[pulseaudio-discuss] [PATCH 2/4] Enabled libsoxr resampler backend.

[Andrey Semashev]

Added ID and names for the resampler presets and also updated the working sample rate deduction to take the new resampler into account. The initial libsoxr backend version does not variable rate resampling, so it is disabled in this case.
---
 src/pulsecore/resampler.c | 33 +++++++++++++++++++++++++++++----
 src/pulsecore/resampler.h |  4 ++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/src/pulsecore/resampler.c b/src/pulsecore/resampler.c
index 183d05f..6bbbff3 100644
--- a/src/pulsecore/resampler.c
+++ b/src/pulsecore/resampler.c
@@ -111,6 +111,15 @@ static int (* const init_table[])(pa_resampler *r) = {
     [PA_RESAMPLER_AUTO]                    = NULL,
     [PA_RESAMPLER_COPY]                    = copy_init,
     [PA_RESAMPLER_PEAKS]                   = pa_resampler_peaks_init,
+#ifdef HAVE_SOXR
+    [PA_RESAMPLER_SOXR_MQ]                 = pa_resampler_soxr_init,
+    [PA_RESAMPLER_SOXR_HQ]                 = pa_resampler_soxr_init,
+    [PA_RESAMPLER_SOXR_VHQ]                = pa_resampler_soxr_init,
+#else
+    [PA_RESAMPLER_SOXR_MQ]                 = NULL,
+    [PA_RESAMPLER_SOXR_HQ]                 = NULL,
+    [PA_RESAMPLER_SOXR_VHQ]                = NULL,
+#endif
 };
 
 static pa_resample_method_t choose_auto_resampler(pa_resample_flags_t flags) {
@@ -156,6 +165,9 @@ static pa_resample_method_t fix_method(
             }
                                      /* Else fall through */
         case PA_RESAMPLER_FFMPEG:
+        case PA_RESAMPLER_SOXR_MQ:
+        case PA_RESAMPLER_SOXR_HQ:
+        case PA_RESAMPLER_SOXR_VHQ:
             if (flags & PA_RESAMPLER_VARIABLE_RATE) {
                 pa_log_info("Resampler '%s' cannot do variable rate, reverting to resampler 'auto'.", pa_resample_method_to_string(method));
                 method = PA_RESAMPLER_AUTO;
@@ -278,10 +290,20 @@ static pa_sample_format_t choose_work_format(
             }
                                                 /* Else fall trough */
         case PA_RESAMPLER_PEAKS:
-            if (a == PA_SAMPLE_S16NE || b == PA_SAMPLE_S16NE)
+            /* PEAKS, COPY and TRIVIAL do not benefit from increased
+             * working precision, so for better performance use s16ne
+             * if either input or output fits in it. */
+            if (a == PA_SAMPLE_S16NE || b == PA_SAMPLE_S16NE) {
                 work_format = PA_SAMPLE_S16NE;
-            else if (sample_format_more_precise(a, PA_SAMPLE_S16NE) ||
-                     sample_format_more_precise(b, PA_SAMPLE_S16NE))
+                break;
+            }
+                                                /* Else fall trough */
+        case PA_RESAMPLER_SOXR_MQ:
+        case PA_RESAMPLER_SOXR_HQ:
+        case PA_RESAMPLER_SOXR_VHQ:
+            /* Do processing with max precision of input and output. */
+            if (sample_format_more_precise(a, PA_SAMPLE_S16NE) ||
+                sample_format_more_precise(b, PA_SAMPLE_S16NE))
                 work_format = PA_SAMPLE_FLOAT32NE;
             else
                 work_format = PA_SAMPLE_S16NE;
@@ -601,7 +623,10 @@ static const char * const resample_methods[] = {
     "ffmpeg",
     "auto",
     "copy",
-    "peaks"
+    "peaks",
+    "soxr-mq",
+    "soxr-hq",
+    "soxr-vhq"
 };
 
 const char *pa_resample_method_to_string(pa_resample_method_t m) {
diff --git a/src/pulsecore/resampler.h b/src/pulsecore/resampler.h
index 5a84cf0..a0306e7 100644
--- a/src/pulsecore/resampler.h
+++ b/src/pulsecore/resampler.h
@@ -59,6 +59,9 @@ typedef enum pa_resample_method {
     PA_RESAMPLER_AUTO, /* automatic select based on sample format */
     PA_RESAMPLER_COPY,
     PA_RESAMPLER_PEAKS,
+    PA_RESAMPLER_SOXR_MQ,
+    PA_RESAMPLER_SOXR_HQ,
+    PA_RESAMPLER_SOXR_VHQ,
     PA_RESAMPLER_MAX
 } pa_resample_method_t;
 
@@ -163,6 +166,7 @@ int pa_resampler_libsamplerate_init(pa_resampler *r);
 int pa_resampler_peaks_init(pa_resampler *r);
 int pa_resampler_speex_init(pa_resampler *r);
 int pa_resampler_trivial_init(pa_resampler*r);
+int pa_resampler_soxr_init(pa_resampler *r);
 
 /* Resampler-specific quirks */
 bool pa_speex_is_fixed_point(void);
-- 
2.1.0