Video Decoder Picture Buffering for Trick Play
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Solution Overview
Problem
Existing video playback systems face decoding challenges during 'trick play' operations like fast forward, reverse, and skip, due to unavailable video data, leading to poor performance and picture quality.
Innovation Solution
The system revises picture buffering parameters to allow the graphics processor to decode current pictures using a different set of reference pictures, omitting unavailable ones and simplifying the decoding process, thereby improving performance during trick play modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system uses standard video decoding procedures during trick play operations, then decoding can proceed with available data, but picture quality and performance deteriorate due to unavailable reference pictures
Solution Approach 1:
The system dynamically adjusts the reference picture set based on the current playback mode. During trick play operations, the decoder modifies which pictures are used as references and how they are applied, allowing flexible adaptation to different playback scenarios while maintaining acceptable picture quality and performance
Solution Approach 2:
The system changes decoding parameters specifically for trick play operations, including modifying reference picture selection, motion compensation parameters, and prediction modes. These parameter adjustments allow the decoder to operate effectively with limited available data while maintaining reasonable output quality
2Reliability
If the decoder waits for all video data to be transferred and decoded before processing, then complete reference pictures are available, but decoding speed and responsiveness decrease
Solution Approach 1:
The system performs preliminary decoding of pictures that may be needed for trick play operations before they are fully requested. By pre-decoding and buffering potential reference pictures in advance, the system ensures data availability when needed without waiting for complete data transfer, thus maintaining both reliability and speed
Solution Approach 2:
The decoder dynamically determines which pictures to decode and buffer based on the current playback position and requested operations. This dynamic picture selection and preprocessing approach ensures that necessary reference data is available without unnecessarily decoding all pictures, balancing data availability with decoding speed
3Reliability
If the system decodes all pictures in sequence for normal playback, then reference picture availability is maximized, but complexity increases for handling trick play operations
Solution Approach 1:
The system segments the picture buffer into different regions or categories (e.g., short-term reference pictures, long-term reference pictures, trick-play-optimized pictures). This segmentation allows selective management and retrieval of reference pictures based on the current operation type, reducing complexity while maintaining availability
Solution Approach 2:
The reference picture buffer is dynamically reorganized and managed based on the current playback mode. During normal playback, pictures are managed in standard sequence; during trick play operations, the buffer management adapts to provide quick access to relevant reference pictures, reducing complexity through mode-specific optimization
Data Source
AI summary
A video decoder obtains a first set of picture buffering parameters associated with a current picture of an encoded video bitstream. The first set of picture buffering parameters identifies a set of one or more reference pictures for use in decoding the current picture by a graphics processor. The video decoder revises the first set of picture buffering parameters into a second (different) set of picture buffering parameters for use in decoding the current picture by the graphics processor. The second set of picture buffering parameters is transferred to the graphics processor for decoding the current picture.