Source: WLEDAudioSyncPacket.h

wled_audio_sync¶

The one place this packet layout lives, built to broadcast our analyzed audio and parsed to drive effects from a peer's.

The contract is fixed upstream, so the bytes must be exact, and a unit test round-trips against a golden vector.

Functions¶

Return	Name	Description
`void`	`wledPutFloatLE` `inline`	Store a float in wire order, which on every target here is the raw bytes.
`float`	`wledGetFloatLE` `inline`
`uint16_t`	`wledFloatToU16` `inline`	Truncate a wire float into a frame field, clamped, since a foreign packet may carry anything.
`size_t`	`buildWledAudioSync` `inline`	Build a packet from a frame; `peak` is the beat flag the caller owns, and it answers the size.
`bool`	`parseWledAudioSync` `inline`	Parse and validate a packet into a frame; true only for a well-formed one of exactly the right size and header.

wledPutFloatLE¶

inline

inline void wledPutFloatLE(uint8_t * p, float v)

Store a float in wire order, which on every target here is the raw bytes.

wledGetFloatLE¶

inline

inline float wledGetFloatLE(const uint8_t * p)

wledFloatToU16¶

inline

inline uint16_t wledFloatToU16(float v)

Truncate a wire float into a frame field, clamped, since a foreign packet may carry anything.

buildWledAudioSync¶

inline

inline size_t buildWledAudioSync(uint8_t out, const AudioFrame & f, bool peak)

Build a packet from a frame; peak is the beat flag the caller owns, and it answers the size.

parseWledAudioSync¶

inline

inline bool parseWledAudioSync(const uint8_t * pkt, size_t len, AudioFrame & out)

Parse and validate a packet into a frame; true only for a well-formed one of exactly the right size and header.

Variables¶

Return	Name	Description
`constexpr uint16_t`	`WLED_SYNC_PORT` `constexpr`
`constexpr size_t`	`WLED_SYNC_PACKET_SIZE` `constexpr`
`constexpr char`	`WLED_SYNC_HEADER` `constexpr`
`constexpr size_t`	`WLED_SYNC_NUM_BANDS` `constexpr`
`constexpr float`	`kWledMagScale` `constexpr`	The divisor the upstream's own effects apply, so a byte of ours matches a native sender's brightness.

WLED_SYNC_PORT¶

constexpr

constexpr uint16_t WLED_SYNC_PORT = 11988

WLED_SYNC_PACKET_SIZE¶

constexpr

constexpr size_t WLED_SYNC_PACKET_SIZE = 44

WLED_SYNC_HEADER¶

constexpr

constexpr char WLED_SYNC_HEADER = "00002"

WLED_SYNC_NUM_BANDS¶

constexpr

constexpr size_t WLED_SYNC_NUM_BANDS = 16

kWledMagScale¶

constexpr

constexpr float kWledMagScale = 16.0f

The divisor the upstream's own effects apply, so a byte of ours matches a native sender's brightness.

More info¶

The packet¶

Forty-four bytes on a fixed port, broadcast: a header string, two levels as floats and a peak flag. Then the sixteen bands as bytes, and the dominant bin's magnitude and frequency. Two padding runs are real wire bytes and go out as zero, and one reserved byte stays zero because the upstream may claim it later. The offsets are hand-serialized rather than trusted to struct packing, and the floats are little-endian, which every target here and upstream shares.

Units convert at this boundary¶

The wire carries the upstream's magnitude units and the audio frame keeps ours, byte-scaled and conditioned by the same noise floor and gain as the bands. The scale factor is exactly the divisor its own effects apply, so a byte of ours lands on the brightness a native source would produce.