libavcodec/wnv1.c

   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 "get_bits.h"
  29 #include "libavutil/common.h"
  30
  31
  32 typedef struct WNV1Context{
  33     AVCodecContext *avctx;
  34     AVFrame pic;
  35
  36     int shift;
  37     GetBitContext gb;
  38 } WNV1Context;
  39
  40 static 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
  47 static VLC code_vlc;
  48
  49 /* returns modified base_value */
  50 static 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
  60 static 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
 131 static 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
 147 static 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
 157 AVCodec wnv1_decoder = {
 158     "wnv1",
 159     CODEC_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 };