*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
*
- *
* Note: 7th December 2004: This file used to be licensed under the GPL,
* but we got permission from Ralp Loader to relicense it to LGPL.
- *
+ *
* $Id$
*
*/
}
stack_entry;
-#define STACK_SIZE (CONVOLVE_DEPTH * 3)
-
struct _struct_convolve_state
{
- double left[CONVOLVE_BIG];
- double right[CONVOLVE_SMALL * 3];
- double scratch[CONVOLVE_SMALL * 3];
- stack_entry stack[STACK_SIZE + 1];
+ int depth, small, big, stack_size;
+ double *left;
+ double *right;
+ double *scratch;
+ stack_entry *stack;
};
/*
* The pointer should be freed when it is finished with, by convolve_close().
*/
convolve_state *
-convolve_init (void)
+convolve_init (int depth)
{
- return (convolve_state *) calloc (1, sizeof (convolve_state));
+ convolve_state *state;
+
+ state = malloc (sizeof (convolve_state));
+ state->depth = depth;
+ state->small = (1 << depth);
+ state->big = (2 << depth);
+ state->stack_size = depth * 3;
+ state->left = calloc (state->big, sizeof (double));
+ state->right = calloc (state->small * 3, sizeof (double));
+ state->scratch = calloc (state->small * 3, sizeof (double));
+ state->stack = calloc (state->stack_size + 1, sizeof (stack_entry));
+ return state;
}
/*
void
convolve_close (convolve_state * state)
{
+ free (state->left);
+ free (state->right);
+ free (state->scratch);
+ free (state->stack);
free (state);
}
} while (top->b.main != NULL);
}
-int
-convolve_match (const int *lastchoice,
- const short *input, convolve_state * state)
-/* lastchoice is a 256 sized array. input is a 512 array. We find the
- * contiguous length 256 sub-array of input that best matches lastchoice.
- * A measure of how good a sub-array is compared with the lastchoice is
- * given by the sum of the products of each pair of entries. We maximise
+/*
+ * convolve_match:
+ * @lastchoice: an array of size SMALL.
+ * @input: an array of size BIG (2*SMALL)
+ * @state: a (non-NULL) pointer returned by convolve_init.
+ *
+ * We find the contiguous SMALL-size sub-array of input that best matches
+ * lastchoice. A measure of how good a sub-array is compared with the lastchoice
+ * is given by the sum of the products of each pair of entries. We maximise
* that, by taking an appropriate convolution, and then finding the maximum
- * entry in the convolutions. state is a (non-NULL) pointer returned by
- * convolve_init. */
+ * entry in the convolutions.
+ *
+ * Return: the position of the best match
+ */
+int
+convolve_match (const int *lastchoice, const short *input,
+ convolve_state * state)
{
- double avg;
+ double avg = 0;
double best;
int p = 0;
int i;
double *left = state->left;
double *right = state->right;
double *scratch = state->scratch;
- stack_entry *top = state->stack + (STACK_SIZE - 1);
+ stack_entry *top = state->stack + (state->stack_size - 1);
-#if 1
- for (i = 0; i < 512; i++)
+ for (i = 0; i < state->big; i++)
left[i] = input[i];
- avg = 0;
- for (i = 0; i < 256; i++) {
- double a = lastchoice[255 - i];
+ for (i = 0; i < state->small; i++) {
+ double a = lastchoice[(state->small - 1) - i];
right[i] = a;
avg += a;
}
-#endif
+
/* We adjust the smaller of the two input arrays to have average
* value 0. This makes the eventual result insensitive to both
* constant offsets and positive multipliers of the inputs. */
- avg /= 256;
- for (i = 0; i < 256; i++)
+ avg /= state->small;
+ for (i = 0; i < state->small; i++)
right[i] -= avg;
/* End-of-stack marker. */
top[1].b.null = scratch;
top[1].b.main = NULL;
- /* The low 256x256, of which we want the high 256 outputs. */
+ /* The low (small x small) part, of which we want the high outputs. */
top->v.left = left;
top->v.right = right;
- top->v.out = right + 256;
- convolve_run (top, 256, scratch);
+ top->v.out = right + state->small;
+ convolve_run (top, state->small, scratch);
- /* The high 256x256, of which we want the low 256 outputs. */
- top->v.left = left + 256;
+ /* The high (small x small) part, of which we want the low outputs. */
+ top->v.left = left + state->small;
top->v.right = right;
top->v.out = right;
- convolve_run (top, 256, scratch);
+ convolve_run (top, state->small, scratch);
/* Now find the best position amoungs this. Apart from the first
* and last, the required convolution outputs are formed by adding
* outputs from the two convolutions above. */
- best = right[511];
- right[767] = 0;
+ best = right[state->big - 1];
+ right[state->big + state->small - 1] = 0;
p = -1;
- for (i = 0; i < 256; i++) {
- double a = right[i] + right[i + 512];
+ for (i = 0; i < state->small; i++) {
+ double a = right[i] + right[i + state->big];
if (a > best) {
best = a;
#if 0
{
/* This is some debugging code... */
- int bad = 0;
-
best = 0;
- for (i = 0; i < 256; i++)
+ for (i = 0; i < state->small; i++)
best += ((double) input[i + p]) * ((double) lastchoice[i] - avg);
- for (i = 0; i < 257; i++) {
+ for (i = 0; i <= state->small; i++) {
double tot = 0;
unsigned int j;
- for (j = 0; j < 256; j++)
+ for (j = 0; j < state->small; j++)
tot += ((double) input[i + j]) * ((double) lastchoice[j] - avg);
if (tot > best)
printf ("(%i)", i);
- if (tot != left[i + 255])
+ if (tot != left[i + (state->small - 1)])
printf ("!");
}
projects / platform / upstream / gst-plugins-good.git / blobdiff