ESP ASRC

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ESP ASRC (esp_asrc) is a sample rate, bit depth, and channel conversion component for audio pipelines, aligning audio formats between modules such as playback, recording, Bluetooth audio, and speech front-end. The component uses a software-hardware co-design architecture: on SoCs with ASRC hardware, the hardware path offers low-latency, low-CPU real-time conversion; otherwise an optimized software path is used, ensuring the same API is usable across different SoCs.

Key Features

  • Sample rate conversion: supports conversion between common speech, music, and communication sample rates, up to 192 kHz (subject to driver verification)

  • Bit depth conversion: supports 8-bit unsigned PCM and 16/24/32-bit signed interleaved PCM

  • Channel conversion: supports mapping and mixing between mono, stereo, and multi-channel, for compatibility with codecs, Bluetooth, and algorithm modules

  • Software-hardware co-design: supports AUTO strategy to automatically select hardware or software paths

  • Low resource usage: hardware path reduces CPU usage; software path trades off quality, speed, and memory via a complexity parameter

  • Alignment helper: provides buffer alignment query and allocation interfaces for safe use in PSRAM, cache, and hardware DMA scenarios

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