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ffmpeg.wasm-core
Commit f503b195 authored by Stefan Gehrer's avatar Stefan Gehrer
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cosmetic patch: 

Doxygen-style comments
added some more comments

Originally committed as revision 5602 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 05103ed3
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Showing with 65 additions and 36 deletions
libavcodec/cavs.c
View file @ f503b195
......@@ -17,6 +17,12 @@
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file cavs.c
* Chinese AVS video (AVS1-P2, JiZhun profile) decoder
* @author Stefan Gehrer <stefan.gehrer@gmx.de>
*/
#include "avcodec.h"
#include "bitstream.h"
#include "golomb.h"
......@@ -25,27 +31,27 @@
typedef struct {
MpegEncContext s;
Picture picture; //currently decoded frame
Picture DPB[2]; //reference frames
int dist[2]; //temporal distances from current frame to ref frames
Picture picture; ///< currently decoded frame
Picture DPB[2]; ///< reference frames
int dist[2]; ///< temporal distances from current frame to ref frames
int profile, level;
int aspect_ratio;
int mb_width, mb_height;
int pic_type;
int progressive;
int pic_structure;
int skip_mode_flag;
int skip_mode_flag; ///< select between skip_count or one skip_flag per MB
int loop_filter_disable;
int alpha_offset, beta_offset;
int ref_flag;
int mbx, mby;
int flags;
int stc;
uint8_t *cy, *cu, *cv;
int mbx, mby; ///< macroblock coordinates
int flags; ///< availability flags of neighbouring macroblocks
int stc; ///< last start code
uint8_t *cy, *cu, *cv; ///< current MB sample pointers
int left_qp;
uint8_t *top_qp;
/* mv motion vector cache
/** mv motion vector cache
0: D3 B2 B3 C2
4: A1 X0 X1 -
8: A3 X2 X3 -
......@@ -61,7 +67,7 @@ typedef struct {
vector_t *top_mv[2];
vector_t *col_mv;
/* luma pred mode cache
/** luma pred mode cache
0: -- B2 B3
3: A1 X0 X1
6: A3 X2 X3 */
......@@ -73,7 +79,7 @@ typedef struct {
int qp_fixed;
int cbp;
/* intra prediction is done with un-deblocked samples
/** intra prediction is done with un-deblocked samples
they are saved here before deblocking the MB */
uint8_t *top_border_y, *top_border_u, *top_border_v;
uint8_t left_border_y[16], left_border_u[10], left_border_v[10];
......@@ -83,9 +89,12 @@ typedef struct {
void (*intra_pred_c[7])(uint8_t *d,uint8_t *top,uint8_t *left,int stride);
uint8_t *col_type_base;
uint8_t *col_type;
int sym_factor;
int direct_den[2];
int scale_den[2];
/* scaling factors for MV prediction */
int sym_factor; ///< for scaling in symmetrical B block
int direct_den[2]; ///< for scaling in direct B block
int scale_den[2]; ///< for scaling neighbouring MVs
int got_keyframe;
} AVSContext;
......@@ -120,7 +129,15 @@ static inline int get_bs_b(vector_t *mvP, vector_t *mvQ) {
return 0;
}
/* boundary strength (bs) mapping:
#define SET_PARAMS \
alpha = alpha_tab[clip(qp_avg + h->alpha_offset,0,63)]; \
beta = beta_tab[clip(qp_avg + h->beta_offset, 0,63)]; \
tc = tc_tab[clip(qp_avg + h->alpha_offset,0,63)];
/**
* in-loop deblocking filter for a single macroblock
*
* boundary strength (bs) mapping:
*
* --4---5--
* 0 2 |
......@@ -129,12 +146,6 @@ static inline int get_bs_b(vector_t *mvP, vector_t *mvQ) {
* ---------
*
*/
#define SET_PARAMS \
alpha = alpha_tab[clip(qp_avg + h->alpha_offset,0,63)]; \
beta = beta_tab[clip(qp_avg + h->beta_offset, 0,63)]; \
tc = tc_tab[clip(qp_avg + h->alpha_offset,0,63)];
static void filter_mb(AVSContext *h, enum mb_t mb_type) {
DECLARE_ALIGNED_8(uint8_t, bs[8]);
int qp_avg, alpha, beta, tc;
......@@ -665,7 +676,7 @@ static void mv_pred(AVSContext *h, enum mv_loc_t nP, enum mv_loc_t nC,
*
****************************************************************************/
/* kth-order exponential golomb code */
/** kth-order exponential golomb code */
static inline int get_ue_code(GetBitContext *gb, int order) {
if(order) {
int ret = get_ue_golomb(gb) << order;
......@@ -674,6 +685,15 @@ static inline int get_ue_code(GetBitContext *gb, int order) {
return get_ue_golomb(gb);
}
/**
* decode coefficients from one 8x8 block, dequantize, inverse transform
* and add them to sample block
* @param r pointer to 2D VLC table
* @param esc_golomb_order escape codes are k-golomb with this order k
* @param qp quantizer
* @param dst location of sample block
* @param stride line stride in frame buffer
*/
static int decode_residual_block(AVSContext *h, GetBitContext *gb,
const residual_vlc_t *r, int esc_golomb_order,
int qp, uint8_t *dst, int stride) {
......@@ -756,6 +776,9 @@ static inline void decode_residual_inter(AVSContext *h) {
*
****************************************************************************/
/**
* initialise predictors for motion vectors and intra prediction
*/
static inline void init_mb(AVSContext *h) {
int i;
......@@ -795,6 +818,11 @@ static inline void init_mb(AVSContext *h) {
static inline void check_for_slice(AVSContext *h);
/**
* save predictors for later macroblocks and increase
* macroblock address
* @returns 0 if end of frame is reached, 1 otherwise
*/
static inline int next_mb(AVSContext *h) {
int i;
......@@ -1259,18 +1287,16 @@ static int decode_pic(AVSContext *h) {
goto done;
}
mb_type = get_ue_golomb(&s->gb) + P_16X16;
} else {
} else
mb_type = get_ue_golomb(&s->gb) + P_SKIP;
}
init_mb(h);
if(mb_type > P_8X8) {
h->cbp = cbp_tab[mb_type - P_8X8 - 1][0];
decode_mb_i(h,0);
} else {
} else
decode_mb_p(h,mb_type);
}
} while(next_mb(h));
} else { //FF_B_TYPE
} else { /* FF_B_TYPE */
do {
if(h->skip_mode_flag) {
skip_count = get_ue_golomb(&s->gb);
......@@ -1283,16 +1309,14 @@ static int decode_pic(AVSContext *h) {
goto done;
}
mb_type = get_ue_golomb(&s->gb) + B_DIRECT;
} else {
} else
mb_type = get_ue_golomb(&s->gb) + B_SKIP;
}
init_mb(h);
if(mb_type > B_8X8) {
h->cbp = cbp_tab[mb_type - B_8X8 - 1][0];
decode_mb_i(h,0);
} else {
} else
decode_mb_b(h,mb_type);
}
} while(next_mb(h));
}
done:
......@@ -1312,6 +1336,11 @@ static int decode_pic(AVSContext *h) {
*
****************************************************************************/
/**
* some predictions require data from the top-neighbouring macroblock.
* this data has to be stored for one complete row of macroblocks
* and this storage space is allocated here
*/
static void init_top_lines(AVSContext *h) {
/* alloc top line of predictors */
h->top_qp = av_malloc( h->mb_width);
......
libavcodec/cavsdata.h
View file @ f503b195
......@@ -194,15 +194,15 @@ DECLARE_ALIGNED_8(typedef, struct) {
int16_t ref;
} vector_t;
// marks block as unavailable, i.e. out of picture
// or not yet decoded
/** marks block as unavailable, i.e. out of picture
or not yet decoded */
static const vector_t un_mv = {0,0,1,NOT_AVAIL};
//marks block as "no prediction from this direction"
// e.g. forward motion vector in BWD partition
/** marks block as "no prediction from this direction"
e.g. forward motion vector in BWD partition */
static const vector_t dir_mv = {0,0,1,REF_DIR};
//marks block as using intra prediction
/** marks block as using intra prediction */
static const vector_t intra_mv = {0,0,1,REF_INTRA};
typedef struct residual_vlc_t {
......
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