Volume loss converting DSF to Wav with Convolution

[Snoopy08]

Using Minimserver 0.8 update 128, Minimstreamer 0.7.12
DAC takes only PCM max 24/192

I am using stream.transcode dsf:wav24;176 to convert dsf (64) music to 24/176. From the documentation, I understand the Minimstreamer has a 2 step process:
- convert DSF to 32/358
- convert 32/358 to 24/176

Conversion to DSF works fine without convolution. However, when convolution is enabled, there is a large volume drop in the region of 20 dB !!!

The convolution impulse files for the different rates are all about the same volume.

Have I missed something? Or is there an issue here?

[simoncn]

Which version of FFmpeg are you using? What is your exact setting of stream.options?

[Snoopy08]

Info from ffmpeg -version

ffmpeg version 4.1.1-0york1~16.04 Copyright © 2000-2019 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.11) 20160609
-------------

stream.options convOut= -i /media/music/pa/convolve/Filters1*.wav -lavfi afir
stream.transcode flac:wav,dsf:wav24;176

Convolution reduces volume by about 1 dB for flac files. For dsf files, volume drops by about 20 dB. Have convolution filters for all sample rates including 356.4 & 176.2 KHz

[simoncn]

Try this instead:

convOut= -i /media/music/pa/convolve/Filters1*.wav -lavfi afir=gtype=gn

[Snoopy08]

(11-05-2019 10:18)simoncn Wrote:  Try this instead:

convOut= -i /media/music/pa/convolve/Filters1*.wav -lavfi afir=gtype=gn

Thank you! Slight drop in volume but much better than previously.

Can't say I understand the new option, but it works!

[simoncn]

Another alternative:

convOut= -i /media/music/pa/convolve/Filters1*.wav -lavfi afir=wet=10

[Snoopy08]

Following up after rechecking convolution volume setting and measuring loudness of various music.
Using option -lavfi afir=gtype=gn fixed the volume drop when converting from DSD to wav.

Using option -lavfi afir=wet=10 does not work. It boosts all the volume of all formats, both flac and DSD. And DSD is very soft compared with flac.

Thank you Simon. I no longer have to convert all my DSD files to flac.

[simoncn]

Thanks for this. I have updated the MinimStreamer user guide to recommend using afir=gtype=gn for volume adjustment.

[Snoopy08]

(13-05-2019 14:10)Snoopy08 Wrote:  Thank you Simon. I no longer have to convert all my DSD files to flac.

Was premature with the above statement. While using option -lavfi afir=gtype=gn fixed the considerable volume drop when converting from DSD, there was still a volume drop which I could have lived with. But in critical listening, the converted 24/176.4 tracks had less body and considerably less bass.

Now the BAD news. CD 16/44.1 was better than ffmpeg on-the-fly conversion!

Same problem, whether convolution is enabled or not. Looks like I will have to convert all my DSD files after all.


If anyone wants to do your own testing, suggest using 2L's free test materials on
http://www.2l.no/hires/
Download (further down page) Hoff Ensemble: Blågutten: original CD 16/44.1, Stereo DSD 64, Stereo 24/96, and other versions as required. Blågutten has good bass as the beginning and the difference should be obvious...

[simoncn]

How did you do on-the-fly transcoding for the DSD version of this test track? The DSD downloads are DFF, not DSF. Only DSF can be transcoded by MinimStreamer and FFmpeg.