使用Zapier+Transloadit合并滚动截图视频、音频与字幕失败求助

我同时在社区论坛也发布了此问题，因为不确定哪个平台使用更广泛。我正尝试使用Zapier搭配Transloadit生成滚动截图视频，再将其与ElevenLabs音频和内嵌字幕合并。此前仅合并滚动视频与ElevenLabs音频的功能可正常运行，但添加字幕之后，音频和字幕均无法被加入，最终只得到滚动视频。请问我哪里操作出错了？

Zap相关部分截图 #

Assembly输出截图 #

有问题的Assembly代码（添加字幕版本） #

{  "steps": {    "screenshot": {      "robot": "/html/convert",      "result": false,      "format": "png",      "fullpage": false,      "width": 720,      "height": 1280,      "url": "${fields.screenshot_url}"    },    "scroll": {      "use": {        "steps": [          {            "name": "screenshot",            "as": "image"          }        ]      },      "robot": "/video/merge",      "result": true,      "duration": 30,      "ffmpeg": {        "vf": "scroll=vertical=0.001",        "f": "mp4",        "pix_fmt": "yuv420p"      },      "ffmpeg_stack": "v6.0.0",      "framerate": 30,      "preset": "empty"    },    ":original": {      "robot": "/upload/handle",      "result": false    },    "video_filtered": {      "use": ":original",      "robot": "/file/filter",      "result": true,      "accepts": [        [          "${file.mime}",          "regex",          "video"        ]      ],      "error_on_decline": false    },    "subtitle_filtered": {      "use": ":original",      "robot": "/file/filter",      "result": true,      "accepts": [        [          "${file.mime}",          "regex",          "application/x-subrip"        ]      ],      "error_on_decline": false    },    "add_subtitles": {      "robot": "/video/subtitle",      "use": {        "steps": [          {            "name": "scroll",            "as": "video"          },          {            "name": "subtitle_filtered",            "as": "subtitles"          }        ]      },      "preset": "ipad-high",      "ffmpeg_stack": "v6.0.0",      "subtitles_type": "burned",      "font": "Arial",      "border_color": "00000000",      "font_color": "FFFFFF",      "border_style": "box"    },    "add_audio": {      "robot": "/video/encode",      "use": {        "steps": [          {            "name": "add_subtitles",            "as": "video"          },          {            "name": ":original",            "as": "audio"          }        ]      },      "preset": "ipad-high",      "ffmpeg_stack": "v6.0.0",      "ffmpeg": {        "c:v": "copy",        "c:a": "aac",        "strict": "experimental"      }    },    "store_video": {      "use": [        "add_audio"      ],      "robot": "/s3/store",      "credentials": "raf",      "path": "final_output/${file.url_name}"    },    "store_original": {      "use": [        ":original"      ],      "robot": "/s3/store",      "credentials": "raf",      "path": "originals/${file.url_name}"    }  }}

正常运行的Assembly代码（仅滚动视频+音频版本） #

{  "steps": {    "screenshot": {      "robot": "/html/convert",      "result": false,      "format": "png",      "fullpage": false,      "width": 720,      "height": 1280,      "url": "${fields.screenshot_url}"    },    "scroll": {      "use": {        "steps": [          {            "name": "screenshot",            "as": "image"          }        ]      },      "robot": "/video/merge",      "result": true,      "duration": 30,      "ffmpeg": {        "vf": "scroll=vertical:0.001",        "f": "mp4",        "pix_fmt": "yuv420p"      },      "ffmpeg_stack": "v6.0.0",      "framerate": 30,      "preset": "empty"    },    ":original": {      "robot": "/upload/handle",      "result": false    },    "merge_audio_video": {      "use": {        "steps": [          {            "name": "scroll",            "as": "video"          },          {            "name": ":original",            "as": "audio"          }        ]      },      "robot": "/video/merge",      "result": true,      "ffmpeg_stack": "v6.0.0",      "preset": "ipad-high"    },    "store_video": {      "use": [        "merge_audio_video"      ],      "robot": "/s3/store",      "credentials": "raf",      "path": "final_output/${file.url_name}"    },    "store_original": {      "use": [        ":original"      ],      "robot": "/s3/store",      "credentials": "raf",      "path": "originals/${file.url_name}"    }  }}

问题分析与修复方案 #

1. 字幕步骤未开启结果输出
   add_subtitles步骤缺少"result": true配置，导致后续步骤无法获取到添加了字幕的视频文件。Transloadit中只有设置result: true的步骤，其输出才会被后续流程引用。

2. 音频合并机器人选择错误
   你用/video/encode机器人合并音频，但该机器人核心功能是视频编码，音频合并应该沿用正常版本中的/video/merge机器人。前者在处理无音频轨道的视频+外部音频时，容易出现合并逻辑失效的问题。

3. 冗余文件过滤步骤
   添加的video_filtered和subtitle_filtered步骤属于冗余操作——:original中仅包含ElevenLabs音频和字幕文件，不存在视频文件，过滤步骤反而可能增加流程复杂度，甚至导致文件匹配异常。可直接移除这两个步骤，后续步骤直接引用:original中的对应文件。

修改后的Assembly代码示例 #

{
  "steps": {
    "screenshot": {
      "robot": "/html/convert",
      "result": false,
      "format": "png",
      "fullpage": false,
      "width": 720,
      "height": 1280,
      "url": "${fields.screenshot_url}"
    },
    "scroll": {
      "use": {
        "steps": [
          {
            "name": "screenshot",
            "as": "image"
          }
        ]
      },
      "robot": "/video/merge",
      "result": true,
      "duration": 30,
      "ffmpeg": {
        "vf": "scroll=vertical=0.001",
        "f": "mp4",
        "pix_fmt": "yuv420p"
      },
      "ffmpeg_stack": "v6.0.0",
      "framerate": 30,
      "preset": "empty"
    },
    ":original": {
      "robot": "/upload/handle",
      "result": false
    },
    "add_subtitles": {
      "robot": "/video/subtitle",
      "use": {
        "steps": [
          {
            "name": "scroll",
            "as": "video"
          },
          {
            "name": ":original",
            "as": "subtitles"
          }
        ]
      },
      "result": true,
      "preset": "ipad-high",
      "ffmpeg_stack": "v6.0.0",
      "subtitles_type": "burned",
      "font": "Arial",
      "border_color": "00000000",
      "font_color": "FFFFFF",
      "border_style": "box"
    },
    "merge_audio_video": {
      "use": {
        "steps": [
          {
            "name": "add_subtitles",
            "as": "video"
          },
          {
            "name": ":original",
            "as": "audio"
          }
        ]
      },
      "robot": "/video/merge",
      "result": true,
      "ffmpeg_stack": "v6.0.0",
      "preset": "ipad-high"
    },
    "store_video": {
      "use": [
        "merge_audio_video"
      ],
      "robot": "/s3/store",
      "credentials": "raf",
      "path": "final_output/${file.url_name}"
    },
    "store_original": {
      "use": [
        ":original"
      ],
      "robot": "/s3/store",
      "credentials": "raf",
      "path": "originals/${file.url_name}"
    }
  }
}

额外检查点 #

• 确认Zapier传递给Transloadit的:original文件包含正确的ElevenLabs音频和SRT格式字幕，且字幕文件MIME类型为application/x-subrip。
• 查看Transloadit的Assembly日志，检查add_subtitles和merge_audio_video步骤是否存在文件找不到、格式不匹配等报错。

内容的提问来源于stack exchange，提问作者user25190614