Miroslav Lichvar цкщеу:
> +/*
> + * This is used to avoid overflow with unusual signals in 32-bit
> + * accumulator in the *precompute_partition_info_sums_* functions.
> + */
> +#define FLAC__MAX_EXTRA_RESIDUAL_BPS 4
> + /* WATCHOUT: "+ bps + FLAC__MAX_EXTRA_RESIDUAL_BPS" is the
> maximum
> + * assumed size of the average residual magnitude */
> + if(FLAC__bitmath_ilog2(default_partition_samples) + bps +
> FLAC__MAX_EXTRA_RESIDUAL_BPS < 32) {
From FLAC__fixed_compute_residual:
residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] +
data[i-4];
so max(residual[i]) == 16 * max(data[j]), or: max_bps(residual[]) == 4 +
max_bps(data[]).
Am I right that it's the reason why FLAC__MAX_EXTRA_RESIDUAL_BPS is equal to 4?
_______________________________________________
flac-dev mailing list
flac-dev@xiph.org
http://lists.xiph.org/mailman/listinfo/flac-dev
