[FFmpeg-devel] [PATCH 5/5] lavfi: addroi filter

Mark Thompson sw at jkqxz.net
Thu Feb 28 00:00:23 EET 2019


This can be used to add region of interest side data to video frames.
---
 libavfilter/Makefile     |   1 +
 libavfilter/allfilters.c |   1 +
 libavfilter/vf_addroi.c  | 237 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 239 insertions(+)
 create mode 100644 libavfilter/vf_addroi.c

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index fef6ec5c55..31ae738a50 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -149,6 +149,7 @@ OBJS-$(CONFIG_SINE_FILTER)                   += asrc_sine.o
 OBJS-$(CONFIG_ANULLSINK_FILTER)              += asink_anullsink.o
 
 # video filters
+OBJS-$(CONFIG_ADDROI_FILTER)                 += vf_addroi.o
 OBJS-$(CONFIG_ALPHAEXTRACT_FILTER)           += vf_extractplanes.o
 OBJS-$(CONFIG_ALPHAMERGE_FILTER)             += vf_alphamerge.o
 OBJS-$(CONFIG_AMPLIFY_FILTER)                += vf_amplify.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index c51ae0f3c7..52413c8f0d 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -140,6 +140,7 @@ extern AVFilter ff_asrc_sine;
 
 extern AVFilter ff_asink_anullsink;
 
+extern AVFilter ff_vf_addroi;
 extern AVFilter ff_vf_alphaextract;
 extern AVFilter ff_vf_alphamerge;
 extern AVFilter ff_vf_amplify;
diff --git a/libavfilter/vf_addroi.c b/libavfilter/vf_addroi.c
new file mode 100644
index 0000000000..c8d323e660
--- /dev/null
+++ b/libavfilter/vf_addroi.c
@@ -0,0 +1,237 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * 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.
+ *
+ * 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/eval.h"
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "internal.h"
+
+enum {
+    TOP,
+    BOTTOM,
+    LEFT,
+    RIGHT,
+};
+
+static const char *const addroi_var_names[] = {
+    "w",
+    "h",
+};
+
+enum {
+    VAR_W,
+    VAR_H,
+    NB_VARS,
+};
+
+typedef struct AddROIContext {
+    const AVClass *class;
+
+    char *region_str[4];
+
+    AVExpr *region_expr[4];
+    double vars[NB_VARS];
+
+    int region[4];
+    AVRational qoffset;
+} AddROIContext;
+
+static int addroi_config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *avctx = inlink->dst;
+    AddROIContext     *ctx = avctx->priv;
+    int i;
+    double val;
+
+    ctx->vars[VAR_W] = inlink->w;
+    ctx->vars[VAR_H] = inlink->h;
+
+    for (i = 0; i < 4; i++) {
+        val = av_expr_eval(ctx->region_expr[i], ctx->vars, NULL);
+        ctx->region[i] = av_clip(rint(val), 0,
+                                 i < 2 ? inlink->h : inlink->w);
+    }
+
+    return 0;
+}
+
+static int addroi_filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *avctx = inlink->dst;
+    AVFilterLink  *outlink = avctx->outputs[0];
+    AddROIContext     *ctx = avctx->priv;
+    AVRegionOfInterest *roi;
+    AVFrameSideData *sd;
+    int err;
+
+    sd = av_frame_get_side_data(frame, AV_FRAME_DATA_REGIONS_OF_INTEREST);
+    if (sd) {
+        const AVRegionOfInterest *old_roi;
+        AVBufferRef *roi_ref;
+        int nb_roi, i;
+
+        old_roi = (const AVRegionOfInterest*)sd->data;
+        nb_roi = sd->size / old_roi->self_size + 1;
+
+        roi_ref = av_buffer_alloc(sizeof(*roi) * nb_roi);
+        if (!roi_ref) {
+            err = AVERROR(ENOMEM);
+            goto fail;
+        }
+        roi = (AVRegionOfInterest*)roi_ref->data;
+
+        for (i = 0; i < nb_roi - 1; i++) {
+            old_roi = (const AVRegionOfInterest*)
+                (sd->data + old_roi->self_size * i);
+
+            roi[i] = (AVRegionOfInterest) {
+                .self_size = sizeof(*roi),
+                .top       = old_roi->top,
+                .bottom    = old_roi->bottom,
+                .left      = old_roi->left,
+                .right     = old_roi->right,
+                .qoffset   = old_roi->qoffset,
+            };
+        }
+
+        roi[nb_roi - 1] = (AVRegionOfInterest) {
+            .self_size = sizeof(*roi),
+            .top       = ctx->region[TOP],
+            .bottom    = ctx->region[BOTTOM],
+            .left      = ctx->region[LEFT],
+            .right     = ctx->region[RIGHT],
+            .qoffset   = ctx->qoffset,
+        };
+
+        av_frame_remove_side_data(frame, AV_FRAME_DATA_REGIONS_OF_INTEREST);
+
+        sd = av_frame_new_side_data_from_buf(frame,
+                                             AV_FRAME_DATA_REGIONS_OF_INTEREST,
+                                             roi_ref);
+        if (!sd) {
+            av_buffer_unref(&roi_ref);
+            err = AVERROR(ENOMEM);
+            goto fail;
+        }
+
+    } else {
+        sd = av_frame_new_side_data(frame, AV_FRAME_DATA_REGIONS_OF_INTEREST,
+                                    sizeof(AVRegionOfInterest));
+        if (!sd) {
+            err = AVERROR(ENOMEM);
+            goto fail;
+        }
+        roi = (AVRegionOfInterest*)sd->data;
+        *roi = (AVRegionOfInterest) {
+            .self_size = sizeof(*roi),
+            .top       = ctx->region[TOP],
+            .bottom    = ctx->region[BOTTOM],
+            .left      = ctx->region[LEFT],
+            .right     = ctx->region[RIGHT],
+            .qoffset   = ctx->qoffset,
+        };
+    }
+
+    return ff_filter_frame(outlink, frame);
+
+fail:
+    av_frame_free(&frame);
+    return err;
+}
+
+static av_cold int addroi_init(AVFilterContext *avctx)
+{
+    AddROIContext *ctx = avctx->priv;
+    int i, err;
+
+    for (i = 0; i < 4; i++) {
+        err = av_expr_parse(&ctx->region_expr[i], ctx->region_str[i],
+                            addroi_var_names, NULL, NULL, NULL, NULL,
+                            0, avctx);
+        if (err < 0) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Error parsing region distance expression '%s'.\n",
+                   ctx->region_str[i]);
+            return err;
+        }
+    }
+
+    return 0;
+}
+
+static av_cold void addroi_uninit(AVFilterContext *avctx)
+{
+    AddROIContext *ctx = avctx->priv;
+    int i;
+
+    for (i = 0; i < 4; i++) {
+        av_expr_free(ctx->region_expr[i]);
+        ctx->region_expr[i] = NULL;
+    }
+}
+
+#define OFFSET(x) offsetof(AddROIContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
+static const AVOption addroi_options[] = {
+    { "top",    "Region distance from top edge of frame",
+      OFFSET(region_str[TOP]),    AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
+    { "bottom", "Region distance from bottom edge of frame",
+      OFFSET(region_str[BOTTOM]), AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
+    { "left",   "Region distance from left edge of frame",
+      OFFSET(region_str[LEFT]),   AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
+    { "right",  "Region distance from right edge of frame",
+      OFFSET(region_str[RIGHT]),  AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
+
+    { "qoffset", "Quantisation offset to apply in the region.",
+      OFFSET(qoffset), AV_OPT_TYPE_RATIONAL, { .dbl = 0.0 }, -1, +1, .flags = FLAGS },
+
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(addroi);
+
+static const AVFilterPad addroi_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = addroi_config_input,
+        .filter_frame = addroi_filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad addroi_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_addroi = {
+    .name        = "addroi",
+    .description = NULL_IF_CONFIG_SMALL("Add region of interest to frame."),
+    .init        = addroi_init,
+    .uninit      = addroi_uninit,
+
+    .priv_size   = sizeof(AddROIContext),
+    .priv_class  = &addroi_class,
+
+    .inputs      = addroi_inputs,
+    .outputs     = addroi_outputs,
+};
-- 
2.19.2



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