music_player/src/decoder.rs

335 lines
7.0 KiB
Rust

use anyhow::{
anyhow,
Result,
};
use byteorder::{
ByteOrder,
LittleEndian,
};
// This crate flitters between being very convenient and being a type labyrinth.
use ffmpeg_next::{
decoder::Audio as DecodeContext,
format::context::Input as DemuxContext,
software::resampling::Context as ResamplingContext,
util::{
channel_layout::ChannelLayout,
format::sample::{
self,
Sample,
},
frame::Audio as FfAudioFrame,
},
};
pub const SAMPLE_RATE: u32 = 48000;
pub struct AudioFrame {
frame: FfAudioFrame,
}
impl AudioFrame {
pub fn data (&self) -> &[u8] {
// Hard-coded because I'm only support f32 interleaved stereo
&self.frame.data (0) [0..self.frame.samples () * 4 * 2]
}
pub fn rate (&self) -> u32 {
self.frame.rate ()
}
pub fn samples (&self) -> usize {
self.frame.samples ()
}
}
impl From <FfAudioFrame> for AudioFrame {
fn from (frame: FfAudioFrame) -> Self {
Self {
frame,
}
}
}
#[derive (Default)]
pub struct PcmBuffers {
buffers: Vec <Vec <u8>>,
// Always points into the first buffer, if any
consumer_cursor: usize,
}
impl PcmBuffers {
pub fn samples_available (&self) -> usize {
(self.buffers.iter ().map (|b| b.len ()).sum::<usize> () - self.consumer_cursor) / 8
}
#[warn(unused_must_use)]
pub fn consume_exact (&mut self, data: &mut [f32]) -> bool {
if data.len () > self.samples_available () {
return false;
}
for x in data {
if self.consumer_cursor >= self.buffers [0].len () {
self.buffers.remove (0);
self.consumer_cursor = 0;
}
*x = LittleEndian::read_f32 (&self.buffers [0][self.consumer_cursor..]);
self.consumer_cursor += 4;
}
true
}
pub fn produce_bytes (&mut self, new_buffer: Vec <u8>) {
self.buffers.push (new_buffer);
}
}
pub struct Decoder <T> {
demuxer: T,
decoder: DecodeContext,
resampler: ResamplingContext,
dummy_frame: Option <FfAudioFrame>,
}
impl <T: Demuxer> Decoder <T> {
pub fn new (demuxer: T, codec: ffmpeg_next::codec::Context) -> Result <Self> {
let decoder = codec.decoder ().audio ()?;
let resampler = decoder.resampler (
Sample::F32 (sample::Type::Packed),
ChannelLayout::STEREO,
48000,
)?;
Ok (Self {
demuxer,
decoder,
resampler,
dummy_frame: None,
})
}
fn new_frame () -> FfAudioFrame {
let mut x = FfAudioFrame::empty ();
x.set_channel_layout (ChannelLayout::STEREO);
x.set_format (Sample::F32 (sample::Type::Packed));
x
}
pub fn next (&mut self) -> Result <Option <AudioFrame>> {
Ok (if let Some (frame) = self.pump ()? {
assert_eq! (frame.rate (), 48000);
assert! (frame.samples () > 0);
Some (frame)
}
else {
None
})
}
fn pump (&mut self) -> Result <Option <AudioFrame>> {
loop {
match self.pump_resampler ()? {
Some (x) => {
// tracing::trace! ("Pumped resampler");
return Ok (Some (x));
},
None => (),
}
match self.pump_decoder ()? {
Some (x) => {
// tracing::trace! ("Pumped decoder");
return Ok (Some (x));
},
None => (),
}
if self.pump_demuxer ()? {
// tracing::trace! ("Pumped demuxer");
continue;
}
else {
break;
}
}
Ok (None)
}
pub fn pump_resampler (&mut self) -> Result <Option <AudioFrame>> {
let frame_src = match self.dummy_frame.as_ref () {
None => return Ok (None),
Some (x) => x,
};
let mut frame_resampled = Self::new_frame ();
let _rc = self.resampler.run (&frame_src, &mut frame_resampled)?;
// dbg! (&frame_resampled, rc);
Ok (if frame_resampled.samples () > 0 {
// tracing::trace! ("Pulled from resampler FIFO");
Some (frame_resampled.into ())
}
else {
None
})
}
pub fn pump_decoder (&mut self) -> Result <Option <AudioFrame>> {
let mut frame_src = FfAudioFrame::empty ();
if let Err (_) = self.decoder.receive_frame (&mut frame_src) {
return Ok (None);
};
if self.dummy_frame.is_none () {
let mut dummy_frame = FfAudioFrame::new (
frame_src.format (),
0,
frame_src.channel_layout (),
);
dummy_frame.set_rate (frame_src.rate ());
self.dummy_frame = Some (dummy_frame);
}
let nb_output_samples = frame_src.samples ();
let mut frame_resampled = FfAudioFrame::new (
Sample::F32 (sample::Type::Packed),
nb_output_samples,
ChannelLayout::STEREO
);
self.resampler.run (&frame_src, &mut frame_resampled)?;
Ok (Some (frame_resampled.into ()))
}
pub fn pump_demuxer (&mut self) -> Result <bool> {
let packet = self.demuxer.pump ()?;
let packet = match packet {
Some (x) => x,
None => return Ok (false),
};
self.decoder.send_packet (&packet)?;
Ok (true)
}
}
pub trait Demuxer {
fn pump (&mut self) -> Result <Option <ffmpeg_next::Packet>>;
}
pub struct FfmpegDemuxer {
input_ctx: DemuxContext,
best_stream_idx: usize,
}
impl FfmpegDemuxer {
pub fn new (filename: &str) -> Result <(Self, ffmpeg_next::codec::Context)> {
let input_ctx = ffmpeg_next::format::input (&filename)?;
let stream = input_ctx
.streams ()
.best (ffmpeg_next::media::Type::Audio)
.ok_or_else (|| anyhow! ("can't find good audio stream"))?;
let best_stream_idx = stream.index ();
let codec = stream.codec ();
Ok ((Self {
input_ctx,
best_stream_idx,
}, codec))
}
}
impl Demuxer for FfmpegDemuxer {
fn pump (&mut self) -> Result <Option <ffmpeg_next::Packet>> {
while let Some ((stream, packet)) = self.input_ctx.packets ().next () {
if stream.index () == self.best_stream_idx {
return Ok (Some (packet));
}
}
Ok (None)
}
}
use crate::net_reader::NetReader;
pub struct HttpOggDemuxer {
ogg_rdr: ogg::reading::PacketReader <std::io::BufReader <NetReader>>,
}
impl HttpOggDemuxer {
pub fn new (url: String) -> Result <(Self, ffmpeg_next::codec::Context)> {
let net_rdr = NetReader::new (url)?;
let buf_rdr = std::io::BufReader::new (net_rdr);
let mut ogg_rdr = ogg::reading::PacketReader::new (buf_rdr);
let codec = {
// Open a local file as a placeholder for figuring out the remote file's codec
let input_ctx = ffmpeg_next::format::input (&"test.ogg")?;
let stream = input_ctx
.streams ()
.best (ffmpeg_next::media::Type::Audio)
.ok_or_else (|| anyhow! ("can't find good audio stream"))?;
stream.codec ()
};
Ok ((Self {
ogg_rdr,
}, codec))
}
}
impl Demuxer for HttpOggDemuxer {
fn pump (&mut self) -> Result <Option <ffmpeg_next::Packet>> {
let packet = match self.ogg_rdr.read_packet () {
Err (e) => {
tracing::error! ("Ogg read error: {:?}", e);
return Ok (None);
},
Ok (x) => x,
};
let packet = match packet {
None => return Ok (None),
Some (x) => x,
};
Ok (Some (ffmpeg_next::Packet::copy (&packet.data)))
}
}
#[cfg (test)]
mod test {
use super::*;
#[test]
fn pcm_buffer () {
let mut x = PcmBuffers::default ();
x.produce (vec! [0.0, 1.0, 2.0, 3.0]);
x.produce (vec! [4.0, 5.0, 6.0, 7.0]);
let mut data = vec! [0.0; 3];
assert! (x.consume_exact (&mut data));
assert_eq! (&data, &[0.0, 1.0, 2.0]);
assert! (x.consume_exact (&mut data));
assert_eq! (&data, &[3.0, 4.0, 5.0]);
}
}