Combining Multiple Inputs

Multiple Containers

Multiple input containers are rendered concurrently. For example the following composition combines the picture and sound from two separate containers:

---
input:
  container:
  - name: picture
  - name: sound
output:
  container:
  - name: output1
    type: 'mp4 '
{
  "input": {
    "container": [
      {
        "name": "picture"
      },
      {
        "name": "sound"
      }
    ]
  },
  "output": {
    "container": [
      {
        "name": "output1",
        "type": "mp4 "
      }
    ]
  }
}

Optional Inputs

An input container may be treated as optional. If the input is not supplied then any output stream referencing that input is removed from the composition.

For example the following composition has an optional subtitle input:

---
input:
  container:
  - name: picture
  - name: sound
  - name: subtitle
    optional: true
output:
  container:
  - name: output1
    type: 'mp4 '
{
  "input": {
    "container": [
      {
        "name": "picture"
      },
      {
        "name": "sound"
      },
      {
        "name": "subtitle",
        "optional": true
      }
    ]
  },
  "output": {
    "container": [
      {
        "name": "output1",
        "type": "mp4 "
      }
    ]
  }
}

Multiple Segments

A composition can contain multiple input segments each spanning a portion of the timeline. By default a composition contains a single segment as shown in the previous example.

Multiple input segments are rendered sequentially. For example the following composition renders the preview container followed by the program container:

---
input:
  segment:
  - name: first
    container:
    - name: preview
  - name: second
    container:
    - name: program
output:
  container:
  - name: output1
    type: 'mp4 '
{
  "input": {
    "segment": [
      {
        "name": "first",
        "container": [
          {
            "name": "preview"
          }
        ]
      },
      {
        "name": "second",
        "container": [
          {
            "name": "program"
          }
        ]
      }
    ]
  }
}

Multiple Streams

Within a segment (including the default segment) each input stream must be assigned a unique name. Input streams are then routed by name to the output container, for example:

---
input:
  container:
  - name: picture
    video:
    - name: v1
    audio: []
  - name: sound
    video: []
    audio:
    - name: a1
output:
  container:
  - name: output1
    type: 'mp4 '
    video:
    - name: v1
    audio:
    - name: a1
{
  "input": {
    "container": [
      {
        "name": "picture",
        "video": [
          {
            "name": "v1"
          }
        ],
        "audio": []
      },
      {
        "name": "sound",
        "video": [],
        "audio": [
          {
            "name": "a1"
          }
        ]
      }
    ]
  },
  "output": {
    "container": [
      {
        "name": "output1",
        "type": "mp4 ",
        "video": [
          {
            "name": "v1"
          }
        ],
        "audio": [
          {
            "name": "a1"
          }
        ]
      }
    ]
  }
}

Stitching

Between segments input streams with the same name are joined (or stitched) together, for example:

---
input:
  reference: program
  segment:
  - name: first
    container:
    - name: preview
      video:
      - name: v1
      audio:
      - name: a1
  - name: second
    container:
    - name: program
      video:
      - name: v1
      audio:
      - name: a1
output:
  container:
  - name: output1
    type: 'mp4 '
    video:
    - name: v1
    audio:
    - name: a1
{
  "input": {
    "container": [
        {
            "name": "input",
                 "path": "input.mov",
            "video": [
                {
                    "name": "v1"
                }
        ],
            "audio": [
                {
                    "name": "a1"
                }
            ]
        }
    ],
    "container": [
        {
            "name": "overlay",
            "path": "overlay.mov",
            "video": [
                {
                    "name": "v2"
                }
            ]
        }
    ]
  },
  "output": {
    "container": [
      {
        "type": "mp4 ",
        "name": "output",
        "path": "output.mp4",
        "video": [
          {
            "overlay": [
              {
                "name": "v1",
                "name": "v2"
              }
            ]
          }
        ],
        "audio": [
          {
            "route": {
              "name": "a1"
            }
          }
        ]
      }
    ]
  }
}

Reference Container

In a composition with multiple containers the reference container provides the default values for media properties such as width, height, sample_rate etc.

For example in the previous composition the preview container will be converted (if necessary) to match the properties of the reference program container.

Mixed Composition

Streams in the default segment are rendered concurrently with streams stitched together by the timeline segments.

For example the following composition renders a logo over both the preview and program segments. Additionally spanish subtitles are add to the program segment.

---
input:
  container:
  - name: logo
  segment:
  - name: first
    container:
    - name: preview
      video:
      - name: v1
      audio:
      - name: a1
  - name: second
    container:
    - name: program
      video:
      - name: v1
      audio:
      - name: a1
    - name: spanish
      subtitle:
      - name: s1
output:
  container:
  - name: output1
    type: 'mp4 '
    video:
    - name: v1
      overlay:
      - name: logo
    audio:
    - name: a1
    subtitle:
    - name: s1
{
  "input": {
    "container": [
      {
        "name": "logo"
      }
    ],
    "segment": [
      {
        "name": "first",
        "container": [
          {
            "name": "preview",
            "video": [
              {
                "name": "v1"
              }
            ],
            "audio": [
              {
                "name": "a1"
              }
            ]
          }
        ]
      },
      {
        "name": "second",
        "container": [
          {
            "name": "program",
            "video": [
              {
                "name": "v1"
              }
            ],
            "audio": [
              {
                "name": "a1"
              }
            ]
          },
          {
            "name": "spanish",
            "subtitle": [
              {
                "name": "s1"
              }
            ]
          }
        ]
      }
    ]
  },
  "output": {
    "container": [
      {
        "name": "output1",
        "type": "mp4 ",
        "video": [
          {
            "name": "v1",
            "overlay": [
              {
                "name": "logo"
              }
            ]
          }
        ],
        "audio": [
          {
            "name": "a1"
          }
        ],
        "subtitle": [
          {
            "name": "s1"
          }
        ]
      }
    ]
  }
}

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