File 0008-add-basic-support-for-I420-NV12-colorspace-conversio.patch of Package gst-plugins-base

From 6a8be0fa9f9b7ea0180173f37103b8734fa8b0b6 Mon Sep 17 00:00:00 2001
From: Rob Clark <rob@ti.com>
Date: Fri, 27 Nov 2009 11:13:47 -0600
Subject: [PATCH 08/38] add basic support for I420->NV12 colorspace conversion

---
 gst/stride/gststridetransform.c |  109 ++++++++++++++++++++++++++++++++++++---
 gst/stride/gststridetransform.h |    2 +-
 2 files changed, 103 insertions(+), 8 deletions(-)

diff --git a/gst/stride/gststridetransform.c b/gst/stride/gststridetransform.c
index 56207d0..03deeb1 100644
--- a/gst/stride/gststridetransform.c
+++ b/gst/stride/gststridetransform.c
@@ -227,11 +227,43 @@ add_all_fields (GstCaps *caps, const gchar *name, GstStructure *s, gboolean rows
   idx = gst_structure_n_fields (s) - 1;
   while (idx >= 0) {
     const gchar *name = gst_structure_nth_field_name (s, idx);
+    idx--;
+    if (!strcmp ("format", name)) {
+      // we can do simple color format translations, such as converting from one
+      // YUV420 format to another:
+      GValue formats = {0};
+      GValue fourccval = {0};
+      guint fourcc;
+      if (gst_structure_get_fourcc (s, name, &fourcc)) {
+        switch (gst_video_format_from_fourcc (fourcc)) {
+          case GST_VIDEO_FORMAT_NV12:
+          case GST_VIDEO_FORMAT_I420:
+GST_DEBUG ("Hmm, let's say I can convert I420<-->NV12..");
+            g_value_init (&formats, GST_TYPE_LIST);
+            g_value_init (&fourccval, GST_TYPE_FOURCC);
+            gst_value_set_fourcc (&fourccval,
+                GST_MAKE_FOURCC ('I', '4', '2', '0'));
+            gst_value_list_append_value (&formats, &fourccval);
+            gst_value_set_fourcc (&fourccval,
+                GST_MAKE_FOURCC ('N', 'V', '1', '2'));
+            gst_value_list_append_value (&formats, &fourccval);
+            gst_structure_set_value (new_s, "format", &formats);
+            continue;
+/* maybe handle other cases later..
+          case GST_VIDEO_FORMAT_YV12:
+          case GST_VIDEO_FORMAT_YUY2:
+          case GST_VIDEO_FORMAT_UYVY:
+*/
+          default:
+            break;
+        }
+      }
+    }
+
     if (strcmp ("rowstride", name)) {
       const GValue *val = gst_structure_get_value (s, name);
       gst_structure_set_value (new_s, name, val);
     }
-    idx--;
   }
 
   gst_caps_merge_structure (caps, new_s);
@@ -287,18 +319,16 @@ gst_stride_transform_set_caps (GstBaseTransform *base,
     GstCaps *incaps, GstCaps *outcaps)
 {
   GstStrideTransform *self = GST_STRIDE_TRANSFORM (base);
-  GstVideoFormat format;
   gint width, height;
 
   LOG_CAPS (self, incaps);
   LOG_CAPS (self, outcaps);
 
   g_return_val_if_fail (gst_video_format_parse_caps_strided (incaps,
-      &self->format, &self->width, &self->height, &self->in_rowstride), FALSE);
+      &self->in_format, &self->width, &self->height, &self->in_rowstride), FALSE);
   g_return_val_if_fail (gst_video_format_parse_caps_strided (outcaps,
-      &format, &width, &height, &self->out_rowstride), FALSE);
+      &self->out_format, &width, &height, &self->out_rowstride), FALSE);
 
-  g_return_val_if_fail (self->format == format, FALSE);
   g_return_val_if_fail (self->width  == width,  FALSE);
   g_return_val_if_fail (self->height == height, FALSE);
 
@@ -307,6 +337,49 @@ gst_stride_transform_set_caps (GstBaseTransform *base,
 
 /* ************************************************************************* */
 
+static void
+memmove_demux (guchar *new_buf, guchar *orig_buf, gint sz, gint pxstride)
+{
+  if (new_buf > orig_buf) {
+    /* copy backwards */
+    new_buf += (sz * pxstride);
+    orig_buf += sz;
+    while(sz--) {
+      *new_buf = *orig_buf;
+      new_buf -= pxstride;
+      orig_buf--;
+    }
+  } else {
+    while(sz--) {
+      *new_buf = *orig_buf;
+      new_buf += pxstride;
+      orig_buf++;
+    }
+  }
+}
+
+static void
+stridemove_demux (guchar *new_buf, guchar *orig_buf, gint new_width, gint orig_width, gint height, gint pxstride)
+{
+  int row;
+
+  GST_DEBUG ("new_buf=%p, orig_buf=%p, new_width=%d, orig_width=%d, height=%d",
+      new_buf, orig_buf, new_width, orig_width, height);
+  /* if increasing the stride, work from bottom-up to avoid overwriting data
+   * that has not been moved yet.. otherwise, work in the opposite order,
+   * for the same reason.
+   */
+  if (new_width > orig_width) {
+    for (row=height-1; row>=0; row--) {
+      memmove_demux (new_buf+(new_width*row), orig_buf+(orig_width*row), orig_width, pxstride);
+    }
+  } else {
+    for (row=0; row<height; row++) {
+      memmove_demux (new_buf+(new_width*row), orig_buf+(orig_width*row), new_width, pxstride);
+    }
+  }
+}
+
 /**
  * Convert from one stride to another... like memmove, but can convert stride in
  * the process.  This function is not aware of pixels, only of bytes.  So widths
@@ -356,7 +429,29 @@ stridify (GstStrideTransform *self, guchar *strided, guchar *unstrided)
   gint height = self->height;
   gint stride = self->out_rowstride;
 
-  switch (self->format) {
+  if (self->out_format != self->in_format) {
+
+    if ((self->in_format == GST_VIDEO_FORMAT_I420) &&
+        (self->out_format == GST_VIDEO_FORMAT_NV12)) {
+      /* note: if not an in-place conversion, then doing the U&V in one pass
+       * would be more efficient... but if it is an in-place conversion, I'd
+       * need to think about whether it is potential for the new UV plane to
+       * corrupt the V plane before it is done copying..
+       */
+      stridemove_demux (
+          strided + (height*stride) + 1,
+          unstrided + (int)(height*width*1.25),
+          stride, width/2, height/2, 2);                        /* move V */
+      stridemove_demux (
+          strided + (height*stride),
+          unstrided + (height*width),
+          stride, width/2, height/2, 2);                        /* move U */
+      stridemove (strided, unstrided, stride, width, height);   /* move Y */
+      return GST_FLOW_OK;
+    }
+  }
+
+  switch (self->out_format) {
     case GST_VIDEO_FORMAT_NV12:
       g_return_val_if_fail (stride >= width, GST_FLOW_ERROR);
       stridemove (strided, unstrided, stride, width, (GST_ROUND_UP_2 (height) * 3) / 2);
@@ -400,7 +495,7 @@ unstridify (GstStrideTransform *self, guchar *unstrided, guchar *strided)
   gint height = self->height;
   gint stride = self->in_rowstride;
 
-  switch (self->format) {
+  switch (self->out_format) {
     case GST_VIDEO_FORMAT_NV12:
       g_return_val_if_fail (stride >= width, GST_FLOW_ERROR);
       stridemove (unstrided, strided, width, stride, (GST_ROUND_UP_2 (height) * 3) / 2);
diff --git a/gst/stride/gststridetransform.h b/gst/stride/gststridetransform.h
index 481959e..0141571 100644
--- a/gst/stride/gststridetransform.h
+++ b/gst/stride/gststridetransform.h
@@ -55,7 +55,7 @@ struct _GstStrideTransform {
   GstVideoFilter videofilter;
 
   /*< private >*/
-  GstVideoFormat format;
+  GstVideoFormat in_format, out_format;
   gint width, height;
   gint in_rowstride;
   gint out_rowstride;
-- 
1.7.5.4