Convolution filtering

[simoncn]

By removing afir from your convOut setting, you are no longer doing convolution. FFmpeg 4.1.6 does support afir.

I will try this with BubbleUPnP as control point and renderer and let you know what happens.

[simoncn]

I have tried this on Raspbian/Buster with FFmpeg 4.1.6 and BubbleUPnP.

Gapless playback doesn't work when playing to the BubbleUPnP local Android renderer but does work when playing to other renderers that support gapless playback. This happens with or without afir.

I can't reproduce the problem with double-speed playing. Please describe exactly what you are doing on BubbleUPnP to make this happen.

[JackFil]

Hello Simon,

I just jump the cursor for instance to the middle of the song as shown in attachement and at this time the rest of the song is played at fast rate.

What kind of gapless renderer on raspberry pi would you recommend?

It's stange because I'm using Twonky as misic server, Bubbleupnp app as controler and Runeaudio as renderer since a few year and all the songs are played gapless.
but in that case it seems to be the cause of the issue.

Thanks again for your support!

[simoncn]

I am testing with moving the cursor in exactly the same way and I don't get fast playback. Something is different between your setup and mine and I am not sure how to find out what this difference is. I wonder whether it could be related to having RuneAudio installed on your RPi.

I also checked the ffmpeg processes after moving the cursor. The first ffmpeg process ends (as expected), leaving only the second ffmpeg process running.

[JackFil]

RuneAudio (Archlinux) is running on a dedicated RPI.

Minimserver/Streamer are also running on another dedicated RPI: I have flashed the BUSTER image (without desktop) on an SD card, installed Java and MinimServer/MinimStreamer following your instructions and also ffmpeg. That's all.

Maybe the issue is related to a parameter in the BubbleUpnp app as controler ? Don't waste your time, I'll try on my side next week-end and go back to you.

[simoncn]

OK, your setup on the second RPi should be the same as mine. The good news (I think) is that my setup is working, so it should be possible to get yours working too.

I am using a 44.1 kHz convolution file with 65536 taps. In case this is relevant, can you post your convolution file?

Which version of MinimServer are you using? Is it MinimServer 0.8 or MinimServer 2?

[simoncn]

When I use your convolution file, I get the "fast playback" issue. I don't see multiple ffmpeg processes running. When I use my own test convolution file, I don't get the "fast playback" issue. So there is something about your convolution file that is causing this problem. I don't know enough about how convolution files work to be able to suggest how to fix this.

[simoncn]

I noticed that my test convolution file is stereo but your convolution file is mono. Is this intentional? Could this perhaps be related to the "fast playback" issue?

[JackFil]

Yes Simon, thank you, that's it! Since the beginning I thought the convolution file had to be generated in mono according to what I saw a couple of pages before but I may have misunderstood.

In stereo, no fast speed issue anymore :-).

Nevertheless I still have a gap (using RuneAudio as renderer) between the songs even when I follow the instructions: Same value "x" for apad & atrim functions => x = 0.5 * (the number of taps in the convolution file).
Would anybody have a RPi renderer to recommend? Maybe shall I install it on the same RPi as Minimserver&Streamer.

Thanks in advance.

[simoncn]

I am not getting a gap between tracks on the renderer that I use. Does RuneAudio always have gaps when streaming from MinimServer or only when you are doing convolution?

You could look at upmpdcli as a Linux renderer that should run on the RPi.