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-rw-r--r--src/map-file2
-rw-r--r--src/pulse/volume.c91
-rw-r--r--src/pulse/volume.h14
-rw-r--r--src/tests/voltest.c29
4 files changed, 136 insertions, 0 deletions
diff --git a/src/map-file b/src/map-file
index 06ee4e17..9c9e1c7c 100644
--- a/src/map-file
+++ b/src/map-file
@@ -100,10 +100,12 @@ pa_cvolume_avg;
pa_cvolume_channels_equal_to;
pa_cvolume_compatible;
pa_cvolume_equal;
+pa_cvolume_get_balance;
pa_cvolume_init;
pa_cvolume_max;
pa_cvolume_remap;
pa_cvolume_set;
+pa_cvolume_set_balance;
pa_cvolume_snprint;
pa_cvolume_valid;
pa_ext_stream_restore_delete;
diff --git a/src/pulse/volume.c b/src/pulse/volume.c
index ace5c4d6..d4b1fd98 100644
--- a/src/pulse/volume.c
+++ b/src/pulse/volume.c
@@ -402,3 +402,94 @@ int pa_cvolume_compatible(const pa_cvolume *v, const pa_sample_spec *ss) {
return v->channels == ss->channels;
}
+
+static void get_avg_lr(const pa_channel_map *map, const pa_cvolume *v, pa_volume_t *l, pa_volume_t *r) {
+ int c;
+ pa_volume_t left = 0, right = 0;
+ unsigned n_left = 0, n_right = 0;
+
+ pa_assert(v);
+ pa_assert(map);
+ pa_assert(map->channels == v->channels);
+ pa_assert(l);
+ pa_assert(r);
+
+ for (c = 0; c < map->channels; c++) {
+ if (on_left(map->map[c])) {
+ left += v->values[c];
+ n_left++;
+ } else if (on_right(map->map[c])) {
+ right += v->values[c];
+ n_right++;
+ }
+ }
+
+ *l = left / n_left;
+ *r = right / n_right;
+}
+
+float pa_cvolume_get_balance(const pa_channel_map *map, const pa_cvolume *v) {
+ pa_volume_t left, right;
+
+ pa_assert(v);
+ pa_assert(map);
+ pa_assert(map->channels == v->channels);
+
+ get_avg_lr(map, v, &left, &right);
+
+ if (left == right)
+ return 0.0f;
+
+ /* 1.0, 0.0 => -1.0
+ 0.0, 1.0 => 1.0
+ 0.0, 0.0 => 0.0
+ 0.5, 0.5 => 0.0
+ 1.0, 0.5 => -0.5
+ 1.0, 0.25 => -0.75
+ 0.75, 0.25 => -0.66
+ 0.5, 0.25 => -0.5 */
+
+ if (left > right)
+ return -1.0f + ((float) right / (float) left);
+ else
+ return 1.0f - ((float) left / (float) right);
+}
+
+pa_cvolume* pa_cvolume_set_balance(const pa_channel_map *map, pa_cvolume *v, float new_balance) {
+ pa_volume_t left, nleft, right, nright, m;
+ unsigned c;
+ pa_assert(map->channels == v->channels);
+
+ pa_assert(map);
+ pa_assert(v);
+ pa_assert(new_balance >= -1.0f);
+ pa_assert(new_balance <= 1.0f);
+
+ get_avg_lr(map, v, &left, &right);
+
+ m = PA_MAX(left, right);
+
+ if (new_balance <= 0) {
+ nright = (new_balance + 1.0f) * m;
+ nleft = m;
+ } else {
+ nleft = (1.0f - new_balance) * m;
+ nright = m;
+ }
+
+ for (c = 0; c < map->channels; c++) {
+ if (on_left(map->map[c])) {
+ if (left == 0)
+ v->values[c] = 0;
+ else
+ v->values[c] = (pa_volume_t) (((uint64_t) v->values[c] * (uint64_t) nleft) / (uint64_t) left);
+ } else if (on_right(map->map[c])) {
+ if (right == 0)
+ v->values[c] = 0;
+ else
+ v->values[c] = (pa_volume_t) (((uint64_t) v->values[c] * (uint64_t) nright) / (uint64_t) right);
+ }
+ }
+
+ return v;
+}
diff --git a/src/pulse/volume.h b/src/pulse/volume.h
index 5815c906..08683ac7 100644
--- a/src/pulse/volume.h
+++ b/src/pulse/volume.h
@@ -233,6 +233,20 @@ pa_cvolume *pa_cvolume_remap(pa_cvolume *v, pa_channel_map *from, pa_channel_map
* the specified sample spec. \since 0.9.13 */
int pa_cvolume_compatible(const pa_cvolume *v, const pa_sample_spec *ss) PA_GCC_PURE;
+/** Calculate a 'balance' value for the specified volume with the
+ * specified channel map. The return value will range from -1.0f
+ * (left) to +1.0f (right) \since 0.9.15 */
+float pa_cvolume_get_balance(const pa_channel_map *map, const pa_cvolume *v) PA_GCC_PURE;
+
+/** Adjust the 'balance' value for the specified volume with the
+ * specified channel map. v will be modified in place and
+ * returned. The balance is a value between -1.0f and +1.0f. This
+ * operation might not be reversable! Also, after this call
+ * pa_cvolume_get_balance() is not guaranteed to actually return the
+ * requested balance (e.g. when the input volume was zero anyway for
+ * all channels)- \since 0.9.15 */
+pa_cvolume* pa_cvolume_set_balance(const pa_channel_map *map, pa_cvolume *v, float new_balance);
+
PA_C_DECL_END
#endif
diff --git a/src/tests/voltest.c b/src/tests/voltest.c
index 5bfc97e0..879d86b9 100644
--- a/src/tests/voltest.c
+++ b/src/tests/voltest.c
@@ -6,6 +6,8 @@
int main(int argc, char *argv[]) {
pa_volume_t v;
pa_cvolume cv;
+ float b;
+ pa_channel_map map;
for (v = PA_VOLUME_MUTED; v <= PA_VOLUME_NORM*2; v += 256) {
@@ -28,5 +30,32 @@ int main(int argc, char *argv[]) {
}
+ map.channels = cv.channels = 2;
+ map.map[0] = PA_CHANNEL_POSITION_LEFT;
+ map.map[1] = PA_CHANNEL_POSITION_RIGHT;
+
+ for (cv.values[0] = PA_VOLUME_MUTED; cv.values[0] <= PA_VOLUME_NORM*2; cv.values[0] += 4096)
+ for (cv.values[1] = PA_VOLUME_MUTED; cv.values[1] <= PA_VOLUME_NORM*2; cv.values[1] += 4096) {
+ char s[PA_CVOLUME_SNPRINT_MAX];
+
+ printf("Volume: [%s]; balance: %2.1f\n", pa_cvolume_snprint(s, sizeof(s), &cv), pa_cvolume_get_balance(&map, &cv));
+ }
+
+ for (cv.values[0] = PA_VOLUME_MUTED+4096; cv.values[0] <= PA_VOLUME_NORM*2; cv.values[0] += 4096)
+ for (cv.values[1] = PA_VOLUME_MUTED; cv.values[1] <= PA_VOLUME_NORM*2; cv.values[1] += 4096)
+ for (b = -1.0f; b <= 1.0f; b += 0.2f) {
+ char s[PA_CVOLUME_SNPRINT_MAX];
+ pa_cvolume r;
+ float k;
+
+ printf("Before: volume: [%s]; balance: %2.1f\n", pa_cvolume_snprint(s, sizeof(s), &cv), pa_cvolume_get_balance(&map, &cv));
+
+ r = cv;
+ pa_cvolume_set_balance(&map, &r, b);
+
+ k = pa_cvolume_get_balance(&map, &r);
+ printf("After: volume: [%s]; balance: %2.1f (intended: %2.1f) %s\n", pa_cvolume_snprint(s, sizeof(s), &r), k, b, k < b-.05 || k > b+.5 ? "MISMATCH" : "");
+ }
+
return 0;
}