Add video crop filter.

Originally committed as revision 20342 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/libavfilter.texi

@@ -84,4 +84,35 @@ Below is a description of the currently available video filters.
 
 Pass the source unchanged to the output.
 
+@section crop
+
+Crop the input video to x:y:width:height.
+
+@example
+./ffmpeg -i in.avi -vfilters "crop=0:0:0:240" out.avi
+@end example
+
+``x'' and ``y'' specify the position of the top-left corner of the
+output (non-cropped) area.
+
+The default value of ``x'' and ``y'' is 0.
+
+The ``w'' and ``h'' parameters specify the width and height of the
+output (non-cropped) area.
+
+A value of 0 is interpreted as the maximum possible size contained in
+the area delimited by the top-left corner at position x:y.
+
+For example the parameters:
+
+@example
+"crop=100:100:0:0"
+@end example
+
+will delimit the rectangle with the top-left corner placed at position
+100:100 and the right-bottom corner corresponding to the right-bottom
+corner of the input image.
+
+The default value of ``w'' and ``h'' is 0.
+
 @bye

libavfilter/Makefile

@@ -11,6 +11,7 @@ OBJS = allfilters.o                                                     \
        defaults.o                                                       \
        formats.o                                                        \
 
+OBJS-$(CONFIG_CROP_FILTER)    += vf_crop.o
 OBJS-$(CONFIG_NULL_FILTER)    += vf_null.o
 
 include $(SUBDIR)../subdir.mak

libavfilter/allfilters.c

@@ -34,5 +34,6 @@ void avfilter_register_all(void)
         return;
     initialized = 1;
 
+    REGISTER_FILTER (CROP,crop,vf);
     REGISTER_FILTER (NULL,null,vf);
 }

libavfilter/vf_crop.c

+/*
+ * 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 libavfilter/vf_crop.c
+ * video crop filter
+ */
+
+#include "avfilter.h"
+
+typedef struct {
+    int  x;             ///< x offset of the non-cropped area with respect to the input area
+    int  y;             ///< y offset of the non-cropped area with respect to the input area
+    int  w;             ///< width of the cropped area
+    int  h;             ///< height of the cropped area
+
+    int bpp;            ///< bits per pixel
+    int hsub, vsub;     ///< chroma subsampling
+} CropContext;
+
+static int query_formats(AVFilterContext *ctx)
+{
+    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_NV12,         PIX_FMT_NV21,
+        PIX_FMT_YUYV422,      PIX_FMT_UYVY422,
+        PIX_FMT_UYYVYY411,
+        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 av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    CropContext *crop = ctx->priv;
+
+    if (args)
+        sscanf(args, "%d:%d:%d:%d", &crop->x, &crop->y, &crop->w, &crop->h);
+
+    return 0;
+}
+
+static int config_input(AVFilterLink *link)
+{
+    AVFilterContext *ctx = link->dst;
+    CropContext *crop = ctx->priv;
+
+    switch (link->format) {
+    case PIX_FMT_RGB48BE:
+    case PIX_FMT_RGB48LE:
+        crop->bpp = 48;
+        break;
+    case PIX_FMT_ARGB:
+    case PIX_FMT_RGBA:
+    case PIX_FMT_ABGR:
+    case PIX_FMT_BGRA:
+        crop->bpp = 32;
+        break;
+    case PIX_FMT_RGB24:
+    case PIX_FMT_BGR24:
+        crop->bpp = 24;
+        break;
+    case PIX_FMT_RGB565BE:
+    case PIX_FMT_RGB565LE:
+    case PIX_FMT_RGB555BE:
+    case PIX_FMT_RGB555LE:
+    case PIX_FMT_BGR565BE:
+    case PIX_FMT_BGR565LE:
+    case PIX_FMT_BGR555BE:
+    case PIX_FMT_BGR555LE:
+    case PIX_FMT_GRAY16BE:
+    case PIX_FMT_GRAY16LE:
+    case PIX_FMT_YUV420P16LE:
+    case PIX_FMT_YUV420P16BE:
+    case PIX_FMT_YUV422P16LE:
+    case PIX_FMT_YUV422P16BE:
+    case PIX_FMT_YUV444P16LE:
+    case PIX_FMT_YUV444P16BE:
+        crop->bpp = 16;
+        break;
+    default:
+        crop->bpp = 8;
+    }
+
+    avcodec_get_chroma_sub_sample(link->format, &crop->hsub, &crop->vsub);
+
+    if (crop->w == 0)
+        crop->w = link->w - crop->x;
+    if (crop->h == 0)
+        crop->h = link->h - crop->y;
+
+    crop->x &= ~((1 << crop->hsub) - 1);
+    crop->y &= ~((1 << crop->vsub) - 1);
+
+    av_log(link->dst, AV_LOG_INFO, "x:%d y:%d w:%d h:%d\n",
+           crop->x, crop->y, crop->w, crop->h);
+
+    if (crop->x <  0 || crop->y <  0                    ||
+        crop->w <= 0 || crop->h <= 0                    ||
+        (unsigned)crop->x + (unsigned)crop->w > link->w ||
+        (unsigned)crop->y + (unsigned)crop->h > link->h) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Output area %d:%d:%d:%d not within the input area 0:0:%d:%d or zero-sized\n",
+               crop->x, crop->y, crop->w, crop->h, link->w, link->h);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int config_output(AVFilterLink *link)
+{
+    CropContext *crop = link->src->priv;
+
+    link->w = crop->w;
+    link->h = crop->h;
+
+    return 0;
+}
+
+static AVFilterPicRef *get_video_buffer(AVFilterLink *link, int perms,
+                                        int w, int h)
+{
+    return avfilter_get_video_buffer(link->dst->outputs[0], perms, w, h);
+}
+
+static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
+{
+    CropContext *crop = link->dst->priv;
+    AVFilterPicRef *ref2 = avfilter_ref_pic(picref, ~0);
+    int i;
+
+    ref2->w        = crop->w;
+    ref2->h        = crop->h;
+
+    ref2->data[0] += crop->y * ref2->linesize[0];
+    ref2->data[0] += (crop->x * crop->bpp) >> 3;
+
+    if (link->format != PIX_FMT_PAL8) {
+        for (i = 1; i < 3; i ++) {
+            if (ref2->data[i]) {
+                ref2->data[i] += (crop->y >> crop->vsub) * ref2->linesize[i];
+                ref2->data[i] +=  crop->x >> crop->hsub;
+            }
+        }
+    }
+
+    /* alpha plane */
+    if (ref2->data[3]) {
+        ref2->data[3] += crop->y * ref2->linesize[3];
+        ref2->data[3] += (crop->x * crop->bpp) >> 3;
+    }
+
+    avfilter_start_frame(link->dst->outputs[0], ref2);
+}
+
+static void draw_slice(AVFilterLink *link, int y, int h)
+{
+    AVFilterContext *ctx = link->dst;
+    CropContext *crop = ctx->priv;
+
+    if (y >= crop->y + crop->h || y + h <= crop->y)
+        return;
+
+    if (y < crop->y) {
+        h -= crop->y - y;
+        y  = crop->y;
+    }
+    if (y + h > crop->y + crop->h)
+        h = crop->y + crop->h - y;
+
+    avfilter_draw_slice(ctx->outputs[0], y - crop->y, h);
+}
+
+AVFilter avfilter_vf_crop = {
+    .name      = "crop",
+    .priv_size = sizeof(CropContext),
+
+    .query_formats = query_formats,
+    .init          = init,
+
+    .inputs    = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = CODEC_TYPE_VIDEO,
+                                    .start_frame      = start_frame,
+                                    .draw_slice       = draw_slice,
+                                    .get_video_buffer = get_video_buffer,
+                                    .config_props     = config_input, },
+                                  { .name = NULL}},
+    .outputs   = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = CODEC_TYPE_VIDEO,
+                                    .config_props     = config_output, },
+                                  { .name = NULL}},
+};