Box::new(MPADecoder::new(2))
}
+#[derive(Clone,Copy,Debug)]
+struct MPAHeader {
+ layer: u8,
+ srate: u32,
+ channels: u8,
+ frame_size: usize,
+ nsamples: usize,
+}
+
+impl PartialEq for MPAHeader {
+ fn eq(&self, other: &Self) -> bool {
+ self.layer == other.layer &&
+ self.srate == other.srate &&
+ self.channels == other.channels
+ }
+}
+
+#[derive(Default)]
+struct MPAPacketiser {
+ buf: Vec<u8>,
+ hdr: Option<MPAHeader>,
+}
+
+impl MPAPacketiser {
+ fn new() -> Self { Self::default() }
+ fn parse_header(&self, off: usize) -> DecoderResult<MPAHeader> {
+ if self.buf.len() < off + 4 { return Err(DecoderError::ShortData); }
+
+ let mut br = BitReader::new(&self.buf[off..], BitReaderMode::BE);
+
+ let syncword = br.read(11)?;
+ validate!(syncword == 0x7FF);
+ let id = br.read(2)?;
+ validate!(id != 1);
+ let layer = (br.read(2)? ^ 3) as u8;
+ validate!(layer != 3);
+ let _protection = br.read_bool()?;
+ let bitrate_index = br.read(4)? as usize;
+ validate!(bitrate_index < 15);
+ if bitrate_index == 0 {
+ //todo freeform eventually
+ unimplemented!();
+ }
+ let mut sf_idx = br.read(2)? as usize;
+ validate!(sf_idx != 3);
+ let padding = br.read_bool()?;
+ let _private = br.read_bool()?;
+ let mode = br.read(2)? as u8;
+
+ match id {
+ 0 => sf_idx += 6,
+ 2 => sf_idx += 3,
+ _ => {},
+ };
+ let mpeg1 = id == 3;
+ let srate = SAMPLING_RATE[sf_idx];
+ let channels = if mode == 3 { 1 } else { 2 };
+ let bitrate = BITRATE[if mpeg1 { 0 } else { 1 }][layer as usize][bitrate_index];
+ let frame_size = match layer {
+ 0 => {
+ ((SAMPLES / 3 / 8 * 1000 * (bitrate as usize) / (srate as usize)) & !3) + if padding { 4 } else { 0 }
+ },
+ 2 if !mpeg1 => {
+ SAMPLES / 2 / 8 * 1000 * (bitrate as usize) / (srate as usize) + if padding { 1 } else { 0 }
+ },
+ _ => {
+ SAMPLES / 8 * 1000 * (bitrate as usize) / (srate as usize) + if padding { 1 } else { 0 }
+ },
+ };
+ let nsamples = if mpeg1 { SAMPLES } else { SAMPLES / 2 };
+
+ Ok(MPAHeader{ layer, srate, channels, frame_size, nsamples })
+ }
+}
+
+impl NAPacketiser for MPAPacketiser {
+ fn add_data(&mut self, src: &[u8]) -> bool {
+ self.buf.extend_from_slice(src);
+ self.buf.len() < 4096
+ }
+ fn parse_stream(&mut self, id: u32) -> DecoderResult<NAStreamRef> {
+ if self.hdr.is_none() {
+ if self.buf.len() < 4 {
+ return Err(DecoderError::ShortData);
+ }
+ let hdr = self.parse_header(0)?;
+ self.hdr = Some(hdr);
+ }
+ let hdr = self.hdr.unwrap();
+ let ainfo = NAAudioInfo::new(hdr.srate, hdr.channels, SND_F32P_FORMAT, hdr.nsamples);
+ let info = NACodecInfo::new("mp3", NACodecTypeInfo::Audio(ainfo), None);
+ Ok(NAStream::new(StreamType::Audio, id, info, hdr.nsamples as u32, hdr.srate, 0).into_ref())
+ }
+ fn skip_junk(&mut self) -> DecoderResult<usize> {
+ if self.buf.len() <= 2 {
+ return Ok(0);
+ }
+ let mut off = 0;
+ let mut hdr = u16::from(self.buf[0]) * 256 + u16::from(self.buf[1]);
+ let mut iter = self.buf[2..].iter();
+ loop {
+ if (hdr & 0xFFE0) != 0xFFE0 {
+ let ret = self.parse_header(off);
+ match ret {
+ Ok(hdr) => {
+ if self.hdr.is_none() {
+ self.hdr = Some(hdr);
+ }
+ if self.hdr.unwrap() != hdr { // header is valid but mismatches
+ self.buf.drain(..off + 1);
+ return Err(DecoderError::InvalidData);
+ }
+ break;
+ },
+ Err(err) => {
+ self.buf.drain(..off + 1);
+ return Err(err);
+ },
+ };
+ }
+ off += 1;
+ if let Some(&b) = iter.next() {
+ hdr = (hdr << 8) | u16::from(b);
+ } else {
+ break;
+ }
+ }
+ self.buf.drain(..off);
+ Ok(off)
+ }
+ fn get_packet(&mut self, stream: NAStreamRef) -> DecoderResult<Option<NAPacket>> {
+ if self.buf.len() < 4 {
+ return Err(DecoderError::ShortData);
+ }
+ let hdr = self.parse_header(0)?;
+ if self.hdr.is_none() {
+ self.hdr = Some(hdr);
+ }
+ if self.hdr.unwrap() != hdr {
+ return Err(DecoderError::InvalidData);
+ }
+ if hdr.frame_size <= self.buf.len() {
+ let mut data = Vec::with_capacity(hdr.frame_size);
+ data.extend_from_slice(&self.buf[..hdr.frame_size]);
+ self.buf.drain(..hdr.frame_size);
+ let ts = NATimeInfo::new(None, None, Some(1), hdr.nsamples as u32, hdr.srate);
+ Ok(Some(NAPacket::new(stream, ts, true, data)))
+ } else {
+ Ok(None)
+ }
+ }
+ fn reset(&mut self) {
+ self.buf.clear();
+ }
+}
+
+pub fn get_packetiser() -> Box<dyn NAPacketiser + Send> {
+ Box::new(MPAPacketiser::new())
+}
+
#[cfg(test)]
mod test {
use nihav_core::codecs::RegisteredDecoders;
use nihav_codec_support::test::dec_video::test_decode_audio;
use crate::mpeg_register_all_decoders;
use nihav_flash::flash_register_all_demuxers;
+ use std::io::Read;
+ use nihav_core::codecs::NAPacketiser;
+
#[test]
fn test_mpeg1_layer3_mono() {
let mut dmx_reg = RegisteredDemuxers::new();
let file = "assets/Flash/lection2-2.flv";
test_decode_audio("flv", file, Some(6000), None/*Some("mp3_3")*/, &dmx_reg, &dec_reg);
}
+ #[test]
+ fn test_mpa_packetiser() {
+ let mut buf = [0; 16384];
+ let mut file = std::fs::File::open("assets/MPEG/1.mp3").unwrap();
+
+ let mut pkts = super::MPAPacketiser::new();
+ file.read_exact(&mut buf).unwrap();
+ pkts.add_data(&buf);
+ let stream = pkts.parse_stream(0).unwrap();
+ let mut frame_sizes = Vec::with_capacity(15);
+ while let Some(pkt) = pkts.get_packet(stream.clone()).unwrap() {
+ let frame_size = pkt.get_buffer().len();
+ println!("pkt size {}", frame_size);
+ frame_sizes.push(frame_size);
+ }
+ assert_eq!(&frame_sizes, &[1044, 1044, 1045, 1045, 1045, 1045, 1045, 1045, 1045, 1045, 1045, 1044, 1045, 1045, 1045]);
+ }
}
const BITRATE: [[[u32; 15]; 3]; 2] = [
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