[FFmpeg-devel] [PATCH 2/4] avfilter/asrc_sine: factorize sampling to a separate context

[Marton Balint]

Signed-off-by: Marton Balint <cus at passwd.hu>
---
 libavfilter/asrc_sine.c | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/libavfilter/asrc_sine.c b/libavfilter/asrc_sine.c
index 96b603dd26..854fba6e37 100644
--- a/libavfilter/asrc_sine.c
+++ b/libavfilter/asrc_sine.c
@@ -30,6 +30,11 @@
 #include "filters.h"
 #include "formats.h"
 
+typedef struct SamplingContext {
+    uint32_t phi;  ///< current phase of the sine (2pi = 1<<32)
+    uint32_t dphi; ///< phase increment between two samples
+} SamplingContext;
+
 typedef struct SineContext {
     const AVClass *class;
     double frequency;
@@ -40,13 +45,11 @@ typedef struct SineContext {
     int64_t duration;
     int16_t *sin;
     int64_t pts;
-    uint32_t phi;  ///< current phase of the sine (2pi = 1<<32)
-    uint32_t dphi; ///< phase increment between two samples
+    SamplingContext signal;
+    SamplingContext beep;
     unsigned beep_period;
     unsigned beep_index;
     unsigned beep_length;
-    uint32_t phi_beep;  ///< current phase of the beep
-    uint32_t dphi_beep; ///< phase increment of the beep
 } SineContext;
 
 #define CONTEXT SineContext
@@ -143,6 +146,16 @@ enum {
     VAR_VARS_NB
 };
 
+static void sampling_init(SamplingContext *c, double frequency, int sample_rate)
+{
+    c->dphi = ldexp(frequency, 32) / sample_rate + 0.5;
+}
+
+static av_always_inline void sampling_advance(SamplingContext *c)
+{
+    c->phi += c->dphi;
+}
+
 static av_cold int init(AVFilterContext *ctx)
 {
     int ret;
@@ -150,14 +163,13 @@ static av_cold int init(AVFilterContext *ctx)
 
     if (!(sine->sin = av_malloc(sizeof(*sine->sin) << LOG_PERIOD)))
         return AVERROR(ENOMEM);
-    sine->dphi = ldexp(sine->frequency, 32) / sine->sample_rate + 0.5;
+    sampling_init(&sine->signal, sine->frequency, sine->sample_rate);
     make_sin_table(sine->sin);
 
     if (sine->beep_factor) {
         sine->beep_period = sine->sample_rate;
         sine->beep_length = sine->beep_period / 25;
-        sine->dphi_beep = ldexp(sine->beep_factor * sine->frequency, 32) /
-                          sine->sample_rate + 0.5;
+        sampling_init(&sine->beep, sine->beep_factor * sine->frequency, sine->sample_rate);
     }
 
     ret = av_expr_parse(&sine->samples_per_frame_expr,
@@ -241,11 +253,11 @@ static int activate(AVFilterContext *ctx)
     samples = (int16_t *)frame->data[0];
 
     for (i = 0; i < nb_samples; i++) {
-        samples[i] = sine->sin[sine->phi >> (32 - LOG_PERIOD)];
-        sine->phi += sine->dphi;
+        samples[i] = sine->sin[sine->signal.phi >> (32 - LOG_PERIOD)];
+        sampling_advance(&sine->signal);
         if (sine->beep_index < sine->beep_length) {
-            samples[i] += sine->sin[sine->phi_beep >> (32 - LOG_PERIOD)] * 2;
-            sine->phi_beep += sine->dphi_beep;
+            samples[i] += sine->sin[sine->beep.phi >> (32 - LOG_PERIOD)] * 2;
+            sampling_advance(&sine->beep);
         }
         if (++sine->beep_index == sine->beep_period)
             sine->beep_index = 0;
-- 
2.43.0