resamplers: Rework the peaks resampler

The algorithm had been implemented the same way as the trivial resampler.  But
an important difference between the two is that the trivial resampler can write
an output as soon as the first corresponding input sample is seen, whereas the
peaks resampler must have read all input samples before writing an output
sample.

With this rework, the peaks resampler now outputs samples correctly when the
input data is spanning multiple memblocks.

diff --git a/src/pulsecore/resampler.c b/src/pulsecore/resampler.c
index c432a6f3d837da91d3f02595c09d1e06461e13d4..26aa4f8448b1cd8b08c589e83eb81e85dd9c62e8 100644 (file)
--- a/src/pulsecore/resampler.c
+++ b/src/pulsecore/resampler.c
@@ -1443,9 +1443,9 @@ static int trivial_init(pa_resampler*r) {
 
 static void peaks_resample(pa_resampler *r, const pa_memchunk *input, unsigned in_n_frames, pa_memchunk *output, unsigned *out_n_frames) {
     size_t fz;
-    unsigned o_index;
+    unsigned c, o_index = 0;
+    unsigned i, i_end = 0;
     void *src, *dst;
-    unsigned start = 0;
 
     pa_assert(r);
     pa_assert(input);
@@ -1457,25 +1457,20 @@ static void peaks_resample(pa_resampler *r, const pa_memchunk *input, unsigned i
     src = (uint8_t*) pa_memblock_acquire(input->memblock) + input->index;
     dst = (uint8_t*) pa_memblock_acquire(output->memblock) + output->index;
 
-    for (o_index = 0;; o_index++, r->peaks.o_counter++) {
-        unsigned j;
+    i = ((r->peaks.o_counter * r->i_ss.rate) / r->o_ss.rate);
+    i = i > r->peaks.i_counter ? i - r->peaks.i_counter : 0;
 
-        j = ((r->peaks.o_counter * r->i_ss.rate) / r->o_ss.rate);
-
-        if (j > r->peaks.i_counter)
-            j -= r->peaks.i_counter;
-        else
-            j = 0;
+    while (i_end < in_n_frames) {
+        i_end = (((r->peaks.o_counter+1) * r->i_ss.rate) / r->o_ss.rate);
+        i_end = i_end > r->peaks.i_counter ? i_end - r->peaks.i_counter : 0;
 
         pa_assert(o_index * fz < pa_memblock_get_length(output->memblock));
 
         if (r->work_format == PA_SAMPLE_S16NE) {
-            unsigned i, c;
-            int16_t *s = (int16_t*) ((uint8_t*) src + fz * start);
+            int16_t *s = (int16_t*) ((uint8_t*) src + fz * i);
             int16_t *d = (int16_t*) ((uint8_t*) dst + fz * o_index);
 
-            for (i = start; i <= j && i < in_n_frames; i++)
-
+            for (; i < i_end && i < in_n_frames; i++)
                 for (c = 0; c < r->o_ss.channels; c++, s++) {
                     int16_t n;
 
@@ -1485,22 +1480,20 @@ static void peaks_resample(pa_resampler *r, const pa_memchunk *input, unsigned i
                         r->peaks.max_i[c] = n;
                 }
 
-            if (i >= in_n_frames)
-                break;
-
-            for (c = 0; c < r->o_ss.channels; c++, d++) {
-                *d = r->peaks.max_i[c];
-                r->peaks.max_i[c] = 0;
+            if (i == i_end) {
+                for (c = 0; c < r->o_ss.channels; c++, d++) {
+                    *d = r->peaks.max_i[c];
+                    r->peaks.max_i[c] = 0;
+                }
+                o_index++, r->peaks.o_counter++;
             }
-
         } else {
-            unsigned i, c;
-            float *s = (float*) ((uint8_t*) src + fz * start);
+            float *s = (float*) ((uint8_t*) src + fz * i);
             float *d = (float*) ((uint8_t*) dst + fz * o_index);
 
             pa_assert(r->work_format == PA_SAMPLE_FLOAT32NE);
 
-            for (i = start; i <= j && i < in_n_frames; i++)
+            for (; i < i_end && i < in_n_frames; i++)
                 for (c = 0; c < r->o_ss.channels; c++, s++) {
                     float n = fabsf(*s);
 
@@ -1508,16 +1501,14 @@ static void peaks_resample(pa_resampler *r, const pa_memchunk *input, unsigned i
                         r->peaks.max_f[c] = n;
                 }
 
-            if (i >= in_n_frames)
-                break;
-
-            for (c = 0; c < r->o_ss.channels; c++, d++) {
-                *d = r->peaks.max_f[c];
-                r->peaks.max_f[c] = 0;
+            if (i == i_end) {
+                for (c = 0; c < r->o_ss.channels; c++, d++) {
+                    *d = r->peaks.max_f[c];
+                    r->peaks.max_f[c] = 0;
+                }
+                o_index++, r->peaks.o_counter++;
             }
         }
-
-        start = j;
     }
 
     pa_memblock_release(input->memblock);