libavcodec/cyuv.c

   1 /*
   2  * Creative YUV (CYUV) Video Decoder
   3  *   by Mike Melanson (melanson@pcisys.net)
   4  * based on "Creative YUV (CYUV) stream format for AVI":
   5  *   http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
   6  *
   7  * Copyright (C) 2003 the ffmpeg project
   8  *
   9  * This file is part of FFmpeg.
  10  *
  11  * FFmpeg is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2.1 of the License, or (at your option) any later version.
  15  *
  16  * FFmpeg is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with FFmpeg; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 /**
  27  * @file libavcodec/cyuv.c
  28  * Creative YUV (CYUV) Video Decoder.
  29  */
  30
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include "avcodec.h"
  36 #include "dsputil.h"
  37
  38
  39 typedef struct CyuvDecodeContext {
  40     AVCodecContext *avctx;
  41     int width, height;
  42     AVFrame frame;
  43 } CyuvDecodeContext;
  44
  45 static av_cold int cyuv_decode_init(AVCodecContext *avctx)
  46 {
  47     CyuvDecodeContext *s = avctx->priv_data;
  48
  49     s->avctx = avctx;
  50     s->width = avctx->width;
  51     /* width needs to be divisible by 4 for this codec to work */
  52     if (s->width & 0x3)
  53         return -1;
  54     s->height = avctx->height;
  55     avctx->pix_fmt = PIX_FMT_YUV411P;
  56
  57     return 0;
  58 }
  59
  60 static int cyuv_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     CyuvDecodeContext *s=avctx->priv_data;
  67
  68     unsigned char *y_plane;
  69     unsigned char *u_plane;
  70     unsigned char *v_plane;
  71     int y_ptr;
  72     int u_ptr;
  73     int v_ptr;
  74
  75     /* prediction error tables (make it clear that they are signed values) */
  76     const signed char *y_table = (const signed char*)buf +  0;
  77     const signed char *u_table = (const signed char*)buf + 16;
  78     const signed char *v_table = (const signed char*)buf + 32;
  79
  80     unsigned char y_pred, u_pred, v_pred;
  81     int stream_ptr;
  82     unsigned char cur_byte;
  83     int pixel_groups;
  84
  85     /* sanity check the buffer size: A buffer has 3x16-bytes tables
  86      * followed by (height) lines each with 3 bytes to represent groups
  87      * of 4 pixels. Thus, the total size of the buffer ought to be:
  88      *    (3 * 16) + height * (width * 3 / 4) */
  89     if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
  90       av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
  91         buf_size,
  92         48 + s->height * (s->width * 3 / 4));
  93       return -1;
  94     }
  95
  96     /* pixel data starts 48 bytes in, after 3x16-byte tables */
  97     stream_ptr = 48;
  98
  99     if(s->frame.data[0])
 100         avctx->release_buffer(avctx, &s->frame);
 101
 102     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
 103     s->frame.reference = 0;
 104     if(avctx->get_buffer(avctx, &s->frame) < 0) {
 105         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 106         return -1;
 107     }
 108
 109     y_plane = s->frame.data[0];
 110     u_plane = s->frame.data[1];
 111     v_plane = s->frame.data[2];
 112
 113     /* iterate through each line in the height */
 114     for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
 115          y_ptr < (s->height * s->frame.linesize[0]);
 116          y_ptr += s->frame.linesize[0] - s->width,
 117          u_ptr += s->frame.linesize[1] - s->width / 4,
 118          v_ptr += s->frame.linesize[2] - s->width / 4) {
 119
 120         /* reset predictors */
 121         cur_byte = buf[stream_ptr++];
 122         u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
 123         y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
 124
 125         cur_byte = buf[stream_ptr++];
 126         v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
 127         y_pred += y_table[cur_byte & 0x0F];
 128         y_plane[y_ptr++] = y_pred;
 129
 130         cur_byte = buf[stream_ptr++];
 131         y_pred += y_table[cur_byte & 0x0F];
 132         y_plane[y_ptr++] = y_pred;
 133         y_pred += y_table[(cur_byte & 0xF0) >> 4];
 134         y_plane[y_ptr++] = y_pred;
 135
 136         /* iterate through the remaining pixel groups (4 pixels/group) */
 137         pixel_groups = s->width / 4 - 1;
 138         while (pixel_groups--) {
 139
 140             cur_byte = buf[stream_ptr++];
 141             u_pred += u_table[(cur_byte & 0xF0) >> 4];
 142             u_plane[u_ptr++] = u_pred;
 143             y_pred += y_table[cur_byte & 0x0F];
 144             y_plane[y_ptr++] = y_pred;
 145
 146             cur_byte = buf[stream_ptr++];
 147             v_pred += v_table[(cur_byte & 0xF0) >> 4];
 148             v_plane[v_ptr++] = v_pred;
 149             y_pred += y_table[cur_byte & 0x0F];
 150             y_plane[y_ptr++] = y_pred;
 151
 152             cur_byte = buf[stream_ptr++];
 153             y_pred += y_table[cur_byte & 0x0F];
 154             y_plane[y_ptr++] = y_pred;
 155             y_pred += y_table[(cur_byte & 0xF0) >> 4];
 156             y_plane[y_ptr++] = y_pred;
 157
 158         }
 159     }
 160
 161     *data_size=sizeof(AVFrame);
 162     *(AVFrame*)data= s->frame;
 163
 164     return buf_size;
 165 }
 166
 167 AVCodec cyuv_decoder = {
 168     "cyuv",
 169     CODEC_TYPE_VIDEO,
 170     CODEC_ID_CYUV,
 171     sizeof(CyuvDecodeContext),
 172     cyuv_decode_init,
 173     NULL,
 174     NULL,
 175     cyuv_decode_frame,
 176     CODEC_CAP_DR1,
 177     NULL,
 178     .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
 179 };
 180