10-10-2020, 08:42 PM
(10-10-2020, 04:06 PM)Tim Curtis Wrote: Examining the source shows that period and buffer size are initially set by librespot.
https://github.com/librespot-org/libresp...nd/alsa.rs
The defaults
Code:const PREFERED_PERIOD_SIZE: Frames = 5512; // Period of roughly 125ms
const BUFFERED_PERIODS: Frames = 4;
Possibly period_size is being overridden in this function ??
Code:fn open_device(dev_name: &str) -> Result<(PCM, Frames), Box<Error>> {
let pcm = PCM::new(dev_name, Direction::Playback, false)?;
let mut period_size = PREFERED_PERIOD_SIZE;
// http://www.linuxjournal.com/article/6735?page=0,1#N0x19ab2890.0x19ba78d8
// latency = period_size * periods / (rate * bytes_per_frame)
// For 16 Bit stereo data, one frame has a length of four bytes.
// 500ms = buffer_size / (44100 * 4)
// buffer_size_bytes = 0.5 * 44100 / 4
// buffer_size_frames = 0.5 * 44100 = 22050
{
// Set hardware parameters: 44100 Hz / Stereo / 16 bit
let hwp = HwParams::any(&pcm)?;
hwp.set_access(Access::RWInterleaved)?;
hwp.set_format(Format::s16())?;
hwp.set_rate(44100, ValueOr::Nearest)?;
hwp.set_channels(2)?;
period_size = hwp.set_period_size_near(period_size, ValueOr::Greater)?;
hwp.set_buffer_size_near(period_size * BUFFERED_PERIODS)?;
pcm.hw_params(&hwp)?;
let swp = pcm.sw_params_current()?;
swp.set_start_threshold(hwp.get_buffer_size()? - hwp.get_period_size()?)?;
pcm.sw_params(&swp)?;
}
Ok((pcm, period_size))
}
The latest git master works correctly. Previous to I think july 26th not so much.