const uint16_t* CLAVPixFmtConverter::GetRandomDitherCoeffs(int height, int coeffs, int bits, int line)
{
if (m_pSettings->GetDitherMode() != LAVDither_Random)
return nullptr;
int totalWidth = 8 * coeffs;
if (!m_pRandomDithers || totalWidth > m_ditherWidth || height > m_ditherHeight || bits != m_ditherBits) {
if (m_pRandomDithers)
_aligned_free(m_pRandomDithers);
m_pRandomDithers = nullptr;
m_ditherWidth = totalWidth;
m_ditherHeight = height;
m_ditherBits = bits;
m_pRandomDithers = (uint16_t *)_aligned_malloc(m_ditherWidth * m_ditherHeight * 2, 16);
#ifdef DEBUG
LARGE_INTEGER frequency, start, end;
QueryPerformanceFrequency(&frequency);
QueryPerformanceCounter(&start);
DbgLog((LOG_TRACE, 10, L"Creating dither matrix"));
#endif
// Seed random number generator
time_t seed = time(nullptr);
seed >>= 1;
srand_sse((unsigned int)seed);
bits = (1 << bits);
for (int i = 0; i < m_ditherHeight; i++) {
uint16_t *ditherline = m_pRandomDithers + (m_ditherWidth * i);
for (int j = 0; j < m_ditherWidth; j += 4) {
int rnds[4];
rand_sse(rnds);
ditherline[j+0] = rnds[0] % bits;
ditherline[j+1] = rnds[1] % bits;
ditherline[j+2] = rnds[2] % bits;
ditherline[j+3] = rnds[3] % bits;
}
}
#ifdef DEBUG
QueryPerformanceCounter(&end);
double diff = (end.QuadPart - start.QuadPart) * 1000.0 / frequency.QuadPart;
DbgLog((LOG_TRACE, 10, L"Finished creating dither matrix (took %2.3fms)", diff));
#endif
}
if (line < 0 || line >= m_ditherHeight)
line = rand() % m_ditherHeight;
return &m_pRandomDithers[line * m_ditherWidth];
}
short rand_sse()
{
unsigned int result[4];
rand_sse(result);
return (short)*result;
}
