This commit is contained in:
Jamie Hardt
2020-11-22 22:38:47 -08:00
parent f410cda9ed
commit 123d971624
2 changed files with 15 additions and 2 deletions

View File

@@ -7,6 +7,8 @@ use byteorder::ReadBytesExt;
use super::chunks::WaveFmt; use super::chunks::WaveFmt;
use super::errors::Error; use super::errors::Error;
/// Read samples from a `WaveFileReader`
///
#[derive(Debug)] #[derive(Debug)]
pub struct AudioFrameReader<R: Read + Seek> { pub struct AudioFrameReader<R: Read + Seek> {
inner : R, inner : R,
@@ -14,7 +16,8 @@ pub struct AudioFrameReader<R: Read + Seek> {
} }
impl<R: Read + Seek> AudioFrameReader<R> { impl<R: Read + Seek> AudioFrameReader<R> {
/// Create a new AudioFrameReader, taking possession of a reader.
/// Create a new `AudioFrameReader`
pub fn new(inner: R, format: WaveFmt) -> Self { pub fn new(inner: R, format: WaveFmt) -> Self {
assert!(format.block_alignment * 8 == format.bits_per_sample * format.channel_count, assert!(format.block_alignment * 8 == format.bits_per_sample * format.channel_count,
"Unable to read audio frames from packed formats: block alignment is {}, should be {}", "Unable to read audio frames from packed formats: block alignment is {}, should be {}",
@@ -24,16 +27,25 @@ impl<R: Read + Seek> AudioFrameReader<R> {
AudioFrameReader { inner , format } AudioFrameReader { inner , format }
} }
/// Locate the read position to a different frame
pub fn locate(&mut self, to :u64) -> Result<u64,Error> { pub fn locate(&mut self, to :u64) -> Result<u64,Error> {
let position = to * self.format.block_alignment as u64; let position = to * self.format.block_alignment as u64;
let seek_result = self.inner.seek(Start(position))?; let seek_result = self.inner.seek(Start(position))?;
Ok( seek_result / self.format.block_alignment as u64 ) Ok( seek_result / self.format.block_alignment as u64 )
} }
/// Create a frame buffer sized to hold frames of the reader
///
/// This is a conveneince method that creates a `Vec<i32>` with
/// as many elements as there are channels in the underlying stream.
pub fn create_frame_buffer(&self) -> Vec<i32> { pub fn create_frame_buffer(&self) -> Vec<i32> {
vec![0i32; self.format.channel_count as usize] vec![0i32; self.format.channel_count as usize]
} }
/// Read a frame
///
/// A single frame is read from the audio stream and the read location
/// is advanced one frame.
pub fn read_integer_frame(&mut self, buffer:&mut [i32]) -> Result<u64,Error> { pub fn read_integer_frame(&mut self, buffer:&mut [i32]) -> Result<u64,Error> {
assert!(buffer.len() as u16 == self.format.channel_count, assert!(buffer.len() as u16 == self.format.channel_count,
"read_integer_frame was called with a mis-sized buffer, expected {}, was {}", "read_integer_frame was called with a mis-sized buffer, expected {}, was {}",

View File

@@ -65,3 +65,4 @@ mod wavewriter;
pub use wavereader::{WaveReader}; pub use wavereader::{WaveReader};
pub use chunks::{WaveFmt,Bext}; pub use chunks::{WaveFmt,Bext};
pub use errors::Error; pub use errors::Error;
pub use audio_frame_reader::AudioFrameReader;