AWS MediaConvert转码MPEG-Dash在Firefox播放跳帧问题求助

问题现象 #

工作流为：媒体文件上传至S3存储桶→通过Lambda脚本提交给MediaConvert→转码为VP9编码视频+AAC编码音频的MPEG-Dash格式→输出至目标S3存储桶。将成品Dash文件通过AWS CLI本地下载后，在Firefox浏览器（Mac/Linux版本121.0）中使用Shaka Player或Dash.js播放时，JavaScript控制台持续出现类似以下的跳帧提示：

Jumping forward 3.0016669999999976 seconds because of gap starting at 84.118 and ending at 87.087

视频全程呈现快进效果，但在Chrome和Safari浏览器中播放完全正常。

测试用Shaka Player代码 #

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="https://cdnjs.cloudflare.com/ajax/libs/shaka-player/4.7.1/shaka-player.compiled.debug.min.js"></script>
    <title>VP9Test</title>
</head>
<body>
    <h1>VP9 Test</h1>
    <video id="video" width="720" controls></video>
    <script>
        const manifestUri = 'http://host/video/master.mpd';
        function initApp() {
            // Install built-in polyfills to patch browser incompatibilities.
            shaka.polyfill.installAll();
            // Check to see if the browser supports the basic APIs Shaka needs.
            if (shaka.Player.isBrowserSupported()) {
                // Everything looks good!
                initPlayer();
            } else {
                // This browser does not have the minimum set of APIs we need.
                console.error('Browser not supported!');
            }
        }
        async function initPlayer() {
            // Create a Player instance.
            const video = document.getElementById('video');
            const player = new shaka.Player();
            await player.attach(video);
            // Attach player to the window to make it easy to access in the JS console.
            window.player = player;
            // Listen for error events.
            player.addEventListener('error', onErrorEvent);
            // Try to load a manifest.
            // This is an asynchronous process.
            try {
                await player.load(manifestUri);
                // This runs if the asynchronous load is successful.
                console.log('The video has now been loaded!');
            } catch (e) {
                // onError is executed if the asynchronous load fails.
                onError(e);
            }
        }
        function onErrorEvent(event) {
            // Extract the shaka.util.Error object from the event.
            onError(event.detail);
        }
        function onError(error) {
            // Log the error.
            console.error('Error code', error.code, 'object', error);
        }
        document.addEventListener('DOMContentLoaded', initApp);
    </script>
</body>
</html>

测试资产结果 #

• abr-dash-amv-vp9：Youtube下载的H.264文件，无法正常播放
• abr-dash-jjk-vp9：Torrent获取的HEVC文件，无法正常播放
• abr-dash-unity-vp9：Youtube下载的H.264文件，可正常播放

MediaConvert转码配置 #

{
  "Queue": "arn:aws:mediaconvert:us-east-1:694531566426:queues/Default",
  "UserMetadata": {
    "assetID": "ffb4b4a5-6746-42e3-bccb-e57a04bc4832"
  },
  "Role": "arn:aws:iam::694531566426:role/MediaConvertRole",
  "Settings": {
    "TimecodeConfig": {
      "Source": "ZEROBASED"
    },
    "OutputGroups": [
      {
        "Name": "DASH ISO",
        "Outputs": [
          {
            "ContainerSettings": {
              "Container": "MPD"
            },
            "VideoDescription": {
              "Width": 1920,
              "Height": 1080,
              "CodecSettings": {
                "Codec": "VP9",
                "Vp9Settings": {
                  "RateControlMode": "VBR",
                  "Bitrate": 4000000
                }
              }
            },
            "NameModifier": "_v1"
          },
          {
            "ContainerSettings": {
              "Container": "MPD"
            },
            "VideoDescription": {
              "Width": 1600,
              "Height": 900,
              "CodecSettings": {
                "Codec": "VP9",
                "Vp9Settings": {
                  "RateControlMode": "VBR",
                  "Bitrate": 2600000
                }
              }
            },
            "NameModifier": "_v2"
          },
          {
            "ContainerSettings": {
              "Container": "MPD"
            },
            "VideoDescription": {
              "Width": 1280,
              "Height": 720,
              "CodecSettings": {
                "Codec": "VP9",
                "Vp9Settings": {
                  "RateControlMode": "VBR",
                  "Bitrate": 1800000
                }
              }
            },
            "NameModifier": "_v3"
          },
          {
            "ContainerSettings": {
              "Container": "MPD"
            },
            "VideoDescription": {
              "Width": 960,
              "Height": 540,
              "CodecSettings": {
                "Codec": "VP9",
                "Vp9Settings": {
                  "RateControlMode": "VBR",
                  "Bitrate": 1200000
                }
              }
            },
            "NameModifier": "_v4"
          },
          {
            "ContainerSettings": {
              "Container": "MPD"
            },
            "AudioDescriptions": [
              {
                "AudioSourceName": "Audio Selector 1",
                "CodecSettings": {
                  "Codec": "AAC",
                  "AacSettings": {
                    "Bitrate": 192000,
                    "CodingMode": "CODING_MODE_2_0",
                    "SampleRate": 48000
                  }
                }
              }
            ],
            "NameModifier": "_a1"
          }
        ],
        "OutputGroupSettings": {
          "Type": "DASH_ISO_GROUP_SETTINGS",
          "DashIsoGroupSettings": {
            "SegmentLength": 30,
            "Destination": "s3://bucket-dest/assets/ffb4b4a5-6746-42e3-bccb-e57a04bc4832/dash/amv",
            "FragmentLength": 2,
            "SegmentControl": "SEGMENTED_FILES"
          }
        }
      }
    ],
    "Inputs": [
      {
        "AudioSelectors": {
          "Audio Selector 1": {
            "DefaultSelection": "DEFAULT"
          }
        },
        "VideoSelector": {},
        "TimecodeSource": "ZEROBASED",
        "FileInput": "s3://bucket-src/amv.mp4"
      }
    ]
  },
  "BillingTagsSource": "JOB",
  "AccelerationSettings": {
    "Mode": "DISABLED"
  },
  "StatusUpdateInterval": "SECONDS_60",
  "Priority": 0
}

目前对该问题毫无头绪，希望得到解决思路或方案。

内容的提问来源于stack exchange，提问作者complex1984