AV Stream Indexing for Rapid Random Access and Quality Preservation
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Solution Overview
Problem
Current recording systems for digital AV signals suffer from picture quality deterioration due to the need for decoding and re-encoding, and face challenges in prompt random access and decoding of AV streams, especially as data volumes increase.
Innovation Solution
An information processing method and apparatus that records start address information, time information, and address information of characteristic pictures in AV streams as Clip information on a recording medium, enabling rapid determination and decoding of readout positions and retrieval of specified marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital video signals are decoded and re-encoded for recording, then the recording rate can be matched to the apparatus, but picture quality deteriorates
Solution Approach 1:
The patent segments the bitstream processing by separating the video data into I-pictures (intra-coded pictures) and other picture types. By recording I-pictures with higher priority and using selective discarding of non-I pictures when buffer capacity is exceeded, the system adapts to recording rate constraints while preserving essential picture quality through selective retention of key frames.
Solution Approach 2:
The patent applies different quality preservation strategies to different parts of the bitstream. I-pictures are protected and retained with higher priority, while P-B pictures (predictive and bi-directional pictures) are selectively discarded when necessary. This local differentiation ensures that critical reference frames maintain quality while less critical frames can be compromised to match recording capacity.
2Productivity
If the transmission rate of input digital signals exceeds the recording rate, then re-encoding is necessary, but this causes picture quality deterioration
Solution Approach 1:
The patent implements partial action by selectively recording only essential portions of the bitstream. When the buffer capacity is exceeded, the system partially discards non-I pictures while retaining I-pictures. This partial recording approach controls the effective recording rate to match apparatus capacity while minimizing quality loss by preserving the most critical picture data.
Solution Approach 2:
The patent extracts and separates I-picture data from the complete bitstream for priority recording. By identifying and extracting I-pictures (which contain complete picture information necessary for independent decoding) from P-B pictures (which depend on previous frames), the system can control recording rate by selectively retaining extracted I-pictures while discarding less critical extracted frames.
3Reliability
If the complete AV stream is recorded without indexing, then all data is preserved, but random access and decoding become slow with increasing data volume
Solution Approach 1:
The patent performs preliminary action by creating an index structure during the recording phase. Entry points (I-pictures) are identified and recorded with associated timing information and position data in an index file. This preliminary organization of data during recording enables rapid random access during playback without requiring complete stream scanning, thus improving access speed while maintaining data completeness.
Solution Approach 2:
The patent introduces an index file as an intermediary between the complete AV stream and the random access functionality. The index file contains pre-extracted information about I-picture positions, timing data, and stream structure, serving as a mediator that enables fast seeking and decoding without requiring the system to parse the entire AV stream during access operations.
4Productivity
If buffer capacity is exceeded in variable rate recording, then data must be discarded, but complete streams are lost
Solution Approach 1:
The patent applies local quality differentiation by assigning different discarding priorities to different picture types within the bitstream. When buffer capacity is exceeded, the system selectively discards non-I pictures (P-B pictures) while preserving I-pictures. This localized quality management ensures that the most critical picture data is retained while less essential data is sacrificed to maintain buffer constraints.
Solution Approach 2:
The patent implements a selective discarding strategy where non-I pictures are discarded when buffer capacity is exceeded, but the ability to recover complete streams is maintained through the preservation of I-picture entry points. Since I-pictures contain complete picture information and can serve as independent decoding starting points, discarding intermediate P-B pictures temporarily does not permanently lose the ability to reconstruct complete streams from the retained I-picture boundaries.
Data Source
AI summary
An AV stream, as an entity of contents, is managed by ClipInformation. The reproduction of the AV stream is managed by PlayList. The attribute information of the AV stream is recorded in the ClipInformation, whereby the attribute information may include address information corresponding to the discontinuous point in the AV stream, information correlating the time information in the AV stream and the address information, and the time information corresponding to a characteristic picture in the AV stream. This enables a preset mark to be retrieved promptly.