145 lines
3.8 KiB
C
145 lines
3.8 KiB
C
/*
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* Winnov WNV1 codec
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* Copyright (c) 2005 Konstantin Shishkov
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file wnv1.c
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* Winnov WNV1 codec.
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*/
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#include "avcodec.h"
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#include "bitstream.h"
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typedef struct WNV1Context{
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AVCodecContext *avctx;
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AVFrame pic;
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int shift;
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GetBitContext gb;
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} WNV1Context;
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static uint16_t code_tab[16][2]={
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{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
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{0x000,1},
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{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
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};
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#define CODE_VLC_BITS 9
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static VLC code_vlc;
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/* returns modified base_value */
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static inline int wnv1_get_code(WNV1Context *w, int base_value)
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{
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int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
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if(v==15)
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return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
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else
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return base_value + ((v - 7)<<w->shift);
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}
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static int decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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uint8_t *buf, int buf_size)
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{
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WNV1Context * const l = avctx->priv_data;
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AVFrame * const p= (AVFrame*)&l->pic;
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unsigned char *Y,*U,*V;
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int i, j;
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int prev_y = 0, prev_u = 0, prev_v = 0;
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if(p->data[0])
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avctx->release_buffer(avctx, p);
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p->reference = 0;
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if(avctx->get_buffer(avctx, p) < 0){
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av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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return -1;
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}
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p->key_frame = 1;
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for(i=8; i<buf_size; i++)
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buf[i]= ff_reverse[ buf[i] ]; //FIXME ensure that the buffer is modifyable or use a temp one
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init_get_bits(&l->gb, buf+8, (buf_size-8)*8);
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if (buf[2] >> 4 == 6)
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l->shift = 2;
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else {
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l->shift = 8 - (buf[2] >> 4);
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if (l->shift > 4) {
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av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
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l->shift = 4;
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}
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if (l->shift < 1) {
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av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
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l->shift = 1;
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}
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}
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Y = p->data[0];
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U = p->data[1];
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V = p->data[2];
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for (j = 0; j < avctx->height; j++) {
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for (i = 0; i < avctx->width / 2; i++) {
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Y[i * 2] = wnv1_get_code(l, prev_y);
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prev_u = U[i] = wnv1_get_code(l, prev_u);
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prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
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prev_v = V[i] = wnv1_get_code(l, prev_v);
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}
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Y += p->linesize[0];
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U += p->linesize[1];
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V += p->linesize[2];
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}
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*data_size = sizeof(AVFrame);
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*(AVFrame*)data = l->pic;
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return buf_size;
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}
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static int decode_init(AVCodecContext *avctx){
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WNV1Context * const l = avctx->priv_data;
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l->avctx = avctx;
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avctx->pix_fmt = PIX_FMT_YUV422P;
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if(!code_vlc.table){
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init_vlc(&code_vlc, CODE_VLC_BITS, 16,
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&code_tab[0][1], 4, 2,
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&code_tab[0][0], 4, 2, 1);
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}
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return 0;
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}
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AVCodec wnv1_decoder = {
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"wnv1",
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CODEC_TYPE_VIDEO,
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CODEC_ID_WNV1,
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sizeof(WNV1Context),
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decode_init,
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NULL,
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NULL,
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decode_frame,
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CODEC_CAP_DR1,
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};
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