Statistics
| Branch: | Revision:

ffmpeg / libavcodec / bmp.c @ 5509bffa

History | View | Annotate | Download (6.27 KB)

1
/*
2
 * BMP image format
3
 * Copyright (c) 2005 Mans Rullgard
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18
 */
19

    
20
#include "avcodec.h"
21
#include "bitstream.h"
22
#include "bswap.h"
23

    
24
typedef struct BMPContext {
25
    AVFrame picture;
26
} BMPContext;
27

    
28
#define BMP_RGB       0
29
#define BMP_RLE8      1
30
#define BMP_RLE4      2
31
#define BMP_BITFIELDS 3
32

    
33
#define read16(bits) bswap_16(get_bits(bits, 16))
34
#define read32(bits) bswap_32(get_bits_long(bits, 32))
35

    
36
static int bmp_decode_init(AVCodecContext *avctx){
37
    BMPContext *s = avctx->priv_data;
38

    
39
    avcodec_get_frame_defaults((AVFrame*)&s->picture);
40
    avctx->coded_frame = (AVFrame*)&s->picture;
41

    
42
    return 0;
43
}
44

    
45
static int bmp_decode_frame(AVCodecContext *avctx,
46
                            void *data, int *data_size,
47
                            uint8_t *buf, int buf_size)
48
{
49
    BMPContext *s = avctx->priv_data;
50
    AVFrame *picture = data;
51
    AVFrame *p = &s->picture;
52
    GetBitContext bits;
53
    unsigned int fsize, hsize;
54
    int width, height;
55
    unsigned int depth;
56
    unsigned int comp;
57
    unsigned int ihsize;
58
    int i, j, n, linesize;
59
    uint32_t rgb[3];
60
    uint8_t *ptr;
61
    int dsize;
62

    
63
    if(buf_size < 14){
64
        av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);
65
        return -1;
66
    }
67

    
68
    init_get_bits(&bits, buf, buf_size);
69

    
70
    if(get_bits(&bits, 16) != 0x424d){ /* 'BM' */
71
        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
72
        return -1;
73
    }
74

    
75
    fsize = read32(&bits);
76
    if(buf_size < fsize){
77
        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
78
               buf_size, fsize);
79
        return -1;
80
    }
81

    
82
    skip_bits(&bits, 16);       /* reserved1 */
83
    skip_bits(&bits, 16);       /* reserved2 */
84

    
85
    hsize = read32(&bits); /* header size */
86
    if(fsize <= hsize){
87
        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
88
               fsize, hsize);
89
        return -1;
90
    }
91

    
92
    ihsize = read32(&bits);       /* more header size */
93
    if(ihsize + 14 > hsize){
94
        av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);
95
        return -1;
96
    }
97

    
98
    width = read32(&bits);
99
    height = read32(&bits);
100

    
101
    if(read16(&bits) != 1){ /* planes */
102
        av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");
103
        return -1;
104
    }
105

    
106
    depth = read16(&bits);
107

    
108
    if(ihsize > 16)
109
        comp = read32(&bits);
110
    else
111
        comp = BMP_RGB;
112

    
113
    if(comp != BMP_RGB && comp != BMP_BITFIELDS){
114
        av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);
115
        return -1;
116
    }
117

    
118
    if(comp == BMP_BITFIELDS){
119
        skip_bits(&bits, 20 * 8);
120
        rgb[0] = read32(&bits);
121
        rgb[1] = read32(&bits);
122
        rgb[2] = read32(&bits);
123
    }
124

    
125
    avctx->codec_id = CODEC_ID_BMP;
126
    avctx->width = width;
127
    avctx->height = height > 0? height: -height;
128

    
129
    avctx->pix_fmt = PIX_FMT_NONE;
130

    
131
    switch(depth){
132
    case 32:
133
        if(comp == BMP_BITFIELDS){
134
            rgb[0] = (rgb[0] >> 15) & 3;
135
            rgb[1] = (rgb[1] >> 15) & 3;
136
            rgb[2] = (rgb[2] >> 15) & 3;
137

    
138
            if(rgb[0] + rgb[1] + rgb[2] != 3 ||
139
               rgb[0] == rgb[1] || rgb[0] == rgb[2] || rgb[1] == rgb[2]){
140
                break;
141
            }
142
        } else {
143
            rgb[0] = 2;
144
            rgb[1] = 1;
145
            rgb[2] = 0;
146
        }
147

    
148
        avctx->pix_fmt = PIX_FMT_BGR24;
149
        break;
150
    case 24:
151
        avctx->pix_fmt = PIX_FMT_BGR24;
152
        break;
153
    case 16:
154
        if(comp == BMP_RGB)
155
            avctx->pix_fmt = PIX_FMT_RGB555;
156
        break;
157
    default:
158
        av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);
159
        return -1;
160
    }
161

    
162
    if(avctx->pix_fmt == PIX_FMT_NONE){
163
        av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
164
        return -1;
165
    }
166

    
167
    p->reference = 0;
168
    if(avctx->get_buffer(avctx, p) < 0){
169
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
170
        return -1;
171
    }
172
    p->pict_type = FF_I_TYPE;
173
    p->key_frame = 1;
174

    
175
    buf += hsize;
176
    dsize = buf_size - hsize;
177

    
178
    n = avctx->width * (depth / 8);
179

    
180
    if(n * avctx->height > dsize){
181
        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
182
               dsize, n * avctx->height);
183
        return -1;
184
    }
185

    
186
    if(height > 0){
187
        ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
188
        linesize = -p->linesize[0];
189
    } else {
190
        ptr = p->data[0];
191
        linesize = p->linesize[0];
192
    }
193

    
194
    switch(depth){
195
    case 24:
196
        for(i = 0; i < avctx->height; i++){
197
            memcpy(ptr, buf, n);
198
            buf += n;
199
            ptr += linesize;
200
        }
201
        break;
202
    case 16:
203
        for(i = 0; i < avctx->height; i++){
204
            uint16_t *src = (uint16_t *) buf;
205
            uint16_t *dst = (uint16_t *) ptr;
206

    
207
            for(j = 0; j < avctx->width; j++)
208
                *dst++ = le2me_16(*src++);
209

    
210
            buf += n;
211
            ptr += linesize;
212
        }
213
        break;
214
    case 32:
215
        for(i = 0; i < avctx->height; i++){
216
            uint8_t *src = buf;
217
            uint8_t *dst = ptr;
218

    
219
            for(j = 0; j < avctx->width; j++){
220
                dst[0] = src[rgb[2]];
221
                dst[1] = src[rgb[1]];
222
                dst[2] = src[rgb[0]];
223
                dst += 3;
224
                src += 4;
225
            }
226

    
227
            buf += n;
228
            ptr += linesize;
229
        }
230
        break;
231
    default:
232
        av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");
233
        return -1;
234
    }
235

    
236
    *picture = s->picture;
237
    *data_size = sizeof(AVPicture);
238

    
239
    return buf_size;
240
}
241

    
242
AVCodec bmp_decoder = {
243
    "bmp",
244
    CODEC_TYPE_VIDEO,
245
    CODEC_ID_BMP,
246
    sizeof(BMPContext),
247
    bmp_decode_init,
248
    NULL,
249
    NULL,
250
    bmp_decode_frame
251
};