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use nihav_core::codecs::*;
use nihav_core::io::bitreader::*;
use nihav_codec_support::codecs::imaadpcm::*;
use std::str::FromStr;
const STEPS: [&[i8]; 4] = [
&[ -1, 2],
&[ -1, -1, 2, 4],
&[ -1, -1, -1, -1, 2, 4, 6, 8],
&[ -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 4, 6, 8, 10, 13, 16 ]
];
#[derive(Clone,Copy)]
struct State {
predictor: i32,
step: usize,
smask: u8,
steps: &'static [i8],
}
impl State {
fn new() -> Self {
Self {
predictor: 0,
step: 0,
smask: 0,
steps: STEPS[2],
}
}
fn expand_sample(&mut self, nibble: u8) -> i16 {
let istep = (self.step as isize) + isize::from(self.steps[(nibble & !self.smask) as usize]);
let sign = (nibble & self.smask) != 0;
let diff = (i32::from(2 * (nibble & !self.smask) + 1) * IMA_STEP_TABLE[self.step]) >> 3;
let sample = if !sign { self.predictor + diff } else { self.predictor - diff };
self.predictor = sample.max(i32::from(std::i16::MIN)).min(i32::from(std::i16::MAX));
self.step = istep.max(0).min(IMA_MAX_STEP as isize) as usize;
self.predictor as i16
}
}
const BLOCK_LEN: usize = 4096;
struct ADPCMDecoder {
ainfo: NAAudioInfo,
chmap: NAChannelMap,
ch_state: [State; 2],
}
impl ADPCMDecoder {
fn new() -> Self {
Self {
ainfo: NAAudioInfo::new(0, 1, SND_S16P_FORMAT, BLOCK_LEN),
chmap: NAChannelMap::new(),
ch_state: [State::new(), State::new()],
}
}
}
impl NADecoder for ADPCMDecoder {
fn init(&mut self, _supp: &mut NADecoderSupport, info: NACodecInfoRef) -> DecoderResult<()> {
if let NACodecTypeInfo::Audio(ainfo) = info.get_properties() {
let channels = ainfo.get_channels() as usize;
validate!(channels == 2 || channels == 1);
self.ainfo = NAAudioInfo::new(ainfo.get_sample_rate(), channels as u8, SND_S16P_FORMAT, 0);
self.chmap = NAChannelMap::from_str(if channels == 1 { "C" } else { "L,R" }).unwrap();
Ok(())
} else {
Err(DecoderError::InvalidData)
}
}
fn decode(&mut self, _supp: &mut NADecoderSupport, pkt: &NAPacket) -> DecoderResult<NAFrameRef> {
let info = pkt.get_stream().get_info();
if let NACodecTypeInfo::Audio(_) = info.get_properties() {
let src = pkt.get_buffer();
let channels = self.chmap.num_channels();
let mut br = BitReader::new(&src, BitReaderMode::BE);
let step_size = br.read(2)? as usize + 2;
let pkt_size = (16 + 6 + (BLOCK_LEN - 1) * step_size) * channels;
let num_pkts = ((br.left() as usize) / pkt_size).max(1);
let nsamples = num_pkts * BLOCK_LEN;
let mut abuf = alloc_audio_buffer(self.ainfo, nsamples, self.chmap.clone())?;
let mut adata = abuf.get_abuf_i16().unwrap();
let mut off = [adata.get_offset(0), adata.get_offset(1)];
let dst = adata.get_data_mut().unwrap();
let mut tot_samples = 0;
for _pkt in 0..num_pkts {
for (ch, state) in self.ch_state[..channels].iter_mut().enumerate() {
state.predictor = br.read_s(16)?;
state.step = br.read(6)? as usize;
state.steps = STEPS[step_size - 2];
state.smask = 1 << (step_size - 1);
dst[off[ch]] = state.predictor as i16;
off[ch] += 1;
}
tot_samples += 1;
let cur_samples = ((br.left() as usize) / step_size / channels).min(BLOCK_LEN - 1);
for _ in 0..cur_samples {
for (ch, state) in self.ch_state[..channels].iter_mut().enumerate() {
let idx = br.read(step_size as u8)? as u8;
dst[off[ch]] = state.expand_sample(idx);
off[ch] += 1;
}
}
tot_samples += cur_samples;
}
abuf.truncate_audio(tot_samples);
let mut frm = NAFrame::new_from_pkt(pkt, info.replace_info(NACodecTypeInfo::Audio(self.ainfo)), abuf);
frm.set_duration(Some(tot_samples as u64));
frm.set_keyframe(true);
Ok(frm.into_ref())
} else {
Err(DecoderError::InvalidData)
}
}
fn flush(&mut self) {
}
}
impl NAOptionHandler for ADPCMDecoder {
fn get_supported_options(&self) -> &[NAOptionDefinition] { &[] }
fn set_options(&mut self, _options: &[NAOption]) { }
fn query_option_value(&self, _name: &str) -> Option<NAValue> { None }
}
pub fn get_decoder() -> Box<dyn NADecoder + Send> {
Box::new(ADPCMDecoder::new())
}
#[cfg(test)]
mod test {
use nihav_core::codecs::RegisteredDecoders;
use nihav_core::demuxers::RegisteredDemuxers;
use nihav_codec_support::test::dec_video::*;
use crate::flash_register_all_decoders;
use crate::flash_register_all_demuxers;
#[test]
fn test_flv_adpcm_mono() {
let mut dmx_reg = RegisteredDemuxers::new();
flash_register_all_demuxers(&mut dmx_reg);
let mut dec_reg = RegisteredDecoders::new();
flash_register_all_decoders(&mut dec_reg);
// sample: https://samples.mplayerhq.hu/FLV/flash_flv_adpcm_testfiles/mono_11k.flv
test_decoding("flv", "flv-adpcm", "assets/Flash/mono_11k.flv", Some(3000), &dmx_reg, &dec_reg,
ExpectedTestResult::MD5([0x4cf30e71, 0x4360c85b, 0x21c52863, 0x1782160e]));
}
#[test]
fn test_flv_adpcm_stereo() {
let mut dmx_reg = RegisteredDemuxers::new();
flash_register_all_demuxers(&mut dmx_reg);
let mut dec_reg = RegisteredDecoders::new();
flash_register_all_decoders(&mut dec_reg);
// sample: https://samples.mplayerhq.hu/FLV/flash_flv_adpcm_testfiles/stereo_44k.flv
test_decoding("flv", "flv-adpcm", "assets/Flash/stereo_44k.flv", Some(3000), &dmx_reg, &dec_reg,
ExpectedTestResult::MD5([0xae108d38, 0xb36236f8, 0x2bc18d31, 0xac600424]));
}
}
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