elv-abr-profile
A package for creating ABR (Adjustable Bitrate) Profiles to use when ingesting media into the Eluvio Content Fabric.
The video bitrate ladder in the generated profile is based on:
- The properties of the video to ingest
- A parametric ladder specification
- A list of standard aspect ratios to (optionally) conform to
The audio bitrate ladder is fixed based on the number of channels in the audio stream.
NOTE: This package currently does not support working with profiles for x265 (hevc) mezzanines.
Installation
Install from NPM:
npm install --save @eluvio/elv-abr-profile
Usage
Generate an ABR Profile based on Production Master metadata and default bitrate ladder / standard aspect ratio list
const ABR = require('elv-abr-profile');
// Normally obtained from production master object's metadata @ /production_master/sources
// For this example, the master contains a single file 'test.mp4'
const prodMasterSources = {
'test.mp4': {
'container_format': {
'duration': 242.875,
'filename': 'test.mp4',
'format_name': 'mov,mp4,m4a,3gp,3g2,mj2',
'start_time': 0
},
'streams': [
{
'bit_rate': 2801771,
'codec_name': 'h264',
'display_aspect_ratio': '16/9',
'duration': 242.875,
'duration_ts': 2984448,
'field_order': '',
'frame_count': 5829,
'frame_rate': '24',
'hdr': null,
'height': 1080,
'language': '',
'max_bit_rate': 0,
'sample_aspect_ratio': '1',
'start_pts': 0,
'start_time': 0,
'time_base': '1/12288',
'type': 'StreamVideo',
'width': 1920
},
{
'bit_rate': 128013,
'channel_layout': 'stereo',
'channels': 2,
'codec_name': 'aac',
'duration': 242.83428571428573,
'duration_ts': 10708992,
'frame_count': 10458,
'language': '',
'max_bit_rate': 0,
'sample_rate': 44100,
'start_pts': 0,
'start_time': 0,
'time_base': '1/44100',
'type': 'StreamAudio'
}
]
}
};
// Normally obtained from production master object's metadata @ /production_master/variants/VARIANT_KEY
// (in the most common case, VARIANT_KEY === 'default')
// prodMasterVariant.log.entries omitted below for brevity
const prodMasterVariant = {
'log': {
'Level': 3,
'entries': []
},
'streams': {
'audio': {
'default_for_media_type': true,
'label': '',
'language': '',
'mapping_info': '',
'sources': [
{
'files_api_path': 'test.mp4',
'stream_index': 1
}
]
},
'video': {
'default_for_media_type': true,
'label': '',
'language': '',
'mapping_info': '',
'sources': [
{
'files_api_path': 'test.mp4',
'stream_index': 0
}
]
}
}
}
const profile = ABR.ABRProfileForVariant(prodMasterSources, prodMasterVariant);
console.log(JSON.stringify(profile, null, 2))Output:
{
"ok": true,
"result": {
"drm_optional": true,
"store_clear": false,
"ladder_specs": {
"{\"media_type\":\"audio\",\"channels\":1}": {
"rung_specs": [
{
"bit_rate": 192000,
"media_type": "audio",
"pregenerate": true
}
]
},
"{\"media_type\":\"audio\",\"channels\":2}": {
"rung_specs": [
{
"bit_rate": 256000,
"media_type": "audio",
"pregenerate": true
}
]
},
"{\"media_type\":\"audio\",\"channels\":6}": {
"rung_specs": [
{
"bit_rate": 384000,
"media_type": "audio",
"pregenerate": true
}
]
},
"{\"media_type\":\"video\",\"aspect_ratio_height\":9,\"aspect_ratio_width\":16}": {
"rung_specs": [
{
"bit_rate": 12600000,
"height": 2160,
"media_type": "video",
"pregenerate": true,
"width": 3840
},
{
"bit_rate": 10400000,
"height": 1440,
"media_type": "video",
"pregenerate": false,
"width": 2560
},
{
"bit_rate": 8550000,
"height": 1080,
"media_type": "video",
"pregenerate": false,
"width": 1920
},
{
"bit_rate": 4050000,
"height": 720,
"media_type": "video",
"pregenerate": false,
"width": 1280
},
{
"bit_rate": 1580000,
"height": 480,
"media_type": "video",
"pregenerate": false,
"width": 854
},
{
"bit_rate": 729000,
"height": 360,
"media_type": "video",
"pregenerate": false,
"width": 640
},
{
"bit_rate": 450000,
"height": 240,
"media_type": "video",
"pregenerate": false,
"width": 426
}
]
}
},
"playout_formats": {
"dash-widevine": {
"drm": {
"content_id": "",
"enc_scheme_name": "cenc",
"license_servers": [],
"type": "DrmWidevine"
},
"protocol": {
"min_buffer_length": 2,
"type": "ProtoDash"
}
},
"hls-aes128": {
"drm": {
"enc_scheme_name": "aes-128",
"type": "DrmAes128"
},
"protocol": {
"type": "ProtoHls"
}
},
"hls-fairplay": {
"drm": {
"enc_scheme_name": "cbcs",
"license_servers": [],
"type": "DrmFairplay"
},
"protocol": {
"type": "ProtoHls"
}
},
"hls-sample-aes": {
"drm": {
"enc_scheme_name": "cbcs",
"type": "DrmSampleAes"
},
"protocol": {
"type": "ProtoHls"
}
},
"dash-clear": {
"drm": null,
"protocol": {
"min_buffer_length": 2,
"type": "ProtoDash"
}
},
"hls-clear": {
"drm": null,
"protocol": {
"type": "ProtoHls"
}
}
},
"segment_specs": {
"audio": {
"segs_per_chunk": 15,
"target_dur": 2
},
"video": {
"segs_per_chunk": 15,
"target_dur": 2
}
}
}
}If an error occurs, the return value will contain ok: false and an errors property containing an array of error message strings. For example, if production master sources listed a frame_rate of zero for the video stream used by the variant, the return value would be:
{
"ok": false,
"errors": [
"VideoProperties: frameRate must be > 0 (got: 0)"
]
}