1 files changed, 74 insertions, 0 deletions
diff --git a/libmpcodecs/vf_field.c b/libmpcodecs/vf_field.c
new file mode 100644
index 0000000000..de321bf645
--- /dev/null
+++ b/libmpcodecs/vf_field.c
@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../config.h"
+#include "../mp_msg.h"
+
+#include "mp_image.h"
+#include "vf.h"
+
+#include "../libvo/fastmemcpy.h"
+
+struct vf_priv_s {
+    int field;
+    mp_image_t *dmpi;
+};
+
+//===========================================================================//
+
+static int config(struct vf_instance_s* vf,
+        int width, int height, int d_width, int d_height,
+	unsigned int flags, unsigned int outfmt){
+    return vf_next_config(vf,width,height/2,d_width,d_height,flags,outfmt);
+}
+
+static int put_image(struct vf_instance_s* vf, mp_image_t *mpi){
+    if(mpi->flags&MP_IMGFLAG_DIRECT){
+	// we've used DR, so we're ready...
+	return vf_next_put_image(vf,(mp_image_t*)mpi->priv);
+    }
+
+    vf->priv->dmpi=vf_get_image(vf->next,mpi->imgfmt,
+	MP_IMGTYPE_EXPORT, MP_IMGFLAG_ACCEPT_STRIDE,
+	mpi->width, mpi->height/2);
+    
+    // set up mpi as a double-stride image of dmpi:
+    vf->priv->dmpi->planes[0]=mpi->planes[0]+mpi->stride[0]*vf->priv->field;
+    vf->priv->dmpi->stride[0]=2*mpi->stride[0];
+    if(vf->priv->dmpi->flags&MP_IMGFLAG_PLANAR){
+        vf->priv->dmpi->planes[1]=mpi->planes[1]+
+	    mpi->stride[1]*vf->priv->field;
+	vf->priv->dmpi->stride[1]=2*mpi->stride[1];
+        vf->priv->dmpi->planes[2]=mpi->planes[2]+
+	    mpi->stride[2]*vf->priv->field;
+	vf->priv->dmpi->stride[2]=2*mpi->stride[2];
+    } else
+	vf->priv->dmpi->planes[1]=mpi->planes[1]; // passthru bgr8 palette!!!
+    
+    return vf_next_put_image(vf,vf->priv->dmpi);
+}
+
+//===========================================================================//
+
+// FIXME - do we need to free dmpi on uninit?
+
+static int open(vf_instance_t *vf, char* args){
+    vf->config=config;
+    vf->put_image=put_image;
+    vf->default_reqs=VFCAP_ACCEPT_STRIDE;
+    vf->priv=calloc(1, sizeof(struct vf_priv_s));
+    if (args) sscanf(args, "%d", &vf->priv->field);
+    vf->priv->field &= 1;
+    return 1;
+}
+
+vf_info_t vf_info_field = {
+    "extract single field",
+    "field",
+    "Rich Felker",
+    "",
+    open
+};
+
+//===========================================================================//