ref: 4a1a3de04de21a211c958ae62a77166cbc258d30
parent: 8873f38b8b4a2ef5210e6b6c870d184f005ae70e
author: robs <robs>
date: Sun Dec 17 04:25:07 EST 2006
Make dither alias for mask, add amount parameter, clipping detection, & nullification
--- a/src/mask.c
+++ b/src/mask.c
@@ -9,6 +9,8 @@
/*
* Sound Tools masking noise effect file.
+ *
+ * TODO: does triangular noise, could do local shaping
*/
#include <stdlib.h>
@@ -15,102 +17,101 @@
#include <math.h>
#include "st_i.h"
-static st_effect_t st_mask_effect;
+typedef struct mask {+ double amount;
+} * mask_t;
-#define HALFABIT 1.44 /* square root of 2 */
+assert_static(sizeof(struct mask) <= ST_MAX_EFFECT_PRIVSIZE,
+ /* else */ mask_PRIVSIZE_too_big);
-/*
- * Problems:
- * 1) doesn't allow specification of noise depth
- * 2) does triangular noise, could do local shaping
- * 3) can run over 32 bits.
- */
-
-/*
- * Process options
- */
-static int st_mask_getopts(eff_t effp UNUSED, int n, char **argv UNUSED)
+static int st_mask_getopts(eff_t effp, int n, char * * argv)
{- if (n)
- {- st_fail(st_mask_effect.usage);
- return (ST_EOF);
- }
- /* should take # of bits */
+ mask_t mask = (mask_t) effp->priv;
- st_initrand();
- return (ST_SUCCESS);
+ if (n > 1) {+ st_fail(effp->h->usage);
+ return ST_EOF;
+ }
+
+ mask->amount = M_SQRT2; /* Default to half a bit. */
+ if (n == 1) {+ double amount;
+ char dummy;
+ int scanned = sscanf(*argv, "%lf %c", &amount, &dummy);
+ if (scanned == 1 && amount > 0)
+ mask->amount *= amount;
+ else {+ st_fail(effp->h->usage);
+ return ST_EOF;
+ }
+ }
+
+ return ST_SUCCESS;
}
-/*
- * Processed signed long samples from ibuf to obuf.
- * Return number of samples processed.
- */
-static int st_mask_flow(eff_t effp, const st_sample_t *ibuf, st_sample_t *obuf,
- st_size_t *isamp, st_size_t *osamp)
+static int st_mask_start(eff_t effp)
{- int len, done;
-
- st_sample_t l;
- st_sample_t tri16; /* 16 signed bits of triangular noise */
+ mask_t mask = (mask_t) effp->priv;
- len = ((*isamp > *osamp) ? *osamp : *isamp);
- switch (effp->outinfo.encoding) {- case ST_ENCODING_ULAW:
- case ST_ENCODING_ALAW:
- for(done = 0; done < len; done++) {- tri16 =
- ((rand()%32768L) + (rand()%32768L)) - 32767;
+ if (effp->outinfo.encoding == ST_ENCODING_ULAW ||
+ effp->outinfo.encoding == ST_ENCODING_ALAW) {+ mask->amount *= 16;
+ return ST_SUCCESS;
+ }
+ if (effp->outinfo.size == ST_SIZE_BYTE) {+ mask->amount *= 256;
+ return ST_SUCCESS;
+ }
+ if (effp->outinfo.size == ST_SIZE_WORD)
+ return ST_SUCCESS;
- l = *ibuf++ + tri16*16*HALFABIT; /* 2^4.5 */
- *obuf++ = l;
- }
- break;
- default:
- switch (effp->outinfo.size) {- case ST_SIZE_BYTE:
- for(done = 0; done < len; done++) {- tri16 =
- ((rand()%32768L) + (rand()%32768L)) - 32767;
+ return ST_EFF_NULL; /* Dithering not needed at >= 24 bits */
+}
- l = *ibuf++ + tri16*256*HALFABIT; /* 2^8.5 */
- *obuf++ = l;
- }
- break;
- case ST_SIZE_WORD:
- for(done = 0; done < len; done++) {- tri16 =
- ((rand()%32768L) + (rand()%32768L)) - 32767;
+static int st_mask_flow(eff_t effp, const st_sample_t * ibuf,
+ st_sample_t * obuf, st_size_t * isamp, st_size_t * osamp)
+{+ mask_t mask = (mask_t) effp->priv;
+ st_size_t len = *isamp > *osamp ? *osamp : *isamp;
- l = *ibuf++ + tri16*HALFABIT; /* 2^.5 */
- *obuf++ = l;
- }
- break;
- default: /* Mask (dither) not needed at >= 24 bits */
- for(done = 0; done < len; done++) {- *obuf++ = *ibuf++;
- }
- break;
- }
- }
+ *isamp = *osamp = len;
+ while (len--)
+ { /* 16 signed bits of triangular noise */+ int tri16 = ((rand() % 32768L) + (rand() % 32768L)) - 32767;
+ double l = *ibuf++ + tri16 * mask->amount;
+ *obuf++ = ST_ROUND_CLIP_COUNT(l, effp->clippedCount);
+ }
+ return ST_SUCCESS;
+}
- *isamp = done;
- *osamp = done;
- return (ST_SUCCESS);
-}
-
static st_effect_t st_mask_effect = {"mask",
- "Usage: Mask effect takes no options",
+ "Usage: mask [amount]",
ST_EFF_MCHAN,
st_mask_getopts,
- st_effect_nothing,
+ st_mask_start,
st_mask_flow,
st_effect_nothing_drain,
st_effect_nothing
};
-const st_effect_t *st_mask_effect_fn(void)
+st_effect_t const * st_mask_effect_fn(void)
{- return &st_mask_effect;
+ return &st_mask_effect;
+}
+
+static st_effect_t st_dither_effect = {+ "dither",
+ "Usage: dither [amount]",
+ ST_EFF_MCHAN,
+ st_mask_getopts,
+ st_mask_start,
+ st_mask_flow,
+ st_effect_nothing_drain,
+ st_effect_nothing
+};
+
+st_effect_t const * st_dither_effect_fn(void)
+{+ return &st_dither_effect;
}
--
⑨