Statistics
| Branch: | Revision:

ffmpeg / libavcodec / cyuv.c @ 029911d1

History | View | Annotate | Download (5.18 KB)

1
/*
2
 *
3
 * Copyright (C) 2003 the ffmpeg project
4
 *
5
 * This library is free software; you can redistribute it and/or
6
 * modify it under the terms of the GNU Lesser General Public
7
 * License as published by the Free Software Foundation; either
8
 * version 2 of the License, or (at your option) any later version.
9
 *
10
 * This library is distributed in the hope that it will be useful,
11
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13
 * Lesser General Public License for more details.
14
 *
15
 * You should have received a copy of the GNU Lesser General Public
16
 * License along with this library; if not, write to the Free Software
17
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18
 *
19
 * Creative YUV (CYUV) Video Decoder
20
 *   by Mike Melanson (melanson@pcisys.net)
21
 * based on "Creative YUV (CYUV) stream format for AVI":
22
 *   http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
23
 *
24
 */
25

    
26
/**
27
 * @file 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 "common.h"
37
#include "avcodec.h"
38
#include "dsputil.h"
39
#include "mpegvideo.h"
40

    
41

    
42
typedef struct CyuvDecodeContext {
43
    AVCodecContext *avctx;
44
    int width, height;
45
    AVFrame frame;
46
} CyuvDecodeContext;
47

    
48
static int cyuv_decode_init(AVCodecContext *avctx)
49
{
50
    CyuvDecodeContext *s = avctx->priv_data;
51

    
52
    s->avctx = avctx;
53
    s->width = avctx->width;
54
    s->height = avctx->height;
55
    avctx->pix_fmt = PIX_FMT_YUV411P;
56
    avctx->has_b_frames = 0;
57

    
58
    return 0;
59
}
60

    
61
static int cyuv_decode_frame(AVCodecContext *avctx, 
62
                             void *data, int *data_size,
63
                             uint8_t *buf, int buf_size)
64
{
65
    CyuvDecodeContext *s=avctx->priv_data;
66

    
67
    unsigned char *y_plane;
68
    unsigned char *u_plane;
69
    unsigned char *v_plane;
70
    int y_ptr;
71
    int u_ptr;
72
    int v_ptr;
73

    
74
    /* prediction error tables (make it clear that they are signed values) */
75
    signed char *y_table = buf +  0;
76
    signed char *u_table = buf + 16;
77
    signed char *v_table = buf + 32;
78

    
79
    unsigned char y_pred, u_pred, v_pred;
80
    int stream_ptr;
81
    unsigned char cur_byte;
82
    int pixel_groups;
83

    
84
    *data_size = 0;
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
      printf ("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.reference = 0;
104
    if(avctx->get_buffer(avctx, &s->frame) < 0) {
105
        fprintf(stderr, "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
static int cyuv_decode_end(AVCodecContext *avctx)
168
{
169
/*    CyuvDecodeContext *s = avctx->priv_data;*/
170

    
171
    return 0;
172
}
173

    
174
AVCodec cyuv_decoder = {
175
    "cyuv",
176
    CODEC_TYPE_VIDEO,
177
    CODEC_ID_CYUV,
178
    sizeof(CyuvDecodeContext),
179
    cyuv_decode_init,
180
    NULL,
181
    cyuv_decode_end,
182
    cyuv_decode_frame,
183
    0,
184
    NULL
185
};
186