duncsimpson wrote: 
> Noise with high sample rate since version 1.40.x, roon_mode, and wav
> codec support not working?
> 
> Hi, I recently updated from 1.25.0 to 1.40.8 of the LMS2UPnP bridge and
> found I get noise with any high sample rate tracks.  
> 
> This is not the wall of white noise problem, I've had that in an earlier
> version where some tracks would just play a wall of white noise and if i
> skipped forwared to another spot in the track, or to the next track, it
> would correct itself.  That was solved by updating to 1.25.0.  
> 
> Instead this current problem is more like garbled digital noise
> modulated by the track itself, ie it varies with the pitch and tone and
> content of the track.  If I skip to another spot in the track, it
> sometimes comes right. If I skip to the next track that will have the
> same problem.
> 
> The issue appears to be any tracks > 16/44.1 which are FLAC or WAV being
> played from Roon (eg 24/44.1, 16/88, 24/88 and so on).  ALAC tracks >
> 16/44.1 playback fine with no noise.  My renderer doesn't support ALAC
> natively, so I think this is because the bridge is transcoding in this
> case.
> 
> I tried all 4 different setting for L24_format, none of them fixed the
> problem.
> 
> I've reverted back to 1.25.0, and the problem goes away, ie it is not
> reproduceable in that version.  I jump forward to 1.40.8 and the problem
> returns.  I've tried all major versions from 1.25.0 to 1.40.0. 
> Everything up to 1.31.0 works fine, the problem seems to be introduced
> with 1.40.0, and is still present in 1.40.7 and 1.40.8.
> 
> I'm running the standalone version of the bridge on Arch Linux with
> roon_mode enabled, and controlling playback from Roon.  My config file
> is the generated config with roon_mode enabled and the sample rate
> changed to 192000.
> 
> My UPnP renderer is a Naim NDX which is capable of playback up to 24/192
> in WAV and 24/96 in LPCM (as reported in DeviceSpy).  I tried reordering
> the raw_audio_format setting to prefer WAV first however the problem is
> also present there.
> 
> LMS endpoints in Roon (when LMS support is enabled) have an option to
> enable or disable FLAC compression.  By default this is enabled, however
> I have it disabled.
> 
> The noise problem with 1.40.x disappears if FLAC compression is enabled
> for the endpoint in Roon, and playback of any file format/codec up to
> 24/192 registers on the NDX as FLAC in the matching sample rate. 
> However the reason I normally have FLAC compression disabled is twofold
> - when FLAC compression is enabled in Roon, then all playback is forced
> in to FLAC and playback of any DSD files is not longer bitperfect as it
> appears to always get resampled to 24/176.4 FLAC (not sure if Roon is
> doing this or the bridge).  Secondly I think with the FLAC compression
> off in Roon, the WAV/LPCM stream is putting less load on the NDX
> processor because it doesn't have to decompress the FLAC stream which
> should result in a lower noise floor assuming its processor has to do
> less, and thus should in theory lead to better sound quality.  During
> critical listening it does sound better for some tracks, more attack in
> the bass, highs sort of "sing" more, slightly more energy, more toe
> tapping goes on etc (however I also accept the times I think I've
> noticed those differences could just be confirmation bias :D ).  When
> DSD's are converted in Roon using DoP with FLAC compression disabled,
> they get reported as WAV 2.8Mhz for example for a DSD64 file, so whilst
> not native DSD playback, it is closer to original quality than FLAC
> 176.4.
> 
> All of this also leads to my second question - what does roon_mode
> actually do?  The user guide documentation doesn't provide any detail
> other than "Set to ‘1’ to if you intend to use this player from a Roon
> server.".  The diagrams in the documentation, for example, don't mention
> this mode at all. 
> 
> I have normally have FLAC compression disabled in Roon for this
> endpoint, and the bridge's mode is set to thru, and yet my NDX reports
> the stream is either LPCM or WAV regardless of what format file is being
> played on Roon, eg FLAC, WAV, ALAC, DSD, etc.  When FLAC compression is
> enabled in Roon the NDX reports everything is FLAC during playback again
> regardless of what format file is being played on Roon, eg FLAC, WAV,
> ALAC, DSD, etc.  
> 
> So it seems that with roon_mode enabled, and if Roon has FLAC
> compression disabled on the playback device, then the bridge is not
> really in pass thru mode and instead it processes all incoming streams
> (FLAC, WAV, ALAC, DSD etc) to the first format listed in the
> raw_audio_format, despite mode being set to thru.  If Roon has FLAC
> compression enabled, the bridge appears to pass through the FLAC (or
> perhaps it is doing some reprocessing the FLAC stream because
> flac_header is enabled by default?).
> 
> I also noticed when using debug logging on the bridge that it is not
> offering wav support to the upstream Roon LMS server when using 1.40.x,
> even though my renderer supports wav and I have regenerated the bridge's
> config.xml to get the additional wav entry in the codec setting.
> 
> In the interim I'm back to running 1.31.0 version of the bridge, but I'd
> be grateful for any help with the noise problem, or explanations of what
> roon_mode is doing behind the scenes, or why the newer wav codec support
> in 1.40.x doesn't appear to work in my setup.

Starting version 1.40 I've added proper header WAV/AIFF parsing and I
guess this is conflicting with DSD or something like that.
<roon_mode> simply forces a couple of parameters to be compatible with
Roon server which is not exactly acting as a proper LMS server



LMS 7.9  on Pi 3B+ & Odroid-C2 - *SqueezeAMP!*, 5xRadio, 3xBoom, 4xDuet,
1xTouch, 1 SB3. Sonos PLAY:3, PLAY:5, Marantz NR1603, Foobar2000,
ShairPortW, JRiver 21, 2xChromecast Audio, Chromecast v1 and v2,
Squeezelite on Pi,  Yamaha WX-010, AppleTV 4, Airport Express, GGMM E5,
Riva 1 & 3
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