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 24 * Winnov WNV1 codec. 25 */ 26 27#include "avcodec.h" 28#include "get_bits.h" 29#include "libavutil/common.h" 30 31 32typedef struct WNV1Context{ 33 AVCodecContext *avctx; 34 AVFrame pic; 35 36 int shift; 37 GetBitContext gb; 38} WNV1Context; 39 40static const uint16_t code_tab[16][2]={ 41{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3}, 42{0x000,1}, 43{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8} 44}; 45 46#define CODE_VLC_BITS 9 47static VLC code_vlc; 48 49/* returns modified base_value */ 50static inline int wnv1_get_code(WNV1Context *w, int base_value) 51{ 52 int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1); 53 54 if(v==15) 55 return av_reverse[ get_bits(&w->gb, 8 - w->shift) ]; 56 else 57 return base_value + ((v - 7)<<w->shift); 58} 59 60static int decode_frame(AVCodecContext *avctx, 61 void *data, int *data_size, 62 AVPacket *avpkt) 63{ 64 const uint8_t *buf = avpkt->data; 65 int buf_size = avpkt->size; 66 WNV1Context * const l = avctx->priv_data; 67 AVFrame * const p= (AVFrame*)&l->pic; 68 unsigned char *Y,*U,*V; 69 int i, j; 70 int prev_y = 0, prev_u = 0, prev_v = 0; 71 uint8_t *rbuf; 72 73 rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); 74 if(!rbuf){ 75 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n"); 76 return -1; 77 } 78 79 if(p->data[0]) 80 avctx->release_buffer(avctx, p); 81 82 p->reference = 0; 83 if(avctx->get_buffer(avctx, p) < 0){ 84 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 85 av_free(rbuf); 86 return -1; 87 } 88 p->key_frame = 1; 89 90 for(i=8; i<buf_size; i++) 91 rbuf[i]= av_reverse[ buf[i] ]; 92 init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8); 93 94 if (buf[2] >> 4 == 6) 95 l->shift = 2; 96 else { 97 l->shift = 8 - (buf[2] >> 4); 98 if (l->shift > 4) { 99 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); 100 l->shift = 4; 101 } 102 if (l->shift < 1) { 103 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); 104 l->shift = 1; 105 } 106 } 107 108 Y = p->data[0]; 109 U = p->data[1]; 110 V = p->data[2]; 111 for (j = 0; j < avctx->height; j++) { 112 for (i = 0; i < avctx->width / 2; i++) { 113 Y[i * 2] = wnv1_get_code(l, prev_y); 114 prev_u = U[i] = wnv1_get_code(l, prev_u); 115 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]); 116 prev_v = V[i] = wnv1_get_code(l, prev_v); 117 } 118 Y += p->linesize[0]; 119 U += p->linesize[1]; 120 V += p->linesize[2]; 121 } 122 123 124 *data_size = sizeof(AVFrame); 125 *(AVFrame*)data = l->pic; 126 av_free(rbuf); 127 128 return buf_size; 129} 130 131static av_cold int decode_init(AVCodecContext *avctx){ 132 WNV1Context * const l = avctx->priv_data; 133 static VLC_TYPE code_table[1 << CODE_VLC_BITS][2]; 134 135 l->avctx = avctx; 136 avctx->pix_fmt = PIX_FMT_YUV422P; 137 138 code_vlc.table = code_table; 139 code_vlc.table_allocated = 1 << CODE_VLC_BITS; 140 init_vlc(&code_vlc, CODE_VLC_BITS, 16, 141 &code_tab[0][1], 4, 2, 142 &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC); 143 144 return 0; 145} 146 147static av_cold int decode_end(AVCodecContext *avctx){ 148 WNV1Context * const l = avctx->priv_data; 149 AVFrame *pic = &l->pic; 150 151 if (pic->data[0]) 152 avctx->release_buffer(avctx, pic); 153 154 return 0; 155} 156 157AVCodec wnv1_decoder = { 158 "wnv1", 159 AVMEDIA_TYPE_VIDEO, 160 CODEC_ID_WNV1, 161 sizeof(WNV1Context), 162 decode_init, 163 NULL, 164 decode_end, 165 decode_frame, 166 CODEC_CAP_DR1, 167 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"), 168}; 169