remap: Refactor channel remap table computation calc_map_table()

[pulseaudio] / src / pulsecore / resampler.c

diff --git a/src/pulsecore/resampler.c b/src/pulsecore/resampler.c
index db65ceaad164037058afeb0b44630eefbb91ebd2..cbe5e522c527ef4ad82b8924b9046acefb7a1a5c 100644 (file)
--- a/src/pulsecore/resampler.c
+++ b/src/pulsecore/resampler.c
@@ -114,7 +114,7 @@ static int peaks_init(pa_resampler*r);
 static int libsamplerate_init(pa_resampler*r);
 #endif
 
-static void calc_map_table(pa_resampler *r);
+static void calc_map_table(const pa_resampler *r, pa_remap_t *m);
 
 static int (* const init_table[])(pa_resampler*r) = {
 #ifdef HAVE_LIBSAMPLERATE
@@ -396,14 +396,12 @@ pa_resampler* pa_resampler_new(
     r->i_fz = pa_frame_size(a);
     r->o_fz = pa_frame_size(b);
 
-    calc_map_table(r);
-
-    pa_log_info("Using resampler '%s'", pa_resample_method_to_string(method));
+    /* compute channel remap table if needed */
+    if ((r->map_required = (r->i_ss.channels != r->o_ss.channels || (!(r->flags & PA_RESAMPLER_NO_REMAP) &&
+        !pa_channel_map_equal(&r->i_cm, &r->o_cm)))))
+        calc_map_table(r, &r->remap);
 
     r->work_format = pa_resampler_choose_work_format(method, a->format, b->format, r->map_required);
-
-    pa_log_info("Using %s as working format.", pa_sample_format_to_string(r->work_format));
-
     r->w_sz = pa_sample_size_of_format(r->work_format);
 
     if (r->i_ss.format != r->work_format) {
@@ -428,14 +426,31 @@ pa_resampler* pa_resampler_new(
         }
     }
 
-    /* leftover buffer is the buffer before the resampling stage */
-    r->leftover_buf = &r->remap_buf;
-    r->leftover_buf_size = &r->remap_buf_size;
-    r->have_leftover = &r->leftover_in_remap;
+    if (r->o_ss.channels <= r->i_ss.channels) {
+        /* pipeline is: format conv. -> remap -> resample -> format conv. */
+        r->work_channels = r->o_ss.channels;
 
-    r->work_channels = r->o_ss.channels;
+        /* leftover buffer is remap output buffer (before resampling) */
+        r->leftover_buf = &r->remap_buf;
+        r->leftover_buf_size = &r->remap_buf_size;
+        r->have_leftover = &r->leftover_in_remap;
+    } else {
+        /* pipeline is: format conv. -> resample -> remap -> format conv. */
+        r->work_channels = r->i_ss.channels;
+
+        /* leftover buffer is to_work output buffer (before resampling) */
+        r->leftover_buf = &r->to_work_format_buf;
+        r->leftover_buf_size = &r->to_work_format_buf_size;
+        r->have_leftover = &r->leftover_in_to_work;
+    }
     r->w_fz = pa_sample_size_of_format(r->work_format) * r->work_channels;
 
+    pa_log_debug("Resampler:");
+    pa_log_debug("  rate %d -> %d (method %s)", a->rate, b->rate, pa_resample_method_to_string(r->method));
+    pa_log_debug("  format %s -> %s (intermediate %s)", pa_sample_format_to_string(a->format),
+                 pa_sample_format_to_string(b->format), pa_sample_format_to_string(r->work_format));
+    pa_log_debug("  channels %d -> %d (resampling %d)", a->channels, b->channels, r->work_channels);
+
     /* initialize implementation */
     if (init_table[method](r) < 0)
         goto fail;
@@ -773,21 +788,16 @@ static int front_rear_side(pa_channel_position_t p) {
     return ON_OTHER;
 }
 
-static void calc_map_table(pa_resampler *r) {
+static void calc_map_table(const pa_resampler *r, pa_remap_t *m) {
     unsigned oc, ic;
     unsigned n_oc, n_ic;
     bool ic_connected[PA_CHANNELS_MAX];
     bool remix;
     pa_strbuf *s;
     char *t;
-    pa_remap_t *m;
 
     pa_assert(r);
-
-    if (!(r->map_required = (r->i_ss.channels != r->o_ss.channels || (!(r->flags & PA_RESAMPLER_NO_REMAP) && !pa_channel_map_equal(&r->i_cm, &r->o_cm)))))
-        return;
-
-    m = &r->remap;
+    pa_assert(m);
 
     n_oc = r->o_ss.channels;
     n_ic = r->i_ss.channels;
@@ -1138,7 +1148,7 @@ static void calc_map_table(pa_resampler *r) {
     pa_xfree(t);
 
     /* initialize the remapping function */
-    pa_init_remap(m);
+    pa_init_remap_func(m);
 }
 
 /* check if buf's memblock is large enough to hold 'len' bytes; create a
@@ -1348,8 +1358,16 @@ void pa_resampler_run(pa_resampler *r, const pa_memchunk *in, pa_memchunk *out)
 
     buf = (pa_memchunk*) in;
     buf = convert_to_work_format(r, buf);
-    buf = remap_channels(r, buf);
-    buf = resample(r, buf);
+
+    /* Try to save resampling effort: if we have more output channels than
+     * input channels, do resampling first, then remapping. */
+    if (r->o_ss.channels <= r->i_ss.channels) {
+        buf = remap_channels(r, buf);
+        buf = resample(r, buf);
+    } else {
+        buf = resample(r, buf);
+        buf = remap_channels(r, buf);
+    }
 
     if (buf->length) {
         buf = convert_from_work_format(r, buf);