SpatialPlayer does not work with set_speed and looped decoder

[Bobitsmagic]

When using a SpatialPlayer the engine sound makes weird noises when the player speed is changed.
This issue does not occur on any playbackspeed when using a normal player/sink.

fn main() {
    let stream_handle = rodio::DeviceSinkBuilder::open_default_sink().unwrap();

    let player = rodio::SpatialPlayer::connect_new(
        stream_handle.mixer(),
        [0.0; 3], 
        [0.0, -1.0, 0.0],
        [0.0, 1.0, 0.0]
    );

    // let player = rodio::Player::connect_new(stream_handle.mixer());

    let file = std::fs::File::open("assets/engine.mp3").unwrap();
    let source = rodio::Decoder::new_looped(file).unwrap();

    player.append(source);
    player.set_speed(1.5);

    player.sleep_until_end();
}

I tried let source = rodio::Decoder::try_from(file).unwrap().repeat_infinite(); instead but it made the sound even worse.

What can i do to fix this, or is this an Issue of the crate itself.

Thank you for your help.

Rodio: 22.2, Windows 11
engine.mp3

[yara-blue]

The mp3 you attached is only 2.7 Kb (basically empty) so we can not hear the issue. Still it sounds like a possible perf issue.

Just to check, are you running in release mode? (cargo r --release)

[Bobitsmagic]

Using release mode does not change things on my end.
Here are 2 files how it sounds for me when using the spatial vs the normal sink/player.

https://github.com/user-attachments/assets/d04a98bf-c700-4b61-a74a-2faf5182cbc2
https://github.com/user-attachments/assets/22d0e09a-66dc-451b-839d-2cd3d71c2fab

[roderickvd]

Thank you for those clips. To isolate the issue:

1. Was it different on Rodio 0.21?
2. Would you be capable of testing it on another platform, like Linux?

[Bobitsmagic]

I tried rodio 22.2 and 21.1 and could not notice a difference.

I have no linux based machine to test this. I just tried with WSL but it only made the problem worse.

[Bobitsmagic]

I figured it has to be the ChannelVolume source that makes this noise.
The following code generates the same popping sound as the Spatial player:

use rodio::{Source, source::ChannelVolume};

fn main() {
    let stream_handle = rodio::DeviceSinkBuilder::open_default_sink().unwrap();

    let player = rodio::Player::connect_new(stream_handle.mixer());

    let file = std::fs::File::open("assets/nyom.m4a").unwrap();
    let source = rodio::Decoder::try_from(file).unwrap().repeat_infinite();

    let cv = ChannelVolume::new(source, vec![0.5, 0.5]);

    player.append(cv);

    player.sleep_until_end();
}

Testing on a different machine running linux yields and a longer audio sample did not fix the problem.

When removing the .repeat_infinite() the noise/popping sounds disapears so its most likely an issue between the ChannelVolume and Repeat struct.

Using a much longer audio sample (2 minutes) also fixes this issue.

[roderickvd]

Great detective work. Are all those files mono? I think the issue may be that ChannelVolume::current_span_len() is reported in the wrong units. ChannelVolume changes the channel count, but its current_span_len just passes the input value straight through.

Try this:

fn current_span_len(&self) -> Option<usize> {
    self.input.current_span_len().map(|len| {
        len / self.input.channels().get() as usize * self.channel_volumes.len()
    })
}

[Bobitsmagic]

Yeah this fixes the issue.

The audio files were all mono.

[roderickvd]

Perfect! Would you submit a PR?