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 #include <unistd.h>
  35
  36 #include "avcodec.h"
  37 #include "dsputil.h"
  38
  39
  40 typedef struct CyuvDecodeContext {
  41     AVCodecContext *avctx;
  42     int width, height;
  43     AVFrame frame;
  44 } CyuvDecodeContext;
  45
  46 static av_cold int cyuv_decode_init(AVCodecContext *avctx)
  47 {
  48     CyuvDecodeContext *s = avctx->priv_data;
  49
  50     s->avctx = avctx;
  51     s->width = avctx->width;
  52     /* width needs to be divisible by 4 for this codec to work */
  53     if (s->width & 0x3)
  54         return -1;
  55     s->height = avctx->height;
  56     avctx->pix_fmt = PIX_FMT_YUV411P;
  57
  58     return 0;
  59 }
  60
  61 static int cyuv_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     CyuvDecodeContext *s=avctx->priv_data;
  68
  69     unsigned char *y_plane;
  70     unsigned char *u_plane;
  71     unsigned char *v_plane;
  72     int y_ptr;
  73     int u_ptr;
  74     int v_ptr;
  75
  76     /* prediction error tables (make it clear that they are signed values) */
  77     const signed char *y_table = (const signed char*)buf +  0;
  78     const signed char *u_table = (const signed char*)buf + 16;
  79     const signed char *v_table = (const signed char*)buf + 32;
  80
  81     unsigned char y_pred, u_pred, v_pred;
  82     int stream_ptr;
  83     unsigned char cur_byte;
  84     int pixel_groups;
  85
  86     /* sanity check the buffer size: A buffer has 3x16-bytes tables
  87      * followed by (height) lines each with 3 bytes to represent groups
  88      * of 4 pixels. Thus, the total size of the buffer ought to be:
  89      *    (3 * 16) + height * (width * 3 / 4) */
  90     if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
  91       av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
  92         buf_size,
  93         48 + s->height * (s->width * 3 / 4));
  94       return -1;
  95     }
  96
  97     /* pixel data starts 48 bytes in, after 3x16-byte tables */
  98     stream_ptr = 48;
  99
 100     if(s->frame.data[0])
 101         avctx->release_buffer(avctx, &s->frame);
 102
 103     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
 104     s->frame.reference = 0;
 105     if(avctx->get_buffer(avctx, &s->frame) < 0) {
 106         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 107         return -1;
 108     }
 109
 110     y_plane = s->frame.data[0];
 111     u_plane = s->frame.data[1];
 112     v_plane = s->frame.data[2];
 113
 114     /* iterate through each line in the height */
 115     for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
 116          y_ptr < (s->height * s->frame.linesize[0]);
 117          y_ptr += s->frame.linesize[0] - s->width,
 118          u_ptr += s->frame.linesize[1] - s->width / 4,
 119          v_ptr += s->frame.linesize[2] - s->width / 4) {
 120
 121         /* reset predictors */
 122         cur_byte = buf[stream_ptr++];
 123         u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
 124         y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
 125
 126         cur_byte = buf[stream_ptr++];
 127         v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
 128         y_pred += y_table[cur_byte & 0x0F];
 129         y_plane[y_ptr++] = y_pred;
 130
 131         cur_byte = buf[stream_ptr++];
 132         y_pred += y_table[cur_byte & 0x0F];
 133         y_plane[y_ptr++] = y_pred;
 134         y_pred += y_table[(cur_byte & 0xF0) >> 4];
 135         y_plane[y_ptr++] = y_pred;
 136
 137         /* iterate through the remaining pixel groups (4 pixels/group) */
 138         pixel_groups = s->width / 4 - 1;
 139         while (pixel_groups--) {
 140
 141             cur_byte = buf[stream_ptr++];
 142             u_pred += u_table[(cur_byte & 0xF0) >> 4];
 143             u_plane[u_ptr++] = u_pred;
 144             y_pred += y_table[cur_byte & 0x0F];
 145             y_plane[y_ptr++] = y_pred;
 146
 147             cur_byte = buf[stream_ptr++];
 148             v_pred += v_table[(cur_byte & 0xF0) >> 4];
 149             v_plane[v_ptr++] = v_pred;
 150             y_pred += y_table[cur_byte & 0x0F];
 151             y_plane[y_ptr++] = y_pred;
 152
 153             cur_byte = buf[stream_ptr++];
 154             y_pred += y_table[cur_byte & 0x0F];
 155             y_plane[y_ptr++] = y_pred;
 156             y_pred += y_table[(cur_byte & 0xF0) >> 4];
 157             y_plane[y_ptr++] = y_pred;
 158
 159         }
 160     }
 161
 162     *data_size=sizeof(AVFrame);
 163     *(AVFrame*)data= s->frame;
 164
 165     return buf_size;
 166 }
 167
 168 AVCodec cyuv_decoder = {
 169     "cyuv",
 170     CODEC_TYPE_VIDEO,
 171     CODEC_ID_CYUV,
 172     sizeof(CyuvDecodeContext),
 173     cyuv_decode_init,
 174     NULL,
 175     NULL,
 176     cyuv_decode_frame,
 177     CODEC_CAP_DR1,
 178     NULL,
 179     .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
 180 };
 181