Stream Operators

The following operators can be applied to a video, audio or subtitle stream.

Property	Type	Description
`select`	object	Maps an input track to a media stream.
`route`	object	Routes a stream from an input to an output.
`decode`	object	Decodes the media stream samples.
`resample`	object	Converts the stream to a different sample rate.
`filter`	array	Lists the filters applied to the media stream samples.
`encode`	object	Encodes the media stream samples.
`layout`	object	Maps a media stream to an output track.

`select`

Maps input container tracks to a video, audio or subtitle stream. For audios stream the operator can select specific audio channels.

Property	Type	Description
`track`	integer	Identifies a specific track by number (1-based).
`pid`	integer	MPEG-2 transport stream packet identifier that selects a specific elementary stream.
`format`	string	Four character code that identifies the media sample format.
`language`	string	Two or three character code that identifies the stream language.
`channel`	array	Identifies each audio channel. The input stream channels property determines the dimension of the array. The array items are either the input channel number (1 based) or a channel object as described below.

The channel object identifies a specific input channel. The object supports the following properties:

Property	Type	Description
`label`	string	Identifies an audio channel by speaker `label`.
`program`	integer	Identifies an audio channel by program number.

For example the following composition selects audio channels by channel number:

---
input:
  container:
  - name: input1
    video:
    - name: v1
    audio:
    - name: surround
      channels: 6
      select:
        channel:
        - 1
        - 2
        - 3
        - 4
        - 5
        - 6
    - name: stereo
      channels: 2
      select:
        channel:
        - 7
        - 8

{
  "input": {
    "container": [
      {
        "name": "input1",
        "video": [
          {
            "name": "v1"
          }
        ],
        "audio": [
          {
            "name": "surround",
            "channels": 6,
            "select": {
              "channel": [
                1,
                2,
                3,
                4,
                5,
                6
              ]
            }
          },
          {
            "name": "stereo",
            "channels": 2,
            "select": {
              "channel": [
                7,
                8
              ]
            }
          }
        ]
      }
    ]
  }
}

`route`

The route operator routes a video, audio or subtitle stream from an input container to an output container. For an audio stream the operator may route specific input channels.

Property	Type	Description
`name`	string	Identifies the input stream.
`channel`	array	Lists the input channels routed to each output channel. The output stream `channels` property determines the dimension of the array. The array items are either the input channel number (1 based) or a channel object as described below.

The channel object allows input channels from different streams to be routed to the output. The channel object supports the following properties:

Property	Type	Description
`name`	string	Identifies the input stream for this channel.
`channel`	integer	Identifies the input channel by number (1 based).
`label`	enum	Identifies the input channel by speaker `label`.
`program`	integer	Identifies the input channel by `program` number.

`resample`

Resamples a media stream to the target sample rate.

Property	Type	Description
`speed`	object	Speed adjustment expressed as a rational number.

`decode`

Decodes the media stream samples using a specific decompressor type.

Property	Type	Description
`type`	string	Four character code that identifies the decompressor implementation.
`properties`	object	Decompressor configuration properties.

`filter`

Processes the stream media samples using a specific filter type.

Property	Type	Description
`type`	string	Four character code that identifies the filter implementation.
`properties`	object	Filter configuration properties.

`encode`

Encodes the media stream samples using a specific compressor type.

Property	Type	Description
`type`	string	Four character code that identifies the compressor implementation.
`properties`	object	Compressor configuration properties.

`layout`

Maps a video, audio or subtitle stream to an output container track. For audio streams the operator can layout each audio channel.

Property	Type
`track`	integer	Specifies the output track (1 based) for this stream.
`channel`	array	Specifies the output channel number (1 based) for each audio channel. The output stream channels property determines the dimension of the array.