# All episodes get the SAME destination file - the LAST one used
df[orig_chunk_col] = video_idx["chunk"]
df[orig_file_col] = video_idx["file"]

# Track which destination file each source file was written to
videos_idx[key]["src_to_dst"][(src_chunk_idx, src_file_idx)] = (chunk_idx, file_idx)

# Map each episode to its CORRECT destination file
for idx in df.index:
    src_key = (int(df.at[idx, "_orig_chunk"]), int(df.at[idx, "_orig_file"]))
    dst_chunk, dst_file = src_to_dst.get(src_key, (video_idx["chunk"], video_idx["file"]))
    df.at[idx, orig_chunk_col] = dst_chunk
    df.at[idx, orig_file_col] = dst_file

current_offset = video_idx["latest_duration"]  # Global running total

# Append to existing file - offset is WRONG (includes videos from other files)
videos_idx[key]["src_to_offset"][(src_chunk_idx, src_file_idx)] = current_offset

# Track duration of EACH destination file separately
if "dst_file_durations" not in videos_idx[key]:
    videos_idx[key]["dst_file_durations"] = {}

dst_file_durations = video_idx["dst_file_durations"]
dst_key = (chunk_idx, file_idx)

# Append to existing destination file
# Offset is the current duration of THIS SPECIFIC destination file
current_dst_duration = dst_file_durations.get(dst_key, 0)
videos_idx[key]["src_to_offset"][(src_chunk_idx, src_file_idx)] = current_dst_duration
# Update duration of this destination file
dst_file_durations[dst_key] = current_dst_duration + src_duration