SignX/eval/attention_analysis.py

#!/usr/bin/env python3
"""
Attention weight analysis and visualization helpers for SignX.

Capabilities:
1. Parse attention weight tensors
2. Map each generated gloss to video frame ranges
3. Render visual assets (heatmaps, alignment plots, timelines)
4. Write detailed analysis reports

Example:
    from eval.attention_analysis import AttentionAnalyzer

    analyzer = AttentionAnalyzer(
        attentions=attention_weights,  # [time, batch, beam, src_len]
        translation="WORD1 WORD2 WORD3",
        video_frames=100
    )

    analyzer.generate_all_visualizations(output_dir="results/")
"""

import os
import io
import json
import shutil
import subprocess
import numpy as np
from pathlib import Path
from datetime import datetime


class AttentionAnalyzer:
    """Analyze attention tensors and generate visual/debug artifacts."""

    def __init__(self, attentions, translation, video_frames, beam_sequences=None, beam_scores=None,
                 video_path=None, original_video_fps=30, original_video_total_frames=None):
        """
        Args:
            attentions: numpy array, shape [time_steps, batch, beam, src_len]
                       or [time_steps, src_len] (best beam already selected)
            translation: str, BPE-removed gloss sequence
            video_frames: int, number of SMKD feature frames
            beam_sequences: list, optional beam texts
            beam_scores: list, optional beam scores
            video_path: str, optional path to original video (for frame grabs)
            original_video_fps: int, FPS of original video (default 30)
            original_video_total_frames: optional exact frame count
        """
        self.attentions = attentions
        self.translation = translation
        self.words = translation.split()
        self.video_frames = video_frames
        self.beam_sequences = beam_sequences
        self.beam_scores = beam_scores

        # Video metadata
        self.video_path = video_path
        self.original_video_fps = original_video_fps
        self.original_video_total_frames = original_video_total_frames
        self._cv2_module = None
        self._cv2_checked = False

        # Auto-read metadata if only video path is given
        if video_path and original_video_total_frames is None:
            metadata = self._read_video_metadata()
            if metadata:
                self.original_video_total_frames = metadata.get('frames')
                if metadata.get('fps'):
                    self.original_video_fps = metadata['fps']
            elif video_path:
                print(f"Warning: failed to parse video metadata; gloss-to-frame visualization may be misaligned ({video_path})")

        # Always operate on the best path (batch=0, beam=0)
        if len(attentions.shape) == 4:
            self.attn_best = attentions[:, 0, 0, :]  # [time, src_len]
        elif len(attentions.shape) == 3:
            self.attn_best = attentions[:, 0, :]  # [time, src_len]
        else:
            self.attn_best = attentions  # [time, src_len]

        # Pre-compute gloss-to-frame ranges
        self.word_frame_ranges = self._compute_word_frame_ranges()
        self.frame_attention_strength = self._compute_frame_attention_strength()

    def _compute_word_frame_ranges(self):
        """
        Compute the dominant video frame range for each generated word.

        Returns:
            list of dict entries containing word, frame range, peak, and confidence.
        """
        word_ranges = []

        for word_idx, word in enumerate(self.words):
            if word_idx >= self.attn_best.shape[0]:
                # Out of range
                word_ranges.append({
                    'word': word,
                    'start_frame': 0,
                    'end_frame': 0,
                    'peak_frame': 0,
                    'avg_attention': 0.0,
                    'confidence': 'unknown'
                })
                continue

            attn_weights = self.attn_best[word_idx, :]

            # Peak frame for this word
            peak_frame = int(np.argmax(attn_weights))
            peak_weight = attn_weights[peak_frame]

            # Frames whose weight >= 90% of the peak
            threshold = peak_weight * 0.9
            significant_frames = np.where(attn_weights >= threshold)[0]

            if len(significant_frames) > 0:
                start_frame = int(significant_frames[0])
                end_frame = int(significant_frames[-1])
                avg_weight = float(attn_weights[significant_frames].mean())
            else:
                start_frame = peak_frame
                end_frame = peak_frame
                avg_weight = float(peak_weight)

            # Qualitative confidence bucket
            if avg_weight > 0.5:
                confidence = 'high'
            elif avg_weight > 0.2:
                confidence = 'medium'
            else:
                confidence = 'low'

            word_ranges.append({
                'word': word,
                'start_frame': start_frame,
                'end_frame': end_frame,
                'peak_frame': peak_frame,
                'avg_attention': avg_weight,
                'confidence': confidence
            })

        return word_ranges

    def _compute_frame_attention_strength(self):
        """Compute average attention per feature frame (normalized 0-1)."""
        if self.attn_best.size == 0:
            return np.zeros(self.video_frames, dtype=np.float32)

        if self.attn_best.ndim == 1:
            frame_strength = self.attn_best.copy()
        else:
            frame_strength = self.attn_best.mean(axis=0)

        if frame_strength.shape[0] != self.video_frames:
            frame_strength = np.resize(frame_strength, self.video_frames)

        max_val = frame_strength.max()
        if max_val > 0:
            frame_strength = frame_strength / max_val
        return frame_strength

    def _map_strength_to_original_frames(self, mapping_list, original_frame_count):
        """Map latent attention strength to original video frame resolution."""
        if not mapping_list or original_frame_count <= 0:
            return None

        orig_strength = np.zeros(original_frame_count, dtype=np.float32)
        counts = np.zeros(original_frame_count, dtype=np.float32)

        for feat_idx, mapping in enumerate(mapping_list):
            if feat_idx >= len(self.frame_attention_strength):
                break
            start = int(mapping.get('frame_start', 0))
            end = int(mapping.get('frame_end', start))
            end = max(end, start + 1)
            start = max(start, 0)
            end = min(end, original_frame_count)
            if start >= end:
                continue
            orig_strength[start:end] += self.frame_attention_strength[feat_idx]
            counts[start:end] += 1

        mask = counts > 0
        if mask.any():
            orig_strength[mask] = orig_strength[mask] / counts[mask]

        max_val = orig_strength.max()
        if max_val > 0:
            orig_strength = orig_strength / max_val
        return orig_strength

    def generate_all_visualizations(self, output_dir):
        """
        Generate every visualization artifact to the provided directory.
        """
        output_dir = Path(output_dir)
        output_dir.mkdir(parents=True, exist_ok=True)

        print(f"\nGenerating visualization assets in: {output_dir}")

        # 1. Attention heatmap
        self.plot_attention_heatmap(output_dir / "attention_heatmap.png")

        # 2. Frame alignment
        self.plot_frame_alignment(output_dir / "frame_alignment.png")

        # 3. JSON metadata
        self.save_alignment_data(output_dir / "frame_alignment.json")

        # 4. Text report
        self.save_text_report(output_dir / "analysis_report.txt")

        # 5. Raw numpy dump (for downstream tooling)
        np.save(output_dir / "attention_weights.npy", self.attentions)

        # 6. Gloss-to-Frames visualization (if video is available)
        # Write debug info to file
        debug_file = output_dir / "debug_video_path.txt"
        with open(debug_file, 'w') as f:
            f.write(f"video_path = {repr(self.video_path)}\n")
            f.write(f"video_path type = {type(self.video_path)}\n")
            f.write(f"video_path is None: {self.video_path is None}\n")
            f.write(f"bool(video_path): {bool(self.video_path)}\n")

        print(f"[DEBUG] video_path = {self.video_path}")
        if self.video_path:
            print(f"[DEBUG] Generating gloss-to-frames visualization with video: {self.video_path}")
            try:
                self.generate_gloss_to_frames_visualization(output_dir / "gloss_to_frames.png")
                print(f"[DEBUG] Successfully generated gloss_to_frames.png")
            except Exception as e:
                print(f"[DEBUG] Failed to generate gloss_to_frames.png: {e}")
                import traceback
                traceback.print_exc()
        else:
            print("[DEBUG] Skipping gloss-to-frames visualization (no video path provided)")

        print(f"✓ Wrote {len(list(output_dir.glob('*')))} file(s)")

    def plot_attention_heatmap(self, output_path):
        """Render the attention heatmap (image + PDF copy)."""
        try:
            import matplotlib
            matplotlib.use('Agg')
            import matplotlib.pyplot as plt
        except ImportError:
            print("  Skipping heatmap: matplotlib is not available")
            return

        fig, ax = plt.subplots(figsize=(14, 8))

        # Heatmap
        im = ax.imshow(self.attn_best.T, cmap='hot', aspect='auto',
                      interpolation='nearest', origin='lower')

        # Axis labels
        ax.set_xlabel('Generated Word Index', fontsize=13)
        ax.set_ylabel('Video Frame Index', fontsize=13)
        ax.set_title('Cross-Attention Weights\n(Decoder → Video Frames)',
                    fontsize=15, pad=20, fontweight='bold')

        # Word labels on the x-axis
        if len(self.words) <= self.attn_best.shape[0]:
            ax.set_xticks(range(len(self.words)))
            ax.set_xticklabels(self.words, rotation=45, ha='right', fontsize=10)

        # Color bar
        cbar = plt.colorbar(im, ax=ax, label='Attention Weight', fraction=0.046, pad=0.04)
        cbar.ax.tick_params(labelsize=10)

        plt.tight_layout()
        plt.savefig(output_path, dpi=150, bbox_inches='tight')
        # also save PDF copy for high-res usage
        pdf_path = Path(output_path).with_suffix('.pdf')
        plt.savefig(str(pdf_path), format='pdf', bbox_inches='tight')
        plt.close()

        print(f"  ✓ {output_path.name} (PDF copy saved)")

    def plot_frame_alignment(self, output_path):
        """Render the frame-alignment charts (full + compact)."""
        try:
            import matplotlib
            matplotlib.use('Agg')
            import matplotlib.pyplot as plt
            import matplotlib.patches as patches
            from matplotlib.gridspec import GridSpec
        except ImportError:
            print("  Skipping alignment plot: matplotlib is not available")
            return

        output_path = Path(output_path)

        # Try to load feature-to-frame mapping
        feature_mapping = None
        output_dir = output_path.parent
        mapping_file = output_dir / "feature_frame_mapping.json"
        if mapping_file.exists():
            try:
                with open(mapping_file, 'r') as f:
                    feature_mapping = json.load(f)
            except Exception as e:
                print(f"  Warning: Failed to load feature mapping: {e}")

        if self.word_frame_ranges:
            max_feat_end = max(w['end_frame'] for w in self.word_frame_ranges)
        else:
            max_feat_end = self.video_frames - 1
        latent_full_limit = self.video_frames + 2
        latent_short_limit = max(min(latent_full_limit, max_feat_end + 2), 5)

        original_frame_count = None
        mapping_list = None
        orig_full_limit = None
        orig_short_limit = None
        pixel_strength_curve = None
        if feature_mapping:
            original_frame_count = feature_mapping.get('original_frame_count', self.video_frames)
            mapping_list = feature_mapping.get('mapping', [])
            orig_full_limit = original_frame_count + 2
            if mapping_list:
                idx = min(max_feat_end, len(mapping_list) - 1)
                orig_short_limit = mapping_list[idx]['frame_end'] + 2
            pixel_strength_curve = self._map_strength_to_original_frames(mapping_list, original_frame_count)

        def render_alignment(out_path, latent_xlim_end, orig_xlim_end=None):
            if feature_mapping:
                fig = plt.figure(figsize=(18, 9))
                gs = GridSpec(3, 1, height_ratios=[4, 1, 1], hspace=0.32)
            else:
                fig = plt.figure(figsize=(18, 7.5))
                gs = GridSpec(2, 1, height_ratios=[4, 1], hspace=0.32)

            # === Top plot: word-to-frame alignment ===
            ax1 = fig.add_subplot(gs[0])
            colors = plt.cm.tab20(np.linspace(0, 1, max(len(self.words), 20)))

            for i, word_info in enumerate(self.word_frame_ranges):
                start = word_info['start_frame']
                end = word_info['end_frame']
                word = word_info['word']
                confidence = word_info['confidence']
                alpha = 0.9 if confidence == 'high' else 0.7 if confidence == 'medium' else 0.5

                rect = patches.Rectangle(
                    (start, i), end - start + 1, 0.8,
                    linewidth=2, edgecolor='black',
                    facecolor=colors[i % 20], alpha=alpha
                )
                ax1.add_patch(rect)

                ax1.text(start + (end - start) / 2, i + 0.4, word,
                        ha='center', va='center', fontsize=11,
                        fontweight='bold', color='white',
                        bbox=dict(boxstyle='round,pad=0.3', facecolor='black', alpha=0.5))

                peak = word_info['peak_frame']
                ax1.plot(peak, i + 0.4, 'r*', markersize=15, markeredgecolor='yellow',
                        markeredgewidth=1.5)

            ax1.set_xlim(-2, latent_xlim_end)
            ax1.set_ylim(-0.5, len(self.words))
            ax1.set_xlabel('')
            ax1.set_ylabel('')
            ax1.set_title('Word-to-Frame Alignment\n(based on attention peaks, ★ = peak frame)',
                         fontsize=15, pad=15, fontweight='bold')
            ax1.grid(True, alpha=0.3, axis='x', linestyle='--')
            ax1.set_yticks(range(len(self.words)))
            ax1.set_yticklabels([w['word'] for w in self.word_frame_ranges], fontsize=10)

            # === Middle plot: latent timeline ===
            ax2 = fig.add_subplot(gs[1])
            ax2.barh(0, self.video_frames, height=0.6, color='lightgray',
                    edgecolor='black', linewidth=2)
            for i, word_info in enumerate(self.word_frame_ranges):
                start = word_info['start_frame']
                end = word_info['end_frame']
                confidence = word_info['confidence']
                alpha = 0.9 if confidence == 'high' else 0.7 if confidence == 'medium' else 0.5
                ax2.barh(0, end - start + 1, left=start, height=0.6,
                        color=colors[i % 20], alpha=alpha, edgecolor='black', linewidth=0.5)

            ax2.set_xlim(-2, latent_xlim_end)
            ax2.set_ylim(-0.4, 0.4)
            ax2.set_xlabel('')
            ax2.set_yticks([0])
            ax2.set_yticklabels(['Latent Space'], fontsize=11, fontweight='bold')
            ax2.tick_params(axis='y', length=0)
            ax2.set_title('Latent Feature Timeline', fontsize=13, fontweight='bold')
            ax2.grid(True, alpha=0.3, axis='x', linestyle='--')

            if self.frame_attention_strength is not None and len(self.frame_attention_strength) >= self.video_frames:
                latent_curve_x = np.arange(self.video_frames)
                latent_curve_y = self.frame_attention_strength[:self.video_frames] * 0.6 - 0.3
                ax2.plot(latent_curve_x, latent_curve_y, color='#E53935', linewidth=1.5, alpha=0.9)

            timeline_axes = [ax2]

            if feature_mapping:
                ax3 = fig.add_subplot(gs[2])
                ax3.barh(0, original_frame_count, height=0.6, color='lightgray',
                        edgecolor='black', linewidth=2)

                for i, word_info in enumerate(self.word_frame_ranges):
                    feat_start = word_info['start_frame']
                    feat_end = word_info['end_frame']
                    confidence = word_info['confidence']
                    alpha = 0.9 if confidence == 'high' else 0.7 if confidence == 'medium' else 0.5
                    if mapping_list and feat_start < len(mapping_list) and feat_end < len(mapping_list):
                        orig_start = mapping_list[feat_start]['frame_start']
                        orig_end = mapping_list[feat_end]['frame_end']
                        ax3.barh(0, orig_end - orig_start, left=orig_start, height=0.6,
                                color=colors[i % 20], alpha=alpha, edgecolor='black', linewidth=0.5)

                ax3_xlim = orig_xlim_end if orig_xlim_end is not None else original_frame_count + 2
                ax3.set_xlim(-2, ax3_xlim)
                ax3.set_ylim(-0.4, 0.4)
                ax3.set_xlabel('')
                ax3.set_yticks([0])
                ax3.set_yticklabels(['Pixel Space'], fontsize=11, fontweight='bold')
                ax3.tick_params(axis='y', length=0)
                ax3.set_title(f'Original Video Timeline ({original_frame_count} frames, '
                             f'{feature_mapping["downsampling_ratio"]:.2f}x downsampling)',
                             fontsize=13, fontweight='bold')
                ax3.grid(True, alpha=0.3, axis='x', linestyle='--')

                if pixel_strength_curve is not None and len(pixel_strength_curve) >= original_frame_count:
                    pixel_curve_x = np.arange(original_frame_count)
                    pixel_curve_y = pixel_strength_curve[:original_frame_count] * 0.6 - 0.3
                    ax3.plot(pixel_curve_x, pixel_curve_y, color='#E53935', linewidth=1.5, alpha=0.9)
                timeline_axes.append(ax3)

            plt.tight_layout()
            fig.canvas.draw()

            ax1_pos = ax1.get_position()
            renderer = fig.canvas.get_renderer()
            ytick_extents = [tick.get_window_extent(renderer) for tick in ax1.get_yticklabels() if tick.get_text()]
            fig_width_px = fig.get_size_inches()[0] * fig.dpi
            if ytick_extents:
                min_x_px = min(ext.x0 for ext in ytick_extents)
            else:
                min_x_px = ax1_pos.x0 * fig_width_px
            line_x = max(0.01, (min_x_px / fig_width_px) - 0.01)
            gw_center = 0.5 * (ax1_pos.y0 + ax1_pos.y1)
            timeline_bounds = [ax.get_position() for ax in timeline_axes]
            timeline_center = 0.5 * (min(pos.y0 for pos in timeline_bounds) + max(pos.y1 for pos in timeline_bounds))
            fig.text(line_x, gw_center, 'Generated Word', rotation='vertical',
                     ha='right', va='center', fontsize=12, fontweight='bold')
            fig.text(line_x, timeline_center, 'Timeline', rotation='vertical',
                     ha='right', va='center', fontsize=12, fontweight='bold')

            png_path = Path(out_path)
            plt.savefig(str(png_path), dpi=150, bbox_inches='tight')
            pdf_path = png_path.with_suffix('.pdf')
            plt.savefig(str(pdf_path), format='pdf', bbox_inches='tight')
            plt.close()

            print(f"  ✓ {png_path.name} (PDF copy saved)")

        render_alignment(output_path, latent_full_limit, orig_full_limit)

        if latent_short_limit < latent_full_limit - 1e-6:
            short_path = output_path.with_name("frame_alignment_short.png")
            render_alignment(short_path, latent_short_limit, orig_short_limit if orig_short_limit else orig_full_limit)

    def save_alignment_data(self, output_path):
        """Persist frame-alignment metadata to JSON."""
        data = {
            'translation': self.translation,
            'words': self.words,
            'total_video_frames': self.video_frames,
            'frame_ranges': self.word_frame_ranges,
            'statistics': {
                'avg_confidence': np.mean([w['avg_attention'] for w in self.word_frame_ranges]),
                'high_confidence_words': sum(1 for w in self.word_frame_ranges if w['confidence'] == 'high'),
                'medium_confidence_words': sum(1 for w in self.word_frame_ranges if w['confidence'] == 'medium'),
                'low_confidence_words': sum(1 for w in self.word_frame_ranges if w['confidence'] == 'low'),
            }
        }

        with open(output_path, 'w', encoding='utf-8') as f:
            json.dump(data, f, indent=2, ensure_ascii=False)

        print(f"  ✓ {output_path.name}")

    def save_text_report(self, output_path):
        """Write a plain-text report (used for analysis_report.txt)."""
        with open(output_path, 'w', encoding='utf-8') as f:
            f.write("=" * 80 + "\n")
            f.write("  Sign Language Recognition - Attention Analysis Report\n")
            f.write("=" * 80 + "\n\n")

            f.write(f"Generated at: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}\n\n")

            f.write("Translation:\n")
            f.write("-" * 80 + "\n")
            f.write(f"{self.translation}\n\n")

            f.write("Video info:\n")
            f.write("-" * 80 + "\n")
            f.write(f"Total feature frames: {self.video_frames}\n")
            f.write(f"Word count: {len(self.words)}\n\n")

            f.write("Attention tensor:\n")
            f.write("-" * 80 + "\n")
            f.write(f"Shape: {self.attentions.shape}\n")
            f.write(f"  - Decoder steps: {self.attentions.shape[0]}\n")
            if len(self.attentions.shape) >= 3:
                f.write(f"  - Batch size: {self.attentions.shape[1]}\n")
            if len(self.attentions.shape) >= 4:
                f.write(f"  - Beam size: {self.attentions.shape[2]}\n")
                f.write(f"  - Source length: {self.attentions.shape[3]}\n")
            f.write("\n")

            f.write("Word-to-frame details:\n")
            f.write("=" * 80 + "\n")
            f.write(f"{'No.':<5} {'Word':<20} {'Frames':<15} {'Peak':<8} {'Attn':<8} {'Conf':<10}\n")
            f.write("-" * 80 + "\n")

            for i, w in enumerate(self.word_frame_ranges):
                frame_range = f"{w['start_frame']}-{w['end_frame']}"
                f.write(f"{i+1:<5} {w['word']:<20} {frame_range:<15} "
                       f"{w['peak_frame']:<8} {w['avg_attention']:<8.3f} {w['confidence']:<10}\n")

            f.write("\n" + "=" * 80 + "\n")

            # Summary
            stats = {
                'avg_confidence': np.mean([w['avg_attention'] for w in self.word_frame_ranges]),
                'high': sum(1 for w in self.word_frame_ranges if w['confidence'] == 'high'),
                'medium': sum(1 for w in self.word_frame_ranges if w['confidence'] == 'medium'),
                'low': sum(1 for w in self.word_frame_ranges if w['confidence'] == 'low'),
            }

            f.write("\nSummary:\n")
            f.write("-" * 80 + "\n")
            f.write(f"Average attention weight: {stats['avg_confidence']:.3f}\n")
            f.write(f"High-confidence words: {stats['high']} ({stats['high']/len(self.words)*100:.1f}%)\n")
            f.write(f"Medium-confidence words: {stats['medium']} ({stats['medium']/len(self.words)*100:.1f}%)\n")
            f.write(f"Low-confidence words: {stats['low']} ({stats['low']/len(self.words)*100:.1f}%)\n")
            f.write("\n" + "=" * 80 + "\n")

        print(f"  ✓ {output_path.name}")


    def _map_feature_frame_to_original(self, feature_frame_idx):
        """
        Map a SMKD feature frame index back to the original video frame index.

        Args:
            feature_frame_idx: Zero-based feature frame index

        Returns:
            int: Original frame index, or None if unavailable.
        """
        if self.original_video_total_frames is None:
            return None

        # Approximate downsampling ratio between latent frames and original frames
        downsample_ratio = self.original_video_total_frames / self.video_frames

        # Map latent index to original frame index
        original_frame_idx = int(feature_frame_idx * downsample_ratio)

        return min(original_frame_idx, self.original_video_total_frames - 1)

    def _extract_video_frames(self, frame_indices):
        """
        Extract the requested original video frames (best-effort).

        Args:
            frame_indices: list[int] of original frame IDs to load

        Returns:
            dict mapping frame index to numpy array (BGR).
        """
        if not self.video_path:
            return {}

        cv2 = self._get_cv2_module()
        if cv2 is not None:
            return self._extract_frames_with_cv2(cv2, frame_indices)

        return self._extract_frames_with_ffmpeg(frame_indices)

    def _get_cv2_module(self):
        """Lazy-load cv2 and cache the import outcome."""
        if self._cv2_checked:
            return self._cv2_module

        try:
            import cv2
            self._cv2_module = cv2
        except ImportError:
            self._cv2_module = None
        finally:
            self._cv2_checked = True

        if self._cv2_module is None:
            print("Warning: opencv-python is missing; falling back to ffmpeg grabs")
        return self._cv2_module

    def _extract_frames_with_cv2(self, cv2, frame_indices):
        """Extract frames via OpenCV if available."""
        frames = {}
        cap = cv2.VideoCapture(self.video_path)

        if not cap.isOpened():
            print(f"Warning: Cannot open video file: {self.video_path}")
            return {}

        for frame_idx in sorted(frame_indices):
            cap.set(cv2.CAP_PROP_POS_FRAMES, frame_idx)
            ret, frame = cap.read()
            if ret:
                frame_rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
                frames[frame_idx] = frame_rgb

        cap.release()
        return frames

    def _extract_frames_with_ffmpeg(self, frame_indices):
        """Extract frames via ffmpeg + Pillow (OpenCV fallback)."""
        if shutil.which("ffmpeg") is None:
            print("Warning: ffmpeg not found; cannot extract frames")
            return {}

        try:
            from PIL import Image
        except ImportError:
            print("Warning: Pillow not installed; cannot decode ffmpeg output")
            return {}

        frames = {}
        for frame_idx in sorted(frame_indices):
            cmd = [
                "ffmpeg",
                "-v", "error",
                "-i", str(self.video_path),
                "-vf", f"select=eq(n\\,{frame_idx})",
                "-vframes", "1",
                "-f", "image2pipe",
                "-vcodec", "png",
                "-"
            ]
            try:
                result = subprocess.run(
                    cmd, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE
                )
                if not result.stdout:
                    continue
                image = Image.open(io.BytesIO(result.stdout)).convert("RGB")
                frames[frame_idx] = np.array(image)
            except subprocess.CalledProcessError as e:
                print(f"Warning: ffmpeg failed to extract frame {frame_idx}: {e}")
            except Exception as ex:
                print(f"Warning: failed to decode frame {frame_idx}: {ex}")

        if frames:
            print(f"  ✓ Extracted {len(frames)} frame(s) via ffmpeg")
        else:
            print("  ⓘ ffmpeg did not return any frames")
        return frames

    def generate_gloss_to_frames_visualization(self, output_path):
        """
        Create the gloss-to-frames visualization:
            Column 1: gloss text
            Column 2: relative time + frame indices
            Column 3: representative video thumbnails
        """
        if not self.video_path:
            print("  ⓘ Skipping gloss-to-frames visualization (no video path provided)")
            return

        try:
            import matplotlib.pyplot as plt
            import matplotlib.gridspec as gridspec
        except ImportError:
            print("Warning: matplotlib not installed")
            return

        # Load feature-to-frame mapping if available
        feature_mapping = None
        output_dir = Path(output_path).parent
        mapping_file = output_dir / "feature_frame_mapping.json"
        if mapping_file.exists():
            try:
                with open(mapping_file, 'r') as f:
                    mapping_data = json.load(f)
                    feature_mapping = mapping_data['mapping']
            except Exception as e:
                print(f"  Warning: Failed to load feature mapping: {e}")

        # Collect every original frame we need to grab
        all_original_frames = set()
        for word_info in self.word_frame_ranges:
            # Feature frame range
            start_feat = word_info['start_frame']
            end_feat = word_info['end_frame']

            # Map the feature range onto original video frames
            if feature_mapping:
                # Use the precomputed mapping data
                for feat_idx in range(start_feat, end_feat + 1):
                    if feat_idx < len(feature_mapping):
                        # Pull every original frame for that feature segment
                        feat_info = feature_mapping[feat_idx]
                        for orig_idx in range(feat_info['frame_start'], feat_info['frame_end']):
                            all_original_frames.add(orig_idx)
            else:
                # Fallback: assume uniform downsampling
                for feat_idx in range(start_feat, end_feat + 1):
                    orig_idx = self._map_feature_frame_to_original(feat_idx)
                    if orig_idx is not None:
                        all_original_frames.add(orig_idx)

        # Extract the necessary frames
        print(f"  Extracting {len(all_original_frames)} original video frame(s)...")
        video_frames_dict = self._extract_video_frames(list(all_original_frames))

        if not video_frames_dict:
            print("  ⓘ No video frames extracted, skipping visualization")
            return

        # Create figure (4 columns: Gloss | Feature Index | Peak Frame | Full Span)
        n_words = len(self.words)
        fig = plt.figure(figsize=(28, 3 * n_words))
        gs = gridspec.GridSpec(n_words, 4, width_ratios=[1.5, 1.5, 2.5, 8], hspace=0.3, wspace=0.2)

        for row_idx, (word, word_info) in enumerate(zip(self.words, self.word_frame_ranges)):
            # Column 1: Gloss label
            ax_gloss = fig.add_subplot(gs[row_idx, 0])
            ax_gloss.text(0.5, 0.5, word, fontsize=24, weight='bold',
                         ha='center', va='center', wrap=True)
            ax_gloss.axis('off')

            # Column 2: Feature index info
            ax_feature = fig.add_subplot(gs[row_idx, 1])

            # Feature frame details
            feat_start = word_info['start_frame']
            feat_end = word_info['end_frame']
            feat_peak = word_info['peak_frame']

            feature_text = f"SMKD Feature Index\n"
            feature_text += f"{'='*20}\n\n"
            feature_text += f"Range:\n  {feat_start} → {feat_end}\n\n"
            feature_text += f"Peak:\n  {feat_peak}\n\n"
            feature_text += f"Count:\n  {feat_end - feat_start + 1} features"

            ax_feature.text(0.5, 0.5, feature_text, fontsize=11, family='monospace',
                           va='center', ha='center',
                           bbox=dict(boxstyle='round,pad=0.8', facecolor='lightblue',
                                   edgecolor='darkblue', linewidth=2, alpha=0.7))
            ax_feature.axis('off')

            # Column 3: Original frames for the peak feature
            ax_peak_frames = fig.add_subplot(gs[row_idx, 2])

            peak_frames_to_show = []
            orig_peak_start, orig_peak_end = None, None
            if feature_mapping and feat_peak is not None and feat_peak < len(feature_mapping):
                # Use detailed mapping to determine the original frame span
                peak_info = feature_mapping[feat_peak]
                orig_peak_start = peak_info['frame_start']
                orig_peak_end = peak_info['frame_end']

                # Show each original frame linked to the peak feature range
                for orig_idx in range(orig_peak_start, orig_peak_end):
                    if orig_idx in video_frames_dict:
                        peak_frames_to_show.append(video_frames_dict[orig_idx])

            if peak_frames_to_show:
                # Horizontally stitch frames
                combined_peak = np.hstack(peak_frames_to_show)
                ax_peak_frames.imshow(combined_peak)

                # Add caption
                ax_peak_frames.text(0.5, -0.05, f"Peak Feature {feat_peak}\nFrames {orig_peak_start}-{orig_peak_end-1} ({len(peak_frames_to_show)} frames)",
                                   ha='center', va='top', transform=ax_peak_frames.transAxes,
                                   fontsize=10, weight='bold', color='red',
                                   bbox=dict(boxstyle='round,pad=0.3', facecolor='yellow', alpha=0.7))
            else:
                ax_peak_frames.text(0.5, 0.5, "No peak frames",
                                   ha='center', va='center', transform=ax_peak_frames.transAxes)

            ax_peak_frames.axis('off')

            # Column 4: All frames covered by the gloss span
            ax_all_frames = fig.add_subplot(gs[row_idx, 3])

            all_frames_to_show = []
            orig_start, orig_end = None, None
            if feature_mapping:
                # Determine range via mapping
                if feat_start < len(feature_mapping) and feat_end < len(feature_mapping):
                    orig_start = feature_mapping[feat_start]['frame_start']
                    orig_end = feature_mapping[feat_end]['frame_end']

                    # Collect every frame in the span
                    for orig_idx in range(orig_start, orig_end):
                        if orig_idx in video_frames_dict:
                            all_frames_to_show.append(video_frames_dict[orig_idx])

            if all_frames_to_show:
                # Stitch all frames horizontally
                combined_all = np.hstack(all_frames_to_show)
                ax_all_frames.imshow(combined_all)

                # Add caption showing total
                frame_count = len(all_frames_to_show)
                ax_all_frames.text(0.5, -0.05, f"All Frames ({frame_count} frames)\nRange: {orig_start}-{orig_end-1}",
                                  ha='center', va='top', transform=ax_all_frames.transAxes,
                                  fontsize=10, weight='bold', color='blue',
                                  bbox=dict(boxstyle='round,pad=0.3', facecolor='lightblue', alpha=0.7))
            else:
                ax_all_frames.text(0.5, 0.5, "No frames available",
                                  ha='center', va='center', transform=ax_all_frames.transAxes)

            ax_all_frames.axis('off')

        plt.suptitle(f"Three-Layer Alignment: Gloss ↔ Feature Index ↔ Original Frames\nTranslation: {self.translation}",
                     fontsize=16, weight='bold', y=0.995)

        plt.savefig(output_path, dpi=150, bbox_inches='tight', facecolor='white')
        plt.close()

        print(f"  ✓ {Path(output_path).name}")

    def _read_video_metadata(self):
        """Attempt to read the original video's frame count and FPS."""
        metadata = self._read_metadata_with_cv2()
        if metadata:
            return metadata
        return self._read_metadata_with_ffprobe()

    def _read_metadata_with_cv2(self):
        cv2 = self._get_cv2_module()
        if cv2 is None:
            return None

        cap = cv2.VideoCapture(self.video_path)
        if not cap.isOpened():
            return None

        total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
        fps = cap.get(cv2.CAP_PROP_FPS)
        cap.release()

        if total_frames <= 0:
            return None

        return {'frames': total_frames, 'fps': fps or self.original_video_fps}

    def _read_metadata_with_ffprobe(self):
        if shutil.which("ffprobe") is None:
            return None

        cmd = [
            "ffprobe",
            "-v", "error",
            "-select_streams", "v:0",
            "-show_entries", "stream=nb_frames,r_frame_rate,avg_frame_rate,duration",
            "-of", "json",
            str(self.video_path)
        ]

        try:
            result = subprocess.run(
                cmd, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True
            )
        except subprocess.CalledProcessError:
            return None

        try:
            info = json.loads(result.stdout)
        except json.JSONDecodeError:
            return None

        streams = info.get("streams") or []
        if not streams:
            return None

        stream = streams[0]
        total_frames = stream.get("nb_frames")
        fps = stream.get("avg_frame_rate") or stream.get("r_frame_rate")
        duration = stream.get("duration")

        fps_value = self._parse_ffprobe_fps(fps)
        total_frames_value = None

        if isinstance(total_frames, str) and total_frames.isdigit():
            total_frames_value = int(total_frames)

        if total_frames_value is None and duration and fps_value:
            try:
                total_frames_value = int(round(float(duration) * fps_value))
            except ValueError:
                total_frames_value = None

        if total_frames_value is None:
            return None

        return {'frames': total_frames_value, 'fps': fps_value or self.original_video_fps}

    @staticmethod
    def _parse_ffprobe_fps(rate_str):
        """Parse an ffprobe frame-rate string such as '30000/1001'."""
        if not rate_str or rate_str in ("0/0", "0"):
            return None

        if "/" in rate_str:
            num, denom = rate_str.split("/", 1)
            try:
                num = float(num)
                denom = float(denom)
                if denom == 0:
                    return None
                return num / denom
            except ValueError:
                return None

        try:
            return float(rate_str)
        except ValueError:
            return None


def analyze_from_numpy_file(attention_file, translation, video_frames, output_dir):
    """
    Load attention weights from a .npy file and generate visualization assets.

    Args:
        attention_file: Path to the numpy file
        translation: Clean translation string
        video_frames: Number of SMKD feature frames
        output_dir: Destination directory for outputs
    """
    attentions = np.load(attention_file)
    analyzer = AttentionAnalyzer(attentions, translation, video_frames)
    analyzer.generate_all_visualizations(output_dir)
    return analyzer