diff options
Diffstat (limited to 'third_party/rust/audio-mixer/src')
| -rw-r--r-- | third_party/rust/audio-mixer/src/channel.rs | 85 | ||||
| -rw-r--r-- | third_party/rust/audio-mixer/src/coefficient.rs | 754 | ||||
| -rw-r--r-- | third_party/rust/audio-mixer/src/lib.rs | 81 | ||||
| -rw-r--r-- | third_party/rust/audio-mixer/src/main.rs | 50 |
4 files changed, 970 insertions, 0 deletions
diff --git a/third_party/rust/audio-mixer/src/channel.rs b/third_party/rust/audio-mixer/src/channel.rs new file mode 100644 index 0000000000..ef58018ad9 --- /dev/null +++ b/third_party/rust/audio-mixer/src/channel.rs @@ -0,0 +1,85 @@ +// The number of channels must be unique and start from 0. They will be treated as indice in the +// mixing matrix and used to form unique bitflags in the channel map, which is a bitmap. +#[derive(Copy, Clone, Debug, PartialEq)] +pub enum Channel { + FrontLeft = 0, + FrontRight = 1, + FrontCenter = 2, + LowFrequency = 3, + BackLeft = 4, + BackRight = 5, + FrontLeftOfCenter = 6, + FrontRightOfCenter = 7, + BackCenter = 8, + SideLeft = 9, + SideRight = 10, + TopCenter = 11, + TopFrontLeft = 12, + TopFrontCenter = 13, + TopFrontRight = 14, + TopBackLeft = 15, + TopBackCenter = 16, + TopBackRight = 17, + Silence = 18, +} + +impl Channel { + pub const fn number(self) -> usize { + self as usize + } + + pub const fn count() -> usize { + Channel::Silence as usize + 1 + } + + pub const fn bitmask(self) -> u32 { + 1 << self as usize + } +} + +bitflags! { + pub struct ChannelMap: u32 { + const FRONT_LEFT = Channel::FrontLeft.bitmask(); + const FRONT_RIGHT = Channel::FrontRight.bitmask(); + const FRONT_CENTER = Channel::FrontCenter.bitmask(); + const LOW_FREQUENCY = Channel::LowFrequency.bitmask(); + const BACK_LEFT = Channel::BackLeft.bitmask(); + const BACK_RIGHT = Channel::BackRight.bitmask(); + const FRONT_LEFT_OF_CENTER = Channel::FrontLeftOfCenter.bitmask(); + const FRONT_RIGHT_OF_CENTER = Channel::FrontRightOfCenter.bitmask(); + const BACK_CENTER = Channel::BackCenter.bitmask(); + const SIDE_LEFT = Channel::SideLeft.bitmask(); + const SIDE_RIGHT = Channel::SideRight.bitmask(); + const TOP_CENTER = Channel::TopCenter.bitmask(); + const TOP_FRONT_LEFT = Channel::TopFrontLeft.bitmask(); + const TOP_FRONT_CENTER = Channel::TopFrontCenter.bitmask(); + const TOP_FRONT_RIGHT = Channel::TopFrontRight.bitmask(); + const TOP_BACK_LEFT = Channel::TopBackLeft.bitmask(); + const TOP_BACK_CENTER = Channel::TopBackCenter.bitmask(); + const TOP_BACK_RIGHT = Channel::TopBackRight.bitmask(); + const SILENCE = Channel::Silence.bitmask(); + } +} + +// Avoid printing the following types in debugging context {:?} by declaring them in impl +// rather than bitflags! {} scope. +impl ChannelMap { + pub const FRONT_2: Self = Self { + bits: Self::FRONT_LEFT.bits() | Self::FRONT_RIGHT.bits(), + }; + pub const BACK_2: Self = Self { + bits: Self::BACK_LEFT.bits() | Self::BACK_RIGHT.bits(), + }; + pub const FRONT_2_OF_CENTER: Self = Self { + bits: Self::FRONT_LEFT_OF_CENTER.bits() | Self::FRONT_RIGHT_OF_CENTER.bits(), + }; + pub const SIDE_2: Self = Self { + bits: Self::SIDE_LEFT.bits() | Self::SIDE_RIGHT.bits(), + }; +} + +impl From<Channel> for ChannelMap { + fn from(channel: Channel) -> Self { + ChannelMap::from_bits(channel.bitmask()).expect("convert an invalid channel") + } +} diff --git a/third_party/rust/audio-mixer/src/coefficient.rs b/third_party/rust/audio-mixer/src/coefficient.rs new file mode 100644 index 0000000000..82ff97dbcf --- /dev/null +++ b/third_party/rust/audio-mixer/src/coefficient.rs @@ -0,0 +1,754 @@ +// The code is based from libcubeb's cubeb_mixer.cpp, +// which adapts the code from libswresample's rematrix.c + +use crate::channel::{Channel, ChannelMap}; + +use std::fmt::Debug; + +const CHANNELS: usize = Channel::count(); + +#[derive(Debug)] +enum Error { + DuplicateNonSilenceChannel, + AsymmetricChannels, +} + +#[derive(Debug)] +struct ChannelLayout { + channels: Vec<Channel>, + channel_map: ChannelMap, +} + +impl ChannelLayout { + fn new(channels: &[Channel]) -> Result<Self, Error> { + let channel_map = Self::get_channel_map(channels)?; + Ok(Self { + channels: channels.to_vec(), + channel_map, + }) + } + + // Except Silence channel, the duplicate channels are not allowed. + fn get_channel_map(channels: &[Channel]) -> Result<ChannelMap, Error> { + let mut map = ChannelMap::empty(); + for channel in channels { + let bitmask = ChannelMap::from(*channel); + if channel != &Channel::Silence && map.contains(bitmask) { + return Err(Error::DuplicateNonSilenceChannel); + } + map.insert(bitmask); + } + Ok(map) + } +} + +#[derive(Debug)] +pub struct Coefficient<T> +where + T: MixingCoefficient, + T::Coef: Copy, +{ + input_layout: ChannelLayout, + output_layout: ChannelLayout, + matrix: Vec<Vec<T::Coef>>, + would_overflow_from_coefficient_value: Option<bool>, // Only used when T is i16 +} + +impl<T> Coefficient<T> +where + T: MixingCoefficient, + T::Coef: Copy, +{ + // Given a M-channel input layout and a N-channel output layout, generate a NxM coefficients + // matrix m such that out_audio = m * in_audio, where in_audio, out_audio are Mx1, Nx1 matrix + // storing input and output audio data in their rows respectively. + // + // data in channel #1 ▸ │ Silence │ │ 0, 0, 0, 0 │ │ FrontRight │ ◂ data in channel #1 + // data in channel #2 ▸ │ FrontRight │ = │ 1, C, 0, L │ x │ FrontCenter │ ◂ data in channel #2 + // data in channel #3 ▸ │ FrontLeft │ │ 0, C, 1, L │ │ FrontLeft │ ◂ data in channel #3 + // ▴ ▴ │ LowFrequency │ ◂ data in channel #4 + // ┊ ┊ ▴ + // ┊ ┊ ┊ + // out_audio mixing matrix m in_audio + // + // The FrontLeft, FrontRight, ... etc label the data for front-left, front-right ... etc channel + // in both input and output audio data buffer. + // + // C and L are coefficients mixing input data from front-center channel and low-frequency channel + // to front-left and front-right. + // + // In math, the in_audio and out_audio should be a 2D-matrix with several rows containing only + // one column. However, the in_audio and out_audio are passed by 1-D matrix here for convenience. + pub fn create(input_channels: &[Channel], output_channels: &[Channel]) -> Self { + let input_layout = ChannelLayout::new(input_channels).expect("Invalid input layout"); + let output_layout = ChannelLayout::new(output_channels).expect("Invalid output layout"); + + let mixing_matrix = + Self::build_mixing_matrix(input_layout.channel_map, output_layout.channel_map) + .unwrap_or_else(|_| Self::get_basic_matrix()); + + let coefficient_matrix = Self::pick_coefficients( + &input_layout.channels, + &output_layout.channels, + &mixing_matrix, + ); + + let normalized_matrix = Self::normalize(T::max_coefficients_sum(), coefficient_matrix); + + let would_overflow = T::would_overflow_from_coefficient_value(&normalized_matrix); + + // Convert the type of the coefficients from f64 to T::Coef. + let matrix = normalized_matrix + .into_iter() + .map(|row| row.into_iter().map(T::coefficient_from_f64).collect()) + .collect(); + + Self { + input_layout, + output_layout, + matrix, + would_overflow_from_coefficient_value: would_overflow, + } + } + + // Return the coefficient for mixing input channel data into output channel. + pub fn get(&self, input: usize, output: usize) -> T::Coef { + assert!(output < self.matrix.len()); + assert!(input < self.matrix[output].len()); + self.matrix[output][input] // Perform copy so T::Coef must implement Copy. + } + + pub fn would_overflow_from_coefficient_value(&self) -> Option<bool> { + self.would_overflow_from_coefficient_value + } + + pub fn input_channels(&self) -> &[Channel] { + &self.input_layout.channels + } + + pub fn output_channels(&self) -> &[Channel] { + &self.output_layout.channels + } + + // Given audio input and output channel-maps, generate a CxC mixing coefficients matrix M, + // whose indice are ordered by the values defined in enum Channel, such that + // output_data(i) = Σ M[i][j] * input_data(j), for all j in [0, C), + // where i is in [0, C) and C is the number of channels defined in enum Channel, + // output_data and input_data are buffers containing data for channels that are also ordered + // by the values defined in enum Channel. + // + // │ FrontLeft │ │ 1, 0, ..., 0 │ │ FrontLeft │ ◂ data in front-left channel + // │ FrontRight │ │ 0, 1, ..., 0 │ │ FrontRight │ ◂ data in front-right channel + // │ FrontCenter │ = │ ........., 0 │ x │ FrontCenter │ ◂ data in front-center channel + // │ ........... │ │ ........., 0 | │ ........... │ ◂ ... + // │ Silence │ │ 0, 0, ..., 0 | │ Silence │ ◂ data in silence channel + // ▴ ▴ ▴ + // out_audio coef matrix M in_audio + // + // ChannelMap would be used as a hash table to check the existence of channels. + #[allow(clippy::cognitive_complexity)] + fn build_mixing_matrix( + input_map: ChannelMap, + output_map: ChannelMap, + ) -> Result<[[f64; CHANNELS]; CHANNELS], Error> { + // Mixing coefficients constants. + use std::f64::consts::FRAC_1_SQRT_2; + use std::f64::consts::SQRT_2; + const CENTER_MIX_LEVEL: f64 = FRAC_1_SQRT_2; + const SURROUND_MIX_LEVEL: f64 = FRAC_1_SQRT_2; + const LFE_MIX_LEVEL: f64 = 1.0; + + // The indices of channels in the mixing coefficients matrix. + const FRONT_LEFT: usize = Channel::FrontLeft.number(); + const FRONT_RIGHT: usize = Channel::FrontRight.number(); + const FRONT_CENTER: usize = Channel::FrontCenter.number(); + const LOW_FREQUENCY: usize = Channel::LowFrequency.number(); + const BACK_LEFT: usize = Channel::BackLeft.number(); + const BACK_RIGHT: usize = Channel::BackRight.number(); + const FRONT_LEFT_OF_CENTER: usize = Channel::FrontLeftOfCenter.number(); + const FRONT_RIGHT_OF_CENTER: usize = Channel::FrontRightOfCenter.number(); + const BACK_CENTER: usize = Channel::BackCenter.number(); + const SIDE_LEFT: usize = Channel::SideLeft.number(); + const SIDE_RIGHT: usize = Channel::SideRight.number(); + + // Return true if mixable channels are symmetric. + fn is_symmetric(map: ChannelMap) -> bool { + fn even(map: ChannelMap) -> bool { + map.bits().count_ones() % 2 == 0 + } + even(map & ChannelMap::FRONT_2) + && even(map & ChannelMap::BACK_2) + && even(map & ChannelMap::FRONT_2_OF_CENTER) + && even(map & ChannelMap::SIDE_2) + } + + if !is_symmetric(input_map) || !is_symmetric(output_map) { + return Err(Error::AsymmetricChannels); + } + + let mut matrix = Self::get_basic_matrix(); + + // Get input channels that are not in the output channels. + let unaccounted_input_map = input_map & !output_map; + + // When input has front-center but output has not, and output has front-stereo, + // mix input's front-center to output's front-stereo. + if unaccounted_input_map.contains(ChannelMap::FRONT_CENTER) + && output_map.contains(ChannelMap::FRONT_2) + { + let coefficient = if input_map.contains(ChannelMap::FRONT_2) { + CENTER_MIX_LEVEL + } else { + FRAC_1_SQRT_2 + }; + matrix[FRONT_LEFT][FRONT_CENTER] += coefficient; + matrix[FRONT_RIGHT][FRONT_CENTER] += coefficient; + } + + // When input has front-stereo but output has not, and output has front-center, + // mix input's front-stereo to output's front-center. + if unaccounted_input_map.contains(ChannelMap::FRONT_2) + && output_map.contains(ChannelMap::FRONT_CENTER) + { + matrix[FRONT_CENTER][FRONT_LEFT] += FRAC_1_SQRT_2; + matrix[FRONT_CENTER][FRONT_RIGHT] += FRAC_1_SQRT_2; + if input_map.contains(ChannelMap::FRONT_CENTER) { + matrix[FRONT_CENTER][FRONT_CENTER] = CENTER_MIX_LEVEL * SQRT_2; + } + } + + // When input has back-center but output has not, + if unaccounted_input_map.contains(ChannelMap::BACK_CENTER) { + // if output has back-stereo, mix input's back-center to output's back-stereo. + if output_map.contains(ChannelMap::BACK_2) { + matrix[BACK_LEFT][BACK_CENTER] += FRAC_1_SQRT_2; + matrix[BACK_RIGHT][BACK_CENTER] += FRAC_1_SQRT_2; + // or if output has side-stereo, mix input's back-center to output's side-stereo. + } else if output_map.contains(ChannelMap::SIDE_2) { + matrix[SIDE_LEFT][BACK_CENTER] += FRAC_1_SQRT_2; + matrix[SIDE_RIGHT][BACK_CENTER] += FRAC_1_SQRT_2; + // or if output has front-stereo, mix input's back-center to output's front-stereo. + } else if output_map.contains(ChannelMap::FRONT_2) { + matrix[FRONT_LEFT][BACK_CENTER] += SURROUND_MIX_LEVEL * FRAC_1_SQRT_2; + matrix[FRONT_RIGHT][BACK_CENTER] += SURROUND_MIX_LEVEL * FRAC_1_SQRT_2; + // or if output has front-center, mix input's back-center to output's front-center. + } else if output_map.contains(ChannelMap::FRONT_CENTER) { + matrix[FRONT_CENTER][BACK_CENTER] += SURROUND_MIX_LEVEL * FRAC_1_SQRT_2; + } + } + + // When input has back-stereo but output has not, + if unaccounted_input_map.contains(ChannelMap::BACK_2) { + // if output has back-center, mix input's back-stereo to output's back-center. + if output_map.contains(ChannelMap::BACK_CENTER) { + matrix[BACK_CENTER][BACK_LEFT] += FRAC_1_SQRT_2; + matrix[BACK_CENTER][BACK_RIGHT] += FRAC_1_SQRT_2; + // or if output has side-stereo, mix input's back-stereo to output's side-stereo. + } else if output_map.contains(ChannelMap::SIDE_2) { + let coefficient = if input_map.contains(ChannelMap::SIDE_2) { + FRAC_1_SQRT_2 + } else { + 1.0 + }; + matrix[SIDE_LEFT][BACK_LEFT] += coefficient; + matrix[SIDE_RIGHT][BACK_RIGHT] += coefficient; + // or if output has front-stereo, mix input's back-stereo to output's side-stereo. + } else if output_map.contains(ChannelMap::FRONT_2) { + matrix[FRONT_LEFT][BACK_LEFT] += SURROUND_MIX_LEVEL; + matrix[FRONT_RIGHT][BACK_RIGHT] += SURROUND_MIX_LEVEL; + // or if output has front-center, mix input's back-stereo to output's front-center. + } else if output_map.contains(ChannelMap::FRONT_CENTER) { + matrix[FRONT_CENTER][BACK_LEFT] += SURROUND_MIX_LEVEL * FRAC_1_SQRT_2; + matrix[FRONT_CENTER][BACK_RIGHT] += SURROUND_MIX_LEVEL * FRAC_1_SQRT_2; + } + } + + // When input has side-stereo but output has not, + if unaccounted_input_map.contains(ChannelMap::SIDE_2) { + // if output has back-stereo, mix input's side-stereo to output's back-stereo. + if output_map.contains(ChannelMap::BACK_2) { + let coefficient = if input_map.contains(ChannelMap::BACK_2) { + FRAC_1_SQRT_2 + } else { + 1.0 + }; + matrix[BACK_LEFT][SIDE_LEFT] += coefficient; + matrix[BACK_RIGHT][SIDE_RIGHT] += coefficient; + // or if output has back-center, mix input's side-stereo to output's back-center. + } else if output_map.contains(ChannelMap::BACK_CENTER) { + matrix[BACK_CENTER][SIDE_LEFT] += FRAC_1_SQRT_2; + matrix[BACK_CENTER][SIDE_RIGHT] += FRAC_1_SQRT_2; + // or if output has front-stereo, mix input's side-stereo to output's front-stereo. + } else if output_map.contains(ChannelMap::FRONT_2) { + matrix[FRONT_LEFT][SIDE_LEFT] += SURROUND_MIX_LEVEL; + matrix[FRONT_RIGHT][SIDE_RIGHT] += SURROUND_MIX_LEVEL; + // or if output has front-center, mix input's side-stereo to output's front-center. + } else if output_map.contains(ChannelMap::FRONT_CENTER) { + matrix[FRONT_CENTER][SIDE_LEFT] += SURROUND_MIX_LEVEL * FRAC_1_SQRT_2; + matrix[FRONT_CENTER][SIDE_RIGHT] += SURROUND_MIX_LEVEL * FRAC_1_SQRT_2; + } + } + + // When input has front-stereo-of-center but output has not, + if unaccounted_input_map.contains(ChannelMap::FRONT_2_OF_CENTER) { + // if output has front-stereo, mix input's front-stereo-of-center to output's front-stereo. + if output_map.contains(ChannelMap::FRONT_2) { + matrix[FRONT_LEFT][FRONT_LEFT_OF_CENTER] += 1.0; + matrix[FRONT_RIGHT][FRONT_RIGHT_OF_CENTER] += 1.0; + // or if output has front-center, mix input's front-stereo-of-center to output's front-center. + } else if output_map.contains(ChannelMap::FRONT_CENTER) { + matrix[FRONT_CENTER][FRONT_LEFT_OF_CENTER] += FRAC_1_SQRT_2; + matrix[FRONT_CENTER][FRONT_RIGHT_OF_CENTER] += FRAC_1_SQRT_2; + } + } + + // When input has low-frequency but output has not, + if unaccounted_input_map.contains(ChannelMap::LOW_FREQUENCY) { + // if output has front-center, mix input's low-frequency to output's front-center. + if output_map.contains(ChannelMap::FRONT_CENTER) { + matrix[FRONT_CENTER][LOW_FREQUENCY] += LFE_MIX_LEVEL; + // or if output has front-stereo, mix input's low-frequency to output's front-stereo. + } else if output_map.contains(ChannelMap::FRONT_2) { + matrix[FRONT_LEFT][LOW_FREQUENCY] += LFE_MIX_LEVEL * FRAC_1_SQRT_2; + matrix[FRONT_RIGHT][LOW_FREQUENCY] += LFE_MIX_LEVEL * FRAC_1_SQRT_2; + } + } + + Ok(matrix) + } + + // Return a CHANNELSxCHANNELS matrix M that is (CHANNELS-1)x(CHANNELS-1) identity matrix + // padding with one extra row and one column containing only zero values. The result would be: + // + // identity padding + // matrix column + // ▾ ▾ + // ┌┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┐ i ┐ + // │ 1, 0, 0, ..., 0 ┊, 0 │ ◂ 0 ┊ channel i + // │ 0, 1, 0, ..., 0 ┊, 0 │ ◂ 1 ┊ for + // │ 0, 0, 1, ..., 0 ┊, 0 │ ◂ 2 ┊ audio + // │ 0, 0, 0, ..., 0 ┊, 0 │ . ┊ output + // │ ............... ┊ │ . ┊ + // │ 0, 0, 0, ..., 1 ┊, 0 │ ◂ 16 ┊ + // ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┼┈┈┈┈┤ ◂ 17 ┊ + // │ 0, 0, 0, ..., 0 ┊, 0 │ ◂ padding row ◂ 18 ┊ + // ▴ ▴ ▴ .... ▴ ▴ ┘ + // j 0 1 2 .... 17 18 + // └┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┘ + // channel j for audio input + // + // Given an audio input buffer, in_audio, and an output buffer, out_audio, + // and their channel data are both ordered by the values defined in enum Channel. + // The generated matrix M makes sure that: + // + // out_audio(i) = in_audio(j), if i == j and both i, j are non-silence channel + // = 0, if i != j or i, j are silence channel + // + // │ FrontLeft │ │ FrontLeft │ ◂ data in front-left channel + // │ FrontRight │ │ FrontRight │ ◂ data in front-right channel + // │ FrontCenter │ = M x │ FrontCenter │ ◂ data in front-center channel + // │ ........... │ │ ........... │ ◂ ... + // │ Silence │ │ Silence │ ◂ data in silence channel + // ▴ ▴ + // out_audio in_audio + // + // That is, + // 1. If the input-channel is silence, it won't be mixed into any channel. + // 2. If the output-channel is silence, its output-channel data will be zero (silence). + // 3. If input-channel j is different from output-channel i, audio data in input channel j + // won't be mixed into the audio output data in channel i + // 4. If input-channel j is same as output-channel i, audio data in input channel j will be + // copied to audio output data in channel i + // + fn get_basic_matrix() -> [[f64; CHANNELS]; CHANNELS] { + const SILENCE: usize = Channel::Silence.number(); + let mut matrix = [[0.0; CHANNELS]; CHANNELS]; + for (i, row) in matrix.iter_mut().enumerate() { + if i != SILENCE { + row[i] = 1.0; + } + } + matrix + } + + // Given is an CHANNELSxCHANNELS mixing matrix whose indice are ordered by the values defined + // in enum Channel, and the channel orders of M-channel input and N-channel output, generate a + // mixing matrix m such that output_data(i) = Σ m[i][j] * input_data(j), for all j in [0, M), + // where i is in [0, N) and {input/output}_data(k) means the data of the number k channel in + // the input/output buffer. + fn pick_coefficients( + input_channels: &[Channel], + output_channels: &[Channel], + source: &[[f64; CHANNELS]; CHANNELS], + ) -> Vec<Vec<f64>> { + let mut matrix = Vec::with_capacity(output_channels.len()); + for output_channel in output_channels { + let output_channel_index = output_channel.clone().number(); + let mut coefficients = Vec::with_capacity(input_channels.len()); + for input_channel in input_channels { + let input_channel_index = input_channel.clone().number(); + coefficients.push(source[output_channel_index][input_channel_index]); + } + matrix.push(coefficients); + } + matrix + } + + fn normalize(max_coefficients_sum: f64, mut coefficients: Vec<Vec<f64>>) -> Vec<Vec<f64>> { + let mut max_sum: f64 = 0.0; + for coefs in &coefficients { + max_sum = max_sum.max(coefs.iter().sum()); + } + if max_sum != 0.0 && max_sum > max_coefficients_sum { + max_sum /= max_coefficients_sum; + for coefs in &mut coefficients { + for coef in coefs { + *coef /= max_sum; + } + } + } + coefficients + } +} + +pub trait MixingCoefficient { + type Coef; + + // TODO: These should be private. + fn max_coefficients_sum() -> f64; // Used for normalizing. + fn coefficient_from_f64(value: f64) -> Self::Coef; + // Precheck if overflow occurs when converting value from Self::Coef type to Self type. + fn would_overflow_from_coefficient_value(coefficient: &[Vec<f64>]) -> Option<bool>; + + fn to_coefficient_value(value: Self) -> Self::Coef; + fn from_coefficient_value(value: Self::Coef, would_overflow: Option<bool>) -> Self; +} + +impl MixingCoefficient for f32 { + type Coef = f32; + + fn max_coefficients_sum() -> f64 { + f64::from(std::i32::MAX) + } + + fn coefficient_from_f64(value: f64) -> Self::Coef { + value as Self::Coef + } + + fn would_overflow_from_coefficient_value(_coefficient: &[Vec<f64>]) -> Option<bool> { + None + } + + fn to_coefficient_value(value: Self) -> Self::Coef { + value + } + + fn from_coefficient_value(value: Self::Coef, would_overflow: Option<bool>) -> Self { + assert!(would_overflow.is_none()); + value + } +} + +impl MixingCoefficient for i16 { + type Coef = i32; + + fn max_coefficients_sum() -> f64 { + 1.0 + } + + fn coefficient_from_f64(value: f64) -> Self::Coef { + (value * f64::from(1 << 15)).round() as Self::Coef + } + + fn would_overflow_from_coefficient_value(coefficient: &[Vec<f64>]) -> Option<bool> { + let mut max_sum: Self::Coef = 0; + for row in coefficient { + let mut sum: Self::Coef = 0; + let mut rem: f64 = 0.0; + for coef in row { + let target = coef * f64::from(1 << 15) + rem; + let value = target.round() as Self::Coef; + rem += target - target.round(); + sum += value.abs(); + } + max_sum = max_sum.max(sum); + } + Some(max_sum > (1 << 15)) + } + + fn to_coefficient_value(value: Self) -> Self::Coef { + Self::Coef::from(value) + } + + fn from_coefficient_value(value: Self::Coef, would_overflow: Option<bool>) -> Self { + use std::convert::TryFrom; + let would_overflow = would_overflow.expect("would_overflow must have value for i16 type"); + let mut converted = (value + (1 << 14)) >> 15; + // clip the signed integer value into the -32768,32767 range. + if would_overflow && ((converted + 0x8000) & !0xFFFF != 0) { + converted = (converted >> 31) ^ 0x7FFF; + } + Self::try_from(converted).expect("Cannot convert coefficient from i32 to i16") + } +} + +#[cfg(test)] +mod test { + use super::*; + + #[test] + fn test_create_f32() { + test_create::<f32>(MixDirection::Downmix); + test_create::<f32>(MixDirection::Upmix); + } + + #[test] + fn test_create_i16() { + test_create::<i16>(MixDirection::Downmix); + test_create::<i16>(MixDirection::Upmix); + } + + fn test_create<T>(direction: MixDirection) + where + T: MixingCoefficient, + T::Coef: Copy + Debug, + { + let (input_channels, output_channels) = get_test_channels(direction); + let coefficient = Coefficient::<T>::create(&input_channels, &output_channels); + println!( + "{:?} = {:?} * {:?}", + output_channels, coefficient.matrix, input_channels + ); + } + + enum MixDirection { + Downmix, + Upmix, + } + fn get_test_channels(direction: MixDirection) -> (Vec<Channel>, Vec<Channel>) { + let more = vec![ + Channel::Silence, + Channel::FrontRight, + Channel::FrontLeft, + Channel::LowFrequency, + Channel::Silence, + Channel::BackCenter, + ]; + let less = vec![ + Channel::FrontLeft, + Channel::Silence, + Channel::FrontRight, + Channel::FrontCenter, + ]; + match direction { + MixDirection::Downmix => (more, less), + MixDirection::Upmix => (less, more), + } + } + + #[test] + fn test_create_with_duplicate_silience_channels_f32() { + test_create_with_duplicate_silience_channels::<f32>() + } + + #[test] + fn test_create_with_duplicate_silience_channels_i16() { + test_create_with_duplicate_silience_channels::<i16>() + } + + #[test] + #[should_panic] + fn test_create_with_duplicate_input_channels_f32() { + test_create_with_duplicate_input_channels::<f32>() + } + + #[test] + #[should_panic] + fn test_create_with_duplicate_input_channels_i16() { + test_create_with_duplicate_input_channels::<i16>() + } + + #[test] + #[should_panic] + fn test_create_with_duplicate_output_channels_f32() { + test_create_with_duplicate_output_channels::<f32>() + } + + #[test] + #[should_panic] + fn test_create_with_duplicate_output_channels_i16() { + test_create_with_duplicate_output_channels::<i16>() + } + + fn test_create_with_duplicate_silience_channels<T>() + where + T: MixingCoefficient, + T::Coef: Copy, + { + // Duplicate of Silence channels is allowed on both input side and output side. + let input_channels = [ + Channel::FrontLeft, + Channel::Silence, + Channel::FrontRight, + Channel::FrontCenter, + Channel::Silence, + ]; + let output_channels = [ + Channel::Silence, + Channel::FrontRight, + Channel::FrontLeft, + Channel::BackCenter, + Channel::Silence, + ]; + let _ = Coefficient::<T>::create(&input_channels, &output_channels); + } + + fn test_create_with_duplicate_input_channels<T>() + where + T: MixingCoefficient, + T::Coef: Copy, + { + let input_channels = [ + Channel::FrontLeft, + Channel::Silence, + Channel::FrontLeft, + Channel::FrontCenter, + ]; + let output_channels = [ + Channel::Silence, + Channel::FrontRight, + Channel::FrontLeft, + Channel::FrontCenter, + Channel::BackCenter, + ]; + let _ = Coefficient::<T>::create(&input_channels, &output_channels); + } + + fn test_create_with_duplicate_output_channels<T>() + where + T: MixingCoefficient, + T::Coef: Copy, + { + let input_channels = [ + Channel::FrontLeft, + Channel::Silence, + Channel::FrontRight, + Channel::FrontCenter, + ]; + let output_channels = [ + Channel::Silence, + Channel::FrontRight, + Channel::FrontLeft, + Channel::FrontCenter, + Channel::FrontCenter, + Channel::BackCenter, + ]; + let _ = Coefficient::<T>::create(&input_channels, &output_channels); + } + + #[test] + fn test_get_redirect_matrix_f32() { + test_get_redirect_matrix::<f32>(); + } + + #[test] + fn test_get_redirect_matrix_i16() { + test_get_redirect_matrix::<i16>(); + } + + fn test_get_redirect_matrix<T>() + where + T: MixingCoefficient, + T::Coef: Copy + Debug + PartialEq, + { + // Create a matrix that only redirect the channels from input side to output side, + // without mixing input audio data to output audio data. + fn compute_redirect_matrix<T>( + input_channels: &[Channel], + output_channels: &[Channel], + ) -> Vec<Vec<T::Coef>> + where + T: MixingCoefficient, + { + let mut matrix = Vec::with_capacity(output_channels.len()); + for output_channel in output_channels { + let mut row = Vec::with_capacity(input_channels.len()); + for input_channel in input_channels { + row.push( + if input_channel != output_channel + || input_channel == &Channel::Silence + || output_channel == &Channel::Silence + { + 0.0 + } else { + 1.0 + }, + ); + } + matrix.push(row); + } + + // Convert the type of the coefficients from f64 to T::Coef. + matrix + .into_iter() + .map(|row| row.into_iter().map(T::coefficient_from_f64).collect()) + .collect() + } + + let input_channels = [ + Channel::FrontLeft, + Channel::Silence, + Channel::FrontRight, + Channel::FrontCenter, + ]; + let output_channels = [ + Channel::Silence, + Channel::FrontLeft, + Channel::Silence, + Channel::FrontCenter, + Channel::BackCenter, + ]; + + // Get a redirect matrix since the output layout is asymmetric. + let coefficient = Coefficient::<T>::create(&input_channels, &output_channels); + + let expected = compute_redirect_matrix::<T>(&input_channels, &output_channels); + assert_eq!(coefficient.matrix, expected); + + println!( + "{:?} = {:?} * {:?}", + output_channels, coefficient.matrix, input_channels + ); + } + + #[test] + fn test_normalize() { + use float_cmp::approx_eq; + + let m = vec![ + vec![1.0_f64, 2.0_f64, 3.0_f64], + vec![4.0_f64, 6.0_f64, 10.0_f64], + ]; + + let mut max_row_sum: f64 = std::f64::MIN; + for row in &m { + max_row_sum = max_row_sum.max(row.iter().sum()); + } + + // Type of Coefficient doesn't matter here. + // If the first argument of normalize >= max_row_sum, do nothing. + let n = Coefficient::<f32>::normalize(max_row_sum, m.clone()); + assert_eq!(n, m); + + // If the first argument of normalize < max_row_sum, do normalizing. + let smaller_max = max_row_sum - 0.5_f64; + assert!(smaller_max > 0.0_f64); + let n = Coefficient::<f32>::normalize(smaller_max, m); + let mut max_row_sum: f64 = std::f64::MIN; + for row in &n { + max_row_sum = max_row_sum.max(row.iter().sum()); + assert!(row.iter().sum::<f64>() <= smaller_max); + } + assert!(approx_eq!(f64, smaller_max, max_row_sum)); + } +} diff --git a/third_party/rust/audio-mixer/src/lib.rs b/third_party/rust/audio-mixer/src/lib.rs new file mode 100644 index 0000000000..10bf54603e --- /dev/null +++ b/third_party/rust/audio-mixer/src/lib.rs @@ -0,0 +1,81 @@ +#[macro_use] +extern crate bitflags; + +mod channel; +mod coefficient; + +// Export Channel outside. +pub use channel::Channel; +use coefficient::{Coefficient, MixingCoefficient}; + +use std::default::Default; +use std::fmt::Debug; +use std::ops::{AddAssign, Mul}; + +// A mixer mixing M-channel input data to N-channel output data. +// T::Coef is an associated type defined in MixingCoefficient, which indicates the type of the +// mixing coefficient that would be used for type T. When T is f32, the T::Coef is f32. When T +// is i16, the T::Coef is i32. When mixing data, a temporary variable with type T::Coef would be +// created to hold the mixing result. Since the type of input and output audio data is T, +// the methods provided from MixingCoefficient trait would be used to convert the value between +// type T and T::Coef. +#[derive(Debug)] +pub struct Mixer<T> +where + T: Copy + Debug + MixingCoefficient, + T::Coef: AddAssign + Copy + Debug + Default + Mul<T::Coef, Output = T::Coef>, +{ + coefficient: Coefficient<T>, +} + +impl<T> Mixer<T> +where + T: Copy + Debug + MixingCoefficient, + T::Coef: AddAssign + Copy + Debug + Default + Mul<T::Coef, Output = T::Coef>, +{ + pub fn new(input_channels: &[Channel], output_channels: &[Channel]) -> Self { + Self { + coefficient: Coefficient::create(input_channels, output_channels), + } + } + + // To mix M-channel audio input data to N-channel output data, the data in output-channel i + // is the sum of product of data in input-channel j and the coefficient for mixing from + // input-channel j to output-channel i, for all j in M channels. That is, + // output_data(i) = Σ coefficient(j, i) * input_data(j), for all j in [0, M), + // where i is in [0, N) and coefficient is a function returning mixing coefficient from + // input channel j to output channel i. + pub fn mix(&self, input_buffer: &[T], output_buffer: &mut [T]) { + assert_eq!( + input_buffer.len(), + self.input_channels().len(), + "input slice must have the same size as the input channel's one." + ); + assert_eq!( + output_buffer.len(), + self.output_channels().len(), + "output slice must have the same size as the output channel's one." + ); + for (i, output) in output_buffer.iter_mut().enumerate() { + // T must implement Default that returns a zero value from default(). + let mut value = T::Coef::default(); // Create a zero value. + for (j, input) in input_buffer.iter().enumerate() { + // T::Coef needs to implement `AddAssign` and `Mul` to make `+=` and `*` work. + // T needs to implement `Copy` so `*input` can be copied. + value += self.coefficient.get(j, i) * T::to_coefficient_value(*input); + } + *output = T::from_coefficient_value( + value, + self.coefficient.would_overflow_from_coefficient_value(), + ); + } + } + + pub fn input_channels(&self) -> &[Channel] { + &self.coefficient.input_channels() + } + + pub fn output_channels(&self) -> &[Channel] { + &self.coefficient.output_channels() + } +} diff --git a/third_party/rust/audio-mixer/src/main.rs b/third_party/rust/audio-mixer/src/main.rs new file mode 100644 index 0000000000..edd6932d77 --- /dev/null +++ b/third_party/rust/audio-mixer/src/main.rs @@ -0,0 +1,50 @@ +extern crate audio_mixer; +use audio_mixer::{Channel, Mixer}; + +fn main() { + // f32 + let input_channels = [ + Channel::FrontLeft, + Channel::Silence, + Channel::FrontRight, + Channel::FrontCenter, + ]; + let output_channels = [Channel::FrontLeft, Channel::FrontRight]; + + let mut input_buffer = vec![0.0; input_channels.len()]; + for (i, data) in input_buffer.iter_mut().enumerate() { + *data = (i + 1) as f32; + } + let mut output_buffer = vec![0.0; output_channels.len()]; + + let mixer = Mixer::new(&input_channels, &output_channels); + + mixer.mix(&input_buffer.as_slice(), &mut output_buffer.as_mut_slice()); + println!("{:?} is mixed to {:?}", input_buffer, output_buffer); + + // i16 + let input_channels = [ + Channel::FrontLeft, + Channel::Silence, + Channel::FrontRight, + Channel::FrontCenter, + Channel::BackLeft, + Channel::SideRight, + Channel::LowFrequency, + Channel::SideLeft, + Channel::BackCenter, + Channel::BackRight, + ]; + let output_channels = [Channel::Silence, Channel::FrontRight, Channel::FrontLeft]; + + let mut input_buffer = vec![0; input_channels.len()]; + for (i, data) in input_buffer.iter_mut().enumerate() { + *data = (i + 0x7FFE) as i16; + } + let mut output_buffer = vec![0; output_channels.len()]; + + let mixer = Mixer::new(&input_channels, &output_channels); + + mixer.mix(&input_buffer.as_slice(), &mut output_buffer.as_mut_slice()); + println!("{:?} is mixed to {:?}", input_buffer, output_buffer); +} |