Fix cropping, depending on enc pix fmt

Originally committed as revision 5134 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 25 insertions, 0 deletions

diff --git a/libavcodec/imgconvert.c b/libavcodec/imgconvert.c
index 850f9b04f4..e03706d440 100644
--- a/libavcodec/imgconvert.c
+++ b/libavcodec/imgconvert.c
@@ -1951,6 +1951,31 @@ static inline int is_yuv_planar(PixFmtInfo *ps)
         ps->pixel_type == FF_PIXEL_PLANAR;
 }
 
+/**
+ * Crop image top and left side
+ */
+int img_crop(AVPicture *dst, const AVPicture *src,
+              int pix_fmt, int top_band, int left_band)
+{
+    int y_shift;
+    int x_shift;
+
+    if (pix_fmt < 0 || pix_fmt >= PIX_FMT_NB || !is_yuv_planar(&pix_fmt_info[pix_fmt]))
+        return -1;
+
+    y_shift = pix_fmt_info[pix_fmt].y_chroma_shift;
+    x_shift = pix_fmt_info[pix_fmt].x_chroma_shift;
+
+    dst->data[0] = src->data[0] + (top_band * src->linesize[0]) + left_band;
+    dst->data[1] = src->data[1] + ((top_band >> y_shift) * src->linesize[1]) + (left_band >> x_shift);
+    dst->data[2] = src->data[2] + ((top_band >> y_shift) * src->linesize[2]) + (left_band >> x_shift);
+
+    dst->linesize[0] = src->linesize[0];
+    dst->linesize[1] = src->linesize[1];
+    dst->linesize[2] = src->linesize[2];
+    return 0;
+}
+
 /* XXX: always use linesize. Return -1 if not supported */
 int img_convert(AVPicture *dst, int dst_pix_fmt,
                 const AVPicture *src, int src_pix_fmt,