---
title: Media agent for Dash JS v4.1.0
source: https://docs.newrelic.com/docs/release-notes/streaming-browser-release-notes/streaming-browser-agent-dashjs-26-03-16
---

## What's new

This release introduces three new bitrate metrics providing comprehensive quality analysis for MPEG-DASH streaming, along with important improvements to existing bitrate calculations and dash.js v4/v5 compatibility.

## New features

### New bitrate metrics

-   `contentManifestBitrate`: Maximum combined (video + audio) bitrate from the MPD manifest. Represents the highest possible stream variant available.

-   `contentMeasuredBitrate`: Network estimated by the player's Adaptive BitRate (ABR) algorithm, based on measured download throughput. Use this metric to analyze ABR decision-making.

-   `contentDownloadBitrate`: Effective download throughput calculated from video segment request data (`bytesDownloaded × 8 / downloadTime`). This Provides real-time network performance monitoring.

## Changes

### Updated bitrate calculations

-   `contentBitrate`: Returns the **video-only** bitrate from the active track and excludes audio. Previous versions included combined bitrate.

-   `contentRenditionBitrate`: Returns the combined **video and audio bandwidth** of the active rendition to provide a complete quality picture.

## Compatibility improvements

-   `getDashBitrate()`: Fixed v4 compatibility issue. Version check now occurs before calling v5-only APIs, preventing errors on dash.js v4.x installations.
-   `getManifestBitrate()`: Introduced a smart version detection that uses `getRepresentationsByType()` on dash.js v5+ and falls back to `getBitrateInfoListFor()` on v4.x.

## Bug fixes

-   Removed duplicate `getPlayhead()` method definition
-   Removed `console.log` statement from `getTrack()` error handler

## Bitrate metrics overview

| Attribute                 | Type       | Description                                 |
| ------------------------- | ---------- | ------------------------------------------- |
| `contentBitrate`          | Video-only | Bitrate of the currently active video track |
| `contentRenditionBitrate` | Combined   | Video + audio bandwidth of active rendition |
| `contentManifestBitrate`  | Maximum    | Highest quality variant from MPD manifest   |
| `contentMeasuredBitrate`  | Estimated  | ABR algorithm bandwidth estimate            |
| `contentDownloadBitrate`  | Real-time  | Effective download throughput               |