bell

Core audio utils library used in cspot and euphonium projects.

What's included:

• HTTPServer, HTTPClient - no need to explain
• BufferedStream - wrapper for ByteStream with a worker-thread ring buffer
• Crypto (openssl and mbedtls backed)
• Audio sinks interface:
  • for Unix/Cygwin: ALSA, PortAudio, named pipe outputs (see root CMakeLists for options)
  • for ESP32: DACs (AC101, ES8388, ES9018, PCM5102, TAS5711), S/PDIF over I2S, internal DAC output
  • → see src/audio/sinks/esp for pin configuration, etc.
• Abstraction layer over multiple audio codecs: (disable with BELL_DISABLE_CODECS)
  • AAC - using libhelix-aac - enabled with BELL_CODEC_AAC
  • MP3 - using libhelix-mp3 - enabled with BELL_CODEC_MP3
  • Vorbis - using Xiph.org's tremor - enabled with BELL_CODEC_VORBIS
  • Opus - using Xiph.org's reference Opus impl - enabled with BELL_CODEC_OPUS
• Audio container reading classes, with random access support:
  • Mpeg4Container - supports MPEG-4 and QuickTime files, either with or without video, fragmented or not
• cJSON library with JSONObject wrapper (disable with BELL_DISABLE_CJSON)
• Logging utilities
• Nanopb protobuf library, for use in CMake
• Semaphore implementations for multiple platforms