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Update the convolution code:

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(1) to be multithreaded,
    (2) to work on multichannel audio and
    (3) to work on 48k and 44.1k audio.

    Allow multiple impulse response (IR) files with a new setting: "convolution_ir_files"
    When convolution starts, Shairport Sync will look for an IR file with a sample rate
    matching the input (44.1k or 48k) and channel count.
    If one can't be found, it will look for a single-channel IR file with the same rate.
    It will always choose the first match in the file list supplied "convolution_ir_files".

    Allow multithreading -- use the "convolution_thread_pool_size" to set the number of threads to use.

    Deprecate "convolution" -- use "convolution_enabled" instead.
    Deprecate "convolution_max_length" -- use "convolution_max_length_in_seconds" instead.
    Deprecate "convolution_ir_file" -- use "convolution_ir_files" instead.
    Update corresponding D-Bus methods and properties.

Update the loudness code to work on 48k and well as 44.1k audio and with multichannel audio.

    Deprecate "loudness" -- use "loudness_enabled" instead.
    Update corresponding D-Bus methods and properties.

Fix a deprecated FFmpeg warning.

Update HiFi-LoFi FFT convolver to latest available.
This commit is contained in:
Mike Brady
2025-10-13 13:26:20 +01:00
parent 08d369385c
commit d043f98330
25 changed files with 2480 additions and 1504 deletions
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scripts/shairport-sync.conf
+17 -17
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@@ -287,33 +287,33 @@ ao =
// --with-convolution
dsp =
{
// NOTE: convolution and loudness filters currently work only for 44100 input and are disabled for other frame rates.
//////////////////////////////////////////
// This convolution filter can be used to apply almost any correction to the audio signal, like frequency and phase correction.
// This convolution filter can be used with inpulse responses files
// to apply almost any correction to the audio signal, like frequency and phase correction.
// For example you could measure (with a good microphone and a sweep-sine) the frequency response of your speakers + room,
// and apply a correction to get a flat response curve.
// Long impulse response files require lots of floating-point processing!
//////////////////////////////////////////
//
// convolution = "no"; // Set this to "yes" to activate the convolution filter.
// convolution_ir_file = "impulse.wav"; // Impulse Response file to be convolved to the audio stream
// convolution_gain = -4.0; // Static gain applied to prevent clipping during the convolution process
// convolution_max_length = 44100; // Truncate the input file to this length in order to save CPU.
// convolution_enabled = "no"; // Set this to "yes" to activate the convolution filter.
// convolution_thread_pool_size = 1; // Number of CPU threads that can work on convolution at the same time.
// convolution_ir_files = "<comma-separated list of full path names to impulse response files, for sample rates of 44100 and 48000 -- stereo or mono only>";
// convolution_gain = -4.0; // Static gain applied after convolution, between -60 and +18 dB. Useful for preventing clipping or amplifying low convolution output levels
// convolution_max_length_in_seconds = 1.0; // Truncate the input file to this length in order to save CPU.
//
//////////////////////////////////////////
// This loudness filter is used to compensate for human ear non linearity.
// When the volume decreases, our ears loose more sentisitivity in the low range frequencies than in the mid range ones.
// This filter aims at compensating for this loss, applying a variable gain to low frequencies depending on the volume.
// When the volume decreases, our ears lose more sensitivity to low frequencies than to mid range ones.
// This filter aims at compensating for this loss, applying a small extra gain to low frequencies, depending on the volume.
// More info can be found here: https://en.wikipedia.org/wiki/Equal-loudness_contour
// For this filter to work properly, you should disable (or set to a fix value) all other volume control and only let shairport-sync control your volume.
// The setting "loudness_reference_volume_db" should be set at the volume reported by shairport-sync when listening to music at a normal listening volume.
//
// NOTE: To use this filter, Shairport Sync must _not_ be controlling a hardware mixer.
//
// The setting "loudness_reference_volume_db" is the highest level at which the loudness filter will take effect. Above this level the filter is off.
//////////////////////////////////////////
//
// loudness = "no"; // Set this to "yes" to activate the loudness filter
// loudness_reference_volume_db = -20.0; // Above this level the filter will have no effect anymore. Below this level it will gradually boost the low frequencies.
// loudness_enabled = "no"; // Set this to "yes" to activate the loudness filter (only works if you are _not_ using hardware volume control)
// loudness_reference_volume_db = -16.0; // Above this level the filter will have no effect. Below this level it will gradually boost the low frequencies.
};
// How to deal with metadata, including artwork