avfilter/select: remove optional avcodec dependency

configure

@@ -2566,6 +2566,7 @@ removelogo_filter_deps="avcodec avformat swscale"
 resample_filter_deps="avresample"
 sab_filter_deps="gpl swscale"
 scale_filter_deps="swscale"
+select_filter_select="pixelutils"
 smartblur_filter_deps="gpl swscale"
 showspectrum_filter_deps="avcodec"
 showspectrum_filter_select="rdft"

libavfilter/f_select.c

@@ -28,16 +28,13 @@
 #include "libavutil/fifo.h"
 #include "libavutil/internal.h"
 #include "libavutil/opt.h"
+#include "libavutil/pixelutils.h"
 #include "avfilter.h"
 #include "audio.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
-#if CONFIG_AVCODEC
-#include "libavcodec/dsputil.h"
-#endif
-
 static const char *const var_names[] = {
     "TB",                ///< timebase
 
@@ -144,11 +141,8 @@ typedef struct SelectContext {
     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)
+    av_pixelutils_sad_fn sad;       ///< Sum of the absolute difference function (scene detect only)
     double prev_mafd;               ///< previous MAFD                             (scene detect only)
-#endif
     AVFrame *prev_picref; ///< previous frame                            (scene detect only)
     double select;
     int select_out;                 ///< mark the selected output pad index
@@ -240,18 +234,14 @@ static int config_input(AVFilterLink *inlink)
     select->var_values[VAR_SAMPLE_RATE] =
         inlink->type == AVMEDIA_TYPE_AUDIO ? inlink->sample_rate : NAN;
 
-#if CONFIG_AVCODEC
     if (select->do_scene_detect) {
-        select->avctx = avcodec_alloc_context3(NULL);
-        if (!select->avctx)
-            return AVERROR(ENOMEM);
-        avpriv_dsputil_init(&select->c, select->avctx);
+        select->sad = av_pixelutils_get_sad_fn(3, 3, 2, select); // 8x8 both sources aligned
+        if (!select->sad)
+            return AVERROR(EINVAL);
     }
-#endif
     return 0;
 }
 
-#if CONFIG_AVCODEC
 static double get_scene_score(AVFilterContext *ctx, AVFrame *frame)
 {
     double ret = 0;
@@ -260,23 +250,22 @@ static double get_scene_score(AVFilterContext *ctx, AVFrame *frame)
 
     if (prev_picref &&
         frame->height == prev_picref->height &&
-        frame->width    == prev_picref->width &&
-        frame->linesize[0] == prev_picref->linesize[0]) {
+        frame->width  == prev_picref->width) {
         int x, y, nb_sad = 0;
         int64_t sad = 0;
         double mafd, diff;
         uint8_t *p1 =      frame->data[0];
         uint8_t *p2 = prev_picref->data[0];
-        const int linesize = frame->linesize[0];
+        const int p1_linesize =       frame->linesize[0];
+        const int p2_linesize = prev_picref->linesize[0];
 
         for (y = 0; y < frame->height - 8; y += 8) {
             for (x = 0; x < frame->width*3 - 8; x += 8) {
-                sad += select->c.sad[1](NULL, p1 + x, p2 + x,
-                                        linesize, 8);
+                sad += select->sad(p1 + x, p1_linesize, p2 + x, p2_linesize);
                 nb_sad += 8 * 8;
             }
-            p1 += 8 * linesize;
-            p2 += 8 * linesize;
+            p1 += 8 * p1_linesize;
+            p2 += 8 * p2_linesize;
         }
         emms_c();
         mafd = nb_sad ? (double)sad / nb_sad : 0;
@@ -288,7 +277,6 @@ static double get_scene_score(AVFilterContext *ctx, AVFrame *frame)
     select->prev_picref = av_frame_clone(frame);
     return ret;
 }
-#endif
 
 #define D2TS(d)  (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
@@ -320,7 +308,6 @@ static void select_frame(AVFilterContext *ctx, AVFrame *frame)
             !frame->interlaced_frame ? INTERLACE_TYPE_P :
         frame->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;
         select->var_values[VAR_PICT_TYPE] = frame->pict_type;
-#if CONFIG_AVCODEC
         if (select->do_scene_detect) {
             char buf[32];
             select->var_values[VAR_SCENE] = get_scene_score(ctx, frame);
@@ -328,7 +315,6 @@ static void select_frame(AVFilterContext *ctx, AVFrame *frame)
             snprintf(buf, sizeof(buf), "%f", select->var_values[VAR_SCENE]);
             av_dict_set(avpriv_frame_get_metadatap(frame), "lavfi.scene_score", buf, 0);
         }
-#endif
         break;
     }
 
@@ -418,15 +404,9 @@ static av_cold void uninit(AVFilterContext *ctx)
     for (i = 0; i < ctx->nb_outputs; i++)
         av_freep(&ctx->output_pads[i].name);
 
-#if CONFIG_AVCODEC
     if (select->do_scene_detect) {
         av_frame_free(&select->prev_picref);
-        if (select->avctx) {
-            avcodec_close(select->avctx);
-            av_freep(&select->avctx);
-        }
     }
-#endif
 }
 
 static int query_formats(AVFilterContext *ctx)
@@ -495,17 +475,11 @@ AVFILTER_DEFINE_CLASS(select);
 
 static av_cold int select_init(AVFilterContext *ctx)
 {
-    SelectContext *select = ctx->priv;
     int ret;
 
     if ((ret = init(ctx)) < 0)
         return ret;
 
-    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;
 }