Remove deprecation of avcodec_get_chroma_sub_sample.

Add explanations what the difference between the 2 functions are and
when either should be used.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/avcodec.h

@@ -4580,10 +4580,21 @@ int av_picture_pad(AVPicture *dst, const AVPicture *src, int height, int width,
  */
 
 /**
- * @deprecated Use av_pix_fmt_get_chroma_sub_sample
+ * Utility function to access log2_chroma_w log2_chroma_h from
+ * the pixel format AVPixFmtDescriptor.
+ *
+ * This function asserts that pix_fmt is valid. See av_pix_fmt_get_chroma_sub_sample
+ * for one that returns a failure code and continues in case of invalid
+ * pix_fmts.
+ *
+ * @param[in]  pix_fmt the pixel format
+ * @param[out] h_shift store log2_chroma_h
+ * @param[out] v_shift store log2_chroma_w
+ *
+ * @see av_pix_fmt_get_chroma_sub_sample
  */
 
-void attribute_deprecated avcodec_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift);
+void avcodec_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift);
 
 /**
  * Return a value representing the fourCC code associated to the

libavcodec/imgconvert.c

@@ -33,6 +33,7 @@
 #include "avcodec.h"
 #include "dsputil.h"
 #include "internal.h"
+#include "libavutil/avassert.h"
 #include "libavutil/colorspace.h"
 #include "libavutil/common.h"
 #include "libavutil/pixdesc.h"
@@ -427,6 +428,7 @@ static const PixFmtInfo pix_fmt_info[AV_PIX_FMT_NB] = {
 void avcodec_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift)
 {
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
+    av_assert0(desc);
     *h_shift = desc->log2_chroma_w;
     *v_shift = desc->log2_chroma_h;
 }

libavutil/pixdesc.h

@@ -210,6 +210,11 @@ enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
  * Utility function to access log2_chroma_w log2_chroma_h from
  * the pixel format AVPixFmtDescriptor.
  *
+ * See avcodec_get_chroma_sub_sample() for a function that asserts a
+ * valid pixel format instead of returning an error code.
+ * Its recommanded that you use avcodec_get_chroma_sub_sample unless
+ * you do check the return code!
+ *
  * @param[in]  pix_fmt the pixel format
  * @param[out] h_shift store log2_chroma_h
  * @param[out] v_shift store log2_chroma_w