avutil/imgutils: remove special case for aligning the palette

This was suggested by wm4 and stefano.
After this patch using align=1 the size used by various functions would not
contain padding, while the palette would be aligned at align>1

This patch makes it required to use align>=4 if the palette is to be accessed
as uint32

As a side-effect It fixes storing pal8 in nut with odd with&height
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavutil/imgutils.c

@@ -125,7 +125,6 @@ int av_image_fill_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt, int hei
 
     if (desc->flags & AV_PIX_FMT_FLAG_PAL ||
         desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL) {
-        size[0] = (size[0] + 3) & ~3;
         data[1] = ptr + size[0]; /* palette is stored here as 256 32 bits words */
         return size[0] + 256 * 4;
     }
@@ -216,8 +215,13 @@ int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
         av_free(buf);
         return ret;
     }
-    if (desc->flags & AV_PIX_FMT_FLAG_PAL || desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL)
+    if (desc->flags & AV_PIX_FMT_FLAG_PAL || desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL) {
         avpriv_set_systematic_pal2((uint32_t*)pointers[1], pix_fmt);
+        if (align < 4) {
+            av_log(NULL, AV_LOG_ERROR, "Formats with a palette require a minimum alignment of 4\n");
+            return AVERROR(EINVAL);
+        }
+    }
 
     if ((desc->flags & AV_PIX_FMT_FLAG_PAL ||
          desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL) &&
@@ -385,7 +389,6 @@ int av_image_copy_to_buffer(uint8_t *dst, int dst_size,
     int i, j, nb_planes = 0, linesize[4];
     int size = av_image_get_buffer_size(pix_fmt, width, height, align);
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
-    uint8_t *orig_dst = dst;
 
     if (size > dst_size || size < 0 || !desc)
         return AVERROR(EINVAL);
@@ -409,10 +412,7 @@ int av_image_copy_to_buffer(uint8_t *dst, int dst_size,
     }
 
     if (desc->flags & AV_PIX_FMT_FLAG_PAL) {
-        uint32_t *d32 = (uint32_t *)(((size_t)dst + 3) & ~3);
-
-        if (dst_size - 1024 < (uint8_t*)d32 - orig_dst)
-            d32 = (uint32_t *)dst;
+        uint32_t *d32 = (uint32_t *)dst;
 
         for (i = 0; i<256; i++)
             AV_WL32(d32 + i, AV_RN32(src_data[1] + 4*i));

libavutil/version.h

@@ -65,7 +65,7 @@
 
 #define LIBAVUTIL_VERSION_MAJOR  55
 #define LIBAVUTIL_VERSION_MINOR  17
-#define LIBAVUTIL_VERSION_MICRO 102
+#define LIBAVUTIL_VERSION_MICRO 103
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
                                                LIBAVUTIL_VERSION_MINOR, \