tc6/infer.py

import time
import torch
import torchaudio
import matplotlib.pyplot as plt
import numpy as np
from .config import SAMPLE_RATE, N_MELS, HOP_LENGTH
import torch.profiler


# --- PREPROCESSING (match training) ---
def preprocess_audio(audio_path):
    wav, sr = torchaudio.load(audio_path)
    wav = wav.mean(dim=0)  # mono
    if sr != SAMPLE_RATE:
        wav = torchaudio.functional.resample(wav, sr, SAMPLE_RATE)
    wav = wav / (wav.abs().max() + 1e-8)  # Normalize audio

    mel_transform = torchaudio.transforms.MelSpectrogram(
        sample_rate=SAMPLE_RATE,
        n_mels=N_MELS,
        hop_length=HOP_LENGTH,
        n_fft=2048,
    )
    mel = mel_transform(wav)
    return mel  # mel is (N_MELS, T_mel)


# --- INFERENCE ---
def run_inference(model, mel_input, nps_input, difficulty_input, level_input, device):
    model.eval()
    with torch.no_grad():
        mel = mel_input.to(device).unsqueeze(0)  # (1, N_MELS, T_mel)
        nps = nps_input.to(device).unsqueeze(0)  # (1,)
        difficulty = difficulty_input.to(device).unsqueeze(0)  # (1,)
        level = level_input.to(device).unsqueeze(0)  # (1,)

        mel_cnn_input = mel.unsqueeze(1)  # (1, 1, N_MELS, T_mel)

        conformer_lengths = torch.tensor(
            [mel_cnn_input.shape[-1]], dtype=torch.long, device=device
        )

        with torch.profiler.profile(
            activities=[
                torch.profiler.ProfilerActivity.CPU,
                *(
                    [torch.profiler.ProfilerActivity.CUDA]
                    if device.type == "cuda"
                    else []
                ),
            ],
            record_shapes=True,
            profile_memory=True,
            with_stack=False,
            with_flops=True,
        ) as prof:
            out_dict = model(mel_cnn_input, conformer_lengths, nps, difficulty, level)
        print(
            prof.key_averages().table(
                sort_by=(
                    "self_cuda_memory_usage"
                    if device.type == "cuda"
                    else "self_cpu_time_total"
                ),
                row_limit=20,
            )
        )

        energies = out_dict["presence"].squeeze(0).cpu().numpy()

        don_energy = energies[:, 0]
        ka_energy = energies[:, 1]
        drumroll_energy = energies[:, 2]

    return don_energy, ka_energy, drumroll_energy


# --- DECODE TO ONSETS ---
def decode_onsets(
    don_energy,
    ka_energy,
    drumroll_energy,
    hop_sec,
    threshold=0.5,
    min_distance_frames=3,
):
    results = []
    T_out = len(don_energy)
    last_onset_frame = -min_distance_frames

    for i in range(1, T_out - 1):  # Iterate considering neighbors for peak detection
        if i < last_onset_frame + min_distance_frames:
            continue

        e_don, e_ka, e_drum = don_energy[i], ka_energy[i], drumroll_energy[i]
        energies_at_i = {
            1: e_don,
            2: e_ka,
            5: e_drum,
        }  # Type mapping: 1:Don, 2:Ka, 5:Drumroll

        # Find which energy is max and if it's a peak above threshold
        # Sort by energy value descending to prioritize higher energy in case of ties for peak condition
        sorted_types_by_energy = sorted(
            energies_at_i.keys(), key=lambda x: energies_at_i[x], reverse=True
        )

        detected_this_frame = False
        for onset_type in sorted_types_by_energy:
            current_energy_series = None
            if onset_type == 1:
                current_energy_series = don_energy
            elif onset_type == 2:
                current_energy_series = ka_energy
            elif onset_type == 5:
                current_energy_series = drumroll_energy

            energy_val = current_energy_series[i]

            if (
                energy_val > threshold
                and energy_val > current_energy_series[i - 1]
                and energy_val > current_energy_series[i + 1]
            ):
                # Check if this energy is the highest among the three at this frame
                # This check is implicitly handled by iterating `sorted_types_by_energy`
                # and breaking after the first detection.
                results.append((i * hop_sec, onset_type))
                last_onset_frame = i
                detected_this_frame = True
                break  # Only one onset type per frame

    return results


# --- VISUALIZATION ---
def plot_results(
    mel_spectrogram,
    don_energy,
    ka_energy,
    drumroll_energy,
    onsets,
    hop_sec,
    out_path=None,
):
    # mel_spectrogram is (N_MELS, T_mel)
    T_mel = mel_spectrogram.shape[1]
    T_out = len(don_energy)  # Length of energy arrays (model output time dimension)

    # Time axes
    time_axis_mel = np.arange(T_mel) * (HOP_LENGTH / SAMPLE_RATE)
    # hop_sec for model output is (HOP_LENGTH * TIME_SUB) / SAMPLE_RATE
    # However, the model output T_out is related to T_mel (input to CNN).
    # If CNN does not change time dimension, T_out = T_mel.
    # If TIME_SUB is used for label generation, T_out = T_mel / TIME_SUB.
    # The `lengths` passed to conformer in `run_inference` is T_mel.
    # The output of conformer `x` has shape (B, T, D_MODEL). This T is `lengths`.
    # So, T_out from model is T_mel.
    # The `hop_sec` for onsets should be based on the model output frame rate.
    # If model output T_out corresponds to T_mel, then hop_sec for plotting energies is HOP_LENGTH / SAMPLE_RATE.
    # The `hop_sec` passed to `decode_onsets` is (HOP_LENGTH * TIME_SUB) / SAMPLE_RATE.
    # This seems inconsistent. Let's clarify: `TIME_SUB` is used in `preprocess.py` to determine `T_sub` for labels.
    # The model's CNN output time dimension T_cnn is used to pad/truncate labels in `collate_fn`.
    # In `model.py`, the CNN does not stride in time. So T_cnn_out = T_mel_input_to_CNN.
    # The `lengths` for the conformer is based on this T_cnn_out.
    # So, the output of the regressor `presence` (B, T_cnn_out, 3) has T_cnn_out time steps.
    # Each step corresponds to `HOP_LENGTH / SAMPLE_RATE` seconds if TIME_SUB is not involved in downsampling features for the conformer.
    # Let's assume the `hop_sec` used for `decode_onsets` is correct for interpreting model output frames.
    time_axis_energies = np.arange(T_out) * hop_sec

    fig, ax1 = plt.subplots(figsize=(100, 10))

    # Plot Mel Spectrogram on ax1
    mel_db = torchaudio.functional.amplitude_to_DB(
        mel_spectrogram, multiplier=10.0, amin=1e-10, db_multiplier=0.0
    )
    img = ax1.imshow(
        mel_db.numpy(),
        aspect="auto",
        origin="lower",
        cmap="magma",
        extent=[time_axis_mel[0], time_axis_mel[-1], 0, N_MELS],
    )
    ax1.set_title("Mel Spectrogram with Predicted Energies and Onsets")
    ax1.set_xlabel("Time (s)")
    ax1.set_ylabel("Mel Bin")
    fig.colorbar(img, ax=ax1, format="%+2.0f dB")

    # Create a second y-axis for energies
    ax2 = ax1.twinx()
    ax2.plot(time_axis_energies, don_energy, label="Don Energy", color="red")
    ax2.plot(time_axis_energies, ka_energy, label="Ka Energy", color="blue")
    ax2.plot(
        time_axis_energies, drumroll_energy, label="Drumroll Energy", color="green"
    )
    ax2.set_ylabel("Energy")
    ax2.set_ylim(0, 1.2)  # Assuming energies are somewhat normalized or bounded

    # Overlay onsets from decode_onsets (t is already in seconds)
    labeled_types = set()
    # Group drumrolls into segments (reuse logic from write_tja)
    drumroll_times = [t_sec for t_sec, typ in onsets if typ == 5]
    drumroll_times.sort()
    drumroll_segments = []
    if drumroll_times:
        seg_start = drumroll_times[0]
        prev = drumroll_times[0]
        for t in drumroll_times[1:]:
            if t - prev <= hop_sec * 6:  # up to 5-frame gap
                prev = t
            else:
                drumroll_segments.append((seg_start, prev))
                seg_start = t
                prev = t
        drumroll_segments.append((seg_start, prev))
    # Plot Don/Ka onsets as vertical lines
    for t_sec, typ in onsets:
        if typ == 5:
            continue  # skip drumroll onsets
        color_map = {1: "darkred", 2: "darkblue"}
        label_map = {1: "Don Onset", 2: "Ka Onset"}
        line_color = color_map.get(typ, "black")
        line_label = label_map.get(typ, f"Type {typ} Onset")
        if typ not in labeled_types:
            ax1.axvline(
                t_sec, color=line_color, linestyle="--", alpha=0.9, label=line_label
            )
            labeled_types.add(typ)
        else:
            ax1.axvline(t_sec, color=line_color, linestyle="--", alpha=0.9)
    # Plot drumroll segments as shaded regions
    for seg_start, seg_end in drumroll_segments:
        ax1.axvspan(
            seg_start,
            seg_end + hop_sec,
            color="green",
            alpha=0.2,
            label="Drumroll Segment" if "drumroll" not in labeled_types else None,
        )
        labeled_types.add("drumroll")

    # Combine legends from both axes
    lines, labels = ax1.get_legend_handles_labels()
    lines2, labels2 = ax2.get_legend_handles_labels()
    ax2.legend(lines + lines2, labels + labels2, loc="upper right")

    fig.tight_layout()

    # Return plot as image buffer or save to file if path provided
    if out_path:
        plt.savefig(out_path)
        print(f"Saved plot to {out_path}")
        plt.close(fig)
        return out_path
    else:
        # Return plot as in-memory buffer
        return fig


def write_tja(onsets, out_path=None, bpm=160, quantize=96, audio="audio.wav", offset=0):
    # TJA types: 0:no note, 1:Don, 2:Ka, 3:BigDon, 4:BigKa, 5:DrumrollStart, 8:DrumrollEnd
    # Model output types: 1:Don, 2:Ka, 5:Drumroll (interpreted as start/single)
    sec_per_beat = 60 / bpm
    beats_per_measure = 4  # Assuming 4/4 time signature
    sec_per_measure = sec_per_beat * beats_per_measure
    # Step 1: Map onsets to (measure_idx, slot, typ)
    slot_events = []
    for t, typ in onsets:
        measure_idx = int(t // sec_per_measure)
        t_in_measure = t % sec_per_measure
        slot = int(round(t_in_measure / sec_per_measure * quantize))
        if slot >= quantize:
            slot = quantize - 1
        slot_events.append((measure_idx, slot, typ))
    # Step 2: Build measure/slot grid
    if slot_events:
        max_measure_idx = max(m for m, _, _ in slot_events)
    else:
        max_measure_idx = -1
    measures = {i: [0] * quantize for i in range(max_measure_idx + 1)}
    # Step 3: Place Don/Ka, collect drumrolls
    drumroll_slots = set()
    for m, s, typ in slot_events:
        if typ in [1, 2]:
            measures[m][s] = typ
        elif typ == 5:
            drumroll_slots.add((m, s))
    # Step 4: Process drumrolls into contiguous regions, mark 5 (start) and 8 (end)
    # Flatten all slots to a list of (measure, slot) sorted
    drumroll_list = sorted(list(drumroll_slots))
    # Group into contiguous regions (allowing a gap of 5 slots)
    grouped = []
    group = []
    for ms in drumroll_list:
        if not group:
            group = [ms]
        else:
            last_m, last_s = group[-1]
            m, s = ms
            # Calculate slot distance, considering measure wrap
            slot_dist = None
            if m == last_m:
                slot_dist = s - last_s
            elif m == last_m + 1 and last_s <= quantize - 1:
                slot_dist = (quantize - 1 - last_s) + s + 1
            else:
                slot_dist = None
            # Allow gap of up to 5 slots (slot_dist <= 6)
            if slot_dist is not None and 1 <= slot_dist <= 6:
                group.append(ms)
            else:
                grouped.append(group)
                group = [ms]
    if group:
        grouped.append(group)
    # Mark 5 (start) and 8 (end) for each group
    for region in grouped:
        if len(region) == 1:
            m, s = region[0]
            measures[m][s] = 5
            # Place 8 in next slot (or next measure if at end)
            if s < quantize - 1:
                measures[m][s + 1] = 8
            elif m < max_measure_idx:
                measures[m + 1][0] = 8
        else:
            m_start, s_start = region[0]
            m_end, s_end = region[-1]
            measures[m_start][s_start] = 5
            measures[m_end][s_end] = 8
            # Fill 0 for middle slots (already 0 by default)
    # Step 5: Generate TJA content
    tja_content = []
    tja_content.append(f"TITLE:{audio} (TC6, {time.strftime('%Y-%m-%d %H:%M:%S')})")
    tja_content.append(f"BPM:{bpm}")
    tja_content.append(f"WAVE:{audio}")
    tja_content.append(f"OFFSET:{offset}")
    tja_content.append("COURSE:Oni\nLEVEL:9\n")
    tja_content.append("#START")
    for i in range(max_measure_idx + 1):
        notes = measures.get(i, [0] * quantize)
        line = "".join(str(n) for n in notes)
        tja_content.append(line + ",")
    tja_content.append("#END")

    tja_string = "\n".join(tja_content)

    # If out_path is provided, also write to file
    if out_path:
        with open(out_path, "w", encoding="utf-8") as f:
            f.write(tja_string)
        print(f"TJA chart saved to {out_path}")

    return tja_string