[FFmpeg-cvslog] dsputil.h: Clean up comments
Diego Biurrun
git at videolan.org
Fri Mar 14 00:16:39 CET 2014
ffmpeg | branch: master | Diego Biurrun <diego at biurrun.de> | Sun Dec 22 17:49:52 2013 +0100| [8199bb7be0db423bcbbd252d092386634fcf1d68] | committer: Diego Biurrun
dsputil.h: Clean up comments
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8199bb7be0db423bcbbd252d092386634fcf1d68
---
libavcodec/dsputil.h | 85 +++++++++++++++++++++++++++-----------------------
1 file changed, 46 insertions(+), 39 deletions(-)
diff --git a/libavcodec/dsputil.h b/libavcodec/dsputil.h
index 81efd42..56bf569 100644
--- a/libavcodec/dsputil.h
+++ b/libavcodec/dsputil.h
@@ -23,8 +23,8 @@
/**
* @file
* DSP utils.
- * note, many functions in here may use MMX which trashes the FPU state, it is
- * absolutely necessary to call emms_c() between dsp & float/double code
+ * Note, many functions in here may use MMX which trashes the FPU state, it is
+ * absolutely necessary to call emms_c() between DSP & float/double code.
*/
#ifndef AVCODEC_DSPUTIL_H
@@ -61,21 +61,22 @@ void ff_gmc_c(uint8_t *dst, uint8_t *src, int stride, int h, int ox, int oy,
int dxx, int dxy, int dyx, int dyy, int shift, int r, int width, int height);
/* minimum alignment rules ;)
-If you notice errors in the align stuff, need more alignment for some ASM code
-for some CPU or need to use a function with less aligned data then send a mail
-to the libav-devel mailing list, ...
-
-!warning These alignments might not match reality, (missing attribute((align))
-stuff somewhere possible).
-I (Michael) did not check them, these are just the alignments which I think
-could be reached easily ...
-
-!future video codecs might need functions with less strict alignment
-*/
+ * If you notice errors in the align stuff, need more alignment for some ASM code
+ * for some CPU or need to use a function with less aligned data then send a mail
+ * to the libav-devel mailing list, ...
+ *
+ * !warning These alignments might not match reality, (missing attribute((align))
+ * stuff somewhere possible).
+ * I (Michael) did not check them, these are just the alignments which I think
+ * could be reached easily ...
+ *
+ * !future video codecs might need functions with less strict alignment
+ */
-/* add and put pixel (decoding) */
-// blocksizes for op_pixels_func are 8x4,8x8 16x8 16x16
-//h for op_pixels_func is limited to {width/2, width} but never larger than 16 and never smaller than 4
+/* add and put pixel (decoding)
+ * Block sizes for op_pixels_func are 8x4,8x8 16x8 16x16.
+ * h for op_pixels_func is limited to { width / 2, width },
+ * but never larger than 16 and never smaller than 4. */
typedef void (*tpel_mc_func)(uint8_t *block/*align width (8 or 16)*/, const uint8_t *pixels/*align 1*/, int line_size, int w, int h);
typedef void (*qpel_mc_func)(uint8_t *dst/*align width (8 or 16)*/, uint8_t *src/*align 1*/, ptrdiff_t stride);
@@ -99,10 +100,14 @@ DEF_OLD_QPEL(qpel8_mc32_old_c)
DEF_OLD_QPEL(qpel8_mc13_old_c)
DEF_OLD_QPEL(qpel8_mc33_old_c)
-/* motion estimation */
-// h is limited to {width/2, width, 2*width} but never larger than 16 and never smaller than 2
-// although currently h<4 is not used as functions with width <8 are neither used nor implemented
-typedef int (*me_cmp_func)(void /*MpegEncContext*/ *s, uint8_t *blk1/*align width (8 or 16)*/, uint8_t *blk2/*align 1*/, int line_size, int h)/* __attribute__ ((const))*/;
+/* Motion estimation:
+ * h is limited to { width / 2, width, 2 * width },
+ * but never larger than 16 and never smaller than 2.
+ * Although currently h < 4 is not used as functions with
+ * width < 8 are neither used nor implemented. */
+typedef int (*me_cmp_func)(void /* MpegEncContext */ *s,
+ uint8_t *blk1 /* align width (8 or 16) */,
+ uint8_t *blk2 /* align 1 */, int line_size, int h);
/**
* Scantable.
@@ -142,7 +147,6 @@ typedef struct DSPContext {
void (*clear_blocks)(int16_t *blocks/*align 16*/);
int (*pix_sum)(uint8_t * pix, int line_size);
int (*pix_norm1)(uint8_t * pix, int line_size);
-// 16x16 8x8 4x4 2x2 16x8 8x4 4x2 8x16 4x8 2x4
me_cmp_func sad[6]; /* identical to pix_absAxA except additional void * */
me_cmp_func sse[6];
@@ -168,10 +172,10 @@ typedef struct DSPContext {
int size);
/**
- * Thirdpel motion compensation with rounding (a+b+1)>>1.
- * this is an array[12] of motion compensation functions for the 9 thirdpe
- * positions<br>
- * *pixels_tab[ xthirdpel + 4*ythirdpel ]
+ * Thirdpel motion compensation with rounding (a + b + 1) >> 1.
+ * this is an array[12] of motion compensation functions for the
+ * 9 thirdpel positions<br>
+ * *pixels_tab[xthirdpel + 4 * ythirdpel]
* @param block destination where the result is stored
* @param pixels source
* @param line_size number of bytes in a horizontal line of block
@@ -187,12 +191,12 @@ typedef struct DSPContext {
me_cmp_func pix_abs[2][4];
- /* huffyuv specific */
+ /* HuffYUV specific */
void (*add_bytes)(uint8_t *dst/*align 16*/, uint8_t *src/*align 16*/, int w);
void (*diff_bytes)(uint8_t *dst/*align 16*/, uint8_t *src1/*align 16*/, uint8_t *src2/*align 1*/,int w);
/**
- * subtract huffyuv's variant of median prediction
- * note, this might read from src1[-1], src2[-1]
+ * Subtract HuffYUV's variant of median prediction.
+ * Note, this might read from src1[-1], src2[-1].
*/
void (*sub_hfyu_median_prediction)(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, int w, int *left, int *left_top);
void (*add_hfyu_median_prediction)(uint8_t *dst, const uint8_t *top, const uint8_t *diff, int w, int *left, int *left_top);
@@ -225,16 +229,18 @@ typedef struct DSPContext {
void (*idct_add)(uint8_t *dest/*align 8*/, int line_size, int16_t *block/*align 16*/);
/**
- * idct input permutation.
- * several optimized IDCTs need a permutated input (relative to the normal order of the reference
- * IDCT)
- * this permutation must be performed before the idct_put/add, note, normally this can be merged
- * with the zigzag/alternate scan<br>
- * an example to avoid confusion:
- * - (->decode coeffs -> zigzag reorder -> dequant -> reference idct ->...)
- * - (x -> reference dct -> reference idct -> x)
- * - (x -> reference dct -> simple_mmx_perm = idct_permutation -> simple_idct_mmx -> x)
- * - (->decode coeffs -> zigzag reorder -> simple_mmx_perm -> dequant -> simple_idct_mmx ->...)
+ * IDCT input permutation.
+ * Several optimized IDCTs need a permutated input (relative to the
+ * normal order of the reference IDCT).
+ * This permutation must be performed before the idct_put/add.
+ * Note, normally this can be merged with the zigzag/alternate scan<br>
+ * An example to avoid confusion:
+ * - (->decode coeffs -> zigzag reorder -> dequant -> reference IDCT -> ...)
+ * - (x -> reference DCT -> reference IDCT -> x)
+ * - (x -> reference DCT -> simple_mmx_perm = idct_permutation
+ * -> simple_idct_mmx -> x)
+ * - (-> decode coeffs -> zigzag reorder -> simple_mmx_perm -> dequant
+ * -> simple_idct_mmx -> ...)
*/
uint8_t idct_permutation[64];
int idct_permutation_type;
@@ -271,7 +277,8 @@ typedef struct DSPContext {
int32_t (*scalarproduct_and_madd_int16)(int16_t *v1/*align 16*/, const int16_t *v2, const int16_t *v3, int len, int mul);
/**
- * Clip each element in an array of int32_t to a given minimum and maximum value.
+ * Clip each element in an array of int32_t to a given minimum and
+ * maximum value.
* @param dst destination array
* constraints: 16-byte aligned
* @param src source array
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