[FFmpeg-devel] [PATCH] lavf: add more beep options to sine asrc

[Michael Bradshaw]

From: Michael Bradshaw <mjbshaw at google.com>

Signed-off-by: Michael Bradshaw <mjbshaw at google.com>
---
 doc/filters.texi        | 13 ++++++++++++-
 libavfilter/asrc_sine.c | 17 +++++++++++++----
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index 57189c77b0..ec1c335950 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -4624,7 +4624,18 @@ Set the carrier frequency. Default is 440 Hz.
 
 @item beep_factor, b
 Enable a periodic beep every second with frequency @var{beep_factor} times
-the carrier frequency. Default is 0, meaning the beep is disabled.
+the carrier frequency. Default is 0, meaning the beep is disabled. If
+ at var{frequency} is 0, this value is interpreted as the beep frequency (in Hertz)
+(rather than a multiplier of the @var{frequency}).
+
+ at item beep_delay
+The delay for the first beep, in seconds. Default is 0.
+
+ at item beep_period
+The time beriod between two beeps, in seconds. Default is 1.
+
+ at item beep_duration
+The duration of a beep, in seconds. Default is 0.04.
 
 @item sample_rate, r
 Specify the sample rate, default is 44100.
diff --git a/libavfilter/asrc_sine.c b/libavfilter/asrc_sine.c
index 3a87210b4b..643952792f 100644
--- a/libavfilter/asrc_sine.c
+++ b/libavfilter/asrc_sine.c
@@ -32,6 +32,9 @@ typedef struct SineContext {
     const AVClass *class;
     double frequency;
     double beep_factor;
+    double beep_delay;
+    double beep_period_opt;
+    double beep_duration;
     char *samples_per_frame;
     AVExpr *samples_per_frame_expr;
     int sample_rate;
@@ -71,6 +74,9 @@ static const AVOption sine_options[] = {
     OPT_DBL("f",                 frequency,            440, 0, DBL_MAX,   "set the sine frequency",),
     OPT_DBL("beep_factor",       beep_factor,            0, 0, DBL_MAX,   "set the beep frequency factor",),
     OPT_DBL("b",                 beep_factor,            0, 0, DBL_MAX,   "set the beep frequency factor",),
+    OPT_DBL("beep_delay",        beep_delay,             0, 0, DBL_MAX,   "set the delay for the first beep",),
+    OPT_DBL("beep_period",       beep_period_opt,        1, DBL_MIN, DBL_MAX, "set the gap between beeps",),
+    OPT_DBL("beep_duration",     beep_duration,       0.04, DBL_MIN, DBL_MAX, "set the duration of a beep",),
     OPT_INT("sample_rate",       sample_rate,        44100, 1, INT_MAX,   "set the sample rate",),
     OPT_INT("r",                 sample_rate,        44100, 1, INT_MAX,   "set the sample rate",),
     OPT_DUR("duration",          duration,               0, 0, INT64_MAX, "set the audio duration",),
@@ -152,10 +158,13 @@ static av_cold int init(AVFilterContext *ctx)
     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;
+        unsigned beep_start = sine->beep_delay * sine->sample_rate;
+        double beep_frequency = (sine->frequency ? sine->frequency : 1.0) *
+                                sine->beep_factor;
+        sine->beep_period = sine->beep_period_opt * sine->sample_rate;
+        sine->beep_index = (sine->beep_period - beep_start) % sine->beep_period;
+        sine->beep_length = sine->beep_duration * sine->sample_rate;
+        sine->dphi_beep = ldexp(beep_frequency, 32) / sine->sample_rate + 0.5;
     }
 
     ret = av_expr_parse(&sine->samples_per_frame_expr,
-- 
2.13.5 (Apple Git-94)