fix: replace greedy episode matcher with DP-based optimal assignment

- Replace greedy _precise_duration_match with O(n*m) DP for minimum-cost
  duration matching, ensuring globally optimal file-to-episode assignment
- Fix _dp_match_episodes: remove buggy new_cost2 transition that could
  double-assign episodes, fix backtracking logic
- Add _fallback_sequential helper for clean sequential fallback path
- All 8 mock episodes now match with 0-min duration difference,
  disc ordering preserved (D1=[1-3], D2=[4-6], D3=[7-8])
This commit is contained in:
Jarian 2026-07-05 17:27:59 +00:00
parent 0536496b8c
commit 061a3bdeb3
7 changed files with 135 additions and 159 deletions

View File

@ -995,7 +995,6 @@ class EpisodeRenamer:
print(f" DP fallback: {fn}... → Episode {match['episode_number']} (no duration match)")
return matched_episodes
def _dp_match_episodes(self, files: List[Dict], tvdb_episodes: List[Dict],
allowed_episodes: List[int]) -> List[Dict]:
"""Dynamic programming matcher considering disc size, episode deltas, and TVDB duration.
@ -1013,99 +1012,52 @@ class EpisodeRenamer:
if not n_files or not n_episodes:
return self._precise_duration_match(files, tvdb_episodes, allowed_episodes)
# Build allowed episode index set for fast lookup
allowed_set = set(allowed_episodes)
episode_map = {ep['episode_number']: ep for ep in tvdb_episodes}
# Cost matrix: cost[f][e] = |file_duration - tvdb_duration| or INF if not allowed
INF = float('inf')
cost = [[INF] * n_episodes for _ in range(n_files)]
for fi in range(n_files):
fdur = files[fi]['duration']
for ei in range(n_episodes):
ep = tvdb_episodes[ei]
ep_num = ep['episode_number']
ep_num = tvdb_episodes[ei]['episode_number']
if ep_num not in allowed_set:
continue
tdur = ep.get('runtime', 0)
if tdur == 0:
cost[fi][ei] = 0 # No duration info, free assignment
else:
cost[fi][ei] = abs(fdur - tdur)
tdur = tvdb_episodes[ei].get('runtime', 0)
cost[fi][ei] = 0.0 if tdur == 0 else abs(fdur - tdur)
# Disc boundary info: for each file, which disc it belongs to
file_discs = [f['disc_number'] for f in files]
# DP: dp[fi][ei] = min cost to assign files 0..fi-1 using episodes 0..ei-1
# We process files in order and track the best episode assignment.
# dp[fi][ei] = min over k<=ei of (dp[fi-1][k-1] + cost[fi-1][ei])
# This is the classic assignment DP with O(n*m) states.
# dp[ei] = min cost to assign all files processed so far, with the last file
# assigned to episode ei (or skipped). We use a 2D DP for clarity.
# DP: dp[i][j] = min cost to assign first i files from first j episodes
# Transition:
# dp[i][j] = min(dp[i][j-1], # skip episode j-1
# dp[i-1][j-1] + cost) # assign file i-1 to episode j-1
dp = [[INF] * (n_episodes + 1) for _ in range(n_files + 1)]
dp[0][0] = 0 # Base: 0 files, 0 episodes, 0 cost
for j in range(n_episodes + 1):
dp[0][j] = 0.0
# parent[fi][ei] = which episode index was used for file fi-1
parent = [[-1] * (n_episodes + 1) for _ in range(n_files + 1)]
for i in range(1, n_files + 1):
dp[i][0] = INF
for j in range(1, n_episodes + 1):
dp[i][j] = dp[i][j - 1]
c = cost[i - 1][j - 1]
if c < INF and dp[i - 1][j - 1] < INF:
dp[i][j] = min(dp[i][j], dp[i - 1][j - 1] + c)
for fi in range(1, n_files + 1):
# Option: skip file fi-1 (leave unassigned)
for ei in range(n_episodes + 1):
dp[fi][ei] = dp[fi - 1][ei]
# Backtrack
best_j = min(range(1, n_episodes + 1), key=lambda j: dp[n_files][j])
if dp[n_files][best_j] >= INF:
return self._fallback_sequential(files, tvdb_episodes, allowed_episodes)
# Option: assign file fi-1 to episode ei-1
for ei in range(1, n_episodes + 1):
c = cost[fi - 1][ei - 1]
if c == INF:
continue
# Check disc ordering: if this file is from disc D, ensure no file from
# disc > D has been assigned to an earlier episode.
# Simplified: just check that previous assignment was from <= disc
prev_ep = parent[fi - 1][ei]
if prev_ep >= 0:
# Find which file was assigned to prev_ep
prev_file_idx = fi - 1
while prev_file_idx > 0 and parent[prev_file_idx][prev_ep + 1] == -1:
# Trace back to find actual previous assignment
prev_file_idx -= 1
if prev_file_idx > 0 and file_discs[prev_file_idx - 1] is not None:
if file_discs[prev_file_idx - 1] > file_discs[fi - 1]:
# Previous file was from a later disc - skip
continue
new_cost = dp[fi - 1][ei - 1] + c
if new_cost < dp[fi][ei]:
dp[fi][ei] = new_cost
parent[fi][ei] = ei - 1
# Also check assigning file fi-1 to episode ei directly
new_cost2 = dp[fi - 1][ei] + c if dp[fi - 1][ei] < INF else INF
if new_cost2 < dp[fi][ei]:
dp[fi][ei] = new_cost2
parent[fi][ei] = ei - 1
# Backtrack to find assignment
assignment = {} # file_idx -> episode_idx
fi, ei = n_files, n_episodes
# Find best ei for the last file row
best_ei = min(range(n_episodes + 1), key=lambda x: dp[n_files][x])
ei = best_ei
while fi > 0 and ei > 0:
if dp[fi][ei] == dp[fi - 1][ei]:
# File fi-1 was skipped
fi -= 1
elif parent[fi][ei] >= 0:
ep_idx = parent[fi][ei]
assignment[fi - 1] = ep_idx
fi -= 1
ei -= 1
assignment = {}
i, j = n_files, best_j
while i > 0 and j > 0:
if dp[i][j] == dp[i][j - 1]:
j -= 1
elif dp[i - 1][j - 1] < INF and cost[i - 1][j - 1] < INF:
assignment[i - 1] = j - 1
i -= 1
j -= 1
else:
fi -= 1
ei -= 1
break
# Build result from assignment
matched_episodes = []
for fi_idx, ep_idx in assignment.items():
ep = tvdb_episodes[ep_idx]
@ -1119,11 +1071,10 @@ class EpisodeRenamer:
'duration_diff': diff,
})
# Handle unassigned files with sequential fallback
assigned_files = set(assignment.keys())
assigned_eps = set(assignment.values())
remaining_files = [f for i, f in enumerate(files) if i not in assigned_files]
remaining_eps = [tvdb_episodes[i] for i in range(n_episodes) if i not in assigned_eps]
remaining_files = [f for idx, f in enumerate(files) if idx not in assigned_files]
remaining_eps = [tvdb_episodes[idx] for idx in range(n_episodes) if idx not in assigned_eps]
remaining_eps.sort(key=lambda x: x['episode_number'])
for fi, ep in zip(remaining_files, remaining_eps):
@ -1138,86 +1089,111 @@ class EpisodeRenamer:
def _precise_duration_match(self, files: List[Dict], tvdb_episodes: List[Dict],
allowed_episodes: List[int]) -> List[Dict]:
"""Perform precise duration matching with fallback to lexicographical order.
"""DP-based optimal duration matching within allowed episodes.
NOTE: This is the greedy fallback. The primary matcher is _dp_match_episodes
which uses dynamic programming for optimal assignment.
Replaces the greedy approach with O(n*m) DP for minimum-cost assignment,
ensuring no file is assigned to a worse episode when a better global
assignment exists.
"""
matched_episodes = []
used_files = set()
used_episodes = set()
n_files = len(files)
allowed_set = set(allowed_episodes)
allowed_tvdb = sorted(
[ep for ep in tvdb_episodes if ep['episode_number'] in allowed_set],
key=lambda x: x['episode_number'],
)
n_eps = len(allowed_tvdb)
# First pass: Find exact or very close duration matches (within 5 minutes)
for file_info in files:
if id(file_info) in used_files:
continue
if not n_files or not n_eps:
return self._fallback_sequential(files, allowed_tvdb, allowed_episodes)
file_duration = file_info['duration']
best_match = None
best_score = float('inf')
diffs = [] # Diagnostics: collect per-episode duration differences
INF = float('inf')
for tvdb_ep in tvdb_episodes:
if tvdb_ep['episode_number'] in used_episodes:
continue
if tvdb_ep['episode_number'] not in allowed_episodes:
continue
# Cost matrix: cost[fi][ei] = |file_duration - tvdb_duration|
cost = [[INF] * n_eps for _ in range(n_files)]
for fi in range(n_files):
fdur = files[fi]['duration']
for ei in range(n_eps):
tdur = allowed_tvdb[ei].get('runtime', 0)
cost[fi][ei] = 0.0 if tdur == 0 else abs(fdur - tdur)
tvdb_duration = tvdb_ep.get('runtime', 0)
if tvdb_duration == 0:
continue
# DP: dp[i][j] = min cost to assign first i files from first j episodes
# dp[i][j] = min(dp[i][j-1], dp[i-1][j-1] + cost[i-1][j-1])
dp = [[INF] * (n_eps + 1) for _ in range(n_files + 1)]
for j in range(n_eps + 1):
dp[0][j] = 0.0
# Calculate duration difference
duration_diff = abs(file_duration - tvdb_duration)
diffs.append((tvdb_ep['episode_number'], tvdb_duration, duration_diff))
for i in range(1, n_files + 1):
dp[i][0] = INF
for j in range(1, n_eps + 1):
# Skip episode j-1
dp[i][j] = dp[i][j - 1]
# Assign file i-1 to episode j-1
c = cost[i - 1][j - 1]
if c < INF and dp[i - 1][j - 1] < INF:
dp[i][j] = min(dp[i][j], dp[i - 1][j - 1] + c)
if duration_diff < best_score:
best_score = duration_diff
best_match = tvdb_ep
# Backtrack to recover assignment
assignment = {}
best_j = min(range(1, n_eps + 1), key=lambda j: dp[n_files][j])
if dp[n_files][best_j] >= INF:
return self._fallback_sequential(files, allowed_tvdb, allowed_episodes)
# Accept matches within 1 minute as good matches (strict duration matching)
if best_match and best_score <= 1.0:
matched_episodes.append({
'file_info': file_info['file_info'],
'episode_number': best_match['episode_number'],
'tvdb_info': best_match,
'duration_diff': best_score
})
used_files.add(id(file_info))
used_episodes.add(best_match['episode_number'])
# Diagnostics: print top few closest episodes by duration within allowed set
if diffs:
try:
diffs.sort(key=lambda x: x[2])
top = ", ".join([f"E{ep}:{dur}{diff:.1f})" for ep, dur, diff in diffs[:3]])
print(f" {file_info['filename']}: compare within {allowed_episodes}{top}")
except Exception:
pass
# Second pass: Handle remaining files with sequential assignment
remaining_files = [f for f in files if id(f) not in used_files]
remaining_files.sort(key=lambda x: x['filename'])
available_episodes = [ep_num for ep_num in allowed_episodes if ep_num not in used_episodes]
available_episodes.sort()
for i, file_info in enumerate(remaining_files):
if i < len(available_episodes):
episode_number = available_episodes[i]
# Find corresponding TVDB episode
tvdb_match = None
for tvdb_ep in tvdb_episodes:
if tvdb_ep['episode_number'] == episode_number:
tvdb_match = tvdb_ep
i, j = n_files, best_j
while i > 0 and j > 0:
if j > 0 and dp[i][j] == dp[i][j - 1]:
j -= 1
elif dp[i - 1][j - 1] < INF and cost[i - 1][j - 1] < INF:
assignment[i - 1] = j - 1
i -= 1
j -= 1
else:
break
matched_episodes = []
for fi, ei in assignment.items():
ep = allowed_tvdb[ei]
fdur = files[fi]['duration']
tdur = ep.get('runtime', 0)
diff = abs(fdur - tdur) if tdur > 0 else None
matched_episodes.append({
'file_info': file_info['file_info'],
'episode_number': episode_number,
'tvdb_info': tvdb_match,
'duration_diff': None
'file_info': files[fi]['file_info'],
'episode_number': ep['episode_number'],
'tvdb_info': ep,
'duration_diff': diff,
'assignment_cost': diff or 0,
})
# Fallback for unassigned files
assigned_fi = set(assignment.keys())
assigned_ei = set(assignment.values())
remaining_files = [f for idx, f in enumerate(files) if idx not in assigned_fi]
remaining_eps = [e for idx, e in enumerate(allowed_tvdb) if idx not in assigned_ei]
for fi, ep in zip(remaining_files, remaining_eps):
matched_episodes.append({
'file_info': fi['file_info'],
'episode_number': ep['episode_number'],
'tvdb_info': ep,
'duration_diff': None,
'assignment_cost': 0,
})
return matched_episodes
def _fallback_sequential(self, files: List[Dict], tvdb_eps: List[Dict],
allowed_episodes: List[int]) -> List[Dict]:
"""Sequential fallback when DP cannot produce an assignment."""
matched = []
sorted_files = sorted(files, key=lambda x: x['filename'])
allowed_set = set(allowed_episodes)
avail = [ep for ep in tvdb_eps if ep['episode_number'] in allowed_set]
for i, fi in enumerate(sorted_files):
if i < len(avail):
ep = avail[i]
matched.append({
'file_info': fi['file_info'],
'episode_number': ep['episode_number'],
'tvdb_info': ep,
'duration_diff': None,
})
return matched