feat(base): 添加单任务内文件传输并发功能

- 引入 ThreadPoolExecutor 实现并行下载和上传
- 新增 download_files_parallel 和 upload_files_parallel 方法
- 添加任务传输并发数配置选项 TASK_DOWNLOAD_CONCURRENCY 和 TASK_UPLOAD_CONCURRENCY
- 实现并发数配置的环境变量解析和验证逻辑
- 在多个处理器中应用并行下载优化文件获取性能
- 更新 .env.example 配置文件模板
- 移除 FFmpeg 命令日志长度限制

handlers/base.py

@@ -12,6 +12,7 @@ import shutil
 import tempfile
 import subprocess
 import threading
+from concurrent.futures import ThreadPoolExecutor, as_completed
 from abc import ABC
 from typing import Optional, List, Dict, Any, Tuple, TYPE_CHECKING
 
@@ -23,7 +24,13 @@ from domain.result import TaskResult, ErrorCode
 from domain.config import WorkerConfig
 from services import storage
 from services.cache import MaterialCache
-from util.tracing import get_current_task_context, mark_span_error, start_span
+from util.tracing import (
+    bind_trace_context,
+    capture_otel_context,
+    get_current_task_context,
+    mark_span_error,
+    start_span,
+)
 from constant import (
     HW_ACCEL_NONE, HW_ACCEL_QSV, HW_ACCEL_CUDA,
     VIDEO_ENCODE_PARAMS, VIDEO_ENCODE_PARAMS_QSV, VIDEO_ENCODE_PARAMS_CUDA
@@ -274,6 +281,9 @@ class BaseHandler(TaskHandler, ABC):
 
     # 线程本地存储：用于存储当前线程的 GPU 设备索引
     _thread_local = threading.local()
+    DEFAULT_TASK_DOWNLOAD_CONCURRENCY = 4
+    DEFAULT_TASK_UPLOAD_CONCURRENCY = 2
+    MAX_TASK_TRANSFER_CONCURRENCY = 16
 
     def __init__(self, config: WorkerConfig, api_client: 'APIClientV2'):
         """
@@ -290,6 +300,251 @@ class BaseHandler(TaskHandler, ABC):
             enabled=config.cache_enabled,
             max_size_gb=config.cache_max_size_gb
         )
+        self.task_download_concurrency = self._resolve_task_transfer_concurrency(
+            "TASK_DOWNLOAD_CONCURRENCY",
+            self.DEFAULT_TASK_DOWNLOAD_CONCURRENCY
+        )
+        self.task_upload_concurrency = self._resolve_task_transfer_concurrency(
+            "TASK_UPLOAD_CONCURRENCY",
+            self.DEFAULT_TASK_UPLOAD_CONCURRENCY
+        )
+
+    def _resolve_task_transfer_concurrency(self, env_name: str, default_value: int) -> int:
+        """读取并规范化任务内传输并发数配置。"""
+        raw_value = os.getenv(env_name)
+        if raw_value is None or not raw_value.strip():
+            return default_value
+
+        try:
+            parsed_value = int(raw_value.strip())
+        except ValueError:
+            logger.warning(
+                f"Invalid {env_name} value '{raw_value}', using default {default_value}"
+            )
+            return default_value
+
+        if parsed_value < 1:
+            logger.warning(f"{env_name} must be >= 1, forcing to 1")
+            return 1
+
+        if parsed_value > self.MAX_TASK_TRANSFER_CONCURRENCY:
+            logger.warning(
+                f"{env_name}={parsed_value} exceeds limit {self.MAX_TASK_TRANSFER_CONCURRENCY}, "
+                f"using {self.MAX_TASK_TRANSFER_CONCURRENCY}"
+            )
+            return self.MAX_TASK_TRANSFER_CONCURRENCY
+
+        return parsed_value
+
+    def download_files_parallel(
+        self,
+        download_jobs: List[Dict[str, Any]],
+        timeout: Optional[int] = None
+    ) -> Dict[str, Dict[str, Any]]:
+        """
+        单任务内并行下载多个文件。
+
+        Args:
+            download_jobs: 下载任务列表。每项字段：
+                - key: 唯一标识
+                - url: 下载地址
+                - dest: 目标文件路径
+                - required: 是否关键文件（可选，默认 True）
+                - use_cache: 是否使用缓存（可选，默认 True）
+            timeout: 单文件下载超时（秒）
+
+        Returns:
+            key -> 结果字典：
+                - success: 是否成功
+                - url: 原始 URL
+                - dest: 目标文件路径
+                - required: 是否关键文件
+        """
+        if not download_jobs:
+            return {}
+
+        normalized_jobs: List[Dict[str, Any]] = []
+        seen_keys = set()
+        for download_job in download_jobs:
+            job_key = str(download_job.get("key", "")).strip()
+            job_url = str(download_job.get("url", "")).strip()
+            job_dest = str(download_job.get("dest", "")).strip()
+            if not job_key or not job_url or not job_dest:
+                raise ValueError("Each download job must include non-empty key/url/dest")
+            if job_key in seen_keys:
+                raise ValueError(f"Duplicate download job key: {job_key}")
+            seen_keys.add(job_key)
+            normalized_jobs.append({
+                "key": job_key,
+                "url": job_url,
+                "dest": job_dest,
+                "required": bool(download_job.get("required", True)),
+                "use_cache": bool(download_job.get("use_cache", True)),
+            })
+
+        if timeout is None:
+            timeout = self.config.download_timeout
+
+        parent_otel_context = capture_otel_context()
+        task_context = get_current_task_context()
+        task_prefix = f"[task:{task_context.task_id}] " if task_context else ""
+        results: Dict[str, Dict[str, Any]] = {}
+
+        def _run_download_job(download_job: Dict[str, Any]) -> bool:
+            with bind_trace_context(parent_otel_context, task_context):
+                return self.download_file(
+                    download_job["url"],
+                    download_job["dest"],
+                    timeout=timeout,
+                    use_cache=download_job["use_cache"],
+                )
+
+        max_workers = min(self.task_download_concurrency, len(normalized_jobs))
+        if max_workers <= 1:
+            for download_job in normalized_jobs:
+                is_success = _run_download_job(download_job)
+                results[download_job["key"]] = {
+                    "success": is_success,
+                    "url": download_job["url"],
+                    "dest": download_job["dest"],
+                    "required": download_job["required"],
+                }
+        else:
+            with ThreadPoolExecutor(
+                max_workers=max_workers,
+                thread_name_prefix="TaskDownload",
+            ) as executor:
+                future_to_job = {
+                    executor.submit(_run_download_job, download_job): download_job
+                    for download_job in normalized_jobs
+                }
+                for completed_future in as_completed(future_to_job):
+                    download_job = future_to_job[completed_future]
+                    is_success = False
+                    try:
+                        is_success = bool(completed_future.result())
+                    except Exception as exc:
+                        logger.error(
+                            f"{task_prefix}Parallel download raised exception for "
+                            f"key={download_job['key']}: {exc}"
+                        )
+                    results[download_job["key"]] = {
+                        "success": is_success,
+                        "url": download_job["url"],
+                        "dest": download_job["dest"],
+                        "required": download_job["required"],
+                    }
+
+        success_count = sum(1 for item in results.values() if item["success"])
+        logger.debug(
+            f"{task_prefix}Parallel download completed: {success_count}/{len(normalized_jobs)}"
+        )
+        return results
+
+    def upload_files_parallel(
+        self,
+        upload_jobs: List[Dict[str, Any]]
+    ) -> Dict[str, Dict[str, Any]]:
+        """
+        单任务内并行上传多个文件。
+
+        Args:
+            upload_jobs: 上传任务列表。每项字段：
+                - key: 唯一标识
+                - task_id: 任务 ID
+                - file_type: 文件类型（video/audio/ts/mp4）
+                - file_path: 本地文件路径
+                - file_name: 文件名（可选）
+                - required: 是否关键文件（可选，默认 True）
+
+        Returns:
+            key -> 结果字典：
+                - success: 是否成功
+                - url: 上传后的访问 URL（失败为 None）
+                - file_path: 本地文件路径
+                - required: 是否关键文件
+        """
+        if not upload_jobs:
+            return {}
+
+        normalized_jobs: List[Dict[str, Any]] = []
+        seen_keys = set()
+        for upload_job in upload_jobs:
+            job_key = str(upload_job.get("key", "")).strip()
+            task_id = str(upload_job.get("task_id", "")).strip()
+            file_type = str(upload_job.get("file_type", "")).strip()
+            file_path = str(upload_job.get("file_path", "")).strip()
+            if not job_key or not task_id or not file_type or not file_path:
+                raise ValueError(
+                    "Each upload job must include non-empty key/task_id/file_type/file_path"
+                )
+            if job_key in seen_keys:
+                raise ValueError(f"Duplicate upload job key: {job_key}")
+            seen_keys.add(job_key)
+            normalized_jobs.append({
+                "key": job_key,
+                "task_id": task_id,
+                "file_type": file_type,
+                "file_path": file_path,
+                "file_name": upload_job.get("file_name"),
+                "required": bool(upload_job.get("required", True)),
+            })
+
+        parent_otel_context = capture_otel_context()
+        task_context = get_current_task_context()
+        task_prefix = f"[task:{task_context.task_id}] " if task_context else ""
+        results: Dict[str, Dict[str, Any]] = {}
+
+        def _run_upload_job(upload_job: Dict[str, Any]) -> Optional[str]:
+            with bind_trace_context(parent_otel_context, task_context):
+                return self.upload_file(
+                    upload_job["task_id"],
+                    upload_job["file_type"],
+                    upload_job["file_path"],
+                    upload_job.get("file_name")
+                )
+
+        max_workers = min(self.task_upload_concurrency, len(normalized_jobs))
+        if max_workers <= 1:
+            for upload_job in normalized_jobs:
+                result_url = _run_upload_job(upload_job)
+                results[upload_job["key"]] = {
+                    "success": bool(result_url),
+                    "url": result_url,
+                    "file_path": upload_job["file_path"],
+                    "required": upload_job["required"],
+                }
+        else:
+            with ThreadPoolExecutor(
+                max_workers=max_workers,
+                thread_name_prefix="TaskUpload",
+            ) as executor:
+                future_to_job = {
+                    executor.submit(_run_upload_job, upload_job): upload_job
+                    for upload_job in normalized_jobs
+                }
+                for completed_future in as_completed(future_to_job):
+                    upload_job = future_to_job[completed_future]
+                    result_url = None
+                    try:
+                        result_url = completed_future.result()
+                    except Exception as exc:
+                        logger.error(
+                            f"{task_prefix}Parallel upload raised exception for "
+                            f"key={upload_job['key']}: {exc}"
+                        )
+                    results[upload_job["key"]] = {
+                        "success": bool(result_url),
+                        "url": result_url,
+                        "file_path": upload_job["file_path"],
+                        "required": upload_job["required"],
+                    }
+
+        success_count = sum(1 for item in results.values() if item["success"])
+        logger.debug(
+            f"{task_prefix}Parallel upload completed: {success_count}/{len(normalized_jobs)}"
+        )
+        return results
 
     # ========== GPU 设备管理 ==========
 
@@ -538,10 +793,8 @@ class BaseHandler(TaskHandler, ABC):
         if cmd_to_run and cmd_to_run[0] == 'ffmpeg' and '-loglevel' not in cmd_to_run:
             cmd_to_run[1:1] = ['-loglevel', FFMPEG_LOGLEVEL]
 
-        # 日志记录命令（限制长度）
+        # 日志记录命令（不限制长度）
         cmd_str = ' '.join(cmd_to_run)
-        if len(cmd_str) > 500:
-            cmd_str = cmd_str[:500] + '...'
         logger.info(f"[task:{task_id}] FFmpeg: {cmd_str}")
 
         with start_span(

handlers/compose_transition.py

@@ -91,23 +91,37 @@ class ComposeTransitionHandler(BaseHandler):
                 f"overlap_tail={overlap_tail_ms}ms, overlap_head={overlap_head_ms}ms"
             )
 
-            # 1. 下载前一个片段视频
+            # 1. 并行下载前后片段视频
             prev_video_file = os.path.join(work_dir, 'prev_segment.mp4')
-            if not self.download_file(prev_segment['videoUrl'], prev_video_file):
+            next_video_file = os.path.join(work_dir, 'next_segment.mp4')
+            download_results = self.download_files_parallel([
+                {
+                    'key': 'prev_video',
+                    'url': prev_segment['videoUrl'],
+                    'dest': prev_video_file,
+                    'required': True
+                },
+                {
+                    'key': 'next_video',
+                    'url': next_segment['videoUrl'],
+                    'dest': next_video_file,
+                    'required': True
+                }
+            ])
+            prev_result = download_results.get('prev_video')
+            if not prev_result or not prev_result['success']:
                 return TaskResult.fail(
                     ErrorCode.E_INPUT_UNAVAILABLE,
                     f"Failed to download prev segment video: {prev_segment['videoUrl']}"
                 )
-
-            # 2. 下载后一个片段视频
-            next_video_file = os.path.join(work_dir, 'next_segment.mp4')
-            if not self.download_file(next_segment['videoUrl'], next_video_file):
+            next_result = download_results.get('next_video')
+            if not next_result or not next_result['success']:
                 return TaskResult.fail(
                     ErrorCode.E_INPUT_UNAVAILABLE,
                     f"Failed to download next segment video: {next_segment['videoUrl']}"
                 )
 
-            # 3. 获取前一个片段的实际时长
+            # 2. 获取前一个片段的实际时长
             prev_duration = self.probe_duration(prev_video_file)
             if not prev_duration:
                 return TaskResult.fail(
@@ -115,7 +129,7 @@ class ComposeTransitionHandler(BaseHandler):
                     "Failed to probe prev segment duration"
                 )
 
-            # 4. 构建转场合成命令
+            # 3. 构建转场合成命令
             output_file = os.path.join(work_dir, 'transition.mp4')
             cmd = self._build_command(
                 prev_video_file=prev_video_file,
@@ -128,25 +142,25 @@ class ComposeTransitionHandler(BaseHandler):
                 output_spec=output_spec
             )
 
-            # 5. 执行 FFmpeg
+            # 4. 执行 FFmpeg
             if not self.run_ffmpeg(cmd, task.task_id):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "FFmpeg transition composition failed"
                 )
 
-            # 6. 验证输出文件
+            # 5. 验证输出文件
             if not self.ensure_file_exists(output_file, min_size=1024):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "Transition output file is missing or too small"
                 )
 
-            # 7. 获取实际时长
+            # 6. 获取实际时长
             actual_duration = self.probe_duration(output_file)
             actual_duration_ms = int(actual_duration * 1000) if actual_duration else transition_duration_ms
 
-            # 8. 上传产物
+            # 7. 上传产物
             transition_video_url = self.upload_file(task.task_id, 'video', output_file)
             if not transition_video_url:
                 return TaskResult.fail(

handlers/finalize_mp4.py

@@ -110,16 +110,26 @@ class FinalizeMp4Handler(BaseHandler):
         Returns:
             TaskResult
         """
-        # 1. 下载所有 TS 分片
+        # 1. 并行下载所有 TS 分片
+        download_jobs = []
+        for i, ts_url in enumerate(ts_list):
+            download_jobs.append({
+                'key': str(i),
+                'url': ts_url,
+                'dest': os.path.join(work_dir, f'seg_{i}.ts'),
+                'required': True
+            })
+        download_results = self.download_files_parallel(download_jobs)
+
         ts_files = []
         for i, ts_url in enumerate(ts_list):
-            ts_file = os.path.join(work_dir, f'seg_{i}.ts')
-            if not self.download_file(ts_url, ts_file):
+            result = download_results.get(str(i))
+            if not result or not result['success']:
                 return TaskResult.fail(
                     ErrorCode.E_INPUT_UNAVAILABLE,
                     f"Failed to download TS segment {i}: {ts_url}"
                 )
-            ts_files.append(ts_file)
+            ts_files.append(result['dest'])
 
         logger.info(f"[task:{task.task_id}] Downloaded {len(ts_files)} TS segments")
 

handlers/package_ts.py

@@ -81,29 +81,43 @@ class PackageSegmentTsHandler(BaseHandler):
             start_sec = start_time_ms / 1000.0
             duration_sec = duration_ms / 1000.0
 
-            # 1. 下载视频片段
+            # 1. 并行下载视频片段与全局音频
             video_file = os.path.join(work_dir, 'video.mp4')
-            if not self.download_file(video_url, video_file):
+            audio_file = os.path.join(work_dir, 'audio.aac')
+            download_results = self.download_files_parallel([
+                {
+                    'key': 'video',
+                    'url': video_url,
+                    'dest': video_file,
+                    'required': True
+                },
+                {
+                    'key': 'audio',
+                    'url': audio_url,
+                    'dest': audio_file,
+                    'required': True
+                }
+            ])
+            video_result = download_results.get('video')
+            if not video_result or not video_result['success']:
                 return TaskResult.fail(
                     ErrorCode.E_INPUT_UNAVAILABLE,
                     f"Failed to download video: {video_url}"
                 )
-
-            # 2. 下载全局音频
-            audio_file = os.path.join(work_dir, 'audio.aac')
-            if not self.download_file(audio_url, audio_file):
+            audio_result = download_results.get('audio')
+            if not audio_result or not audio_result['success']:
                 return TaskResult.fail(
                     ErrorCode.E_INPUT_UNAVAILABLE,
                     f"Failed to download audio: {audio_url}"
                 )
 
-            # 3. 判断是否需要精确裁剪视频
+            # 2. 判断是否需要精确裁剪视频
             needs_video_trim = not is_transition_segment and (
                 (trim_head and trim_head_ms > 0) or
                 (trim_tail and trim_tail_ms > 0)
             )
 
-            # 4. 如果需要裁剪，先重编码裁剪视频
+            # 3. 如果需要裁剪，先重编码裁剪视频
             processed_video_file = video_file
             if needs_video_trim:
                 processed_video_file = os.path.join(work_dir, 'trimmed_video.mp4')
@@ -129,7 +143,7 @@ class PackageSegmentTsHandler(BaseHandler):
                         "Trimmed video file is missing or too small"
                     )
 
-            # 5. 构建 TS 封装命令
+            # 4. 构建 TS 封装命令
             output_file = os.path.join(work_dir, 'segment.ts')
             cmd = self._build_package_command(
                 video_file=processed_video_file,
@@ -139,14 +153,14 @@ class PackageSegmentTsHandler(BaseHandler):
                 duration_sec=duration_sec
             )
 
-            # 6. 执行 FFmpeg
+            # 5. 执行 FFmpeg
             if not self.run_ffmpeg(cmd, task.task_id):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "TS packaging failed"
                 )
 
-            # 7. 验证输出文件
+            # 6. 验证输出文件
             if not self.ensure_file_exists(output_file, min_size=1024):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,

handlers/prepare_audio.py

@@ -55,32 +55,60 @@ class PrepareJobAudioHandler(BaseHandler):
             bgm_url = task.get_bgm_url()
             segments = task.get_segments()
 
-            # 1. 下载 BGM（如有）
-            bgm_file = None
+            # 1. 并行下载 BGM 与叠加音效
+            bgm_file = os.path.join(work_dir, 'bgm.mp3') if bgm_url else None
+            download_jobs = []
+            if bgm_url and bgm_file:
+                download_jobs.append({
+                    'key': 'bgm',
+                    'url': bgm_url,
+                    'dest': bgm_file,
+                    'required': False
+                })
+
+            sfx_download_candidates = []
+            for i, seg in enumerate(segments):
+                audio_spec_data = seg.get('audioSpecJson')
+                if not audio_spec_data:
+                    continue
+                audio_spec = AudioSpec.from_dict(audio_spec_data)
+                if not audio_spec or not audio_spec.audio_url:
+                    continue
+                sfx_file = os.path.join(work_dir, f'sfx_{i}.mp3')
+                job_key = f'sfx_{i}'
+                sfx_download_candidates.append({
+                    'key': job_key,
+                    'file': sfx_file,
+                    'spec': audio_spec,
+                    'segment': seg
+                })
+                download_jobs.append({
+                    'key': job_key,
+                    'url': audio_spec.audio_url,
+                    'dest': sfx_file,
+                    'required': False
+                })
+
+            download_results = self.download_files_parallel(download_jobs)
             if bgm_url:
-                bgm_file = os.path.join(work_dir, 'bgm.mp3')
-                if not self.download_file(bgm_url, bgm_file):
+                bgm_result = download_results.get('bgm')
+                if not bgm_result or not bgm_result['success']:
                     logger.warning(f"[task:{task.task_id}] Failed to download BGM")
                     bgm_file = None
 
-            # 2. 下载叠加音效
             sfx_files = []
-            for i, seg in enumerate(segments):
-                audio_spec_data = seg.get('audioSpecJson')
-                if audio_spec_data:
-                    audio_spec = AudioSpec.from_dict(audio_spec_data)
-                    if audio_spec and audio_spec.audio_url:
-                        sfx_file = os.path.join(work_dir, f'sfx_{i}.mp3')
-                        if self.download_file(audio_spec.audio_url, sfx_file):
-                            sfx_files.append({
-                                'file': sfx_file,
-                                'spec': audio_spec,
-                                'segment': seg
-                            })
-                        else:
-                            logger.warning(f"[task:{task.task_id}] Failed to download SFX {i}")
+            for sfx_candidate in sfx_download_candidates:
+                sfx_result = download_results.get(sfx_candidate['key'])
+                if sfx_result and sfx_result['success']:
+                    sfx_files.append({
+                        'file': sfx_candidate['file'],
+                        'spec': sfx_candidate['spec'],
+                        'segment': sfx_candidate['segment']
+                    })
+                else:
+                    logger.warning(f"[task:{task.task_id}] Failed to download SFX {sfx_candidate['key']}")
 
-            # 3. 构建音频混音命令
+            # 2. 构建音频混音命令
             output_file = os.path.join(work_dir, 'audio_full.aac')
             cmd = self._build_audio_command(
                 bgm_file=bgm_file,
@@ -90,21 +118,21 @@ class PrepareJobAudioHandler(BaseHandler):
                 audio_profile=audio_profile
             )
 
-            # 4. 执行 FFmpeg
+            # 3. 执行 FFmpeg
             if not self.run_ffmpeg(cmd, task.task_id):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "Audio mixing failed"
                 )
 
-            # 5. 验证输出文件
+            # 4. 验证输出文件
             if not self.ensure_file_exists(output_file, min_size=1024):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "Audio output file is missing or too small"
                 )
 
-            # 6. 上传产物
+            # 5. 上传产物
             audio_url = self.upload_file(task.task_id, 'audio', output_file)
             if not audio_url:
                 return TaskResult.fail(

handlers/render_video.py

@@ -85,13 +85,63 @@ class RenderSegmentVideoHandler(BaseHandler):
             else:
                 input_file = os.path.join(work_dir, 'input.mp4')
 
-            # 2. 下载素材
-            if not self.download_file(material_url, input_file):
+            # 2. 构建并行下载任务（主素材 + 可选 LUT + 可选叠加层）
+            lut_file = os.path.join(work_dir, 'lut.cube') if render_spec.lut_url else None
+            overlay_file = None
+            if render_spec.overlay_url:
+                # 根据 URL 后缀确定文件扩展名
+                overlay_url_lower = render_spec.overlay_url.lower()
+                if overlay_url_lower.endswith('.jpg') or overlay_url_lower.endswith('.jpeg'):
+                    overlay_ext = '.jpg'
+                elif overlay_url_lower.endswith('.mov'):
+                    overlay_ext = '.mov'
+                else:
+                    overlay_ext = '.png'
+                overlay_file = os.path.join(work_dir, f'overlay{overlay_ext}')
+
+            download_jobs = [
+                {
+                    'key': 'material',
+                    'url': material_url,
+                    'dest': input_file,
+                    'required': True
+                }
+            ]
+            if render_spec.lut_url and lut_file:
+                download_jobs.append({
+                    'key': 'lut',
+                    'url': render_spec.lut_url,
+                    'dest': lut_file,
+                    'required': False
+                })
+            if render_spec.overlay_url and overlay_file:
+                download_jobs.append({
+                    'key': 'overlay',
+                    'url': render_spec.overlay_url,
+                    'dest': overlay_file,
+                    'required': False
+                })
+            download_results = self.download_files_parallel(download_jobs)
+
+            material_result = download_results.get('material')
+            if not material_result or not material_result['success']:
                 return TaskResult.fail(
                     ErrorCode.E_INPUT_UNAVAILABLE,
                     f"Failed to download material: {material_url}"
                 )
 
+            if render_spec.lut_url:
+                lut_result = download_results.get('lut')
+                if not lut_result or not lut_result['success']:
+                    logger.warning(f"[task:{task.task_id}] Failed to download LUT, continuing without it")
+                    lut_file = None
+
+            if render_spec.overlay_url:
+                overlay_result = download_results.get('overlay')
+                if not overlay_result or not overlay_result['success']:
+                    logger.warning(f"[task:{task.task_id}] Failed to download overlay, continuing without it")
+                    overlay_file = None
+
             # 3. 图片素材转换为视频
             if is_image:
                 video_input_file = os.path.join(work_dir, 'input_video.mp4')
@@ -111,31 +161,7 @@ class RenderSegmentVideoHandler(BaseHandler):
                 input_file = video_input_file
                 logger.info(f"[task:{task.task_id}] Image converted to video successfully")
 
-            # 4. 下载 LUT（如有）
-            lut_file = None
-            if render_spec.lut_url:
-                lut_file = os.path.join(work_dir, 'lut.cube')
-                if not self.download_file(render_spec.lut_url, lut_file):
-                    logger.warning(f"[task:{task.task_id}] Failed to download LUT, continuing without it")
-                    lut_file = None
-
-            # 5. 下载叠加层（如有）
-            overlay_file = None
-            if render_spec.overlay_url:
-                # 根据 URL 后缀确定文件扩展名
-                url_lower = render_spec.overlay_url.lower()
-                if url_lower.endswith('.jpg') or url_lower.endswith('.jpeg'):
-                    ext = '.jpg'
-                elif url_lower.endswith('.mov'):
-                    ext = '.mov'
-                else:
-                    ext = '.png'  # 默认
-                overlay_file = os.path.join(work_dir, f'overlay{ext}')
-                if not self.download_file(render_spec.overlay_url, overlay_file):
-                    logger.warning(f"[task:{task.task_id}] Failed to download overlay, continuing without it")
-                    overlay_file = None
-
-            # 6. 探测源视频时长（仅对视频素材）
+            # 4. 探测源视频时长（仅对视频素材）
             # 用于检测时长不足并通过冻结最后一帧补足
             source_duration_sec = None
             if not is_image:
@@ -158,13 +184,13 @@ class RenderSegmentVideoHandler(BaseHandler):
                                 f"will freeze last frame for {shortage_sec:.2f}s"
                             )
 
-            # 7. 计算 overlap 时长（用于转场帧冻结）
+            # 5. 计算 overlap 时长（用于转场帧冻结）
             # 头部 overlap: 来自前一片段的出场转场
             overlap_head_ms = task.get_overlap_head_ms()
             # 尾部 overlap: 当前片段的出场转场
             overlap_tail_ms = task.get_overlap_tail_ms_v2()
 
-            # 8. 构建 FFmpeg 命令
+            # 6. 构建 FFmpeg 命令
             output_file = os.path.join(work_dir, 'output.mp4')
             cmd = self._build_command(
                 input_file=input_file,
@@ -179,25 +205,25 @@ class RenderSegmentVideoHandler(BaseHandler):
                 source_duration_sec=source_duration_sec
             )
 
-            # 9. 执行 FFmpeg
+            # 7. 执行 FFmpeg
             if not self.run_ffmpeg(cmd, task.task_id):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "FFmpeg rendering failed"
                 )
 
-            # 10. 验证输出文件
+            # 8. 验证输出文件
             if not self.ensure_file_exists(output_file, min_size=4096):
                 return TaskResult.fail(
                     ErrorCode.E_FFMPEG_FAILED,
                     "Output file is missing or too small"
                 )
 
-            # 11. 获取实际时长
+            # 9. 获取实际时长
             actual_duration = self.probe_duration(output_file)
             actual_duration_ms = int(actual_duration * 1000) if actual_duration else duration_ms
 
-            # 12. 上传产物
+            # 10. 上传产物
             video_url = self.upload_file(task.task_id, 'video', output_file)
             if not video_url:
                 return TaskResult.fail(
@@ -205,7 +231,7 @@ class RenderSegmentVideoHandler(BaseHandler):
                     "Failed to upload video"
                 )
 
-            # 13. 构建结果（包含 overlap 信息）
+            # 11. 构建结果（包含 overlap 信息）
             result_data = {
                 'videoUrl': video_url,
                 'actualDurationMs': actual_duration_ms,