Libav 0.7.1
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00001 /* 00002 * Winnov WNV1 codec 00003 * Copyright (c) 2005 Konstantin Shishkov 00004 * 00005 * This file is part of Libav. 00006 * 00007 * Libav 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 * Libav 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 Libav; 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 "get_bits.h" 00029 #include "libavutil/common.h" 00030 00031 00032 typedef struct WNV1Context{ 00033 AVCodecContext *avctx; 00034 AVFrame pic; 00035 00036 int shift; 00037 GetBitContext gb; 00038 } WNV1Context; 00039 00040 static const uint16_t code_tab[16][2]={ 00041 {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3}, 00042 {0x000,1}, 00043 {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8} 00044 }; 00045 00046 #define CODE_VLC_BITS 9 00047 static VLC code_vlc; 00048 00049 /* returns modified base_value */ 00050 static inline int wnv1_get_code(WNV1Context *w, int base_value) 00051 { 00052 int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1); 00053 00054 if(v==15) 00055 return av_reverse[ get_bits(&w->gb, 8 - w->shift) ]; 00056 else 00057 return base_value + ((v - 7)<<w->shift); 00058 } 00059 00060 static int decode_frame(AVCodecContext *avctx, 00061 void *data, int *data_size, 00062 AVPacket *avpkt) 00063 { 00064 const uint8_t *buf = avpkt->data; 00065 int buf_size = avpkt->size; 00066 WNV1Context * const l = avctx->priv_data; 00067 AVFrame * const p= (AVFrame*)&l->pic; 00068 unsigned char *Y,*U,*V; 00069 int i, j; 00070 int prev_y = 0, prev_u = 0, prev_v = 0; 00071 uint8_t *rbuf; 00072 00073 rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); 00074 if(!rbuf){ 00075 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n"); 00076 return -1; 00077 } 00078 00079 if(p->data[0]) 00080 avctx->release_buffer(avctx, p); 00081 00082 p->reference = 0; 00083 if(avctx->get_buffer(avctx, p) < 0){ 00084 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 00085 av_free(rbuf); 00086 return -1; 00087 } 00088 p->key_frame = 1; 00089 00090 for(i=8; i<buf_size; i++) 00091 rbuf[i]= av_reverse[ buf[i] ]; 00092 init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8); 00093 00094 if (buf[2] >> 4 == 6) 00095 l->shift = 2; 00096 else { 00097 l->shift = 8 - (buf[2] >> 4); 00098 if (l->shift > 4) { 00099 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n", 00100 buf[2] >> 4); 00101 l->shift = 4; 00102 } 00103 if (l->shift < 1) { 00104 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n", 00105 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 static VLC_TYPE code_table[1 << CODE_VLC_BITS][2]; 00136 00137 l->avctx = avctx; 00138 avctx->pix_fmt = PIX_FMT_YUV422P; 00139 00140 code_vlc.table = code_table; 00141 code_vlc.table_allocated = 1 << CODE_VLC_BITS; 00142 init_vlc(&code_vlc, CODE_VLC_BITS, 16, 00143 &code_tab[0][1], 4, 2, 00144 &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC); 00145 00146 return 0; 00147 } 00148 00149 static av_cold int decode_end(AVCodecContext *avctx){ 00150 WNV1Context * const l = avctx->priv_data; 00151 AVFrame *pic = &l->pic; 00152 00153 if (pic->data[0]) 00154 avctx->release_buffer(avctx, pic); 00155 00156 return 0; 00157 } 00158 00159 AVCodec ff_wnv1_decoder = { 00160 "wnv1", 00161 AVMEDIA_TYPE_VIDEO, 00162 CODEC_ID_WNV1, 00163 sizeof(WNV1Context), 00164 decode_init, 00165 NULL, 00166 decode_end, 00167 decode_frame, 00168 CODEC_CAP_DR1, 00169 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"), 00170 };