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.


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