00001 /* 00002 * Winnov WNV1 codec 00003 * Copyright (c) 2005 Konstantin Shishkov 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00027 #include "avcodec.h" 00028 #include "bitstream.h" 00029 00030 00031 typedef struct WNV1Context{ 00032 AVCodecContext *avctx; 00033 AVFrame pic; 00034 00035 int shift; 00036 GetBitContext gb; 00037 } WNV1Context; 00038 00039 static const uint16_t code_tab[16][2]={ 00040 {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3}, 00041 {0x000,1}, 00042 {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8} 00043 }; 00044 00045 #define CODE_VLC_BITS 9 00046 static VLC code_vlc; 00047 00048 /* returns modified base_value */ 00049 static inline int wnv1_get_code(WNV1Context *w, int base_value) 00050 { 00051 int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1); 00052 00053 if(v==15) 00054 return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ]; 00055 else 00056 return base_value + ((v - 7)<<w->shift); 00057 } 00058 00059 static int decode_frame(AVCodecContext *avctx, 00060 void *data, int *data_size, 00061 const uint8_t *buf, int buf_size) 00062 { 00063 WNV1Context * const l = avctx->priv_data; 00064 AVFrame * const p= (AVFrame*)&l->pic; 00065 unsigned char *Y,*U,*V; 00066 int i, j; 00067 int prev_y = 0, prev_u = 0, prev_v = 0; 00068 uint8_t *rbuf; 00069 00070 if(buf_size<=8) { 00071 av_log(avctx, AV_LOG_ERROR, "buf_size %d is too small\n", buf_size); 00072 return AVERROR_INVALIDDATA; 00073 } 00074 00075 rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); 00076 if(!rbuf){ 00077 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n"); 00078 return -1; 00079 } 00080 00081 if(p->data[0]) 00082 avctx->release_buffer(avctx, p); 00083 00084 p->reference = 0; 00085 if(avctx->get_buffer(avctx, p) < 0){ 00086 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 00087 av_free(rbuf); 00088 return -1; 00089 } 00090 p->key_frame = 1; 00091 00092 for(i=8; i<buf_size; i++) 00093 rbuf[i]= ff_reverse[ buf[i] ]; 00094 init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8); 00095 00096 if (buf[2] >> 4 == 6) 00097 l->shift = 2; 00098 else { 00099 l->shift = 8 - (buf[2] >> 4); 00100 if (l->shift > 4) { 00101 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); 00102 l->shift = 4; 00103 } 00104 if (l->shift < 1) { 00105 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); 00106 l->shift = 1; 00107 } 00108 } 00109 00110 Y = p->data[0]; 00111 U = p->data[1]; 00112 V = p->data[2]; 00113 for (j = 0; j < avctx->height; j++) { 00114 for (i = 0; i < avctx->width / 2; i++) { 00115 Y[i * 2] = wnv1_get_code(l, prev_y); 00116 prev_u = U[i] = wnv1_get_code(l, prev_u); 00117 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]); 00118 prev_v = V[i] = wnv1_get_code(l, prev_v); 00119 } 00120 Y += p->linesize[0]; 00121 U += p->linesize[1]; 00122 V += p->linesize[2]; 00123 } 00124 00125 00126 *data_size = sizeof(AVFrame); 00127 *(AVFrame*)data = l->pic; 00128 av_free(rbuf); 00129 00130 return buf_size; 00131 } 00132 00133 static av_cold int decode_init(AVCodecContext *avctx){ 00134 WNV1Context * const l = avctx->priv_data; 00135 00136 l->avctx = avctx; 00137 avctx->pix_fmt = PIX_FMT_YUV422P; 00138 00139 if(!code_vlc.table){ 00140 init_vlc(&code_vlc, CODE_VLC_BITS, 16, 00141 &code_tab[0][1], 4, 2, 00142 &code_tab[0][0], 4, 2, 1); 00143 } 00144 00145 return 0; 00146 } 00147 00148 AVCodec wnv1_decoder = { 00149 "wnv1", 00150 CODEC_TYPE_VIDEO, 00151 CODEC_ID_WNV1, 00152 sizeof(WNV1Context), 00153 decode_init, 00154 NULL, 00155 NULL, 00156 decode_frame, 00157 CODEC_CAP_DR1, 00158 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"), 00159 };