#ifdef local_abs
#undef local_abs
#endif
-#define local_abs(x) ((x)<0? -(x) : (x))
+#define local_abs(x) ((unsigned)((x)<0? -(x) : (x)))
unsigned FLAC__fixed_compute_best_predictor(const int32 data[], unsigned data_len, real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
{
int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
int32 error_0, error_1, error_2, error_3, error_4;
- int32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
+ uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
unsigned i, order;
for(i = 0; i < data_len; i++) {
error_3 = error_2 - last_error_2; total_error_3 += local_abs(error_3);
error_4 = error_3 - last_error_3; total_error_4 += local_abs(error_4);
+ /* WATCHOUT - total_error_* has been know to overflow when encoding
+ * erratic signals when the bits-per-sample is large. We avoid the
+ * speed penalty of watching for overflow, and instead rely on the
+ * encoder's evaluation of the subframe to catch these cases.
+ */
+
last_error_0 = error_0;
last_error_1 = error_1;
last_error_2 = error_2;
/* Estimate the expected number of bits per residual signal sample. */
/* 'total_error*' is linearly related to the variance of the residual */
/* signal, so we use it directly to compute E(|x|) */
- residual_bits_per_sample[0] = (real)((total_error_0 > 0 && data_len > 0) ? log(M_LN2 * total_error_0 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[1] = (real)((total_error_1 > 0 && data_len > 0) ? log(M_LN2 * total_error_1 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[2] = (real)((total_error_2 > 0 && data_len > 0) ? log(M_LN2 * total_error_2 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[3] = (real)((total_error_3 > 0 && data_len > 0) ? log(M_LN2 * total_error_3 / (real) data_len) / M_LN2 : 0.0);
- residual_bits_per_sample[4] = (real)((total_error_4 > 0 && data_len > 0) ? log(M_LN2 * total_error_4 / (real) data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[0] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_0 / (real) data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[1] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_1 / (real) data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[2] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_2 / (real) data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[3] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_3 / (real) data_len) / M_LN2 : 0.0);
+ residual_bits_per_sample[4] = (real)((data_len > 0) ? log(M_LN2 * (real)total_error_4 / (real) data_len) / M_LN2 : 0.0);
return order;
}