DVR Trick-Play Frame Accuracy via I-Frame Distance Statistics

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Solution Overview

Problem

Existing digital video playback systems face challenges in accurately locating and displaying reference frames during fast forward, rewind, or skip operations due to variations in the distance between intra-frames, which affects the smoothness and accuracy of trick-play functionalities.

Innovation Solution

A method that involves storing statistics related to the average distances between reference video frames in a statistics file, allowing the recording and playback manager to accurately locate and display frames during fast forward, rewind, or skip processes by using these pre-calculated distances to determine the correct frame positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional indexing mechanisms are used to locate I-frames by parsing video streams, then the system can find reference frames for trick-play operations, but the accuracy and smoothness of fast forward, rewind, and skip operations deteriorate due to variations in distances between intra-frames

Engineering Contradiction:
Improveframe location accuracyVSAvoidtrick-play smoothness
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs preliminary analysis during the first playback of a recording to calculate and store average distances between I-frames for different blocks of video data. This pre-calculated statistical information is stored in a statistics file, enabling accurate frame location during subsequent fast forward, rewind, and skip operations without requiring real-time parsing of the entire video stream.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the system parses video streams to find frame headers and creates CPI files for indexing, then reference frames can be located for trick-play, but the device complexity increases due to separate coupled files and parsing mechanisms

Engineering Contradiction:
Improvetrick-play functionalityVSAvoidindexing system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention merges the indexing functionality into the existing video file structure by storing statistical information about I-frame distances directly within the video file or as integrated metadata. This eliminates the need for separate CPI files and complex parsing mechanisms, reducing device complexity while maintaining full trick-play functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If statistical information is collected during normal reproduction for later use, then the system can improve subsequent trick-play operations, but the initial playback time increases due to statistics collection

Engineering Contradiction:
Improvetrick-play accuracyVSAvoidinitial playback time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system collects statistical information partially by analyzing only specific blocks of video data and calculating average I-frame distances for those blocks rather than processing the entire video stream. This partial analysis approach reduces the time penalty during initial playback while still providing sufficient statistical information for accurate trick-play operations in subsequent playbacks.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2647211B1Systems and methods for digital video high accuracy fast forward, rewind and skip
Publication Date: 2019.12.25 DISH TECHNOLOGIES LLC
  • EP2647211B1 patent drawingFigure 1
  • EP2647211B1 patent drawingFigure 2
  • EP2647211B1 patent drawingFigure 3

AI summary

In various embodiments, a recording and playback manager of a digital video recorder (DVR), set top box, receiver or other device stores and accesses statistics in a statistics file related to average distances between reference frames (e.g., intra frames or I-frames) within blocks of the video data of the recording. Accessing these statistics during playback enables the system to more accurately locate reference frames to display while executing the playback in a trick mode such as fast forward, rewind or skip. The average distance between reference frames for a particular block of video data may be used to jump from one reference frame to the next reference frame in that block during playback in trick mode.