---
updatedAt: 2026-08-31T10:33:06.000Z
agentTools:
  projectIndex: https://docs.telestream.dev/llms.txt
---

# Miscellaneous

## `$annotation`

Contains comments or descriptions for sibling properties, for example:

[block:code]
{
  "codes": [
    {
      "code": "---\nvideo:\n- format: avc1\n  sample_rate:\n    numerator: 30000\n    denominator: 1001\n  duration: 419966\n  bit_rate: 344639\n  width: 300\n  height: 240\n  clean_aperture:\n    left: 0\n    right: 0\n    top: 0\n    bottom: 0\n  orientation:\n    rotation: 0\n    mirrored: false\n  field_order: progressive\n  pixel_aspect_ratio:\n    numerator: 1\n    denominator: 1\n  bit_depth: 8\n  chroma_subsampling:\n    horizontal: 2\n    vertical: 2\n  chroma_location: vertical_midpoint\n  color_primaries: 6\n  transfer_characteristics: 6\n  matrix_coefficients: 6\n  video_range: narrow\n  black_level: 0.0\n  white_level: 1.0\n  $annotation:\n    format: AVC (ISO 14496-10)\n    sample_rate: 29.97 fps\n    duration: 14.013 seconds\n    bit_rate: 344.639 Kbit/s\n    clean_aperture: 300x240\n    pixel_aspect_ratio: '1:1'\n    chroma_subsampling: '4:2:0'\n    color_primaries: ITU-R BT.601-6 (525)\n    transfer_characteristics: ITU-R BT.601-6\n    matrix_coefficients: ITU-R BT.601-6\n    black_level: 0%\n    white_level: 100%",
      "language": "yaml"
    },
    {
      "code": "{\n  \"video\": [\n    {\n      \"format\": \"avc1\",\n      \"sample_rate\": {\n        \"numerator\": 30000,\n        \"denominator\": 1001\n      },\n      \"duration\": 419966,\n      \"bit_rate\": 344639,\n      \"width\": 300,\n      \"height\": 240,\n      \"clean_aperture\": {\n        \"left\": 0,\n        \"right\": 0,\n        \"top\": 0,\n        \"bottom\": 0\n      },\n      \"orientation\": {\n        \"rotation\": 0,\n        \"mirrored\": false\n      },\n      \"field_order\": \"progressive\",\n      \"pixel_aspect_ratio\": {\n        \"numerator\": 1,\n        \"denominator\": 1\n      },\n      \"bit_depth\": 8,\n      \"chroma_subsampling\": {\n        \"horizontal\": 2,\n        \"vertical\": 2\n      },\n      \"chroma_location\": \"vertical_midpoint\",\n      \"color_primaries\": 6,\n      \"transfer_characteristics\": 6,\n      \"matrix_coefficients\": 6,\n      \"video_range\": \"narrow\",\n      \"black_level\": 0.0,\n      \"white_level\": 1.0,\n      \"$annotation\": {\n        \"format\": \"AVC (ISO 14496-10)\",\n        \"sample_rate\": \"29.97 fps\",\n        \"duration\": \"14.013 seconds\",\n        \"bit_rate\": \"344.639 Kbit/s\",\n        \"clean_aperture\": \"300x240\",\n        \"pixel_aspect_ratio\": \"1:1\",\n        \"chroma_subsampling\": \"4:2:0\",\n        \"color_primaries\": \"ITU-R BT.601-6 (525)\",\n        \"transfer_characteristics\": \"ITU-R BT.601-6\",\n        \"matrix_coefficients\": \"ITU-R BT.601-6\",\n        \"black_level\": \"0%\",\n        \"white_level\": \"100%\"\n      }\n    }\n  ]\n}",
      "language": "json"
    }
  ]
}
[/block]

## `extension`

Represents a property extension that is uniquely identified by a four character `type` code. An extension typically contains properties for a specific media or container format, for example:

[block:code]
{
  "codes": [
    {
      "code": "---\naudio:\n- format: mp4a\n  sample_rate:\n    numerator: 44100\n    denominator: 1024\n  duration: 601630\n  bit_rate: 796229186\n  language: und\n  region: '@@@'\n  channels: 2\n  label:\n  - L\n  - R\n  bits_per_sample: 16\n  properties:\n    Mpeg4ObjectType: 2\n    $annotation:\n      Mpeg4ObjectType: Low Complexity (LC)\n  extension:\n  - type: mp4a\n    audio_object_type: 2\n    sampling_frequency_index: 4\n    channel_configuration: 2\n    extension_sampling_frequency_index: 0\n    extension_audio_object_type: 0\n    $annotation:\n      type: MPEG-4 Audio Specific Config (ISO 14496-3)\n      audio_object_type: Low Complexity (LC)\n  - type: mp4s\n    format: mp4a\n    extension:\n    - type: esds\n      object_type_indication: 64\n      stream_type: 21\n    - type: chnl\n      stream_structure: 1\n      defined_layout: 0\n      channel:\n      - speaker_position: 0\n      - speaker_position: 1\n    version: 2\n    channel_count: 2\n    sample_rate: 310866464\n    sample_size: 16\n    $annotation:\n      type: MPEG-4 Sample Entry (ISO 14496-12)\n  $annotation:\n    format: AAC\n    sample_rate: 44.1 kHz\n    duration: 13.642 seconds\n    bit_rate: 796.229 Mbit/s",
      "language": "yaml"
    },
    {
      "code": "{\n  \"audio\": [\n    {\n      \"format\": \"mp4a\",\n      \"sample_rate\": {\n        \"numerator\": 44100,\n        \"denominator\": 1024\n      },\n      \"duration\": 601630,\n      \"bit_rate\": 796229186,\n      \"language\": \"und\",\n      \"region\": \"@@@\",\n      \"channels\": 2,\n      \"label\": [\n        \"L\",\n        \"R\"\n      ],\n      \"bits_per_sample\": 16,\n      \"properties\": {\n        \"Mpeg4ObjectType\": 2,\n        \"$annotation\": {\n          \"Mpeg4ObjectType\": \"Low Complexity (LC)\"\n        }\n      },\n      \"extension\": [\n        {\n          \"type\": \"mp4a\",\n          \"audio_object_type\": 2,\n          \"sampling_frequency_index\": 4,\n          \"channel_configuration\": 2,\n          \"extension_sampling_frequency_index\": 0,\n          \"extension_audio_object_type\": 0,\n          \"$annotation\": {\n            \"type\": \"MPEG-4 Audio Specific Config (ISO 14496-3)\",\n            \"audio_object_type\": \"Low Complexity (LC)\"\n          }\n        },\n        {\n          \"type\": \"mp4s\",\n          \"format\": \"mp4a\",\n          \"extension\": [\n            {\n              \"type\": \"esds\",\n              \"object_type_indication\": 64,\n              \"stream_type\": 21\n            },\n            {\n              \"type\": \"chnl\",\n              \"stream_structure\": 1,\n              \"defined_layout\": 0,\n              \"channel\": [\n                {\n                  \"speaker_position\": 0\n                },\n                {\n                  \"speaker_position\": 1\n                }\n              ]\n            }\n          ],\n          \"version\": 2,\n          \"channel_count\": 2,\n          \"sample_rate\": 310866464,\n          \"sample_size\": 16,\n          \"$annotation\": {\n            \"type\": \"MPEG-4 Sample Entry (ISO 14496-12)\"\n          }\n        }\n      ],\n      \"$annotation\": {\n        \"format\": \"AAC\",\n        \"sample_rate\": \"44.1 kHz\",\n        \"duration\": \"13.642 seconds\",\n        \"bit_rate\": \"796.229 Mbit/s\"\n      }\n    }\n  ]\n}",
      "language": "json"
    }
  ]
}
[/block]

## `properties`

A collection of named properties that are implementation specific. Properties can be applied to media containers, media streams and various stream operators.

Property names are `CamelCased` to distinguish them from the composition schema. For example the following composition sets audio codec specific properties:

[block:code]
{
  "codes": [
    {
      "code": "---\ninput:\n  container:\n  - name: pcm\n    audio:\n    - name: a1\noutput:\n  container:\n  - name: aac\n    type: audi\n    audio:\n    - route:\n        name: a1\n      encode:\n        type: mcac\n        properties:\n          BitRate: 128000\n          MpegVersion: 1",
      "language": "yaml"
    },
    {
      "code": "{\n  \"input\": {\n    \"container\": [\n      {\n        \"name\": \"pcm\",\n        \"audio\": [\n          {\n            \"name\": \"a1\"\n          }\n        ]\n      }\n    ]\n  },\n  \"output\": {\n    \"container\": [\n      {\n        \"name\": \"aac\",\n        \"type\": \"audi\",\n        \"audio\": [\n          {\n            \"route\": {\n              \"name\": \"a1\"\n            },\n            \"encode\": {\n              \"type\": \"mcac\",\n              \"properties\": {\n                \"BitRate\": 128000,\n                \"MpegVersion\": 2\n              }\n            }\n          }\n        ]\n      }\n    ]\n  }\n}",
      "language": "json"
    }
  ]
}
[/block]