How to Configure SSIM

Table of Contents

Overview

What is SSIM?

SSIM (Structural Similarity Index Measure) is a perceptual video quality metric that compares each test frame to a reference frame, focusing on structural information, contrast, and luminance. Unlike simpler metrics like PSNR (Peak Signal-to-Noise Ratio) or MSE (Mean Squared Error), SSIM aligns more closely with how the human eye perceives video quality.

SSIM Values in MCS

MCS provides four SSIM values for display:

• SSIM – Displays the lowest SSIM value among the Y (luma) and U/V (chroma) channels.

• SSIMY – Displays the SSIM value for the luminance (Y) channel.

• SSIMCB – Displays the SSIM value for the Cb (chroma) channel.

• SSIMCR – Displays the SSIM value for the Cr (chroma) channel.

Why Use SSIM in MCS?

• Better Correlation with Human Perception: SSIM highlights visual distortions that impact viewer experience.

• Proactive Quality Assurance: Detects issues like blocking, blurring, noise, and color distortions before they affect viewers.

• Seamless Integration: Supports real-time monitoring across various video formats, ensuring high-quality viewing for live production, playout, distribution, and OTT services.

Use Cases

• Live & On-Demand Content: Monitor SSIM scores to detect and address quality drops in real-time.

• Compression Optimization: Balance quality and bandwidth by comparing different encoding settings.

• Content Delivery: Track SSIM metrics to identify and resolve degradation in distribution networks.

How to Configure SSIM in MCS

Enable Fingerprinting

1. Log in to MCS.

2. Click on the menu icon to open the widget menu.

   Open

   

   • A display of all the available widgets will open.

3. Navigate to Sources → Sources Config.

   Open

   

   • Sources Configuration will open.

4. For both the reference and test streams:

   • Double-click an existing source configuration that is disabled (Fingerprinting cannot be enabled for active sources) or create a new source configuration.

   • In the Common tab, locate the Finger Printing toggle at the top of the page and switch it to "on."

Configure the Path

1. Click the menu icon to open the widget menu.

   • A display of all the available widgets will open.

2. Navigate to Sources → Paths.

   • Channel Path Configuration will open.

3. Click the Add button (plus icon) on the top right corner to create a new channel path.

4. Enter a name for the channel path in the Label field.

5. From the Available Sources menu on the left, drag the reference and test streams to the configuration area.

6. Position the reference stream to the left of the test stream.

7. Create a connection by clicking the blue circle on the reference stream box and drag a line to the test stream box.

8. Save the configuration by clicking Save.

Achieve Content Matching

Once the reference and test streams are fingerprinted and connected, MCS will automatically identify matching frames.

Configure UMD Hashtags in the Layout

Prerequisites

1. Configure a Tile to display UMD objects:

   1. Edit or Create a Tile in the Tile Editor:

      • To edit an existing tile, double-click a tile from the Tiles List in the right menu.

      • Refer to this guide to create a new tile.

   2. Add a UMD Object for Each SSIM Value (There are 4 SSIM options to display):

      • Drag a UMD object type from the Types menu on the left into the tile displayed in the middle of the screen.

   3. Align UMD Indexes:

      • The UMD index in the Tile Editor will correspond to the UMD index in the Layout configuration where the tile is placed.

         

         

   4. For more details, refer to the guide on configuring tiles.

2. Configure a Layout Template. Refer to the layout template configuration guide.

Steps

1. Click the menu icon to open the widget menu.

   • A display of all the available widgets will open.

2. Navigate to Outputs → Layouts.

   • Layouts Configuration will open.

3. Open an existing layout configuration or create a new layout configuration.

4. In the middle section of the Layout Configuration:

   • Assign UMD values to the test stream. (Do not assign values to the reference stream; they will not display.)

   • Assign up to 4 UMD values using the following hashtags:

     • #SSIM# – Lowest SSIM value across Y (luma) and U/V (chroma).

     • #SSIMY# – SSIM value for luminance (Y).

     • #SSIMCB# – SSIM value for Cb (chroma).

     • #SSIMCR# – SSIM value for Cr (chroma).

View SSIM Values

1. Click the menu icon to open the widget menu.

2. Navigate to Outputs → Operator Console.

   • Operator Console will open.

3. Click the Layout Select button at the bottom of the page.

4. Choose the layout you configured.

5. The SSIM values for the test stream will display in the corresponding UMD objects on the tile.

Adjust Sampling Interval (Optional)

• By default, SSIM values are sampled every 10 seconds.

• To adjust this interval, modify the APP_SSIM_INTERVAL value (in milliseconds) in the .env file.
  For example:

  • APP_SSIM_INTERVAL=10000

Related Articles

Layouts

Templates

Tiles

Sources Config

Operator Console