[FFmpeg-devel] [PATCH 2/2] Add hflip filter.

Stefano Sabatini stefano.sabatini-lala
Sat Jul 31 02:07:29 CEST 2010


---
 doc/filters.texi         |   10 ++++
 libavfilter/Makefile     |    1 +
 libavfilter/allfilters.c |    1 +
 libavfilter/vf_hflip.c   |  127 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 139 insertions(+), 0 deletions(-)
 create mode 100644 libavfilter/vf_hflip.c

diff --git a/doc/filters.texi b/doc/filters.texi
index 3ce60b3..4186301 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -56,6 +56,16 @@ The following command:
 
 will convert the input video to the format ``yuv420p''.
 
+ at section hflip
+
+Flip the input video horizontally.
+
+For example to horizontally flip the video in input with
+ at file{ffmpeg}:
+ at example
+ffmpeg -i in.avi -vf "hflip" out.avi
+ at end example
+
 @section noformat
 
 Force libavfilter not to use any of the specified pixel formats for the
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index b7d3ddb..e25ff85 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -17,6 +17,7 @@ OBJS = allfilters.o                                                     \
 OBJS-$(CONFIG_ASPECT_FILTER)                 += vf_aspect.o
 OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o
 OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o
+OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o
 OBJS-$(CONFIG_NOFORMAT_FILTER)               += vf_format.o
 OBJS-$(CONFIG_NULL_FILTER)                   += vf_null.o
 OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 3282a31..657e5d5 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -37,6 +37,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (ASPECT,      aspect,      vf);
     REGISTER_FILTER (CROP,        crop,        vf);
     REGISTER_FILTER (FORMAT,      format,      vf);
+    REGISTER_FILTER (HFLIP,       hflip,       vf);
     REGISTER_FILTER (NOFORMAT,    noformat,    vf);
     REGISTER_FILTER (NULL,        null,        vf);
     REGISTER_FILTER (PAD,         pad,         vf);
diff --git a/libavfilter/vf_hflip.c b/libavfilter/vf_hflip.c
new file mode 100644
index 0000000..199b33f
--- /dev/null
+++ b/libavfilter/vf_hflip.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2007 Benoit Fouet
+ * Copyright (c) 2010 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 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
+ */
+
+/**
+ * @flip
+ * horizontal flip filter
+ */
+
+#include "avfilter.h"
+#include "libavutil/pixdesc.h"
+
+typedef struct {
+    int max_step[4];    ///< max pixel step for each plane, expressed as a number of bytes
+    int hsub, vsub;     ///< chroma subsampling
+} FlipContext;
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum PixelFormat pix_fmts[] = {
+        PIX_FMT_RGB48BE,      PIX_FMT_RGB48LE,
+        PIX_FMT_ARGB,         PIX_FMT_RGBA,
+        PIX_FMT_ABGR,         PIX_FMT_BGRA,
+        PIX_FMT_RGB24,        PIX_FMT_BGR24,
+        PIX_FMT_RGB565BE,     PIX_FMT_RGB565LE,
+        PIX_FMT_RGB555BE,     PIX_FMT_RGB555LE,
+        PIX_FMT_BGR565BE,     PIX_FMT_BGR565LE,
+        PIX_FMT_BGR555BE,     PIX_FMT_BGR555LE,
+        PIX_FMT_GRAY16BE,     PIX_FMT_GRAY16LE,
+        PIX_FMT_YUV420P16LE,  PIX_FMT_YUV420P16BE,
+        PIX_FMT_YUV422P16LE,  PIX_FMT_YUV422P16BE,
+        PIX_FMT_YUV444P16LE,  PIX_FMT_YUV444P16BE,
+        PIX_FMT_YUV444P,      PIX_FMT_YUV422P,
+        PIX_FMT_YUV420P,      PIX_FMT_YUV411P,
+        PIX_FMT_YUV410P,      PIX_FMT_YUV440P,
+        PIX_FMT_YUVJ444P,     PIX_FMT_YUVJ422P,
+        PIX_FMT_YUVJ420P,     PIX_FMT_YUVJ440P,
+        PIX_FMT_YUVA420P,
+        PIX_FMT_RGB8,         PIX_FMT_BGR8,
+        PIX_FMT_RGB4_BYTE,    PIX_FMT_BGR4_BYTE,
+        PIX_FMT_PAL8,         PIX_FMT_GRAY8,
+        PIX_FMT_NONE
+    };
+
+    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int config_props(AVFilterLink *inlink)
+{
+    FlipContext *flip = inlink->dst->priv;
+    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
+    int i;
+
+    memset(flip->max_step, 0, sizeof(flip->max_step));
+    for (i = 0; i < 4; i++) {
+        const AVComponentDescriptor *comp = &(pix_desc->comp[i]);
+        if ((comp->step_minus1+1) > flip->max_step[comp->plane])
+            flip->max_step[comp->plane] = comp->step_minus1+1;
+    }
+
+    flip->hsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
+    flip->vsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
+
+    return 0;
+}
+
+static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
+{
+    FlipContext *flip = inlink->dst->priv;
+    AVFilterPicRef *inpic  = inlink->cur_pic;
+    AVFilterPicRef *outpic = inlink->dst->outputs[0]->outpic;
+    uint8_t *inrow, *outrow;
+    int i, j, plane, step, hsub, vsub;
+
+    for (plane = 0; plane < 4 && inpic->data[plane]; plane++) {
+        step = flip->max_step[plane];
+        hsub = (plane == 1 || plane == 2) ? flip->hsub : 0;
+        vsub = (plane == 1 || plane == 2) ? flip->vsub : 0;
+
+        outrow = outpic->data[plane] + (y>>vsub) * outpic->linesize[plane];
+        inrow  = inpic ->data[plane] + (y>>vsub) * inpic ->linesize[plane] + ((inlink->w >> hsub) - 1) * step;
+        for (i = 0; i < h>>vsub; i++) {
+            for (j = 0; j < (inlink->w >> hsub); j++)
+                memcpy(outrow + j*step, inrow - j*step, step);
+            inrow  += inpic ->linesize[plane];
+            outrow += outpic->linesize[plane];
+        }
+    }
+
+    avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
+}
+
+AVFilter avfilter_vf_hflip = {
+    .name      = "hflip",
+    .description = NULL_IF_CONFIG_SMALL("Horizontally flip the input video"),
+    .priv_size = sizeof(FlipContext),
+    .query_formats = query_formats,
+
+    .inputs    = (AVFilterPad[]) {{ .name            = "default",
+                                    .type            = AVMEDIA_TYPE_VIDEO,
+                                    .draw_slice      = draw_slice,
+                                    .config_props    = config_props,
+                                    .min_perms       = AV_PERM_READ, },
+                                  { .name = NULL}},
+    .outputs   = (AVFilterPad[]) {{ .name            = "default",
+                                    .type            = AVMEDIA_TYPE_VIDEO, },
+                                  { .name = NULL}},
+};
+
-- 
1.7.0.4




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