1/* 2 * Winnov WNV1 codec 3 * Copyright (c) 2005 Konstantin Shishkov 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file libavcodec/wnv1.c 24 * Winnov WNV1 codec. 25 */ 26 27#include "avcodec.h" 28#include "bitstream.h" 29 30 31typedef struct WNV1Context{ 32 AVCodecContext *avctx; 33 AVFrame pic; 34 35 int shift; 36 GetBitContext gb; 37} WNV1Context; 38 39static const uint16_t code_tab[16][2]={ 40{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3}, 41{0x000,1}, 42{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8} 43}; 44 45#define CODE_VLC_BITS 9 46static VLC code_vlc; 47 48/* returns modified base_value */ 49static inline int wnv1_get_code(WNV1Context *w, int base_value) 50{ 51 int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1); 52 53 if(v==15) 54 return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ]; 55 else 56 return base_value + ((v - 7)<<w->shift); 57} 58 59static int decode_frame(AVCodecContext *avctx, 60 void *data, int *data_size, 61 const uint8_t *buf, int buf_size) 62{ 63 WNV1Context * const l = avctx->priv_data; 64 AVFrame * const p= (AVFrame*)&l->pic; 65 unsigned char *Y,*U,*V; 66 int i, j; 67 int prev_y = 0, prev_u = 0, prev_v = 0; 68 uint8_t *rbuf; 69 70 rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); 71 if(!rbuf){ 72 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n"); 73 return -1; 74 } 75 76 if(p->data[0]) 77 avctx->release_buffer(avctx, p); 78 79 p->reference = 0; 80 if(avctx->get_buffer(avctx, p) < 0){ 81 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 82 av_free(rbuf); 83 return -1; 84 } 85 p->key_frame = 1; 86 87 for(i=8; i<buf_size; i++) 88 rbuf[i]= ff_reverse[ buf[i] ]; 89 init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8); 90 91 if (buf[2] >> 4 == 6) 92 l->shift = 2; 93 else { 94 l->shift = 8 - (buf[2] >> 4); 95 if (l->shift > 4) { 96 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); 97 l->shift = 4; 98 } 99 if (l->shift < 1) { 100 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); 101 l->shift = 1; 102 } 103 } 104 105 Y = p->data[0]; 106 U = p->data[1]; 107 V = p->data[2]; 108 for (j = 0; j < avctx->height; j++) { 109 for (i = 0; i < avctx->width / 2; i++) { 110 Y[i * 2] = wnv1_get_code(l, prev_y); 111 prev_u = U[i] = wnv1_get_code(l, prev_u); 112 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]); 113 prev_v = V[i] = wnv1_get_code(l, prev_v); 114 } 115 Y += p->linesize[0]; 116 U += p->linesize[1]; 117 V += p->linesize[2]; 118 } 119 120 121 *data_size = sizeof(AVFrame); 122 *(AVFrame*)data = l->pic; 123 av_free(rbuf); 124 125 return buf_size; 126} 127 128static av_cold int decode_init(AVCodecContext *avctx){ 129 WNV1Context * const l = avctx->priv_data; 130 131 l->avctx = avctx; 132 avctx->pix_fmt = PIX_FMT_YUV422P; 133 134 if(!code_vlc.table){ 135 init_vlc(&code_vlc, CODE_VLC_BITS, 16, 136 &code_tab[0][1], 4, 2, 137 &code_tab[0][0], 4, 2, 1); 138 } 139 140 return 0; 141} 142 143AVCodec wnv1_decoder = { 144 "wnv1", 145 CODEC_TYPE_VIDEO, 146 CODEC_ID_WNV1, 147 sizeof(WNV1Context), 148 decode_init, 149 NULL, 150 NULL, 151 decode_frame, 152 CODEC_CAP_DR1, 153 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"), 154}; 155