AWS MediaConvert输出视频时长翻倍问题求助

问题详情 #

原视频时长30秒，经MediaConvert转换后输出视频时长变为60秒，作业配置如下：

{
  "Queue": "arn:aws:mediaconvert:us-west-2:730335xxxxx:queues/Default",
  "UserMetadata": {},
  "Role": "arn:aws:iam::73033541xxxx:role/service-role/MediaConvert_Default_Role",
  "Settings": {
    "TimecodeConfig": {
      "Source": "ZEROBASED"
    },
    "OutputGroups": [
      {
        "Name": "DASH ISO",
        "Outputs": [
          {
            "ContainerSettings": {
              "Container": "MPD"
            },
            "VideoDescription": {
              "CodecSettings": {
                "Codec": "H_264",
                "H264Settings": {
                  "MaxBitrate": 3500000,
                  "RateControlMode": "QVBR",
                  "SceneChangeDetect": "TRANSITION_DETECTION"
                }
              }
            },
            "NameModifier": "_output1"
          }
        ],
        "OutputGroupSettings": {
          "Type": "DASH_ISO_GROUP_SETTINGS",
          "DashIsoGroupSettings": {
            "SegmentLength": 30,
            "Destination": "s3://tutorial/video/",
            "FragmentLength": 2,
            "SegmentControl": "SINGLE_FILE"
          }
        }
      }
    ],
    "FollowSource": 1,
    "Inputs": [
      {
        "AudioSelectors": {
          "Audio Selector 1": {
            "DefaultSelection": "DEFAULT"
          }
        },
        "VideoSelector": {},
        "TimecodeSource": "ZEROBASED",
        "FileInput": "s3://tutorial/video/11 - video.mp4"
      }
    ]
  },
  "BillingTagsSource": "JOB",
  "AccelerationSettings": {
    "Mode": "DISABLED"
  },
  "StatusUpdateInterval": "SECONDS_60",
  "Priority": 0
}

排查与解决步骤 #

1. 明确视频轨道选择 #

空的VideoSelector可能导致MediaConvert误处理多轨道输入，添加轨道指定与帧速率控制：
修改Inputs[0].VideoSelector为：

"VideoSelector": {
  "TrackNumber": 1,
  "FrameRateControl": "INITIALIZE_FROM_SOURCE",
  "ColorSpace": "FOLLOW"
}

2. 调整DASH分段配置 #

SINGLE_FILE模式结合等于原视频时长的SegmentLength可能引发时长计算异常，改为分段模式并调整分段长度：
修改DashIsoGroupSettings中的对应参数：

"SegmentControl": "SEGMENTED_FILES",
"SegmentLength": 10

3. 处理可变帧速率（VFR）输入 #

若原视频为可变帧速率，明确指定输出帧速率可修正时长计算偏差：
在VideoDescription中添加帧速率配置：

"VideoDescription": {
  "CodecSettings": {
    // 保留原有H.264配置
  },
  "FrameRateControl": "SPECIFIED",
  "FrameRateNumerator": 30,
  "FrameRateDenominator": 1
}

4. 验证时间码配置 #

若问题仍存在，可尝试将全局TimecodeConfig.Source改为EMBEDDED（需原视频包含嵌入时间码），确保时间码逻辑统一。

按上述修改后重新提交作业，测试输出时长是否恢复正常。

内容的提问来源于stack exchange，提问作者user1hjgjhgjhggjhg