Implement av_get_image_linesize() and use it in

ff_get_plane_bytewidth().

The new implementation is more generic, more compact and more correct.

Originally committed as revision 24786 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 24 insertions, 0 deletions

diff --git a/libavcore/imgutils.c b/libavcore/imgutils.c
index f3d75eecb2..84db01ae77 100644
--- a/libavcore/imgutils.c
+++ b/libavcore/imgutils.c
@@ -24,6 +24,30 @@
 #include "imgutils.h"
 #include "libavutil/pixdesc.h"
 
+int av_get_image_linesize(enum PixelFormat pix_fmt, int width, int plane)
+{
+    const AVPixFmtDescriptor *desc = &av_pix_fmt_descriptors[pix_fmt];
+    int max_step     [4];       /* max pixel step for each plane */
+    int max_step_comp[4];       /* the component for each plane which has the max pixel step */
+    int s, i;
+
+    if (desc->flags & PIX_FMT_BITSTREAM)
+        return (width * (desc->comp[0].step_minus1+1) + 7) >> 3;
+
+    memset(max_step     , 0, sizeof(max_step     ));
+    memset(max_step_comp, 0, sizeof(max_step_comp));
+    for (i = 0; i < 4; i++) {
+        const AVComponentDescriptor *comp = &(desc->comp[i]);
+        if ((comp->step_minus1+1) > max_step[comp->plane]) {
+            max_step     [comp->plane] = comp->step_minus1+1;
+            max_step_comp[comp->plane] = i;
+        }
+    }
+
+    s = (max_step_comp[plane] == 1 || max_step_comp[plane] == 2) ? desc->log2_chroma_w : 0;
+    return max_step[plane] * (((width + (1 << s) - 1)) >> s);
+}
+
 int av_fill_image_linesizes(int linesizes[4], enum PixelFormat pix_fmt, int width)
 {
     int i;