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/*
* Winnov WNV1 codec
* Copyright (c) 2005 Konstantin Shishkov
*
* This file is part of FFmpeg.
*
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file wnv1.c
* Winnov WNV1 codec.
*/
#include "avcodec.h"
#include "bitstream.h"
typedef struct WNV1Context{
AVCodecContext *avctx;
AVFrame pic;
int shift;
GetBitContext gb;
} WNV1Context;
static uint16_t code_tab[16][2]={
{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
{0x000,1},
{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
};
#define CODE_VLC_BITS 9
static VLC code_vlc;
/* returns modified base_value */
static inline int wnv1_get_code(WNV1Context *w, int base_value)
{
int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
if(v==15)
return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
else
return base_value + ((v - 7)<<w->shift);
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
WNV1Context * const l = avctx->priv_data;
AVFrame * const p= (AVFrame*)&l->pic;
unsigned char *Y,*U,*V;
int i, j;
int prev_y = 0, prev_u = 0, prev_v = 0;
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;
for(i=8; i<buf_size; i++)
buf[i]= ff_reverse[ buf[i] ]; //FIXME ensure that the buffer is modifyable or use a temp one
init_get_bits(&l->gb, buf+8, (buf_size-8)*8);
if (buf[2] >> 4 == 6)
l->shift = 2;
else {
l->shift = 8 - (buf[2] >> 4);
if (l->shift > 4) {
av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
l->shift = 4;
}
if (l->shift < 1) {
av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
l->shift = 1;
}
}
Y = p->data[0];
U = p->data[1];
V = p->data[2];
for (j = 0; j < avctx->height; j++) {
for (i = 0; i < avctx->width / 2; i++) {
Y[i * 2] = wnv1_get_code(l, prev_y);
prev_u = U[i] = wnv1_get_code(l, prev_u);
prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
prev_v = V[i] = wnv1_get_code(l, prev_v);
}
Y += p->linesize[0];
U += p->linesize[1];
V += p->linesize[2];
}
*data_size = sizeof(AVFrame);
*(AVFrame*)data = l->pic;
return buf_size;
}
static av_cold int decode_init(AVCodecContext *avctx){
WNV1Context * const l = avctx->priv_data;
l->avctx = avctx;
avctx->pix_fmt = PIX_FMT_YUV422P;
if(!code_vlc.table){
init_vlc(&code_vlc, CODE_VLC_BITS, 16,
&code_tab[0][1], 4, 2,
&code_tab[0][0], 4, 2, 1);
}
return 0;
}
AVCodec wnv1_decoder = {
"wnv1",
CODEC_TYPE_VIDEO,
CODEC_ID_WNV1,
sizeof(WNV1Context),
decode_init,
NULL,
NULL,
decode_frame,
CODEC_CAP_DR1,
};
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