libavcodec/wnv1.c

   1 /*
   2  * Winnov WNV1 codec
   3  * Copyright (c) 2005 Konstantin Shishkov
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 "internal.h"
  30 #include "mathops.h"
  31
  32
  33 typedef struct WNV1Context{
  34     AVCodecContext *avctx;
  35     AVFrame pic;
  36
  37     int shift;
  38     GetBitContext gb;
  39 } WNV1Context;
  40
  41 static const uint16_t code_tab[16][2]={
  42 {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
  43 {0x000,1},
  44 {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
  45 };
  46
  47 #define CODE_VLC_BITS 9
  48 static VLC code_vlc;
  49
  50 /* returns modified base_value */
  51 static inline int wnv1_get_code(WNV1Context *w, int base_value)
  52 {
  53     int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
  54
  55     if(v==15)
  56         return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
  57     else
  58         return base_value + ((v - 7)<<w->shift);
  59 }
  60
  61 static int decode_frame(AVCodecContext *avctx,
  62                         void *data, int *data_size,
  63                         AVPacket *avpkt)
  64 {
  65     const uint8_t *buf = avpkt->data;
  66     int buf_size = avpkt->size;
  67     WNV1Context * const l = avctx->priv_data;
  68     AVFrame * const p = &l->pic;
  69     unsigned char *Y,*U,*V;
  70     int i, j;
  71     int prev_y = 0, prev_u = 0, prev_v = 0;
  72     uint8_t *rbuf;
  73
  74     rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
  75     if(!rbuf){
  76         av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
  77         return -1;
  78     }
  79
  80     if(p->data[0])
  81         avctx->release_buffer(avctx, p);
  82
  83     p->reference = 0;
  84     if(ff_get_buffer(avctx, p) < 0){
  85         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
  86         av_free(rbuf);
  87         return -1;
  88     }
  89     p->key_frame = 1;
  90
  91     for(i=8; i<buf_size; i++)
  92         rbuf[i]= ff_reverse[ buf[i] ];
  93     init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8);
  94
  95     if (buf[2] >> 4 == 6)
  96         l->shift = 2;
  97     else {
  98         l->shift = 8 - (buf[2] >> 4);
  99         if (l->shift > 4) {
 100             av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
 101                                   buf[2] >> 4);
 102             l->shift = 4;
 103         }
 104         if (l->shift < 1) {
 105             av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
 106                                   buf[2] >> 4);
 107             l->shift = 1;
 108         }
 109     }
 110
 111     Y = p->data[0];
 112     U = p->data[1];
 113     V = p->data[2];
 114     for (j = 0; j < avctx->height; j++) {
 115         for (i = 0; i < avctx->width / 2; i++) {
 116             Y[i * 2] = wnv1_get_code(l, prev_y);
 117             prev_u = U[i] = wnv1_get_code(l, prev_u);
 118             prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
 119             prev_v = V[i] = wnv1_get_code(l, prev_v);
 120         }
 121         Y += p->linesize[0];
 122         U += p->linesize[1];
 123         V += p->linesize[2];
 124     }
 125
 126
 127     *data_size = sizeof(AVFrame);
 128     *(AVFrame*)data = l->pic;
 129     av_free(rbuf);
 130
 131     return buf_size;
 132 }
 133
 134 static av_cold int decode_init(AVCodecContext *avctx){
 135     WNV1Context * const l = avctx->priv_data;
 136     static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
 137
 138     l->avctx = avctx;
 139     avctx->pix_fmt = AV_PIX_FMT_YUV422P;
 140
 141     code_vlc.table = code_table;
 142     code_vlc.table_allocated = 1 << CODE_VLC_BITS;
 143     init_vlc(&code_vlc, CODE_VLC_BITS, 16,
 144              &code_tab[0][1], 4, 2,
 145              &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
 146
 147     return 0;
 148 }
 149
 150 static av_cold int decode_end(AVCodecContext *avctx){
 151     WNV1Context * const l = avctx->priv_data;
 152     AVFrame *pic = &l->pic;
 153
 154     if (pic->data[0])
 155         avctx->release_buffer(avctx, pic);
 156
 157     return 0;
 158 }
 159
 160 AVCodec ff_wnv1_decoder = {
 161     .name           = "wnv1",
 162     .type           = AVMEDIA_TYPE_VIDEO,
 163     .id             = AV_CODEC_ID_WNV1,
 164     .priv_data_size = sizeof(WNV1Context),
 165     .init           = decode_init,
 166     .close          = decode_end,
 167     .decode         = decode_frame,
 168     .capabilities   = CODEC_CAP_DR1,
 169     .long_name      = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
 170 };