From ea82dec294310b83be25b4e0c940fd2cd2c7eeb3 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 2 Oct 2008 02:29:56 +0200
Subject: when we mix into a 16bit accumulator make sure we clamp before we
 scale with a volume to avoid range faults when multiplying

---
 src/pulsecore/sample-util.c | 8 ++++----
 src/tests/mix-test.c        | 6 ++++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/pulsecore/sample-util.c b/src/pulsecore/sample-util.c
index b4234af5..25178a8a 100644
--- a/src/pulsecore/sample-util.c
+++ b/src/pulsecore/sample-util.c
@@ -214,8 +214,8 @@ size_t pa_mix(
                     m->ptr = (uint8_t*) m->ptr + sizeof(int16_t);
                 }
 
-                sum = (sum * linear[channel]) / 0x10000;
                 sum = PA_CLAMP_UNLIKELY(sum, -0x8000, 0x7FFF);
+                sum = (sum * linear[channel]) / 0x10000;
                 *((int16_t*) data) = (int16_t) sum;
 
                 data = (uint8_t*) data + sizeof(int16_t);
@@ -253,8 +253,8 @@ size_t pa_mix(
                     m->ptr = (uint8_t*) m->ptr + sizeof(int16_t);
                 }
 
-                sum = (sum * linear[channel]) / 0x10000;
                 sum = PA_CLAMP_UNLIKELY(sum, -0x8000, 0x7FFF);
+                sum = (sum * linear[channel]) / 0x10000;
                 *((int16_t*) data) = PA_INT16_SWAP((int16_t) sum);
 
                 data = (uint8_t*) data + sizeof(int16_t);
@@ -411,8 +411,8 @@ size_t pa_mix(
                     m->ptr = (uint8_t*) m->ptr + 1;
                 }
 
-                sum = (sum * linear[channel]) / 0x10000;
                 sum = PA_CLAMP_UNLIKELY(sum, -0x8000, 0x7FFF);
+                sum = (sum * linear[channel]) / 0x10000;
                 *((uint8_t*) data) = (uint8_t) st_14linear2ulaw((int16_t) sum >> 2);
 
                 data = (uint8_t*) data + 1;
@@ -450,8 +450,8 @@ size_t pa_mix(
                     m->ptr = (uint8_t*) m->ptr + 1;
                 }
 
-                sum = (sum * linear[channel]) / 0x10000;
                 sum = PA_CLAMP_UNLIKELY(sum, -0x8000, 0x7FFF);
+                sum = (sum * linear[channel]) / 0x10000;
                 *((uint8_t*) data) = (uint8_t) st_13linear2alaw((int16_t) sum >> 3);
 
                 data = (uint8_t*) data + 1;
diff --git a/src/tests/mix-test.c b/src/tests/mix-test.c
index 759d7690..cc21ab03 100644
--- a/src/tests/mix-test.c
+++ b/src/tests/mix-test.c
@@ -221,6 +221,8 @@ int main(int argc, char *argv[]) {
         i.length = pa_memblock_get_length(i.memblock);
         i.index = 0;
 
+        dump_block(&a, &i);
+
         /* Make a copy */
         j = i;
         pa_memblock_ref(j.memblock);
@@ -229,6 +231,8 @@ int main(int argc, char *argv[]) {
         /* Adjust volume of the copy */
         pa_volume_memchunk(&j, &a, &v);
 
+        dump_block(&a, &j);
+
         m[0].chunk = i;
         m[0].volume.values[0] = PA_VOLUME_NORM;
         m[0].volume.channels = a.channels;
@@ -244,8 +248,6 @@ int main(int argc, char *argv[]) {
         pa_mix(m, 2, ptr, k.length, &a, NULL, FALSE);
         pa_memblock_release(k.memblock);
 
-        dump_block(&a, &i);
-        dump_block(&a, &j);
         dump_block(&a, &k);
 
         pa_memblock_unref(i.memblock);
-- 
cgit