Convolution filtering

[JackFil]

Hello,

I just discovered a few weeks ago MinimServer and Minimstramer and I feel really interested.

I'm currently using Runeaudio as a streamer on a Raspberry Pi with convolution using Brutefir.
It works quite well, the sound is fine and the songs are played gapless.

I'd like to tune the upsamling parameters of soxr and bypass those of my DAC by reaching its top frequency (352.8 / 384 kHz).
But using brutefir, it reaches almost 100% of the CPU. Then I tried Minimstreamer and noticed it used only 13% on the same Raspberry :-).

It sounds nice but for the moment I still have 2 main issues:
1. I always get a blank between 2 songs of the same album (I don't get any with Runeaudio),
2. If I move to another part of a song, the rest is played at about twice the normal speed.

For the record I don't get these issues when I disable the convolution.
I use Runeaudio as renderer, my convolution filter is generate by Rephase in 64 bits IEE mono (.wav) / 352.8kHz with 131072 taps and my parameters are the following:

- stream.converter : /usr/bin/ffmpeg
- stream.options : convOut=-i /home/pi/Convolution/impulseS352.wav -lavfi "apad=pad_len=65536,afir=gtype=gn,atrim=start_sample=65536,aresample=resampler=so​xr:precision=33:cheby=1:dither_method=triangular"
- stream.transcode : flac:wav24;352, dsf:wav24;352, aac:wav24;352, mp4:wav24;352, wav:wav24;352, mp3:wav24;352

I tried to follow the recommandations that consist in setting the parameters apad=pad_len= and start_sample= to the half of the number of taps.

In terms of ffmpeg processes, here is what I noticed

One procces when I start the song (13% CPU)

Code:

ffmpeg -v 0 -analyzeduration 0 -f flac -request_sample_fmt flt -i /home/pi/Music/Live From Joshua Tree/01 Valley of the Yuccas  (Live from Joshua Tree).flac -i /home/pi/Convolution/impulseS352.wav -lavfi apad=pad_len=65536,afir=gtype=gn,atrim=start_sample=65536,aresample=resampler=so​xr:precision=33:cheby=1:dither_method=triangular -vn -ar 352800 -f s24le -acodec pcm_s24le -sample_fmt s32 pipe:

If I move to another part of the song I get 2 processes (and the dual speed play), from which one that takes 25% of CPU and get the parameters "-ss 171.995" et "-ss 1.000":

Code:

ffmpeg -v 0 -analyzeduration 0 -f flac -request_sample_fmt flt -i /home/pi/Music/Live From Joshua Tree/01 Valley of the Yuccas  (Live from Joshua Tree).flac -i /home/pi/Convolution/impulseS352.wav -lavfi apad=pad_len=65536,afir=gtype=gn,atrim=start_sample=65536,aresample=resampler=so​xr:precision=33:cheby=1:dither_method=triangular -vn -ar 352800 -f s24le -acodec pcm_s24le -sample_fmt s32 pipe:
ffmpeg -v 0 -analyzeduration 0 -f flac -ss 171.995 -request_sample_fmt flt -i /home/pi/Music/Live From Joshua Tree/01 Valley of the Yuccas  (Live from Joshua Tree).flac -i /home/pi/Convolution/impulseS352.wav -lavfi apad=pad_len=65536,afir=gtype=gn,atrim=start_sample=65536,aresample=resampler=so​xr:precision=33:cheby=1:dither_method=triangular -vn -ss 1.000 -ar 352800 -f s24le -acodec pcm_s24le -sample_fmt s32 pipe:

I also tried the following parametes since the song is encoded in 24/44, without success
- stream.converter : /usr/bin/ffmpeg
- stream.options : convOut=-i /home/pi/Convolution/impulseS*.wav -lavfi "apad=pad_len=65536,afir=gtype=gn,atrim=start_sample=65536,aresample=resampler=so​xr:precision=33:cheby=1:dither_method=triangular"
- stream.transcode : flac:wav;44, dsf:wav;44, aac:wav;44, mp4:wav;44, wav:wav;44, mp3:wav;44

This song comes from Qobuz, so I have tried another song that I ripped from a CD but I got the same behavior :-(

Thanks in advance for your help!