[Android Apps and Games] Locutus73:
Good, point. I’m new in this thread and my explanation was based purely on a guess (black box reasoning) and I don’t know if yours is based on source code or on a deeper knowledge of BubbleUPnP Server that I really lack (but read ahead). I based part of my speculations on previous posts regarding MQA; reading these posts I had the impression (I might be wrong) that it was believed that MQA is a special file format to be explicitly requested and specially processed. Using this assumption I tried to make some MQA aspects clear (probably they were already clear, but it doesn’t hurt) and I made an hypothesis.

So let me try again exposing the evidences I collected so far (again, if these are known facts, I'll hurt no one):

MQA is not a file/streaming format like other compression methods (MP3, FLAC, AAC, ALAC, etc.) aimed to encode a PCM binary stream in a compact form (lossy or lossless). MQA is a new technique that embeds additional data (lossy compressed high frequency component of a song, info on filters to be used by DACs and digital signature of the audio data) in the least significant bits of a PCM stream. Essentially, it’s a way to embed additional data in the inaudible noise of a PCM binary stream. So MQA resides in PCM and it can be stored/streamed in any lossless format (WAV, FLAC, ALAC). An MQA song can be played by any non MQA enabled software/hardware; it will be played as a normal PCM song with some clever noise that remains noise. An MQA song played by a MQA enabled software/hardware is processed in order to extract the additional info from the noise; this stuff is used to add audio informations to the song.

TIDAL has different albums id for the MQA and the non MQA versions of the same LP regardless of the streaming setting chosen in the client. E.g. Led Zeppelin’s “Led Zeppelin IV (Remastered)” album is h***s://listen.t***l.com/album/53660446 for the non MQA version and h**ps://listen.t***l.com/album/68691370 for the MQA one.

Using TIDAL interface the MQA version is decorated by a tiny box near the album name with an M inside (like the explicit lyrics albums that have an E inside the box); using BubbleUPnP Server and Linn Kazoo I can see the same albums (e.g. two istances of “Led Zeppelin IV (Remastered)”) without indication of the MQA/noMQA version, but this is a marginal issue, it’s not really a problem.

Investigating further using another software I don’t want to publicize (for various reasons) I can choose between HI-FI and Master settings, and, using Master setting, with h***s://listen.t***l.com/album/53660446 I get the 16bit/44KHz FLAC version and with h***s://listen.t***l.com/album/68691370 I get the 24bit/48KHz version (with MQA encoding embedded in the PCM stream), while using HI-FI setting, with h***s://listen.t***l.com/album/53660446 I get the same 16bit/44KHz FLAC version as above (same CRC) and with h***s://listen.t***l.com/album/68691370 I get a new 16bit/44KHz version with different CRC (this seems to be the one I get with BubbleUPnP server). So your hypothesis seems to be confirmed.

Full MQA decoding DACs are able to process the MQA data embedded in the PCM stream extracted from a FLAC file if they are fetched with the bitperfect PCM stream. So foobar2000+foo_upnp or a RPI3 with one of these DACs (e.g. Meridian Explorer 2) are UPnP renderers able to play MQA FLAC files with full MQA unfolding/processing.

So in the end: [MENTION=3373153]bubbleguuum[/MENTION] can you kindly implement a new “Master” setting for TIDAL maximum audio quality that forces BubbleUPnP server to ask for a different FLAC quality (I think it has something to do with a “HI_RES” value instead of “LOSSLESS” for some tokens like “soundQuality” and “audioquality” in the requests, but I might be wrong)? No special processing for the resulting FLAC file and no special changes to the way TIDAL library is browsed by the OpenHome control point; just (I know, it’s easy to say “just” being far away from the source code) a new quality setting.

Many many thanks in advance.

Best regards.

Locutus73