Pre-roll and Post-roll Buffers for Seamless Digital TV Multiplex Switching

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Solution Overview

Problem

Digital TV systems face challenges in seamless addressable content switching due to bandwidth allocation and memory constraints, with existing methods either requiring local storage or causing latency during multiplex switching.

Innovation Solution

The Splice'nSwitch system enables seamless switching by using temporary local storage for Pre-roll and Post-roll content sets, allowing tuners to switch between primary and addressable content streams without latency, optimizing bandwidth allocation and utilizing available storage on digital TV receivers and set-top boxes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If addressable content streams are transmitted on a different transport multiplex from the primary channel, then bandwidth allocation is optimized, but switching latency occurs during multiplex changes

Engineering Contradiction:

Improvebandwidth allocation efficiencyVSAvoidswitching latency

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The system performs preliminary actions by storing pre-roll content (frames before the ad) and post-roll content (frames after the ad) in local memory before the actual multiplex switching occurs. This preparation allows the tuner to switch multiplexes without causing visible artifacts, as the stored content fills the transition gap. The pre-roll and post-roll buffers are populated in advance during content reception and storage phases.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pre-roll and post-roll content buffers act as intermediaries between the primary channel multiplex and the addressable content multiplex. During the multiplex switching transition, these buffered content sets serve as a mediator that bridges the gap, allowing seamless visual transition while the tuner switches between different transport multiplexes. This intermediary content prevents direct exposure to the switching artifact.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If complete addressable content is stored locally on digital TV receivers, then seamless switching is enabled, but memory requirements increase significantly

Engineering Contradiction:

Improveseamless switching capabilityVSAvoidlocal storage memory

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The system extracts only the essential portions of addressable content (pre-roll and post-roll frames) and stores them locally in memory, while the complete addressable content streams remain on the transport multiplex. This selective extraction approach enables seamless switching functionality without requiring storage of the entire addressable content library, significantly reducing local memory requirements while maintaining the core benefit of artifact-free transitions.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of storing complete addressable content streams locally, the system performs partial action by storing only the minimal necessary content portions (pre-roll and post-roll frames) required for seamless switching. This partial storage approach provides sufficient functionality for artifact-free transitions without the excessive memory requirements of storing complete content sets, achieving an optimal balance between switching quality and storage efficiency.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If filler content is transmitted during multiplex switching, then video artifacts are prevented, but bandwidth efficiency decreases

Engineering Contradiction:

Improvevideo quality during switchingVSAvoidbandwidth utilization

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of transmitting filler content during multiplex switching, the system uses copied content from local memory (pre-roll and post-roll frames that were previously stored). These copied frames are retrieved from local storage and displayed during the switching transition, eliminating the need for real-time filler content transmission over the network. This approach maintains video quality while preserving bandwidth efficiency, as the content is reused from existing local copies rather than requiring additional transmission resources.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS8782728B2Stream conditioning for seamless switching of addressable content across transport multiplex, using local stored content as pre-roll and post-roll buffers; in digital television receivers

Publication Date: 2014.07.15 MS AMAGI MEDIA LABS PVT LTD

AI summary

A system, method and apparatus to enable addressable advertising content delivery in which multiple addressable content streams are sent in a transport multiplex, Addressable Content Channel Multiplex, different from the Primary Channel Multiplex on which the Primary Channel is delivered. The Primary Channel is network stream onto which the addressable content is to be inserted. Seamless switch between the Primary Channel and the addressable content streams on the Addressable Content Channel Multiplex is accomplished by using Receiver stored content as interim buffers to which the switching happens prior to switching to a different transport multiplex. These buffers feed the audio and video decoders with content, during the time it takes for the tuner to switch to a different transport multiplex. Pre-roll and Post-roll content buffers are used during switching, one from Primary Channel Multiplex to Addressable Content Channel Multiplex and from Addressable Content Channel Multiplex to Primary Channel Multiplex.