Content Templates
Contents templates are used in ew-vod2cbm to specify the output segmentation and tracks of a channel, but also serve as measures to check if asset entries in a schedule are compatible with the channel. They are further used to generate the manifest and playlist media data properties as well as the media init segments. Therefore, bitrate, resolution, frame rate, video parameter sets, number audio channels are included in the template. The assets do not need to have exactly the same parameter values, but are allowed to vary as described later.
JSON Schema for Content Template
The JSON schema of the content template contains core parameters of the
content_info.json schema, and some additional parametersfor bitrate matching.
It can contain variants of video, audio, and subtitles as signaled in the media_type field.
The variant array can contain multiple variants
of each type. The table below the schema shows the required parameters for each
media type.
{
"type": "object",
"properties": {
"version": {
"type": "string"
},
"constant_gop_duration_ms": {
"type": "integer"
},
"variants": {
"type": "array",
"items": [
{
"type": "object",
"properties": {
"media_type": {
"type": "string"
},
"subtype": {
"type": "string"
},
"name": {
"type": "string"
},
"bitrate": {
"type": "integer"
},
"width": {
"type": "integer"
},
"height": {
"type": "integer"
},
"sample_aspect_ratio": {
"type": "string"
},
"picture_aspect_ratio": {
"type": "string"
},
"scan_type": {
"type": "string"
},
"sps": {
"type": "string"
},
"pps": {
"type": "string"
},
"codec": {
"type": "string"
},
"frame_rate_fraction": {
"type": "array",
"items": [
{
"type": "integer"
},
{
"type": "integer"
}
]
},
"num_channels": {
"type": "integer"
},
"samplerate": {
"type": "integer"
},
"decoder_config": {
"type": "string"
},
"lang": {
"type": "string"
},
"max_bitrate": {
"type": "integer"
},
"min_bitrate": {
"type": "integer"
}
},
"required": [
"media_type",
"name",
"bitrate",
"codec"
]
}
]
}
}
}
Depending on the media type, there are required fields for a variant. The table below lists all the required fields depending on media type.
| Media type | Required fields |
|---|---|
| Video | media_type subtype name bitrate width height sample_aspect_ratio picture_aspect_ratio scan_type sps pps codec frame_rate_fraction |
| Audio | media_type subtype name bitrate codec num_channels samplerate decoder_config lang |
| Subtitles | media_type name bitrate lang codec |
The fields max_bitrate and min_bitrate are optional for all media types.
Example content template
{
"version": "1.0",
"constant_gop_duration_ms": 1920,
"variants": [
{
"media_type": "video",
"subtype": "h264",
"name": "V1000",
"bitrate": 1000000,
"width": 640,
"height": 360,
"sample_aspect_ratio": "1:1",
"picture_aspect_ratio": "16:9",
"scan_type": "progressive",
"sps": "6764001eacb201405ff2a0",
"pps": "68ebccb22c",
"codec": "avc1.64001E",
"frame_rate_fraction": [
25,
1
],
"max_bitrate": 1500000,
"min_bitrate": 900000
},
{
"media_type": "video",
"subtype": "h264",
"name": "V1500",
"bitrate": 1500000,
"width": 768,
"height": 432,
"sample_aspect_ratio": "1:1",
"picture_aspect_ratio": "16:9",
"scan_type": "progressive",
"sps": "6764001eacb201806f20",
"pps": "68ebccb22c",
"codec": "avc1.64001E",
"frame_rate_fraction": [
25,
1
],
"max_bitrate": 1600000,
"min_bitrate": 1400000
},
{
"media_type": "audio",
"subtype": "aac",
"name": "A128",
"bitrate": 128000,
"codec": "mp4a.40.2",
"num_channels": 2,
"samplerate": 48000,
"decoder_config": "1190",
"lang": "eng"
},
{
"media_type": "subtitles",
"name": "eng_1",
"bitrate": 1000,
"lang": "eng",
"codec": "wvtt"
}
]
}