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24ceb753ee
Integer nanosecond conversion so 44.1 kHz stays exact, float seconds for the VAD and diarization messages, and saturating s16le encode so an overshooting sample cannot wrap to the opposite sign. Assisted-by: Claude:claude-opus-5 [Claude Code] Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
67 lines
2.3 KiB
C++
67 lines
2.3 KiB
C++
#include "audio_units.h"
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#include <algorithm>
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#include <cmath>
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namespace audiocpp_backend {
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std::int64_t samples_to_nanoseconds(std::int64_t samples, int sample_rate) {
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if (sample_rate <= 0) {
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return 0;
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}
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// Split into whole seconds plus a remainder so the intermediate product
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// cannot overflow on long recordings, and so rates like 44100 stay exact.
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const std::int64_t rate = static_cast<std::int64_t>(sample_rate);
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const std::int64_t whole_seconds = samples / rate;
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const std::int64_t remainder = samples % rate;
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return whole_seconds * 1000000000LL + (remainder * 1000000000LL) / rate;
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}
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float samples_to_seconds(std::int64_t samples, int sample_rate) {
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if (sample_rate <= 0) {
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return 0.0f;
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}
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return static_cast<float>(static_cast<double>(samples) /
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static_cast<double>(sample_rate));
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}
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std::int64_t seconds_to_samples(double seconds, int sample_rate) {
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if (sample_rate <= 0 || seconds <= 0.0) {
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return 0;
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}
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return static_cast<std::int64_t>(seconds * static_cast<double>(sample_rate));
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}
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std::vector<float> s16le_to_f32(const std::string &bytes) {
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std::vector<float> samples;
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const size_t count = bytes.size() / 2;
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samples.reserve(count);
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for (size_t i = 0; i < count; ++i) {
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const auto low = static_cast<unsigned char>(bytes[i * 2]);
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const auto high = static_cast<unsigned char>(bytes[i * 2 + 1]);
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const auto raw = static_cast<std::int16_t>(
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static_cast<std::uint16_t>(low) |
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(static_cast<std::uint16_t>(high) << 8));
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samples.push_back(static_cast<float>(raw) / 32768.0f);
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}
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return samples;
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}
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std::string f32_to_s16le(const std::vector<float> &samples) {
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std::string bytes;
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bytes.reserve(samples.size() * 2);
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for (const float sample : samples) {
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const float clamped = std::max(-1.0f, std::min(1.0f, sample));
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// 32767 rather than 32768 so +1.0 saturates at INT16_MAX instead of
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// overflowing to INT16_MIN.
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const auto value =
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static_cast<std::int16_t>(std::lround(clamped * 32767.0f));
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const auto raw = static_cast<std::uint16_t>(value);
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bytes.push_back(static_cast<char>(raw & 0xFF));
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bytes.push_back(static_cast<char>((raw >> 8) & 0xFF));
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}
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return bytes;
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}
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} // namespace audiocpp_backend
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