) isn’t MQA player, it means CE cannot recognizes MQA content inside normal FLAC (PCM) files or streams, plays all MQA files as normal PCM and plays from MQA files core content only, usually as normal 44,1/16 and maximally as 48/24, depending of MQA core file or stream. Because of CE don’t recognize MQA content and don’t have MQA playback license, CE cannot makes first unfold MQA file and if we have MQA DAC as renderer only, DAC don’t recognize MQA content and plays core only.
But because CE plays audio content as bit perfect (except DSD) we can play full MQA with full quality files if we have DAC MQA full decoder (not renderer only).
In this configuration all are working perfectly, CE plays MQA files without problem, DAC right recognizes MQA content and makes final MQA unfold with full original quality without problem. It works from file on filesystem, works perfect with TIDAL Master and TIDAL2 addon and works also as stream from my Android phone with mconnect application streamed via DLNA to CE
My configuration: CE on S905x3 (X99Max Plus) and IFi ZEN DAC V2 connected via USB.
Last remain is unsolved. Bit perfect playing DSD (SACD) format. Problem is, CE always does transcoding DSD format to PCM. I cannot find way, how to sent DSD stream from CE to my DAC without transcoding to PCM.