lavfi: rename decimate to mpdecimate.

The next commit will introduce a proper decimation filter to be used
along with the field matching filter. To avoid confusion with this
filter which has currently a very limited usage (and will not work
properly with the fieldmatching filter), the new decimation filter will
take the decimate name, and this filter is renamed to mpdecimate.

1 files changed, 258 insertions, 0 deletions

diff --git a/libavfilter/vf_mpdecimate.c b/libavfilter/vf_mpdecimate.c
new file mode 100644
index 0000000000..55f0f27ae0
--- /dev/null
+++ b/libavfilter/vf_mpdecimate.c
@@ -0,0 +1,258 @@
+/*
+ * Copyright (c) 2003 Rich Felker
+ * Copyright (c) 2012 Stefano Sabatini
+ *
+ * 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 mpdecimate filter, ported from libmpcodecs/vf_decimate.c by
+ * Rich Felker.
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/timestamp.h"
+#include "libavcodec/dsputil.h"
+#include "avfilter.h"
+#include "internal.h"
+#include "formats.h"
+#include "video.h"
+
+typedef struct {
+    const AVClass *class;
+    int lo, hi;                    ///< lower and higher threshold number of differences
+                                   ///< values for 8x8 blocks
+
+    float frac;                    ///< threshold of changed pixels over the total fraction
+
+    int max_drop_count;            ///< if positive: maximum number of sequential frames to drop
+                                   ///< if negative: minimum number of frames between two drops
+
+    int drop_count;                ///< if positive: number of frames sequentially dropped
+                                   ///< if negative: number of sequential frames which were not dropped
+
+    int hsub, vsub;                ///< chroma subsampling values
+    AVFrame *ref;                  ///< reference picture
+    DSPContext dspctx;             ///< context providing optimized diff routines
+    AVCodecContext *avctx;         ///< codec context required for the DSPContext
+} DecimateContext;
+
+#define OFFSET(x) offsetof(DecimateContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption mpdecimate_options[] = {
+    { "max",  "set the maximum number of consecutive dropped frames (positive), or the minimum interval between dropped frames (negative)",
+      OFFSET(max_drop_count), AV_OPT_TYPE_INT, {.i64=0}, INT_MIN, INT_MAX, FLAGS },
+    { "hi",   "set high dropping threshold", OFFSET(hi), AV_OPT_TYPE_INT, {.i64=64*12}, INT_MIN, INT_MAX, FLAGS },
+    { "lo",   "set low dropping threshold", OFFSET(lo), AV_OPT_TYPE_INT, {.i64=64*5}, INT_MIN, INT_MAX, FLAGS },
+    { "frac", "set fraction dropping threshold",  OFFSET(frac), AV_OPT_TYPE_FLOAT, {.dbl=0.33}, 0, 1, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(mpdecimate);
+
+/**
+ * Return 1 if the two planes are different, 0 otherwise.
+ */
+static int diff_planes(AVFilterContext *ctx,
+                       uint8_t *cur, uint8_t *ref, int linesize,
+                       int w, int h)
+{
+    DecimateContext *decimate = ctx->priv;
+    DSPContext *dspctx = &decimate->dspctx;
+
+    int x, y;
+    int d, c = 0;
+    int t = (w/16)*(h/16)*decimate->frac;
+    int16_t block[8*8];
+
+    /* compute difference for blocks of 8x8 bytes */
+    for (y = 0; y < h-7; y += 4) {
+        for (x = 8; x < w-7; x += 4) {
+            dspctx->diff_pixels(block,
+                                cur+x+y*linesize,
+                                ref+x+y*linesize, linesize);
+            d = dspctx->sum_abs_dctelem(block);
+            if (d > decimate->hi)
+                return 1;
+            if (d > decimate->lo) {
+                c++;
+                if (c > t)
+                    return 1;
+            }
+        }
+    }
+    return 0;
+}
+
+/**
+ * Tell if the frame should be decimated, for example if it is no much
+ * different with respect to the reference frame ref.
+ */
+static int decimate_frame(AVFilterContext *ctx,
+                          AVFrame *cur, AVFrame *ref)
+{
+    DecimateContext *decimate = ctx->priv;
+    int plane;
+
+    if (decimate->max_drop_count > 0 &&
+        decimate->drop_count >= decimate->max_drop_count)
+        return 0;
+    if (decimate->max_drop_count < 0 &&
+        (decimate->drop_count-1) > decimate->max_drop_count)
+        return 0;
+
+    for (plane = 0; ref->data[plane] && ref->linesize[plane]; plane++) {
+        int vsub = plane == 1 || plane == 2 ? decimate->vsub : 0;
+        int hsub = plane == 1 || plane == 2 ? decimate->hsub : 0;
+        if (diff_planes(ctx,
+                        cur->data[plane], ref->data[plane], ref->linesize[plane],
+                        ref->width>>hsub, ref->height>>vsub))
+            return 0;
+    }
+
+    return 1;
+}
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    DecimateContext *decimate = ctx->priv;
+
+    av_log(ctx, AV_LOG_VERBOSE, "max_drop_count:%d hi:%d lo:%d frac:%f\n",
+           decimate->max_drop_count, decimate->hi, decimate->lo, decimate->frac);
+
+    decimate->avctx = avcodec_alloc_context3(NULL);
+    if (!decimate->avctx)
+        return AVERROR(ENOMEM);
+    dsputil_init(&decimate->dspctx, decimate->avctx);
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    DecimateContext *decimate = ctx->priv;
+    av_frame_free(&decimate->ref);
+    if (decimate->avctx) {
+        avcodec_close(decimate->avctx);
+        av_freep(&decimate->avctx);
+    }
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUV444P,      AV_PIX_FMT_YUV422P,
+        AV_PIX_FMT_YUV420P,      AV_PIX_FMT_YUV411P,
+        AV_PIX_FMT_YUV410P,      AV_PIX_FMT_YUV440P,
+        AV_PIX_FMT_YUVJ444P,     AV_PIX_FMT_YUVJ422P,
+        AV_PIX_FMT_YUVJ420P,     AV_PIX_FMT_YUVJ440P,
+        AV_PIX_FMT_YUVA420P,
+        AV_PIX_FMT_NONE
+    };
+
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+
+    return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    DecimateContext *decimate = ctx->priv;
+    const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
+    decimate->hsub = pix_desc->log2_chroma_w;
+    decimate->vsub = pix_desc->log2_chroma_h;
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *cur)
+{
+    DecimateContext *decimate = inlink->dst->priv;
+    AVFilterLink *outlink = inlink->dst->outputs[0];
+    int ret;
+
+    if (decimate->ref && decimate_frame(inlink->dst, cur, decimate->ref)) {
+        decimate->drop_count = FFMAX(1, decimate->drop_count+1);
+    } else {
+        av_frame_free(&decimate->ref);
+        decimate->ref = cur;
+        decimate->drop_count = FFMIN(-1, decimate->drop_count-1);
+
+        if (ret = ff_filter_frame(outlink, av_frame_clone(cur)) < 0)
+            return ret;
+    }
+
+    av_log(inlink->dst, AV_LOG_DEBUG,
+           "%s pts:%s pts_time:%s drop_count:%d\n",
+           decimate->drop_count > 0 ? "drop" : "keep",
+           av_ts2str(cur->pts), av_ts2timestr(cur->pts, &inlink->time_base),
+           decimate->drop_count);
+
+    if (decimate->drop_count > 0)
+        av_frame_free(&cur);
+
+    return 0;
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+    DecimateContext *decimate = outlink->src->priv;
+    AVFilterLink *inlink = outlink->src->inputs[0];
+    int ret;
+
+    do {
+        ret = ff_request_frame(inlink);
+    } while (decimate->drop_count > 0 && ret >= 0);
+
+    return ret;
+}
+
+static const AVFilterPad mpdecimate_inputs[] = {
+    {
+        .name             = "default",
+        .type             = AVMEDIA_TYPE_VIDEO,
+        .get_video_buffer = ff_null_get_video_buffer,
+        .config_props     = config_input,
+        .filter_frame     = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad mpdecimate_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .request_frame = request_frame,
+    },
+    { NULL }
+};
+
+AVFilter avfilter_vf_mpdecimate = {
+    .name        = "mpdecimate",
+    .description = NULL_IF_CONFIG_SMALL("Remove near-duplicate frames."),
+    .init        = init,
+    .uninit      = uninit,
+
+    .priv_size = sizeof(DecimateContext),
+    .query_formats = query_formats,
+    .inputs        = mpdecimate_inputs,
+    .outputs       = mpdecimate_outputs,
+    .priv_class    = &mpdecimate_class,
+};