Audio Decoder Special Frames for Seamless Codec Switching
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Solution Overview
Problem
Existing audio encoding and decoding technologies face challenges in seamlessly switching between different codec configurations, leading to disruptions in audio playback when adapting to varying network conditions, such as those encountered in DSL, WiFi, 3G, and LTE environments, due to fluctuations in bitrate.
Innovation Solution
Incorporating a special frame within the audio data stream that includes additional information from preceding frames encoded using the same codec configuration, allowing the decoder to initialize and switch seamlessly between different codec configurations, ensuring immediate playback and adaptation to changing network conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the decoder switches between different codec configurations to adapt to varying network conditions, then the adaptability is improved, but the continuity of audio playback deteriorates due to initialization disruptions
Solution Approach 1:
The patent embeds pre-roll frames (additional information) within the bit stream that contain encoded audio sample values from preceding frames. When the decoder encounters a special frame indicating a codec configuration change, it can immediately initialize using these pre-loaded frames without waiting for subsequent frames to arrive, thereby maintaining playback continuity while switching between different codec configurations to adapt to network conditions
2Loss of time
If the decoder initializes with pre-roll frames to enable immediate playback, then the startup time is reduced, but the bit stream complexity increases due to additional information embedding
Solution Approach 1:
The patent merges the pre-roll frames (additional information) directly into the existing bit stream structure by embedding them within special frames. This integration approach allows the decoder to access initialization data without requiring separate initialization sequences or additional processing steps, thereby reducing initialization time while minimizing the increase in bit stream complexity
3Reliability
If the bit stream includes additional information from preceding frames, then the decoder initialization capability is improved, but the data transmission volume increases
Solution Approach 1:
The patent embeds copies of encoded audio sample values from preceding frames (pre-roll frames) into the bit stream at strategic positions. These copied frames provide the decoder with all necessary initialization data to immediately reconstruct audio output when switching codec configurations, ensuring reliable initialization while keeping the additional data volume minimal by only copying essential frames rather than entire audio sequences
Data Source
AI summary
An audio decoder decodes a bit stream of encoded audio data, which bit stream represents a sequence of audio sample values and includes a plurality of frames, wherein each frame includes associated encoded audio sample values. The audio decoder includes a determiner configured to determine whether a frame of the encoded audio data is a special frame including encoded audio sample values associated with the special frame and additional information, wherein the additional information include encoded audio sample values of a number of frames preceding the special frame, wherein the encoded audio sample values of the preceding frames are encoded using the same codec configuration as the special frame, wherein the number of preceding frames is sufficient to initialize the decoder to be in a position to decode the audio sample values associated with the special frame if the special frame is the first frame upon start-up of the decoder.