[FFmpeg-devel,v4] avfilter/avf_aphasemeter: Add out-of-phase and mono detection

Submitted by Romane Lafon on July 3, 2019, 1:33 p.m.

Details

Message ID CAMe7PWScypoKjiAbBt0Q_BMT73f=C4RDP-CUW4foEwD=OoTO8w@mail.gmail.com
State New
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Commit Message

Romane Lafon July 3, 2019, 1:33 p.m.
I've added documentation for the extension of aphasemeter filter.
Also, I'm not sure that "phasing" is the right word to describe the
detection.

Comments

Michael Niedermayer July 5, 2019, 2:42 p.m.
On Wed, Jul 03, 2019 at 03:33:46PM +0200, Romane Lafon wrote:
> I've added documentation for the extension of aphasemeter filter.
> Also, I'm not sure that "phasing" is the right word to describe the
> detection.

>  doc/filters.texi              |   32 ++++++++++
>  libavfilter/avf_aphasemeter.c |  127 ++++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 155 insertions(+), 4 deletions(-)
> d7ceb2e8f553300c6ba9058bd292244bc072173f  0001-avfilter-avf_aphasemeter-Add-out-of-phase-and_v4.patch
> From 1e356929e878a2081add102b77a9560647232ef8 Mon Sep 17 00:00:00 2001
> From: Romane Lafon <romane@nomalab.com>
> Date: Wed, 3 Jul 2019 15:15:16 +0200
> Subject: [PATCH] avfilter/avf_aphasemeter: Add out of phase and mono detection
> 
> Signed-off-by: Romane Lafon <romane@nomalab.com>
> ---
>  doc/filters.texi              |  32 +++++++++++
>  libavfilter/avf_aphasemeter.c | 127 ++++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 155 insertions(+), 4 deletions(-)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 700a76f239..ec8c73d558 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -20656,6 +20656,38 @@ Set color which will be used for drawing median phase. If color is
>  Enable video output. Default is enabled.
>  @end table
>  
> +@subsection phasing detection
> +
> +The filter also detects out of phase and mono sequences in stereo streams.
> +It logs the sequence start, end and duration when it lasts longer or as long as the minimum set.
> +
> +The filter accepts the following options for this detection:
> +
> +@table @option
> +@item phasing
> +Enable mono and out of phase detection. Default is disabled.
> +
> +@item tolerance
> +Set phase tolerance for mono detection, in amplitude ratio. Default is @code{0}.
> +Allowed range is @code{[0, 1]}.
> +
> +@item angle
> +Set angle threshold for out of phase detection, in degree. Default is @code{170}.
> +Allowed range is @code{[0, 180]}.
> +
> +@item duration
> +Set mono or out of phase duration until notification, expressed in seconds. Default is @code{2}.
> +
> +@subsection Examples
> +
> +@itemize
> +@item
> +Complete example with @command{ffmpeg} to detect 1 second of mono with 0.001 phase tolerance:
> +@example
> +ffmpeg -i stereo.wav -af aphasemeter=video=0:phasing=1:duration=1:tolerance=0.001 -f null -
> +@end example
> +@end itemize
> +
>  @section avectorscope
>  
>  Convert input audio to a video output, representing the audio vector

this breaks building docs

HTML	doc/ffmpeg-all.html
doc/filters.texi:20681: @subsection seen before @end table
make: *** [doc/ffmpeg-all.html] Error 1

[...]
Devin Heitmueller July 5, 2019, 2:47 p.m.
On Wed, Jul 3, 2019 at 9:34 AM Romane Lafon <romane@nomalab.com> wrote:
>
> I've added documentation for the extension of aphasemeter filter.
> Also, I'm not sure that "phasing" is the right word to describe the
> detection.

In some commercial analyzers I've also seen audio phase presented
using the term "lissajous" (after the name of the actual curve), but
personally I prefer to refer to it as audio phase.

Devin
Romane Lafon July 8, 2019, 11:49 a.m.
Ok, thanks

Le ven. 5 juil. 2019 à 16:54, Devin Heitmueller <dheitmueller@kernellabs.com>
a écrit :

> On Wed, Jul 3, 2019 at 9:34 AM Romane Lafon <romane@nomalab.com> wrote:
> >
> > I've added documentation for the extension of aphasemeter filter.
> > Also, I'm not sure that "phasing" is the right word to describe the
> > detection.
>
> In some commercial analyzers I've also seen audio phase presented
> using the term "lissajous" (after the name of the actual curve), but
> personally I prefer to refer to it as audio phase.
>
> Devin
>
> --
> Devin J. Heitmueller - Kernel Labs
> http://www.kernellabs.com
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Patch hide | download patch | download mbox

From 1e356929e878a2081add102b77a9560647232ef8 Mon Sep 17 00:00:00 2001
From: Romane Lafon <romane@nomalab.com>
Date: Wed, 3 Jul 2019 15:15:16 +0200
Subject: [PATCH] avfilter/avf_aphasemeter: Add out of phase and mono detection

Signed-off-by: Romane Lafon <romane@nomalab.com>
---
 doc/filters.texi              |  32 +++++++++++
 libavfilter/avf_aphasemeter.c | 127 ++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 155 insertions(+), 4 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index 700a76f239..ec8c73d558 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -20656,6 +20656,38 @@  Set color which will be used for drawing median phase. If color is
 Enable video output. Default is enabled.
 @end table
 
+@subsection phasing detection
+
+The filter also detects out of phase and mono sequences in stereo streams.
+It logs the sequence start, end and duration when it lasts longer or as long as the minimum set.
+
+The filter accepts the following options for this detection:
+
+@table @option
+@item phasing
+Enable mono and out of phase detection. Default is disabled.
+
+@item tolerance
+Set phase tolerance for mono detection, in amplitude ratio. Default is @code{0}.
+Allowed range is @code{[0, 1]}.
+
+@item angle
+Set angle threshold for out of phase detection, in degree. Default is @code{170}.
+Allowed range is @code{[0, 180]}.
+
+@item duration
+Set mono or out of phase duration until notification, expressed in seconds. Default is @code{2}.
+
+@subsection Examples
+
+@itemize
+@item
+Complete example with @command{ffmpeg} to detect 1 second of mono with 0.001 phase tolerance:
+@example
+ffmpeg -i stereo.wav -af aphasemeter=video=0:phasing=1:duration=1:tolerance=0.001 -f null -
+@end example
+@end itemize
+
 @section avectorscope
 
 Convert input audio to a video output, representing the audio vector
diff --git a/libavfilter/avf_aphasemeter.c b/libavfilter/avf_aphasemeter.c
index f497bc9969..77701e5cde 100644
--- a/libavfilter/avf_aphasemeter.c
+++ b/libavfilter/avf_aphasemeter.c
@@ -28,26 +28,41 @@ 
 #include "libavutil/intreadwrite.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
+#include "libavutil/timestamp.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "audio.h"
 #include "video.h"
 #include "internal.h"
+#include "stdbool.h"
+#include "float.h"
 
 typedef struct AudioPhaseMeterContext {
     const AVClass *class;
     AVFrame *out;
     int do_video;
+    int do_phasing_detection;
     int w, h;
     AVRational frame_rate;
     int contrast[4];
     uint8_t *mpc_str;
     uint8_t mpc[4];
     int draw_median_phase;
+    int is_mono;
+    int is_out_phase;
+    int start_mono_presence;
+    int start_out_phase_presence;
+    float tolerance;
+    float angle;
+    float phase;
+    float mono_idx[2];
+    float out_phase_idx[2];
+    double duration;
 } AudioPhaseMeterContext;
 
 #define OFFSET(x) offsetof(AudioPhaseMeterContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+#define get_duration(index) (index[1] - index[0])
 
 static const AVOption aphasemeter_options[] = {
     { "rate", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
@@ -59,6 +74,10 @@  static const AVOption aphasemeter_options[] = {
     { "bc", "set blue contrast",  OFFSET(contrast[2]), AV_OPT_TYPE_INT, {.i64=1}, 0, 255, FLAGS },
     { "mpc", "set median phase color", OFFSET(mpc_str), AV_OPT_TYPE_STRING, {.str = "none"}, 0, 0, FLAGS },
     { "video", "set video output", OFFSET(do_video), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },
+    { "phasing", "set mono and out-of-phase detection output", OFFSET(do_phasing_detection), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS },
+    { "tolerance", "set phase tolerance for mono detection", OFFSET(tolerance), AV_OPT_TYPE_FLOAT, {.dbl = 0.}, 0, 1, FLAGS },
+    { "angle", "set angle threshold for out-of-phase detection", OFFSET(angle), AV_OPT_TYPE_FLOAT, {.dbl = 170.}, 90, 180, FLAGS },
+    { "duration", "set minimum mono or out-of-phase duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl=2.}, 0, 24*60*60, FLAGS },
     { NULL }
 };
 
@@ -140,6 +159,22 @@  static inline int get_x(float phase, int w)
   return (phase + 1.) / 2. * (w - 1);
 }
 
+static inline float get_index(AVFilterLink *inlink, AVFrame *in)
+{
+    char *index_str = av_ts2timestr(in->pts, &inlink->time_base);
+    return atof(index_str);
+}
+
+static inline void add_metadata(AVFrame *insamples, const char *key, float value)
+{
+    char buf[128];
+    char str[128];
+
+    snprintf(str, sizeof(str), "%f", value);
+    snprintf(buf, sizeof(buf), "lavfi.aphasemeter.%s", key);
+    av_dict_set(&insamples->metadata, buf, str, 0);
+}
+
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
@@ -154,6 +189,10 @@  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
     AVFrame *out;
     uint8_t *dst;
     int i;
+    int mono_measurement;
+    int out_phase_measurement;
+    float tolerance = 1.0f - s->tolerance;
+    float angle = cosf(s->angle/180.0f*M_PI);
 
     if (s->do_video && (!s->out || s->out->width  != outlink->w ||
                                    s->out->height != outlink->h)) {
@@ -193,7 +232,7 @@  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
         fphase += phase;
     }
     fphase /= in->nb_samples;
-
+    s->phase = fphase;
     if (s->do_video) {
         if (s->draw_median_phase) {
             dst = out->data[0] + get_x(fphase, s->w) * 4;
@@ -206,10 +245,64 @@  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 
     metadata = &in->metadata;
     if (metadata) {
-        uint8_t value[128];
+        add_metadata(in, "phase", fphase);
+    }
 
-        snprintf(value, sizeof(value), "%f", fphase);
-        av_dict_set(metadata, "lavfi.aphasemeter.phase", value, 0);
+    if (s->do_phasing_detection) {
+        mono_measurement = (tolerance - fphase) < FLT_EPSILON;
+        out_phase_measurement = (angle - fphase) > FLT_EPSILON;
+        if (!s->is_mono && mono_measurement) {
+            s->is_mono = 1;
+            s->start_mono_presence = 1;
+            s->mono_idx[0] = get_index(inlink, in);
+        }
+        if (s->is_mono && mono_measurement && s->start_mono_presence) {
+            float mono_duration;
+            s->mono_idx[1] = get_index(inlink, in);
+            mono_duration = get_duration(s->mono_idx);
+            if (mono_duration >= s->duration) {
+                add_metadata(in, "mono_start", s->mono_idx[0]);
+                av_log(s, AV_LOG_INFO, "mono_start: %f\n", s->mono_idx[0]);
+                s->start_mono_presence = 0;
+            }
+        }
+        if (s->is_mono && !mono_measurement) {
+            float mono_duration;
+            s->mono_idx[1] = get_index(inlink, in);
+            mono_duration = get_duration(s->mono_idx);
+            if (mono_duration > s->duration) {
+                add_metadata(in, "mono_end", s->mono_idx[1]);
+                add_metadata(in, "mono_duration", mono_duration);
+                av_log(s, AV_LOG_INFO, "mono_end: %f | mono_duration: %f\n", s->mono_idx[1], mono_duration);
+            }
+            s->is_mono = 0;
+        }
+        if (!s->is_out_phase && out_phase_measurement) {
+            s->out_phase_idx[0] = get_index(inlink, in);
+            s->is_out_phase = 1;
+            s->start_out_phase_presence = 1;
+        }
+        if (s->is_out_phase && out_phase_measurement && s->start_out_phase_presence) {
+            float out_phase_duration;
+            s->out_phase_idx[1] = get_index(inlink, in);
+            out_phase_duration = get_duration(s->out_phase_idx);
+            if (out_phase_duration >= s->duration) {
+                add_metadata(in, "out_phase_start", s->out_phase_idx[0]);
+                av_log(s, AV_LOG_INFO, "out_phase_start: %f\n", s->out_phase_idx[0]);
+                s->start_out_phase_presence = 0;
+            }
+        }
+        if (s->is_out_phase && !out_phase_measurement) {
+            float out_phase_duration;
+            s->out_phase_idx[1] = get_index(inlink, in);
+            out_phase_duration = get_duration(s->out_phase_idx);
+            if (out_phase_duration > s->duration) {
+                add_metadata(in, "out_phase_end", s->out_phase_idx[1]);
+                add_metadata(in, "out_phase_duration", out_phase_duration);
+                av_log(s, AV_LOG_INFO, "out_phase_end: %f | out_phase_duration: %f\n", s->out_phase_idx[1], out_phase_duration);
+            }
+            s->is_out_phase = 0;
+        }
     }
 
     if (s->do_video) {
@@ -224,6 +317,32 @@  static av_cold void uninit(AVFilterContext *ctx)
     AudioPhaseMeterContext *s = ctx->priv;
     int i;
 
+    if (s->do_phasing_detection) {
+        float tolerance = 1.0f - s->tolerance;
+        float angle = cosf(s->angle/180.0f*M_PI);
+        float mono_duration;
+        float out_phase_duration;
+        AVFilterLink *inlink = ctx->inputs[0];
+
+        if (s->is_mono) {
+            char *index_str = av_ts2timestr(inlink->current_pts, &inlink->time_base);
+            s->mono_idx[1] = atof(index_str);
+            mono_duration = get_duration(s->mono_idx);
+            if (mono_duration > s->duration) {
+                av_log(s, AV_LOG_INFO, "mono_end: %f | mono_duration: %f\n", s->mono_idx[1], mono_duration);
+            }
+            s->is_mono = 0;
+        }
+        if (s->is_out_phase) {
+            char *index_str = av_ts2timestr(inlink->current_pts, &inlink->time_base);
+            s->out_phase_idx[1] = atof(index_str);
+            out_phase_duration = get_duration(s->out_phase_idx);
+            if (out_phase_duration > s->duration) {
+                av_log(s, AV_LOG_INFO, "out_phase_end: %f | out_phase_duration: %f\n", s->out_phase_idx[1], out_phase_duration);
+            }
+            s->is_out_phase = 0;
+        }
+    }
     av_frame_free(&s->out);
     for (i = 0; i < ctx->nb_outputs; i++)
         av_freep(&ctx->output_pads[i].name);
-- 
2.11.0