use crate::error::{Error, Result};
use crate::execution::ModelConfig as ExecutionConfig;
use ndarray::{Array1, Array2, Array3, Array4};
use ort::session::Session;
use std::path::Path;
/// Encoder cache state for streaming inference
/// The cache maintains temporal context across chunks
pub struct EncoderCache {
/// channel cache: [1, 1, 70, 512] - batch=1, 70 frame lookback
pub cache_last_channel: Array4<f32>,
/// time cache: [1, 1, 512, 8] - batch=1, fixed 8 time steps
pub cache_last_time: Array4<f32>,
/// cache length: [1] with value 0 initially
pub cache_last_channel_len: Array1<i64>,
}
impl EncoderCache {
/// 17 layers, batch=1, 70 frame lookback, 512 features
pub fn new() -> Self {
Self {
cache_last_channel: Array4::zeros((17, 1, 70, 512)),
cache_last_time: Array4::zeros((17, 1, 512, 8)),
cache_last_channel_len: Array1::from_vec(vec![0i64]),
}
}
}
pub struct ParakeetEOUModel {
encoder: Session,
decoder_joint: Session,
}
impl ParakeetEOUModel {
pub fn from_pretrained<P: AsRef<Path>>(
model_dir: P,
exec_config: ExecutionConfig,
) -> Result<Self> {
let model_dir = model_dir.as_ref();
let encoder_path = model_dir.join("encoder.onnx");
let decoder_path = model_dir.join("decoder_joint.onnx");
if !encoder_path.exists() || !decoder_path.exists() {
return Err(Error::Config(format!(
"Missing ONNX files in {}. Expected encoder.onnx and decoder_joint.onnx",
model_dir.display()
)));
}
// Load encoder
let builder = Session::builder()?;
let builder = exec_config.apply_to_session_builder(builder)?;
let encoder = builder.commit_from_file(&encoder_path)?;
// Load decoder
let builder = Session::builder()?;
let builder = exec_config.apply_to_session_builder(builder)?;
let decoder_joint = builder.commit_from_file(&decoder_path)?;
Ok(Self {
encoder,
decoder_joint,
})
}
/// Run the stateful encoder with cache
/// Input: features [1, 128, T], cache state
/// Output: (encoded [1, 512, T], new_cache)
pub fn run_encoder(
&mut self,
features: &Array3<f32>,
length: i64,
cache: &EncoderCache
) -> Result<(Array3<f32>, EncoderCache)> {
let length_arr = Array1::from_vec(vec![length]);
let outputs = self.encoder.run(ort::inputs![
"audio_signal" => ort::value::Value::from_array(features.clone())?,
"length" => ort::value::Value::from_array(length_arr)?,
"cache_last_channel" => ort::value::Value::from_array(cache.cache_last_channel.clone())?,
"cache_last_time" => ort::value::Value::from_array(cache.cache_last_time.clone())?,
"cache_last_channel_len" => ort::value::Value::from_array(cache.cache_last_channel_len.clone())?
])?;
// Extract encoder output [1, 512, T]
let (shape, data) = outputs["outputs"]
.try_extract_tensor::<f32>()
.map_err(|e| Error::Model(format!("Failed to extract encoder output: {e}")))?;
let shape_dims = shape.as_ref();
let b = shape_dims[0] as usize;
let d = shape_dims[1] as usize;
let t = shape_dims[2] as usize;
let encoder_out = Array3::from_shape_vec((b, d, t), data.to_vec())
.map_err(|e| Error::Model(format!("Failed to reshape encoder output: {e}")))?;
// Extract new cache states
let (ch_shape, ch_data) = outputs["new_cache_last_channel"]
.try_extract_tensor::<f32>()
.map_err(|e| Error::Model(format!("Failed to extract cache_last_channel: {e}")))?;
let (tm_shape, tm_data) = outputs["new_cache_last_time"]
.try_extract_tensor::<f32>()
.map_err(|e| Error::Model(format!("Failed to extract cache_last_time: {e}")))?;
let (len_shape, len_data) = outputs["new_cache_last_channel_len"]
.try_extract_tensor::<i64>()
.map_err(|e| Error::Model(format!("Failed to extract cache_len: {e}")))?;
// Build new cache with extracted shapes
let new_cache = EncoderCache {
cache_last_channel: Array4::from_shape_vec(
(ch_shape[0] as usize, ch_shape[1] as usize, ch_shape[2] as usize, ch_shape[3] as usize),
ch_data.to_vec()
).map_err(|e| Error::Model(format!("Failed to reshape cache_last_channel: {e}")))?,
cache_last_time: Array4::from_shape_vec(
(tm_shape[0] as usize, tm_shape[1] as usize, tm_shape[2] as usize, tm_shape[3] as usize),
tm_data.to_vec()
).map_err(|e| Error::Model(format!("Failed to reshape cache_last_time: {e}")))?,
cache_last_channel_len: Array1::from_shape_vec(
len_shape[0] as usize,
len_data.to_vec()
).map_err(|e| Error::Model(format!("Failed to reshape cache_len: {e}")))?,
};
Ok((encoder_out, new_cache))
}
/// Run the stateful decoder
/// Returns: (logits [1, 1, 1, vocab], new_state_h, new_state_c)
pub fn run_decoder(
&mut self,
encoder_frame: &Array3<f32>, // [1, 512, 1]
last_token: &Array2<i32>, // [1, 1]
state_h: &Array3<f32>, // [1, 1, 640]
state_c: &Array3<f32>, // [1, 1, 640]
) -> Result<(Array3<f32>, Array3<f32>, Array3<f32>)> {
// Target length is always 1 for single step
let target_len = Array1::from_vec(vec![1i32]);
let outputs = self.decoder_joint.run(ort::inputs![
"encoder_outputs" => ort::value::Value::from_array(encoder_frame.clone())?,
"targets" => ort::value::Value::from_array(last_token.clone())?,
"target_length" => ort::value::Value::from_array(target_len)?,
"input_states_1" => ort::value::Value::from_array(state_h.clone())?,
"input_states_2" => ort::value::Value::from_array(state_c.clone())?
])?;
// 1. Extract Logits
let (l_shape, l_data) = outputs["outputs"]
.try_extract_tensor::<f32>()
.map_err(|e| Error::Model(format!("Failed to extract logits: {e}")))?;
// 2. Extract States (output_states_1, output_states_2)
let (_h_shape, h_data) = outputs["output_states_1"]
.try_extract_tensor::<f32>()
.map_err(|e| Error::Model(format!("Failed to extract state h: {e}")))?;
let (_c_shape, c_data) = outputs["output_states_2"]
.try_extract_tensor::<f32>()
.map_err(|e| Error::Model(format!("Failed to extract state c: {e}")))?;
// Reconstruct Arrays
// Logits: I simplify to [1, 1, vocab]
let vocab_size = l_shape[3] as usize;
let logits = Array3::from_shape_vec((1, 1, vocab_size), l_data.to_vec())
.map_err(|e| Error::Model(format!("Reshape logits failed: {e}")))?;
// States: [1, 1, 640]
let new_h = Array3::from_shape_vec((1, 1, 640), h_data.to_vec())
.map_err(|e| Error::Model(format!("Reshape state h failed: {e}")))?;
let new_c = Array3::from_shape_vec((1, 1, 640), c_data.to_vec())
.map_err(|e| Error::Model(format!("Reshape state c failed: {e}")))?;
Ok((logits, new_h, new_c))
}
}
