Virtual Field Buffer Decoding for Interlaced Video
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Solution Overview
Problem
Current video compression techniques, such as HEVC, do not explicitly support interlaced video coding, leading to inefficiencies in decoding and potential artifacts when handling interlaced signals, as they are primarily designed for progressive scan imagery.
Innovation Solution
The implementation of a virtual field buffer decoding system that assigns complementary picture fields to frames before decoding, using a virtual field buffer decoder with components like a coded picture buffer, picture command generator, and frame-based decoded picture buffer, to efficiently support interlaced video coding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If current video compression techniques (HEVC) are used, then compression performance is improved, but interlaced video decoding efficiency deteriorates and artifacts are introduced
Solution Approach 1:
The patent segments the interlaced video signal into separate top field and bottom field pictures, treating each field as an independent picture unit. This segmentation allows the decoding system to process each field separately using frame-based decoding circuitry, thereby maintaining decoding efficiency while preserving compression performance.
Solution Approach 2:
The patent introduces a field picture conversion mechanism as an intermediary step between the compressed interlaced video stream and the frame-based decoding circuitry. This intermediary converts interlaced frame data into separate field pictures, enabling the use of existing frame-based decoders without direct modification, thus resolving the contradiction between compression optimization and decoding efficiency.
2Device complexity
If frame-based decoding circuitry is reused for interlaced video, then device complexity is reduced, but decoding accuracy deteriorates due to lack of explicit interlaced support
Solution Approach 1:
The patent performs preliminary conversion of interlaced frame data into separate field pictures before decoding. By pre-processing the interlaced signal to extract top and bottom fields as distinct picture units, the system prepares the data in a format suitable for frame-based decoders, thereby maintaining decoding accuracy without requiring complex interlaced-specific decoding circuitry.
Solution Approach 2:
The patent creates separate copies of the top field and bottom field from the interlaced frame data. These field copies are then processed independently through the frame-based decoding circuitry, allowing the reuse of simpler decoder hardware while maintaining the integrity and accuracy of the original interlaced signal.
3Ease of operation
If interlaced video is decoded using progressive scan techniques, then decoding process is simplified, but video artifacts increase
Solution Approach 1:
The patent segments the interlaced video signal into separate top and bottom field pictures, preserving the temporal and spatial relationships specific to interlaced scanning. This segmentation allows the decoding process to maintain simplicity while avoiding artifacts by treating each field as a distinct unit that can be processed independently yet maintain their original interlaced characteristics.
Data Source
AI summary
Aspects of virtual field buffer based decoding are described. In one embodiment, a current picture field is read from a coded picture buffer comprising coded pictures of video, for example. The current picture may be associated with a top or bottom field polarity. According to decoding and picture output orders, the current picture field is assigned to an available field entry of a virtual field buffer, and an available frame index of a virtual frame map is assigned to the current picture field. The assignment of the available frame index to the current picture field is indicated to a decoder that decodes the current picture field with reference to the assigned frame index. According to aspects of the embodiments described herein, rather than determining complimentary picture fields after decoding, the assignment of complimentary picture fields to virtual frame indexes before decoding provides certain efficiencies.