PCM Audio Frame Footer Marking for DSD Format Identification
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Solution Overview
Problem
Conventional audio data transmission methods, such as DSD over PCM, incur bandwidth overhead due to header marking, leading to increased power consumption and complexity in multi-purpose data lines, particularly in consumer devices like mobile phones.
Innovation Solution
Using a footer stored in low-order bits of audio data frames to indicate encoding, allowing for improved bandwidth utilization and reduced power consumption by marking PCM data instead of DSD data, enabling operation at lower sample rates without additional overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a header marker is used to indicate DSD data in a PCM data stream, then the encoding can be identified, but bandwidth is reduced due to overhead
Solution Approach 1:
Instead of placing the marker at the beginning of the data frame (header), the patent places it at the end (footer). This inversion allows the marker to be appended without interfering with the main data payload, thereby preserving bandwidth while still enabling format identification. The footer approach minimizes overhead impact on the primary data transmission.
Solution Approach 2:
The marker is extracted from the main data payload and placed in a separate footer section. This separation allows the marker to be processed independently without consuming bandwidth that would otherwise be available for audio data transmission, thus resolving the contradiction between identification reliability and bandwidth efficiency.
2Reliability
If a control line is added to indicate data encoding, then format identification is enabled, but circuit complexity increases
Solution Approach 1:
The patent merges the format identification function with the existing audio data transmission by embedding the marker within the same data stream as the audio payload. This eliminates the need for a separate control line, thereby maintaining format identification capability while avoiding additional circuit complexity.
Solution Approach 2:
The data stream is designed to serve multiple functions: it carries both the audio data payload and the format identification marker within the same transmission channel. This multi-functionality eliminates the need for dedicated control lines, reducing circuit complexity while maintaining reliable format identification.
3Quantity of substance
If more data is transmitted per frame, then bandwidth efficiency improves, but error detection becomes more difficult
Solution Approach 1:
The data frame is segmented into distinct sections: the main audio payload and the footer marker. This segmentation allows the marker to be independently processed for error detection and format identification, while the main payload carries maximum audio data. The separation enables efficient error detection without sacrificing bandwidth efficiency.
Data Source
AI summary
An encoding for data in an audio data stream may be indicated in the data stream using a footer stored in low-order bits of data frames in the audio data stream. When the audio data stream may include either Pulse Code Modulation (PCM) or Direct Stream Digital (DSD) data, PCM data may be marked with a footer to indicate the encoding as PCM. The footer may be a fixed value, an alternating fixed value, a predetermined sequence of values, or a value computed based on the PCM data. Examples of computed values for the footer marker may include an error code, an error correction code (ECC), and a scrambled code.