lofty/musepack/sv7/

properties.rs

use crate::error::Result;
use crate::macros::decode_err;
use crate::musepack::constants::{
	FREQUENCY_TABLE, MPC_DECODER_SYNTH_DELAY, MPC_FRAME_LENGTH, MPC_OLD_GAIN_REF,
};
use crate::properties::FileProperties;

use std::io::Read;
use std::time::Duration;

use byteorder::{LittleEndian, ReadBytesExt};

/// Used profile
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum Profile {
	/// No profile
	#[default]
	None,
	/// Unstable/Experimental
	Unstable,
	/// Profiles 2-4
	Unused,
	/// Below Telephone (q= 0.0)
	BelowTelephone0,
	/// Below Telephone (q= 1.0)
	BelowTelephone1,
	/// Telephone (q= 2.0)
	Telephone,
	/// Thumb (q= 3.0)
	Thumb,
	/// Radio (q= 4.0)
	Radio,
	/// Standard (q= 5.0)
	Standard,
	/// Xtreme (q= 6.0)
	Xtreme,
	/// Insane (q= 7.0)
	Insane,
	/// BrainDead (q= 8.0)
	BrainDead,
	/// Above BrainDead (q= 9.0)
	AboveBrainDead9,
	/// Above BrainDead (q= 10.0)
	AboveBrainDead10,
}

impl Profile {
	/// Get a `Profile` from a u8
	///
	/// The mapping is available here: <http://trac.musepack.net/musepack/wiki/SV7Specification>
	#[rustfmt::skip]
	pub fn from_u8(value: u8) -> Option<Self> {
		match value {
			0         => Some(Self::None),
			1         => Some(Self::Unstable),
			2 | 3 | 4 => Some(Self::Unused),
			5         => Some(Self::BelowTelephone0),
			6         => Some(Self::BelowTelephone1),
			7         => Some(Self::Telephone),
			8         => Some(Self::Thumb),
			9         => Some(Self::Radio),
			10        => Some(Self::Standard),
			11        => Some(Self::Xtreme),
			12        => Some(Self::Insane),
			13        => Some(Self::BrainDead),
			14        => Some(Self::AboveBrainDead9),
			15        => Some(Self::AboveBrainDead10),
			_         => None,
		}
	}
}

/// Volume description for the start and end of the title
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum Link {
	/// Title starts or ends with a very low level (no live or classical genre titles)
	#[default]
	VeryLowStartOrEnd,
	/// Title ends loudly
	LoudEnd,
	/// Title starts loudly
	LoudStart,
	/// Title starts loudly and ends loudly
	LoudStartAndEnd,
}

impl Link {
	/// Get a `Link` from a u8
	///
	/// The mapping is available here: <http://trac.musepack.net/musepack/wiki/SV7Specification>
	pub fn from_u8(value: u8) -> Option<Self> {
		match value {
			0 => Some(Self::VeryLowStartOrEnd),
			1 => Some(Self::LoudEnd),
			2 => Some(Self::LoudStart),
			3 => Some(Self::LoudStartAndEnd),
			_ => None,
		}
	}
}

// http://trac.musepack.net/musepack/wiki/SV7Specification

/// MPC stream version 7 audio properties
#[derive(Debug, Clone, PartialEq, Default)]
#[allow(clippy::struct_excessive_bools)]
pub struct MpcSv7Properties {
	pub(crate) duration: Duration,
	pub(crate) average_bitrate: u32,
	pub(crate) channels: u8, // NOTE: always 2
	// -- Section 1 --
	pub(crate) frame_count: u32,
	// -- Section 2 --
	pub(crate) intensity_stereo: bool,
	pub(crate) mid_side_stereo: bool,
	pub(crate) max_band: u8,
	pub(crate) profile: Profile,
	pub(crate) link: Link,
	pub(crate) sample_freq: u32,
	pub(crate) max_level: u16,
	// -- Section 3 --
	pub(crate) title_gain: i16,
	pub(crate) title_peak: u16,
	// -- Section 4 --
	pub(crate) album_gain: i16,
	pub(crate) album_peak: u16,
	// -- Section 5 --
	pub(crate) true_gapless: bool,
	pub(crate) last_frame_length: u16,
	pub(crate) fast_seeking_safe: bool,
	// -- Section 6 --
	pub(crate) encoder_version: u8,
}

impl From<MpcSv7Properties> for FileProperties {
	fn from(input: MpcSv7Properties) -> Self {
		Self {
			duration: input.duration,
			overall_bitrate: Some(input.average_bitrate),
			audio_bitrate: Some(input.average_bitrate),
			sample_rate: Some(input.sample_freq),
			bit_depth: None,
			channels: Some(input.channels),
			channel_mask: None,
		}
	}
}

impl MpcSv7Properties {
	/// Duration of the audio
	pub fn duration(&self) -> Duration {
		self.duration
	}

	/// Average bitrate (kbps)
	pub fn average_bitrate(&self) -> u32 {
		self.average_bitrate
	}

	/// Sample rate (Hz)
	pub fn sample_rate(&self) -> u32 {
		self.sample_freq
	}

	/// Channel count
	pub fn channels(&self) -> u8 {
		self.channels
	}

	/// Total number of audio frames
	pub fn frame_count(&self) -> u32 {
		self.frame_count
	}

	/// Whether intensity stereo coding (IS) is used
	pub fn intensity_stereo(&self) -> bool {
		self.intensity_stereo
	}

	/// Whether MidSideStereo is used
	pub fn mid_side_stereo(&self) -> bool {
		self.mid_side_stereo
	}

	/// Last subband used in the whole file
	pub fn max_band(&self) -> u8 {
		self.max_band
	}

	/// Profile used
	pub fn profile(&self) -> Profile {
		self.profile
	}

	/// Volume description of the start and end
	pub fn link(&self) -> Link {
		self.link
	}

	/// Maximum level of the coded PCM input signal
	pub fn max_level(&self) -> u16 {
		self.max_level
	}

	/// Change in the replay level
	///
	/// The value is a signed 16-bit integer, with the level being attenuated by that many mB
	pub fn title_gain(&self) -> i16 {
		self.title_gain
	}

	/// Maximum level of the decoded title
	///
	/// * 16422: -6 dB
	/// * 32767:  0 dB
	/// * 65379: +6 dB
	pub fn title_peak(&self) -> u16 {
		self.title_peak
	}

	/// Change in the replay level if the whole CD is supposed to be played with the same level change
	///
	/// The value is a signed 16-bit integer, with the level being attenuated by that many mB
	pub fn album_gain(&self) -> i16 {
		self.album_gain
	}

	/// Maximum level of the whole decoded CD
	///
	/// * 16422: -6 dB
	/// * 32767:  0 dB
	/// * 65379: +6 dB
	pub fn album_peak(&self) -> u16 {
		self.album_peak
	}

	/// Whether true gapless is used
	pub fn true_gapless(&self) -> bool {
		self.true_gapless
	}

	/// Used samples of the last frame
	///
	/// * TrueGapless = 0: always 0
	/// * TrueGapless = 1: 1...1152
	pub fn last_frame_length(&self) -> u16 {
		self.last_frame_length
	}

	/// Whether fast seeking can be used safely
	pub fn fast_seeking_safe(&self) -> bool {
		self.fast_seeking_safe
	}

	/// Encoder version
	///
	/// * Encoder version * 100  (106 = 1.06)
	/// * EncoderVersion % 10 == 0        Release (1.0)
	/// * EncoderVersion %  2 == 0        Beta (1.06)
	/// * EncoderVersion %  2 == 1        Alpha (1.05a...z)
	pub fn encoder_version(&self) -> u8 {
		self.encoder_version
	}

	pub(crate) fn read<R>(reader: &mut R, stream_length: u64) -> Result<Self>
	where
		R: Read,
	{
		let version = reader.read_u8()?;
		if version & 0x0F != 7 {
			decode_err!(@BAIL Mpc, "Expected stream version 7");
		}

		let mut properties = MpcSv7Properties {
			channels: 2, // Always 2 channels
			..Self::default()
		};

		// TODO: Make a Bitreader, would be nice crate-wide but especially here
		// The SV7 header is split into 6 32-bit sections

		// -- Section 1 --
		properties.frame_count = reader.read_u32::<LittleEndian>()?;

		// -- Section 2 --
		let chunk = reader.read_u32::<LittleEndian>()?;

		let byte1 = ((chunk & 0xFF00_0000) >> 24) as u8;

		properties.intensity_stereo = ((byte1 & 0x80) >> 7) == 1;
		properties.mid_side_stereo = ((byte1 & 0x40) >> 6) == 1;
		properties.max_band = byte1 & 0x3F;

		let byte2 = ((chunk & 0xFF_0000) >> 16) as u8;

		properties.profile = Profile::from_u8((byte2 & 0xF0) >> 4).unwrap(); // Infallible
		properties.link = Link::from_u8((byte2 & 0x0C) >> 2).unwrap(); // Infallible

		let sample_freq_index = byte2 & 0x03;
		properties.sample_freq = FREQUENCY_TABLE[sample_freq_index as usize];

		let remaining_bytes = (chunk & 0xFFFF) as u16;
		properties.max_level = remaining_bytes;

		// -- Section 3 --
		let title_peak = reader.read_u16::<LittleEndian>()?;
		let title_gain = reader.read_u16::<LittleEndian>()?;

		// -- Section 4 --
		let album_peak = reader.read_u16::<LittleEndian>()?;
		let album_gain = reader.read_u16::<LittleEndian>()?;

		// -- Section 5 --
		let chunk = reader.read_u32::<LittleEndian>()?;

		properties.true_gapless = (chunk >> 31) == 1;

		if properties.true_gapless {
			properties.last_frame_length = ((chunk >> 20) & 0x7FF) as u16;
		}

		properties.fast_seeking_safe = (chunk >> 19) & 1 == 1;

		// NOTE: Rest of the chunk is zeroed and unused

		// -- Section 6 --
		properties.encoder_version = reader.read_u8()?;

		// -- End of parsing --

		// Convert ReplayGain values
		let set_replay_gain = |gain: u16| -> i16 {
			if gain == 0 {
				return 0;
			}

			let gain = ((MPC_OLD_GAIN_REF - f32::from(gain) / 100.0) * 256.0 + 0.5) as i16;
			if !(0..i16::MAX).contains(&gain) {
				return 0;
			}
			gain
		};
		let set_replay_peak = |peak: u16| -> u16 {
			if peak == 0 {
				return 0;
			}

			((f64::from(peak).log10() * 20.0 * 256.0) + 0.5) as u16
		};

		properties.title_gain = set_replay_gain(title_gain);
		properties.title_peak = set_replay_peak(title_peak);
		properties.album_gain = set_replay_gain(album_gain);
		properties.album_peak = set_replay_peak(album_peak);

		if properties.last_frame_length > MPC_FRAME_LENGTH as u16 {
			decode_err!(@BAIL Mpc, "Invalid last frame length");
		}

		if properties.sample_freq == 0 {
			log::warn!("Sample rate is 0, unable to calculate duration and bitrate");
			return Ok(properties);
		}

		if properties.frame_count == 0 {
			log::warn!("Frame count is 0, unable to calculate duration and bitrate");
			return Ok(properties);
		}

		let time_per_frame = (MPC_FRAME_LENGTH as f64) / f64::from(properties.sample_freq);
		let length = (f64::from(properties.frame_count) * time_per_frame) * 1000.0;
		properties.duration = Duration::from_millis(length as u64);

		let total_samples;
		if properties.true_gapless {
			total_samples = (u64::from(properties.frame_count) * MPC_FRAME_LENGTH)
				- (MPC_FRAME_LENGTH - u64::from(properties.last_frame_length));
		} else {
			total_samples =
				(u64::from(properties.frame_count) * MPC_FRAME_LENGTH) - MPC_DECODER_SYNTH_DELAY;
		}

		properties.average_bitrate = ((stream_length * 8 * u64::from(properties.sample_freq))
			/ (total_samples * 1000)) as u32;

		Ok(properties)
	}
}