libavcodec/xl.c

   1 /*
   2  * Miro VideoXL codec
   3  * Copyright (c) 2004 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  * Miro VideoXL codec.
  25  */
  26
  27 #include "libavutil/common.h"
  28 #include "libavutil/intreadwrite.h"
  29 #include "avcodec.h"
  30 #include "internal.h"
  31
  32 static const int xl_table[32] = {
  33    0,   1,   2,   3,   4,   5,   6,   7,
  34    8,   9,  12,  15,  20,  25,  34,  46,
  35   64,  82,  94, 103, 108, 113, 116, 119,
  36  120, 121, 122, 123, 124, 125, 126, 127
  37 };
  38
  39 static int decode_frame(AVCodecContext *avctx,
  40                         void *data, int *got_frame,
  41                         AVPacket *avpkt)
  42 {
  43     const uint8_t *buf = avpkt->data;
  44     int buf_size       = avpkt->size;
  45     AVFrame *const p   = data;
  46     uint8_t *Y, *U, *V;
  47     int i, j, ret;
  48     int stride;
  49     uint32_t val;
  50     int y0, y1, y2, y3 = 0, c0 = 0, c1 = 0;
  51
  52     if (avctx->width % 4) {
  53         av_log(avctx, AV_LOG_ERROR, "Width not a multiple of 4.\n");
  54         return AVERROR_INVALIDDATA;
  55     }
  56
  57     if (buf_size < avctx->width * avctx->height) {
  58         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
  59         return AVERROR_INVALIDDATA;
  60     }
  61
  62     if ((ret = ff_get_buffer(avctx, p, 0)) < 0) {
  63         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
  64         return ret;
  65     }
  66     p->pict_type = AV_PICTURE_TYPE_I;
  67     p->key_frame = 1;
  68
  69     Y = p->data[0];
  70     U = p->data[1];
  71     V = p->data[2];
  72
  73     stride = avctx->width - 4;
  74
  75     for (i = 0; i < avctx->height; i++) {
  76         /* lines are stored in reversed order */
  77         buf += stride;
  78
  79         for (j = 0; j < avctx->width; j += 4) {
  80             /* value is stored in LE dword with word swapped */
  81             val  = AV_RL32(buf);
  82             buf -= 4;
  83             val  = ((val >> 16) & 0xFFFF) | ((val & 0xFFFF) << 16);
  84
  85             if (!j)
  86                 y0 = (val & 0x1F) << 2;
  87             else
  88                 y0 = y3 + xl_table[val & 0x1F];
  89             val >>= 5;
  90             y1    = y0 + xl_table[val & 0x1F];
  91             val >>= 5;
  92             y2    = y1 + xl_table[val & 0x1F];
  93             val >>= 6; /* align to word */
  94             y3    = y2 + xl_table[val & 0x1F];
  95             val >>= 5;
  96             if (!j)
  97                 c0 = (val & 0x1F) << 2;
  98             else
  99                 c0 += xl_table[val & 0x1F];
 100             val >>= 5;
 101             if (!j)
 102                 c1 = (val & 0x1F) << 2;
 103             else
 104                 c1 += xl_table[val & 0x1F];
 105
 106             Y[j + 0] = y0 << 1;
 107             Y[j + 1] = y1 << 1;
 108             Y[j + 2] = y2 << 1;
 109             Y[j + 3] = y3 << 1;
 110
 111             U[j >> 2] = c0 << 1;
 112             V[j >> 2] = c1 << 1;
 113         }
 114
 115         buf += avctx->width + 4;
 116         Y   += p->linesize[0];
 117         U   += p->linesize[1];
 118         V   += p->linesize[2];
 119     }
 120
 121     *got_frame = 1;
 122
 123     return buf_size;
 124 }
 125
 126 static av_cold int decode_init(AVCodecContext *avctx)
 127 {
 128     avctx->pix_fmt = AV_PIX_FMT_YUV411P;
 129
 130     return 0;
 131 }
 132
 133 AVCodec ff_xl_decoder = {
 134     .name         = "xl",
 135     .long_name    = NULL_IF_CONFIG_SMALL("Miro VideoXL"),
 136     .type         = AVMEDIA_TYPE_VIDEO,
 137     .id           = AV_CODEC_ID_VIXL,
 138     .init         = decode_init,
 139     .decode       = decode_frame,
 140     .capabilities = AV_CODEC_CAP_DR1,
 141 };