sbl::diagnostics::AudioCapture< MaxFrames > Class Template Reference

Detailed Description

template<uint16_t MaxFrames = 4096>
class sbl::diagnostics::AudioCapture< MaxFrames >

Always-on audio capture ring buffer for host-side analysis.

Continuously records the last MaxFrames of audio into a circular buffer. No arming needed — the buffer always has the latest audio. To read:

1. Freeze the buffer (via SWD write or app trigger) — audio keeps playing
2. Read pos_ to know the ring head position
3. Read buf_left_/buf_right_ via sbl-debugger
4. Unfreeze to resume capture
5. Unroll the ring: [pos_..MaxFrames) then [0..pos_) = chronological order

The sbl-debugger audio_capture tool handles all of this automatically.

Example: static sbl::diagnostics::AudioCapture<4096> s_audio_capture;

void audio_callback(int32_t* tx, const int32_t* rx, uint16_t frames) { render(left_buf, right_buf, frames); s_audio_capture.feed(left_buf, right_buf, frames); sbl::dsp::types::interleave_from_float(left_buf, right_buf, tx, frames); }

Cost: ~1us per 48-frame block when active. Single branch when frozen.

Template parameter MaxFrames controls buffer size and capture duration: 2048 -> 16 KB stereo, 42.7 ms @ 48kHz 4096 -> 32 KB stereo, 85.3 ms @ 48kHz (default) 8192 -> 64 KB stereo, 170.7 ms @ 48kHz 16384 -> 128 KB stereo, 341.3 ms @ 48kHz

Definition at line 43 of file audio_capture.hpp.

#include <audio_capture.hpp>

Public Member Functions
void	feed (const float *left, const float *right, uint16_t frames)
void	freeze ()
void	unfreeze ()
	Resume writing after a freeze.

Public Attributes
volatile bool	frozen_ = false
volatile bool	ready_ = false
volatile uint16_t	pos_ = 0
volatile uint32_t	written_ = 0
float	buf_left_ [MaxFrames] = {}
float	buf_right_ [MaxFrames] = {}

Static Public Attributes
static constexpr uint16_t	max_frames = MaxFrames

Member Function Documentation

feed()

template<uint16_t MaxFrames = 4096>

void sbl::diagnostics::AudioCapture< MaxFrames >::feed ( const float *  left, const float *  right, uint16_t  frames  )

inline

Call from audio callback every block. Always-on ring buffer write. No-op when frozen. ~1us for 48 stereo frames.

Definition at line 47 of file audio_capture.hpp.

References sbl::diagnostics::AudioCapture< MaxFrames >::buf_left_, sbl::diagnostics::AudioCapture< MaxFrames >::buf_right_, sbl::diagnostics::AudioCapture< MaxFrames >::frozen_, sbl::diagnostics::AudioCapture< MaxFrames >::pos_, sbl::diagnostics::AudioCapture< MaxFrames >::ready_, and sbl::diagnostics::AudioCapture< MaxFrames >::written_.

freeze()

template<uint16_t MaxFrames = 4096>

void sbl::diagnostics::AudioCapture< MaxFrames >::freeze ( )

inline

Freeze the buffer — stops writing. Audio callback continues normally. Safe to call from any context (ISR, main loop, SWD write to frozen_).

Definition at line 65 of file audio_capture.hpp.

References sbl::diagnostics::AudioCapture< MaxFrames >::frozen_.

unfreeze()

template<uint16_t MaxFrames = 4096>

void sbl::diagnostics::AudioCapture< MaxFrames >::unfreeze ( )

inline

Resume writing after a freeze.

Definition at line 68 of file audio_capture.hpp.

References sbl::diagnostics::AudioCapture< MaxFrames >::frozen_.

Member Data Documentation

frozen_

template<uint16_t MaxFrames = 4096>

volatile bool sbl::diagnostics::AudioCapture< MaxFrames >::frozen_ = false

Definition at line 128 of file audio_capture.hpp.

Referenced by sbl::diagnostics::AudioCapture< MaxFrames >::feed(), sbl::diagnostics::AudioCapture< MaxFrames >::freeze(), and sbl::diagnostics::AudioCapture< MaxFrames >::unfreeze().

ready_

template<uint16_t MaxFrames = 4096>

volatile bool sbl::diagnostics::AudioCapture< MaxFrames >::ready_ = false

Definition at line 129 of file audio_capture.hpp.

Referenced by sbl::diagnostics::AudioCapture< MaxFrames >::feed().

pos_

template<uint16_t MaxFrames = 4096>

volatile uint16_t sbl::diagnostics::AudioCapture< MaxFrames >::pos_ = 0

Definition at line 130 of file audio_capture.hpp.

Referenced by sbl::diagnostics::AudioCapture< MaxFrames >::feed().

written_

template<uint16_t MaxFrames = 4096>

volatile uint32_t sbl::diagnostics::AudioCapture< MaxFrames >::written_ = 0

Definition at line 131 of file audio_capture.hpp.

Referenced by sbl::diagnostics::AudioCapture< MaxFrames >::feed().

buf_left_

template<uint16_t MaxFrames = 4096>

float sbl::diagnostics::AudioCapture< MaxFrames >::buf_left_[MaxFrames] = {}

Definition at line 135 of file audio_capture.hpp.

Referenced by sbl::diagnostics::AudioCapture< MaxFrames >::feed().

buf_right_

template<uint16_t MaxFrames = 4096>

float sbl::diagnostics::AudioCapture< MaxFrames >::buf_right_[MaxFrames] = {}

Definition at line 136 of file audio_capture.hpp.

Referenced by sbl::diagnostics::AudioCapture< MaxFrames >::feed().

max_frames

template<uint16_t MaxFrames = 4096>

constexpr uint16_t sbl::diagnostics::AudioCapture< MaxFrames >::max_frames = MaxFrames

staticconstexpr

Definition at line 138 of file audio_capture.hpp.

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The documentation for this class was generated from the following file:

• src/sbl/common/diagnostics/audio_capture.hpp