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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
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 };