[FFmpeg-devel] [PATCH] lavfi: add fade filter
Stefano Sabatini
stefano.sabatini-lala
Mon Feb 21 12:02:57 CET 2011
From: Brandon Mintern <bmintern at gmail.com>
Port fade filter from libavfilter soc repo, with minor fixes by
Stefano.
---
doc/filters.texi | 33 +++++++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_fade.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 205 insertions(+), 0 deletions(-)
create mode 100644 libavfilter/vf_fade.c
diff --git a/doc/filters.texi b/doc/filters.texi
index 049e2bd..bbc730d 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -465,6 +465,39 @@ within the parameter list.
For more information about libfreetype, check:
@url{http://www.freetype.org/}
+ at section fade
+
+Apply fade-in/out effect to input video.
+
+It accepts the parameters:
+ at var{type}:@var{start_frame}:@var{nb_frames}
+
+ at var{type} specifies if the effect type, can be either "in" for
+fade-in, or "out" for a fade-out effect.
+
+ at var{start_frame} specifies the number of the start frame for starting
+to apply the fade effect.
+
+ at var{nb_frames} specifies the number of frames for which the fade
+effect has to last. At the end of the fade-in effect the output video
+will have the same intensity as the input video, at the end of the
+fade-out transition the output video will be completely black.
+
+A few usage examples follow, usable too as test scenarios.
+ at example
+# fade in first 30 frames of video
+fade=in:0:30
+
+# fade out last 45 frames of a 200-frame video
+fade=out:155:45
+
+# fade in first 25 frames and fade out last 25 frames of a 1000-frame video
+fade=in:0:25, fade=out:975:25
+
+# make first 5 frames black, then fade in from frame 5-24
+fade=in:5:20
+ at end example
+
@section fifo
Buffer input images and send them when they are requested.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index b3f77a0..f116fe5 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -27,6 +27,7 @@ OBJS-$(CONFIG_CROP_FILTER) += vf_crop.o
OBJS-$(CONFIG_CROPDETECT_FILTER) += vf_cropdetect.o
OBJS-$(CONFIG_DRAWBOX_FILTER) += vf_drawbox.o
OBJS-$(CONFIG_DRAWTEXT_FILTER) += vf_drawtext.o
+OBJS-$(CONFIG_FADE_FILTER) += vf_fade.o
OBJS-$(CONFIG_FIFO_FILTER) += vf_fifo.o
OBJS-$(CONFIG_FORMAT_FILTER) += vf_format.o
OBJS-$(CONFIG_FREI0R_FILTER) += vf_frei0r.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 347a728..0fdd09b 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -46,6 +46,7 @@ void avfilter_register_all(void)
REGISTER_FILTER (CROPDETECT, cropdetect, vf);
REGISTER_FILTER (DRAWBOX, drawbox, vf);
REGISTER_FILTER (DRAWTEXT, drawtext, vf);
+ REGISTER_FILTER (FADE, fade, vf);
REGISTER_FILTER (FIFO, fifo, vf);
REGISTER_FILTER (FORMAT, format, vf);
REGISTER_FILTER (FREI0R, frei0r, vf);
diff --git a/libavfilter/vf_fade.c b/libavfilter/vf_fade.c
new file mode 100644
index 0000000..203a186
--- /dev/null
+++ b/libavfilter/vf_fade.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2010 Brandon Mintern
+ * Copyright (c) 2007 Bobby Bingham
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * video fade filter
+ * based heavily on vf_negate.c by Bobby Bingham
+ */
+
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+
+typedef struct {
+ int factor, fade_per_frame;
+ unsigned int frame_index, start_frame, stop_frame;
+ int hsub, vsub, bpp;
+} FadeContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+ FadeContext *fade = ctx->priv;
+ unsigned int nb_frames;
+ char in_out[4];
+
+ if (!args ||
+ sscanf(args, " %3[^:]:%u:%u", in_out, &fade->start_frame, &nb_frames) != 3) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Expected 3 arguments '(in|out):#:#':'%s'\n", args);
+ return AVERROR(EINVAL);
+ }
+
+ nb_frames = nb_frames ? nb_frames : 1;
+ fade->fade_per_frame = (1 << 16) / nb_frames;
+ if (!strcmp(in_out, "in"))
+ fade->factor = 0;
+ else if (!strcmp(in_out, "out")) {
+ fade->fade_per_frame = -fade->fade_per_frame;
+ fade->factor = (1 << 16);
+ } else {
+ av_log(ctx, AV_LOG_ERROR,
+ "first argument must be 'in' or 'out':'%s'\n", in_out);
+ return AVERROR(EINVAL);
+ }
+ fade->stop_frame = fade->start_frame + nb_frames;
+
+ av_log(ctx, AV_LOG_INFO,
+ "type:%s start_frame:%d nb_frames:%d\n",
+ in_out, fade->start_frame, nb_frames);
+ return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+ const static enum PixelFormat pix_fmts[] = {
+ PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV420P,
+ PIX_FMT_YUV411P, PIX_FMT_YUV410P,
+ PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
+ PIX_FMT_YUV440P, PIX_FMT_YUVJ440P,
+ PIX_FMT_RGB24, PIX_FMT_BGR24,
+ PIX_FMT_NONE
+ };
+
+ avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
+ return 0;
+}
+
+static int config_props(AVFilterLink *inlink)
+{
+ FadeContext *fade = inlink->dst->priv;
+ const AVPixFmtDescriptor *pixdesc = &av_pix_fmt_descriptors[inlink->format];
+
+ fade->hsub = pixdesc->log2_chroma_w;
+ fade->vsub = pixdesc->log2_chroma_h;
+
+ fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
+ return 0;
+}
+
+static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
+{
+ FadeContext *fade = inlink->dst->priv;
+ AVFilterBufferRef *outpic = inlink->cur_buf;
+ uint8_t *p;
+ int i, j, plane;
+
+ if (fade->factor < 65536) {
+ /* luma or rgb plane */
+ for (i = 0; i < h; i++) {
+ p = outpic->data[0] + (y+i) * outpic->linesize[0];
+ for (j = 0; j < inlink->w * fade->bpp; j++) {
+ /* fade->factor is using 16 lower-order bits for decimal
+ * places. 32768 = 1 << 15, it is an integer representation
+ * of 0.5 and is for rounding. */
+ *p = (*p * fade->factor + 32768) >> 16;
+ p++;
+ }
+ }
+
+ if (outpic->data[0] && outpic->data[1]) {
+ /* chroma planes */
+ for (plane = 1; plane < 3; plane++) {
+ for (i = 0; i < h; i++) {
+ p = outpic->data[plane] + ((y+i) >> fade->vsub) * outpic->linesize[plane];
+ for (j = 0; j < inlink->w >> fade->hsub; j++) {
+ /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
+ * representation of 128.5. The .5 is for rounding
+ * purposes. */
+ *p = ((*p - 128) * fade->factor + 8421367) >> 16;
+ p++;
+ }
+ }
+ }
+ }
+ }
+
+ avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
+}
+
+static void end_frame(AVFilterLink *inlink)
+{
+ FadeContext *fade = inlink->dst->priv;
+
+ avfilter_end_frame(inlink->dst->outputs[0]);
+
+ if (fade->frame_index >= fade->start_frame &&
+ fade->frame_index <= fade->stop_frame)
+ fade->factor += fade->fade_per_frame;
+ fade->factor = av_clip_uint16(fade->factor);
+ fade->frame_index++;
+}
+
+AVFilter avfilter_vf_fade = {
+ .name = "fade",
+ .description = NULL_IF_CONFIG_SMALL("Fade in/out input video"),
+ .init = init,
+ .priv_size = sizeof(FadeContext),
+ .query_formats = query_formats,
+
+ .inputs = (AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .config_props = config_props,
+ .get_video_buffer = avfilter_null_get_video_buffer,
+ .start_frame = avfilter_null_start_frame,
+ .draw_slice = draw_slice,
+ .end_frame = end_frame,
+ .min_perms = AV_PERM_READ | AV_PERM_WRITE,
+ .rej_perms = AV_PERM_PRESERVE, },
+ { .name = NULL}},
+ .outputs = (AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO, },
+ { .name = NULL}},
+};
--
1.7.2.3
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