1 files changed, 97 insertions, 18 deletions

diff --git a/libavfilter/vf_select.c b/libavfilter/vf_select.c
index 25c6a14..143e8cc 100644
--- a/libavfilter/vf_select.c
+++ b/libavfilter/vf_select.c
@@ -1,20 +1,20 @@
 /*
  * Copyright (c) 2011 Stefano Sabatini
  *
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
- * Libav is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
- * License along with Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -26,16 +26,16 @@
 #include "libavutil/eval.h"
 #include "libavutil/fifo.h"
 #include "libavutil/internal.h"
-#include "libavutil/mathematics.h"
 #include "avfilter.h"
+#include "formats.h"
 #include "internal.h"
 #include "video.h"
 
-static const char *const var_names[] = {
-    "E",                 ///< Euler number
-    "PHI",               ///< golden ratio
-    "PI",                ///< greek pi
+#if CONFIG_AVCODEC
+#include "libavcodec/dsputil.h"
+#endif
 
+static const char *const var_names[] = {
     "TB",                ///< timebase
 
     "pts",               ///< original pts in the file of the frame
@@ -69,14 +69,12 @@ static const char *const var_names[] = {
     "key",               ///< tell if the frame is a key frame
     "pos",               ///< original position in the file of the frame
 
+    "scene",
+
     NULL
 };
 
 enum var_name {
-    VAR_E,
-    VAR_PHI,
-    VAR_PI,
-
     VAR_TB,
 
     VAR_PTS,
@@ -110,6 +108,8 @@ enum var_name {
     VAR_KEY,
     VAR_POS,
 
+    VAR_SCENE,
+
     VAR_VARS_NB
 };
 
@@ -118,6 +118,13 @@ enum var_name {
 typedef struct {
     AVExpr *expr;
     double var_values[VAR_VARS_NB];
+    int do_scene_detect;            ///< 1 if the expression requires scene detection variables, 0 otherwise
+#if CONFIG_AVCODEC
+    AVCodecContext *avctx;          ///< codec context required for the DSPContext (scene detect only)
+    DSPContext c;                   ///< context providing optimized SAD methods   (scene detect only)
+    double prev_mafd;               ///< previous MAFD                             (scene detect only)
+#endif
+    AVFilterBufferRef *prev_picref; ///< previous frame                            (scene detect only)
     double select;
     int cache_frames;
     AVFifoBuffer *pending_frames; ///< FIFO buffer of video frames
@@ -139,6 +146,12 @@ static av_cold int init(AVFilterContext *ctx, const char *args)
         av_log(ctx, AV_LOG_ERROR, "Failed to allocate pending frames buffer.\n");
         return AVERROR(ENOMEM);
     }
+
+    select->do_scene_detect = args && strstr(args, "scene");
+    if (select->do_scene_detect && !CONFIG_AVCODEC) {
+        av_log(ctx, AV_LOG_ERROR, "Scene detection is not available without libavcodec.\n");
+        return AVERROR(EINVAL);
+    }
     return 0;
 }
 
@@ -150,10 +163,6 @@ static int config_input(AVFilterLink *inlink)
 {
     SelectContext *select = inlink->dst->priv;
 
-    select->var_values[VAR_E]   = M_E;
-    select->var_values[VAR_PHI] = M_PHI;
-    select->var_values[VAR_PI]  = M_PI;
-
     select->var_values[VAR_N]          = 0.0;
     select->var_values[VAR_SELECTED_N] = 0.0;
 
@@ -173,11 +182,53 @@ static int config_input(AVFilterLink *inlink)
 
     select->var_values[VAR_INTERLACE_TYPE_P] = INTERLACE_TYPE_P;
     select->var_values[VAR_INTERLACE_TYPE_T] = INTERLACE_TYPE_T;
-    select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;;
+    select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;
 
+    if (CONFIG_AVCODEC && select->do_scene_detect) {
+        select->avctx = avcodec_alloc_context3(NULL);
+        if (!select->avctx)
+            return AVERROR(ENOMEM);
+        dsputil_init(&select->c, select->avctx);
+    }
     return 0;
 }
 
+#if CONFIG_AVCODEC
+static double get_scene_score(AVFilterContext *ctx, AVFilterBufferRef *picref)
+{
+    double ret = 0;
+    SelectContext *select = ctx->priv;
+    AVFilterBufferRef *prev_picref = select->prev_picref;
+
+    if (prev_picref &&
+        picref->video->h    == prev_picref->video->h &&
+        picref->video->w    == prev_picref->video->w &&
+        picref->linesize[0] == prev_picref->linesize[0]) {
+        int x, y;
+        int64_t sad;
+        double mafd, diff;
+        uint8_t *p1 =      picref->data[0];
+        uint8_t *p2 = prev_picref->data[0];
+        const int linesize = picref->linesize[0];
+
+        for (sad = y = 0; y < picref->video->h; y += 8)
+            for (x = 0; x < linesize; x += 8)
+                sad += select->c.sad[1](select,
+                                        p1 + y * linesize + x,
+                                        p2 + y * linesize + x,
+                                        linesize, 8);
+        emms_c();
+        mafd = sad / (picref->video->h * picref->video->w * 3);
+        diff = fabs(mafd - select->prev_mafd);
+        ret  = av_clipf(FFMIN(mafd, diff) / 100., 0, 1);
+        select->prev_mafd = mafd;
+        avfilter_unref_buffer(prev_picref);
+    }
+    select->prev_picref = avfilter_ref_buffer(picref, ~0);
+    return ret;
+}
+#endif
+
 #define D2TS(d)  (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
 
@@ -187,6 +238,8 @@ static int select_frame(AVFilterContext *ctx, AVFilterBufferRef *picref)
     AVFilterLink *inlink = ctx->inputs[0];
     double res;
 
+    if (CONFIG_AVCODEC && select->do_scene_detect)
+        select->var_values[VAR_SCENE] = get_scene_score(ctx, picref);
     if (isnan(select->var_values[VAR_START_PTS]))
         select->var_values[VAR_START_PTS] = TS2D(picref->pts);
     if (isnan(select->var_values[VAR_START_T]))
@@ -338,6 +391,30 @@ static av_cold void uninit(AVFilterContext *ctx)
         avfilter_unref_buffer(picref);
     av_fifo_free(select->pending_frames);
     select->pending_frames = NULL;
+
+    if (select->do_scene_detect) {
+        avfilter_unref_bufferp(&select->prev_picref);
+        if (select->avctx) {
+            avcodec_close(select->avctx);
+            av_freep(&select->avctx);
+        }
+    }
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    SelectContext *select = ctx->priv;
+
+    if (!select->do_scene_detect) {
+        return ff_default_query_formats(ctx);
+    } else {
+        static const enum AVPixelFormat pix_fmts[] = {
+            AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
+            AV_PIX_FMT_NONE
+        };
+        ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+    }
+    return 0;
 }
 
 static const AVFilterPad avfilter_vf_select_inputs[] = {
@@ -345,6 +422,7 @@ static const AVFilterPad avfilter_vf_select_inputs[] = {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
         .get_video_buffer = ff_null_get_video_buffer,
+        .min_perms        = AV_PERM_PRESERVE,
         .config_props     = config_input,
         .start_frame      = start_frame,
         .draw_slice       = draw_slice,
@@ -368,6 +446,7 @@ AVFilter avfilter_vf_select = {
     .description = NULL_IF_CONFIG_SMALL("Select frames to pass in output."),
     .init      = init,
     .uninit    = uninit,
+    .query_formats = query_formats,
 
     .priv_size = sizeof(SelectContext),