ffmpeg/libavcodec/loco.c

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/*
* LOCO codec
* Copyright (c) 2005 Konstantin Shishkov
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/**
* @file loco.c
* LOCO codec.
*/
#include "avcodec.h"
#include "common.h"
#include "bitstream.h"
#include "golomb.h"
enum LOCO_MODE {LOCO_UNKN=0, LOCO_CYUY2=-1, LOCO_CRGB=-2, LOCO_CYV12=-3,
LOCO_YUY2=1, LOCO_UYVY=2, LOCO_RGB=3, LOCO_RGBA=4, LOCO_YV12=5};
typedef struct LOCOContext{
AVCodecContext *avctx;
AVFrame pic;
int lossy;
int mode;
} LOCOContext;
typedef struct RICEContext{
GetBitContext gb;
int save, run, run2; /* internal rice decoder state */
int sum, count; /* sum and count for getting rice parameter */
}RICEContext;
/* could use get_sr_golomb() but is behaves differently on numbers like Rice(2, -64) */
static inline int get_rice(GetBitContext *gb, int K)
{
int i;
int V = 0;
for(i = 0; !get_bits1(gb); i++);
V = i;
for(i = 0; i < K; i++) V = (V << 1) | get_bits1(gb);
if(V & 1) return (V + 1) >> 1;
return -(V >> 1);
}
static inline int get_u_rice(GetBitContext *gb, int K)
{
int i;
int V = 0;
for(i = 0; !get_bits1(gb); i++);
V = i;
for(i = 0; i < K; i++) V = (V << 1) | get_bits1(gb);
return V;
}
static int loco_get_rice_param(RICEContext *r)
{
int cnt = 0;
int val = r->count;
while(r->sum > val && cnt < 9) {
val <<= 1;
cnt++;
}
return cnt;
}
static inline void loco_update_rice_param(RICEContext *r, int val)
{
if (val < 0)
val = -val;
r->sum += val;
r->count++;
if(r->count == 16) {
r->sum >>= 1;
r->count >>= 1;
}
}
static inline int loco_get_rice(RICEContext *r)
{
int v;
if (r->run > 0) { /* we have zero run */
r->run--;
return 0;
}
v = -get_rice(&r->gb, loco_get_rice_param(r));
if (!v) {
if (r->save >= 0) {
r->run = get_u_rice(&r->gb, 2);
if(r->run > 1)
r->save += r->run + 1;
else
r->save -= 3;
}
else
r->run2++;
} else if (r->run2 > 0) {
if (r->run2 > 2)
r->save += r->run2;
else
r->save -= 3;
r->run2 = 0;
}
return v;
}
/* LOCO main predictor - LOCO-I/JPEG-LS predictor */
static inline int loco_predict(uint8_t* data, int stride, int step)
{
int max_ab, min_ab;
int a, b, c;
a = data[-stride];
b = data[-step];
c = data[-stride - step];
max_ab = (a > b) ? a : b;
min_ab = (a < b) ? a : b;
if (c >= max_ab) return min_ab;
if (c <= min_ab) return max_ab;
return (a + b - c);
}
static int loco_decode_plane(LOCOContext *l, uint8_t *data, int width, int height,
int stride, uint8_t *buf, int buf_size, int step)
{
RICEContext rc;
int val;
int i, j;
init_get_bits(&rc.gb, buf, buf_size*8);
rc.save = 0;
rc.run = 0;
rc.run2 = 0;
rc.sum = 8;
rc.count = 1;
/* restore top left pixel */
val = loco_get_rice(&rc);
loco_update_rice_param(&rc, val);
if (val < 0) val -= l->lossy;
if (val > 0) val += l->lossy;
data[0] = 128 + val;
/* restore top line */
for (i = 1; i < width; i++) {
val = loco_get_rice(&rc);
loco_update_rice_param(&rc, val);
if (val < 0) val -= l->lossy;
if (val > 0) val += l->lossy;
data[i * step] = data[i * step - step] + val;
}
data += stride;
for (j = 1; j < height; j++) {
/* restore left column */
val = loco_get_rice(&rc);
loco_update_rice_param(&rc, val);
if (val < 0) val -= l->lossy;
if (val > 0) val += l->lossy;
data[0] = data[-stride] + val;
/* restore all other pixels */
for (i = 1; i < width; i++) {
val = loco_get_rice(&rc);
loco_update_rice_param(&rc, val);
if (val < 0) val -= l->lossy;
if (val > 0) val += l->lossy;
data[i * step] = loco_predict(&data[i * step], stride, step) + val;
}
data += stride;
}
return ((get_bits_count(&rc.gb) + 7) >> 3);
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
LOCOContext * const l = avctx->priv_data;
AVFrame * const p= (AVFrame*)&l->pic;
int decoded;
if(p->data[0])
avctx->release_buffer(avctx, p);
p->reference = 0;
if(avctx->get_buffer(avctx, p) < 0){
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
p->key_frame = 1;
switch(l->mode) {
case LOCO_CYUY2: case LOCO_YUY2: case LOCO_UYVY:
decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 1);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[1], avctx->width / 2, avctx->height,
p->linesize[1], buf, buf_size, 1);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[2], avctx->width / 2, avctx->height,
p->linesize[2], buf, buf_size, 1);
break;
case LOCO_CYV12: case LOCO_YV12:
decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 1);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[1], avctx->width / 2, avctx->height / 2,
p->linesize[1], buf, buf_size, 1);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[2], avctx->width / 2, avctx->height / 2,
p->linesize[2], buf, buf_size, 1);
break;
case LOCO_CRGB: case LOCO_RGB:
decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 3);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[0] + 1, avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 3);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[0] + 2, avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 3);
break;
case LOCO_RGBA:
decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 4);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[0] + 1, avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 4);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[0] + 2, avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 4);
buf += decoded; buf_size -= decoded;
decoded = loco_decode_plane(l, p->data[0] + 3, avctx->width, avctx->height,
p->linesize[0], buf, buf_size, 4);
break;
}
*data_size = sizeof(AVFrame);
*(AVFrame*)data = l->pic;
return buf_size;
}
static int decode_init(AVCodecContext *avctx){
LOCOContext * const l = avctx->priv_data;
int version;
l->avctx = avctx;
if (avctx->extradata_size < 12) {
av_log(avctx, AV_LOG_ERROR, "Extradata size must be >= 12 instead of %i\n",
avctx->extradata_size);
return -1;
}
version = LE_32(avctx->extradata);
switch(version) {
case 1:
l->lossy = 0;
break;
case 2:
l->lossy = LE_32(avctx->extradata + 8);
break;
default:
l->lossy = LE_32(avctx->extradata + 8);
av_log(avctx, AV_LOG_INFO, "This is LOCO codec version %i, please upload file for study\n", version);
}
l->mode = LE_32(avctx->extradata + 4);
switch(l->mode) {
case LOCO_CYUY2: case LOCO_YUY2: case LOCO_UYVY:
avctx->pix_fmt = PIX_FMT_YUV422P;
break;
case LOCO_CRGB: case LOCO_RGB:
avctx->pix_fmt = PIX_FMT_BGR24;
break;
case LOCO_CYV12: case LOCO_YV12:
avctx->pix_fmt = PIX_FMT_YUV420P;
break;
case LOCO_RGBA:
avctx->pix_fmt = PIX_FMT_RGBA32;
break;
default:
av_log(avctx, AV_LOG_INFO, "Unknown colorspace, index = %i\n", l->mode);
return -1;
}
return 0;
}
AVCodec loco_decoder = {
"loco",
CODEC_TYPE_VIDEO,
CODEC_ID_LOCO,
sizeof(LOCOContext),
decode_init,
NULL,
NULL,
decode_frame,
CODEC_CAP_DR1,
};