lofty/iff/aiff/

properties.rs

use super::read::CompressionPresent;
use crate::error::Result;
use crate::macros::{decode_err, try_vec};
use crate::properties::FileProperties;
use crate::util::text::utf8_decode;

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

use crate::io::ReadExt;
use byteorder::{BigEndian, ReadBytesExt};

/// The AIFC compression type
///
/// This contains a non-exhaustive list of compression types
#[allow(non_camel_case_types)]
#[derive(Clone, Eq, PartialEq, Default, Debug)]
pub enum AiffCompressionType {
	#[default]
	/// PCM
	None,
	/// 2-to-1 IIGS ACE (Audio Compression / Expansion)
	ACE2,
	/// 8-to-3 IIGS ACE (Audio Compression / Expansion)
	ACE8,
	/// 3-to-1 Macintosh Audio Compression / Expansion
	MAC3,
	/// 6-to-1 Macintosh Audio Compression / Expansion
	MAC6,
	/// PCM (byte swapped)
	sowt,
	/// IEEE 32-bit float
	fl32,
	/// IEEE 64-bit float
	fl64,
	/// 8-bit ITU-T G.711 A-law
	alaw,
	/// 8-bit ITU-T G.711 µ-law
	ulaw,
	/// 8-bit ITU-T G.711 µ-law (64 kb/s)
	ULAW,
	/// 8-bit ITU-T G.711 A-law (64 kb/s)
	ALAW,
	/// IEEE 32-bit float (From SoundHack & Csound)
	FL32,
	/// Catch-all for unknown compression algorithms
	Other {
		/// Identifier from the compression algorithm
		compression_type: [u8; 4],
		/// Human-readable description of the compression algorithm
		compression_name: String,
	},
}

impl AiffCompressionType {
	/// Get the compression name for a compression type
	///
	/// For variants other than [`AiffCompressionType::Other`], this will use statically known names.
	///
	/// # Examples
	///
	/// ```rust
	/// use lofty::iff::aiff::AiffCompressionType;
	///
	/// let compression_type = AiffCompressionType::alaw;
	/// assert_eq!(compression_type.compression_name(), "ALaw 2:1");
	/// ```
	pub fn compression_name(&self) -> Cow<'_, str> {
		match self {
			AiffCompressionType::None => Cow::Borrowed("not compressed"),
			AiffCompressionType::ACE2 => Cow::Borrowed("ACE 2-to-1"),
			AiffCompressionType::ACE8 => Cow::Borrowed("ACE 8-to-3"),
			AiffCompressionType::MAC3 => Cow::Borrowed("MACE 3-to-1"),
			AiffCompressionType::MAC6 => Cow::Borrowed("MACE 6-to-1"),
			AiffCompressionType::sowt => Cow::Borrowed(""), // Has no compression name
			AiffCompressionType::fl32 => Cow::Borrowed("32-bit floating point"),
			AiffCompressionType::fl64 => Cow::Borrowed("64-bit floating point"),
			AiffCompressionType::alaw => Cow::Borrowed("ALaw 2:1"),
			AiffCompressionType::ulaw => Cow::Borrowed("µLaw 2:1"),
			AiffCompressionType::ULAW => Cow::Borrowed("CCITT G.711 u-law"),
			AiffCompressionType::ALAW => Cow::Borrowed("CCITT G.711 A-law"),
			AiffCompressionType::FL32 => Cow::Borrowed("Float 32"),
			AiffCompressionType::Other {
				compression_name, ..
			} => Cow::from(compression_name),
		}
	}
}

/// A AIFF file's audio properties
#[derive(Debug, PartialEq, Eq, Clone, Default)]
#[non_exhaustive]
pub struct AiffProperties {
	pub(crate) duration: Duration,
	pub(crate) overall_bitrate: u32,
	pub(crate) audio_bitrate: u32,
	pub(crate) sample_rate: u32,
	pub(crate) sample_size: u16,
	pub(crate) channels: u16,
	pub(crate) compression_type: Option<AiffCompressionType>,
}

impl From<AiffProperties> for FileProperties {
	fn from(value: AiffProperties) -> Self {
		Self {
			duration: value.duration,
			overall_bitrate: Some(value.overall_bitrate),
			audio_bitrate: Some(value.audio_bitrate),
			sample_rate: Some(value.sample_rate),
			bit_depth: Some(value.sample_size as u8),
			channels: Some(value.channels as u8),
			channel_mask: None,
		}
	}
}

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

	/// Overall bitrate (kbps)
	pub fn overall_bitrate(&self) -> u32 {
		self.overall_bitrate
	}

	/// Audio bitrate (kbps)
	pub fn audio_bitrate(&self) -> u32 {
		self.audio_bitrate
	}

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

	/// Bits per sample
	pub fn sample_size(&self) -> u16 {
		self.sample_size
	}

	/// Channel count
	pub fn channels(&self) -> u16 {
		self.channels
	}

	/// AIFC compression type, if an AIFC file was read
	pub fn compression_type(&self) -> Option<&AiffCompressionType> {
		self.compression_type.as_ref()
	}
}

pub(super) fn read_properties(
	comm: &mut &[u8],
	compression_present: CompressionPresent,
	stream_len: u32,
	file_length: u64,
) -> Result<AiffProperties> {
	let channels = comm.read_u16::<BigEndian>()?;

	if channels == 0 {
		decode_err!(@BAIL Aiff, "File contains 0 channels");
	}

	let sample_frames = comm.read_u32::<BigEndian>()?;
	let sample_size = comm.read_u16::<BigEndian>()?;

	let sample_rate_extended = comm.read_f80()?;
	let sample_rate_64 = sample_rate_extended.as_f64();
	if !sample_rate_64.is_finite() || !sample_rate_64.is_sign_positive() {
		decode_err!(@BAIL Aiff, "Invalid sample rate");
	}

	let sample_rate = sample_rate_64.round() as u32;

	let (duration, overall_bitrate, audio_bitrate) = if sample_rate > 0 && sample_frames > 0 {
		let length = (f64::from(sample_frames) * 1000.0) / f64::from(sample_rate);

		(
			Duration::from_millis(length as u64),
			((file_length as f64) * 8.0 / length + 0.5) as u32,
			(f64::from(stream_len) * 8.0 / length + 0.5) as u32,
		)
	} else {
		(Duration::ZERO, 0, 0)
	};

	let is_compressed = comm.len() >= 5 && compression_present == CompressionPresent::Yes;
	if !is_compressed {
		return Ok(AiffProperties {
			duration,
			overall_bitrate,
			audio_bitrate,
			sample_rate,
			sample_size,
			channels,
			compression_type: None,
		});
	}

	let mut compression_type = [0u8; 4];
	comm.read_exact(&mut compression_type)?;

	let compression = Some(match &compression_type {
		b"NONE" => AiffCompressionType::None,
		b"ACE2" => AiffCompressionType::ACE2,
		b"ACE8" => AiffCompressionType::ACE8,
		b"MAC3" => AiffCompressionType::MAC3,
		b"MAC6" => AiffCompressionType::MAC6,
		b"sowt" => AiffCompressionType::sowt,
		b"fl32" => AiffCompressionType::fl32,
		b"fl64" => AiffCompressionType::fl64,
		b"alaw" => AiffCompressionType::alaw,
		b"ulaw" => AiffCompressionType::ulaw,
		b"ULAW" => AiffCompressionType::ULAW,
		b"ALAW" => AiffCompressionType::ALAW,
		b"FL32" => AiffCompressionType::FL32,
		_ => {
			log::debug!(
				"Encountered unknown compression type: {:?}",
				compression_type
			);

			// We have to read the compression name string
			let mut compression_name = String::new();

			let compression_name_size = comm.read_u8()?;
			if compression_name_size > 0 {
				let mut compression_name_bytes = try_vec![0u8; compression_name_size as usize];
				comm.read_exact(&mut compression_name_bytes)?;

				compression_name = utf8_decode(compression_name_bytes)?;
			}

			AiffCompressionType::Other {
				compression_type,
				compression_name,
			}
		},
	});

	Ok(AiffProperties {
		duration,
		overall_bitrate,
		audio_bitrate,
		sample_rate,
		sample_size,
		channels,
		compression_type: compression,
	})
}