@@ -41,6 +41,7 @@ version <next>:

 - make the crop filter accept parametric expressions

 - make ffprobe accept AVFormatContext options

 - yadif filter

+- blackframe filter

 version 0.6:

@@ -1401,6 +1401,7 @@ tcp_protocol_deps="network"

 udp_protocol_deps="network"

 # filters

+blackframe_filter_deps="gpl"

 ocv_smooth_filter_deps="libopencv"

 yadif_filter_deps="gpl"

@@ -71,6 +71,27 @@ build.

 Below is a description of the currently available video filters.

+@section blackframe

+

+Detect frames that are (almost) completely black. Can be useful to

+detect chapter transitions or commercials. Output lines consist of

+the frame number of the detected frame, the percentage of blackness,

+the position in the file if known or -1 and the timestamp in seconds.

+

+In order to display the output lines, you need to set the loglevel at

+least to the AV_LOG_INFO value.

+

+The filter accepts the syntax:

+@example

+blackframe[=@var{amount}:[@var{threshold}]]

+@end example

+

+@var{amount} is the percentage of the pixels that have to be below the

+threshold, and defaults to 98.

+

+@var{threshold} is the threshold below which a pixel value is

+considered black, and defaults to 32.

+

 @section crop

 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.

@@ -21,6 +21,7 @@ OBJS-$(CONFIG_ANULLSRC_FILTER)               += asrc_anullsrc.o

 OBJS-$(CONFIG_ANULLSINK_FILTER)              += asink_anullsink.o

 OBJS-$(CONFIG_ASPECT_FILTER)                 += vf_aspect.o

+OBJS-$(CONFIG_BLACKFRAME_FILTER)             += vf_blackframe.o

 OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o

 OBJS-$(CONFIG_FIFO_FILTER)                   += vf_fifo.o

 OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o

@@ -41,6 +41,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER (ANULLSINK,   anullsink,   asink);

     REGISTER_FILTER (ASPECT,      aspect,      vf);

+    REGISTER_FILTER (BLACKFRAME,  blackframe,  vf);

     REGISTER_FILTER (CROP,        crop,        vf);

     REGISTER_FILTER (FIFO,        fifo,        vf);

     REGISTER_FILTER (FORMAT,      format,      vf);

@@ -25,7 +25,7 @@

 #include "libavutil/avutil.h"

 #define LIBAVFILTER_VERSION_MAJOR  1

-#define LIBAVFILTER_VERSION_MINOR 45

+#define LIBAVFILTER_VERSION_MINOR 46

 #define LIBAVFILTER_VERSION_MICRO  0

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,129 @@

+/*

+ * Copyright (C) 2010 Stefano Sabatini

+ * Copyright (C) 2006 Ivo van Poorten

+ * Copyright (C) 2006 Julian Hall

+ * Copyright (C) 2002-2003 Brian J. Murrell

+ *

+ * This file is part of FFmpeg.

+ *

+ * FFmpeg is free software; you can redistribute it and/or modify

+ * it under the terms of the GNU General Public License as published by

+ * the Free Software Foundation; either version 2 of the License, or

+ * (at your option) any later version.

+ *

+ * 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 General Public License for more details.

+ *

+ * You should have received a copy of the GNU General Public License along

+ * with FFmpeg; if not, write to the Free Software Foundation, Inc.,

+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

+ */

+

+/**

+ * @file

+ * Search for black frames to detect scene transitions.

+ * Ported from MPlayer libmpcodecs/vf_blackframe.c.

+ */

+

+#include "avfilter.h"

+

+typedef struct {

+    unsigned int bamount; ///< black amount

+    unsigned int bthresh; ///< black threshold

+    unsigned int frame;   ///< frame number

+    unsigned int nblack;  ///< number of black pixels counted so far

+} BlackFrameContext;

+

+static int query_formats(AVFilterContext *ctx)

+{

+    static const enum PixelFormat pix_fmts[] = {

+        PIX_FMT_YUV410P, PIX_FMT_YUV420P, PIX_FMT_GRAY8, PIX_FMT_NV12,

+        PIX_FMT_NV21, PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV411P,

+        PIX_FMT_NONE

+    };

+

+    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));

+    return 0;

+}

+

+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)

+{

+    BlackFrameContext *blackframe = ctx->priv;

+

+    blackframe->bamount = 98;

+    blackframe->bthresh = 32;

+    blackframe->nblack = 0;

+    blackframe->frame = 0;

+

+    if (args)

+        sscanf(args, "%u:%u", &blackframe->bamount, &blackframe->bthresh);

+

+    av_log(ctx, AV_LOG_INFO, "bamount:%u bthresh:%u\n",

+           blackframe->bamount, blackframe->bthresh);

+

+    if (blackframe->bamount > 100 || blackframe->bthresh > 255) {

+        av_log(ctx, AV_LOG_ERROR, "Too big value for bamount (max is 100) or bthresh (max is 255)\n");

+        return AVERROR(EINVAL);

+    }

+

+    return 0;

+}

+

+static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)

+{

+    AVFilterContext *ctx = inlink->dst;

+    BlackFrameContext *blackframe = ctx->priv;

+    AVFilterBufferRef *picref = inlink->cur_buf;

+    int x, i;

+    uint8_t *p = picref->data[0] + y * picref->linesize[0];

+

+    for (i = 0; i < h; i++) {

+        for (x = 0; x < inlink->w; x++)

+            blackframe->nblack += p[x] < blackframe->bthresh;

+        p += picref->linesize[0];

+    }

+

+    avfilter_draw_slice(ctx->outputs[0], y, h, slice_dir);

+}

+

+static void end_frame(AVFilterLink *inlink)

+{

+    AVFilterContext *ctx = inlink->dst;

+    BlackFrameContext *blackframe = ctx->priv;

+    AVFilterBufferRef *picref = inlink->cur_buf;

+    int pblack = 0;

+

+    pblack = blackframe->nblack * 100 / (inlink->w * inlink->h);

+    if (pblack >= blackframe->bamount)

+        av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pos:%"PRId64" pts:%f\n",

+               blackframe->frame, pblack, picref->pos,

+               picref->pts == AV_NOPTS_VALUE ? -1 : (double)picref->pts / AV_TIME_BASE);

+

+    blackframe->frame++;

+    blackframe->nblack = 0;

+    avfilter_end_frame(inlink->dst->outputs[0]);

+}

+

+AVFilter avfilter_vf_blackframe = {

+    .name        = "blackframe",

+    .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),

+

+    .priv_size = sizeof(BlackFrameContext),

+    .init      = init,

+

+    .query_formats = query_formats,

+

+    .inputs    = (AVFilterPad[]) {{ .name = "default",

+                                    .type             = AVMEDIA_TYPE_VIDEO,

+                                    .draw_slice       = draw_slice,

+                                    .get_video_buffer = avfilter_null_get_video_buffer,

+                                    .start_frame      = avfilter_null_start_frame,

+                                    .end_frame        = end_frame, },

+                                  { .name = NULL}},

+

+    .outputs   = (AVFilterPad[]) {{ .name             = "default",

+                                    .type             = AVMEDIA_TYPE_VIDEO },

+                                  { .name = NULL}},

+};