Google Cloud单个转码作业耗时较同配置批量转码高2-3倍问题咨询

与在单个配置文件/作业中批量处理相比，单独执行转码作业的耗时会呈指数级增长。

测试流程 #

测试按以下步骤执行：

• 第一步：使用单个配置文件对同一份源内容转码，生成5个及以上不同规格的输出文件，记录整体转码总时长
• 第二步：将原配置文件中的每个输出版本拆分为独立的转码作业分别执行，记录每个作业的单独耗时后求和
• 第三步：将单独执行的总耗时和第一步批量转码的总耗时做对比

实测结果：单独转码的总耗时是批量转码的2~3倍。

测试用作业配置 #

{
  "config": {
    "elementaryStreams": [
      {
        "key": "360p1-125kbps-h264",
        "videoStream": {
          "codec": "h264",
          "profile": "high",
          "preset": "slow",
          "widthPixels": 640,
          "heightPixels": 360,
          "frameRate": 29.97,
          "pixelFormat": "yuv420p",
          "bitrateBps": 125000,
          "rateControlMode": "vbr",
          "enableTwoPass": true,
          "gopDuration": "4s",
          "allowOpenGop": true,
          "entropyCoder": "cabac",
          "bFrameCount": 3,
          "bPyramid": true
        }
      },
      {
        "key": "360p2-250kbps-h264",
        "videoStream": {
          "codec": "h264",
          "profile": "high",
          "preset": "slow",
          "widthPixels": 640,
          "heightPixels": 360,
          "frameRate": 29.97,
          "pixelFormat": "yuv420p",
          "bitrateBps": 250000,
          "rateControlMode": "vbr",
          "enableTwoPass": true,
          "gopDuration": "4s",
          "allowOpenGop": true,
          "entropyCoder": "cabac",
          "bFrameCount": 3,
          "bPyramid": true
        }
      },
      {
        "key": "480p1-400kbps-h264",
        "videoStream": {
          "codec": "h264",
          "profile": "high",
          "preset": "slow",
          "widthPixels": 854,
          "heightPixels": 480,
          "frameRate": 29.97,
          "pixelFormat": "yuv420p",
          "bitrateBps": 400000,
          "rateControlMode": "vbr",
          "enableTwoPass": true,
          "gopDuration": "4s",
          "allowOpenGop": true,
          "entropyCoder": "cabac",
          "bFrameCount": 3,
          "bPyramid": true
        }
      },
      {
        "key": "480p2-800kbps-h264",
        "videoStream": {
          "codec": "h264",
          "profile": "high",
          "preset": "slow",
          "widthPixels": 854,
          "heightPixels": 480,
          "frameRate": 29.97,
          "pixelFormat": "yuv420p",
          "bitrateBps": 800000,
          "rateControlMode": "vbr",
          "enableTwoPass": true,
          "gopDuration": "4s",
          "allowOpenGop": true,
          "entropyCoder": "cabac",
          "bFrameCount": 3,
          "bPyramid": true
        }
      },
      {
        "key": "720p-1600kbps-h264",
        "videoStream": {
          "codec": "h264",
          "profile": "high",
          "preset": "slow",
          "widthPixels": 1280,
          "heightPixels": 720,
          "frameRate": 29.97,
          "pixelFormat": "yuv420p",
          "bitrateBps": 1600000,
          "rateControlMode": "vbr",
          "enableTwoPass": true,
          "gopDuration": "4s",
          "allowOpenGop": true,
          "entropyCoder": "cabac",
          "bFrameCount": 3,
          "bPyramid": true
        }
      },
      {
        "key": "720p-2500kbps-h264",
        "videoStream": {
          "codec": "h264",
          "profile": "high",
          "preset": "slow",
          "widthPixels": 1280,
          "heightPixels": 720,
          "frameRate": 29.97,
          "pixelFormat": "yuv420p",
          "bitrateBps": 2500000,
          "rateControlMode": "vbr",
          "enableTwoPass": true,
          "gopDuration": "4s",
          "allowOpenGop": true,
          "entropyCoder": "cabac",
          "bFrameCount": 3,
          "bPyramid": true
        }
      },
      {
        "key": "1080p-5500kbps-h264",
        "videoStream": {
          "codec": "h264",
          "profile": "high",
          "preset": "slow",
          "widthPixels": 1920,
          "heightPixels": 1080,
          "frameRate": 29.97,
          "pixelFormat": "yuv420p",
          "bitrateBps": 5500000,
          "rateControlMode": "vbr",
          "enableTwoPass": true,
          "gopDuration": "4s",
          "allowOpenGop": true,
          "entropyCoder": "cabac",
          "bFrameCount": 3,
          "bPyramid": true
        }
      }
    ],
    "muxStreams": [
      {
        "key": "360p1-125kbps-h264",
        "container": "mp4",
        "elementaryStreams": [
          "360p1-125kbps-h264"
        ]
      },
      {
        "key": "360p2-250kbps-h264",
        "container": "mp4",
        "elementaryStreams": [
          "360p2-250kbps-h264"
        ]
      },
      {
        "key": "460p1-400kbps-h264",
        "container": "mp4",
        "elementaryStreams": [
          "480p1-400kbps-h264"
        ]
      },
      {
        "key": "460p2-800kbps-h264",
        "container": "mp4",
        "elementaryStreams": [
          "480p2-800kbps-h264"
        ]
      },
      {
        "key": "720p-1600kbps-h264",
        "container": "mp4",
        "elementaryStreams": [
          "720p-1600kbps-h264"
        ]
      },
      {
        "key": "720p-2500kbps-h264",
        "container": "mp4",
        "elementaryStreams": [
          "720p-2500kbps-h264"
        ]
      },
      {
        "key": "1080p-5500kbps-h264",
        "container": "mp4",
        "elementaryStreams": [
          "1080p-5500kbps-h264"
        ]
      }
    ]
  }
}

内容的提问来源于stack exchange，提问作者TJ Liu