Transcoding flac:wav24; but DAC showing flac resolution

[Cornan]

I am running MiminServer/MinimStreamer on iMAC. Local music on the same iMAC. Transcoding with FFmpeg with flac:wav24; (plus flac:wav32; ) and with MinimStreamer with flac:wav24 (plus flac:wav32) but Brooklyn DAC is only showing flac original resolution. Jplay for iOS is showing correct. iFi Zen Stream is also showing correct. Tried numerous times to rescan MinimServer, rebuild MinimServer in Jplay, removed played tracks and restart everything with same results. Allowed ports 9790, 9791, 49190 (proxy server with BubbleUPnP server) in the router.
Have run out if ideas. Any help appreciated.

   

Best regards,
Micael

[simoncn]

My DAC (a dCS Rossini) does something similar with the transcoding settings you are using. If I set flac:wav24 or flac:wav32 in stream.transcode, the DAC display shows 16/44100 for a CD-quality file.

This isn't a problem and MinimStreamer transcoding is working correctly. Because FLAC uses lossless compression, the only change to the PCM audio data sent to the DAC is adding zeros to each audio sample to extend the sample from 16 bits to 24 or 32 bits.

With some DACs, extending the sample in this way is beneficial because it avoids the need for the DAC to do this internally. In other cases, the DAC is doing internal upsampling of the audio samples it receives and is "smart" enough to detect the added zeros and remove them before doing its upsampling. If this is happening, the DAC shows the audio data as 16/44100 instead of 24/44100 or 32/44100.

Having MinimStreamer transcode from FLAC to WAV is beneficial because it avoids the need for the DAC to decode FLAC to PCM. With my DAC, flac:wav sounds better than no transcoding but flac:wav24 and flac:wav32 sound the same as flac:wav.

[Cornan]

(03-04-2025 10:33)simoncn Wrote:  My DAC (a dCS Rossini) does something similar with the transcoding settings you are using. If I set flac:wav24 or flac:wav32 in stream.transcode, the DAC display shows 16/44100 for a CD-quality file.

This isn't a problem and MinimStreamer transcoding is working correctly. Because FLAC uses lossless compression, the only change to the PCM audio data sent to the DAC is adding zeros to each audio sample to extend the sample from 16 bits to 24 or 32 bits.

With some DACs, extending the sample in this way is beneficial because it avoids the need for the DAC to do this internally. In other cases, the DAC is doing internal upsampling of the audio samples it receives and is "smart" enough to detect the added zeros and remove them before doing its upsampling. If this is happening, the DAC shows the audio data as 16/44100 instead of 24/44100 or 32/44100.

Having MinimStreamer transcode from FLAC to WAV is beneficial because it avoids the need for the DAC to decode FLAC to PCM. With my DAC, flac:wav sounds better than no transcoding but flac:wav24 and flac:wav32 sound the same as flac:wav.

Thanks a lot for your reply Simon! I have noticed that it sounds better with flac:wav32 and a tiny bit better with ffmpeg. I was just concerned if there was something wrong. With your reply I can now relax and just enjoy the improved SQ. Awesome!

[lyapounov]

Simon,

For my understanding: you say that flac:wav24 only adds zeros. However, I am using Chebyshev polynomial in the resampling, as well as adding dither

convOut=-af aresample=resampler=soxr:precision=33:cheby=1:dither_method=shibata

Am I right to say that, in that case, the result should be more precise than just adding zeros ?

[simoncn]

Yes, using this convOut setting will use the full 24 bits in the output stream. I don't think this is what the OP was doing.