avfilter/vf_idet: add a "half_life" option for statistics

This can be useful for videos in which the interlacing pattern changes.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

4 files changed, 69 insertions, 28 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 33f842be1d..ae08f3221c 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -5625,6 +5625,11 @@ The filter accepts the following options:
 Set interlacing threshold.
 @item prog_thres
 Set progressive threshold.
+@item half_life
+Number of frames after which a given frame's contribution to the
+statistics is halved (i.e., it contributes only 0.5 to it's
+classification). The default of 0 means that all frames seen are given
+full weight of 1.0 forever.
 @end table
 
 @section il
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 440c587981..dab9b45e94 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -31,7 +31,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  5
 #define LIBAVFILTER_VERSION_MINOR  2
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MICRO 102
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \
diff --git a/libavfilter/vf_idet.c b/libavfilter/vf_idet.c
index 6f99f39f00..01d7eca5a7 100644
--- a/libavfilter/vf_idet.c
+++ b/libavfilter/vf_idet.c
@@ -32,6 +32,7 @@
 static const AVOption idet_options[] = {
     { "intl_thres", "set interlacing threshold", OFFSET(interlace_threshold),   AV_OPT_TYPE_FLOAT, {.dbl = 1.04}, -1, FLT_MAX, FLAGS },
     { "prog_thres", "set progressive threshold", OFFSET(progressive_threshold), AV_OPT_TYPE_FLOAT, {.dbl = 1.5},  -1, FLT_MAX, FLAGS },
+    { "half_life", "half life of cumulative statistics", OFFSET(half_life),     AV_OPT_TYPE_FLOAT, {.dbl = 0.0},  -1, INT_MAX, FLAGS },
     { NULL }
 };
 
@@ -48,6 +49,24 @@ static const char *type2str(Type type)
     return NULL;
 }
 
+#define PRECISION 1048576
+
+static uint64_t uintpow(uint64_t b,unsigned int e)
+{
+    uint64_t r=1;
+    while(e--) r*=b;
+    return r;
+}
+
+static int av_dict_set_fxp(AVDictionary **pm, const char *key, uint64_t value, unsigned int digits,
+                int flags)
+{
+    char valuestr[44];
+    snprintf(valuestr, sizeof(valuestr), "%"PRId64".%0*"PRId64,
+             value / PRECISION, digits, ( value % PRECISION ) / ( PRECISION / uintpow(10,digits) ));
+    return av_dict_set(pm, key, valuestr, flags);
+}
+
 int ff_idet_filter_line_c(const uint8_t *a, const uint8_t *b, const uint8_t *c, int w)
 {
     int x;
@@ -146,23 +165,32 @@ static void filter(AVFilterContext *ctx)
         idet->cur->interlaced_frame = 0;
     }
 
-    idet->prestat [           type] ++;
-    idet->poststat[idet->last_type] ++;
+
+
+    for(i=0; i<4; i++){
+        idet->prestat [i] = (idet->decay_coefficient * idet->prestat [i]) / PRECISION;
+        idet->poststat[i] = (idet->decay_coefficient * idet->poststat[i]) / PRECISION;
+    }
+
+    idet->total_prestat [           type] ++;
+    idet->prestat       [           type] += PRECISION;
+
+    idet->total_poststat[idet->last_type] ++;
+    idet->poststat      [idet->last_type] += PRECISION;
 
     av_log(ctx, AV_LOG_DEBUG, "Single frame:%12s, Multi frame:%12s\n", type2str(type), type2str(idet->last_type));
 
-    av_dict_set    (metadata, "lavfi.idet.single.current_frame", type2str(type), 0);
-    av_dict_set_int(metadata, "lavfi.idet.single.tff", idet->prestat[TFF], 0);
-    av_dict_set_int(metadata, "lavfi.idet.single.bff", idet->prestat[BFF], 0);
-    av_dict_set_int(metadata, "lavfi.idet.single.progressive", idet->prestat[PROGRESSIVE], 0);
-    av_dict_set_int(metadata, "lavfi.idet.single.undetermined", idet->prestat[UNDETERMINED], 0);
+    av_dict_set    (metadata, "lavfi.idet.single.current_frame",   type2str(type), 0);
+    av_dict_set_fxp(metadata, "lavfi.idet.single.tff",             idet->prestat[TFF], 2 , 0);
+    av_dict_set_fxp(metadata, "lavfi.idet.single.bff",             idet->prestat[BFF], 2, 0);
+    av_dict_set_fxp(metadata, "lavfi.idet.single.progressive",     idet->prestat[PROGRESSIVE], 2, 0);
+    av_dict_set_fxp(metadata, "lavfi.idet.single.undetermined",    idet->prestat[UNDETERMINED], 2, 0);
 
     av_dict_set    (metadata, "lavfi.idet.multiple.current_frame", type2str(idet->last_type), 0);
-    av_dict_set_int(metadata, "lavfi.idet.multiple.tff", idet->poststat[TFF], 0);
-    av_dict_set_int(metadata, "lavfi.idet.multiple.bff", idet->poststat[BFF], 0);
-    av_dict_set_int(metadata, "lavfi.idet.multiple.progressive", idet->poststat[PROGRESSIVE], 0);
-    av_dict_set_int(metadata, "lavfi.idet.multiple.undetermined", idet->poststat[UNDETERMINED], 0);
-
+    av_dict_set_fxp(metadata, "lavfi.idet.multiple.tff",           idet->poststat[TFF], 2, 0);
+    av_dict_set_fxp(metadata, "lavfi.idet.multiple.bff",           idet->poststat[BFF], 2, 0);
+    av_dict_set_fxp(metadata, "lavfi.idet.multiple.progressive",   idet->poststat[PROGRESSIVE], 2, 0);
+    av_dict_set_fxp(metadata, "lavfi.idet.multiple.undetermined",  idet->poststat[UNDETERMINED], 2, 0);
 }
 
 static int filter_frame(AVFilterLink *link, AVFrame *picref)
@@ -228,18 +256,18 @@ static av_cold void uninit(AVFilterContext *ctx)
 {
     IDETContext *idet = ctx->priv;
 
-    av_log(ctx, AV_LOG_INFO, "Single frame detection: TFF:%d BFF:%d Progressive:%d Undetermined:%d\n",
-           idet->prestat[TFF],
-           idet->prestat[BFF],
-           idet->prestat[PROGRESSIVE],
-           idet->prestat[UNDETERMINED]
-    );
-    av_log(ctx, AV_LOG_INFO, "Multi frame detection: TFF:%d BFF:%d Progressive:%d Undetermined:%d\n",
-           idet->poststat[TFF],
-           idet->poststat[BFF],
-           idet->poststat[PROGRESSIVE],
-           idet->poststat[UNDETERMINED]
-    );
+    av_log(ctx, AV_LOG_INFO, "Single frame detection: TFF:%6"PRId64" BFF:%6"PRId64" Progressive:%6"PRId64" Undetermined:%6"PRId64"\n",
+           idet->total_prestat[TFF],
+           idet->total_prestat[BFF],
+           idet->total_prestat[PROGRESSIVE],
+           idet->total_prestat[UNDETERMINED]
+        );
+    av_log(ctx, AV_LOG_INFO, "Multi frame detection: TFF:%6"PRId64" BFF:%6"PRId64" Progressive:%6"PRId64" Undetermined:%6"PRId64"\n",
+           idet->total_poststat[TFF],
+           idet->total_poststat[BFF],
+           idet->total_poststat[PROGRESSIVE],
+           idet->total_poststat[UNDETERMINED]
+        );
 
     av_frame_free(&idet->prev);
     av_frame_free(&idet->cur );
@@ -290,6 +318,11 @@ static av_cold int init(AVFilterContext *ctx)
     idet->last_type = UNDETERMINED;
     memset(idet->history, UNDETERMINED, HIST_SIZE);
 
+    if( idet->half_life > 0 )
+        idet->decay_coefficient = (uint64_t) round( PRECISION * pow(2.0,-1.0 / idet->half_life) );
+    else
+        idet->decay_coefficient = PRECISION;
+
     idet->filter_line = ff_idet_filter_line_c;
 
     if (ARCH_X86)
@@ -298,7 +331,6 @@ static av_cold int init(AVFilterContext *ctx)
     return 0;
 }
 
-
 static const AVFilterPad idet_inputs[] = {
     {
         .name         = "default",
diff --git a/libavfilter/vf_idet.h b/libavfilter/vf_idet.h
index 57332dfbdd..05aa1e0506 100644
--- a/libavfilter/vf_idet.h
+++ b/libavfilter/vf_idet.h
@@ -37,10 +37,14 @@ typedef struct {
     const AVClass *class;
     float interlace_threshold;
     float progressive_threshold;
+    float half_life;
+    uint64_t decay_coefficient;
 
     Type last_type;
-    int prestat[4];
-    int poststat[4];
+    uint64_t prestat[4];
+    uint64_t poststat[4];
+    uint64_t total_prestat[4];
+    uint64_t total_poststat[4];
 
     uint8_t history[HIST_SIZE];