aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/bmpenc.c
blob: 3d4597c52c5c9ce545d9d7e0757b5949fad4741b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/*
 * BMP image format encoder
 * Copyright (c) 2006, 2007 Michel Bardiaux
 * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "bytestream.h"
#include "bmp.h"

static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
static const uint32_t rgb565_masks[]  = { 0xF800, 0x07E0, 0x001F };

static av_cold int bmp_encode_init(AVCodecContext *avctx){
    BMPContext *s = avctx->priv_data;

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

    switch (avctx->pix_fmt) {
    case PIX_FMT_BGR24:
        avctx->bits_per_coded_sample = 24;
        break;
    case PIX_FMT_RGB555:
        avctx->bits_per_coded_sample = 16;
        break;
    case PIX_FMT_RGB565:
        avctx->bits_per_coded_sample = 16;
        break;
    case PIX_FMT_RGB8:
    case PIX_FMT_BGR8:
    case PIX_FMT_RGB4_BYTE:
    case PIX_FMT_BGR4_BYTE:
    case PIX_FMT_GRAY8:
    case PIX_FMT_PAL8:
        avctx->bits_per_coded_sample = 8;
        break;
    case PIX_FMT_MONOBLACK:
        avctx->bits_per_coded_sample = 1;
        break;
    default:
        av_log(avctx, AV_LOG_INFO, "unsupported pixel format\n");
        return -1;
    }

    return 0;
}

static int bmp_encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
    BMPContext *s = avctx->priv_data;
    AVFrame *pict = data;
    AVFrame * const p= (AVFrame*)&s->picture;
    int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize;
    const uint32_t *pal = NULL;
    int pad_bytes_per_row, pal_entries = 0, compression = BMP_RGB;
    int bit_count = avctx->bits_per_coded_sample;
    uint8_t *ptr;
    unsigned char* buf0 = buf;
    *p = *pict;
    p->pict_type= FF_I_TYPE;
    p->key_frame= 1;
    switch (avctx->pix_fmt) {
    case PIX_FMT_RGB565:
        compression = BMP_BITFIELDS;
        pal = rgb565_masks; // abuse pal to hold color masks
        pal_entries = 3;
        break;
    case PIX_FMT_RGB8:
    case PIX_FMT_BGR8:
    case PIX_FMT_RGB4_BYTE:
    case PIX_FMT_BGR4_BYTE:
    case PIX_FMT_GRAY8:
        ff_set_systematic_pal2((uint32_t*)p->data[1], avctx->pix_fmt);
    case PIX_FMT_PAL8:
        pal = (uint32_t *)p->data[1];
        break;
    case PIX_FMT_MONOBLACK:
        pal = monoblack_pal;
        break;
    }
    if (pal && !pal_entries) pal_entries = 1 << bit_count;
    n_bytes_per_row = ((int64_t)avctx->width * (int64_t)bit_count + 7LL) >> 3LL;
    pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
    n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);

    // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
    // and related pages.
#define SIZE_BITMAPFILEHEADER 14
#define SIZE_BITMAPINFOHEADER 40
    hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);
    n_bytes = n_bytes_image + hsize;
    if(n_bytes>buf_size) {
        av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", n_bytes, buf_size);
        return -1;
    }
    bytestream_put_byte(&buf, 'B');                   // BITMAPFILEHEADER.bfType
    bytestream_put_byte(&buf, 'M');                   // do.
    bytestream_put_le32(&buf, n_bytes);               // BITMAPFILEHEADER.bfSize
    bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved1
    bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved2
    bytestream_put_le32(&buf, hsize);                 // BITMAPFILEHEADER.bfOffBits
    bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize
    bytestream_put_le32(&buf, avctx->width);          // BITMAPINFOHEADER.biWidth
    bytestream_put_le32(&buf, avctx->height);         // BITMAPINFOHEADER.biHeight
    bytestream_put_le16(&buf, 1);                     // BITMAPINFOHEADER.biPlanes
    bytestream_put_le16(&buf, bit_count);             // BITMAPINFOHEADER.biBitCount
    bytestream_put_le32(&buf, compression);           // BITMAPINFOHEADER.biCompression
    bytestream_put_le32(&buf, n_bytes_image);         // BITMAPINFOHEADER.biSizeImage
    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biXPelsPerMeter
    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biYPelsPerMeter
    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrUsed
    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrImportant
    for (i = 0; i < pal_entries; i++)
        bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);
    // BMP files are bottom-to-top so we start from the end...
    ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
    buf = buf0 + hsize;
    for(i = 0; i < avctx->height; i++) {
        if (bit_count == 16) {
            const uint16_t *src = (const uint16_t *) ptr;
            uint16_t *dst = (uint16_t *) buf;
            for(n = 0; n < avctx->width; n++)
                AV_WL16(dst + n, src[n]);
        } else {
            memcpy(buf, ptr, n_bytes_per_row);
        }
        buf += n_bytes_per_row;
        memset(buf, 0, pad_bytes_per_row);
        buf += pad_bytes_per_row;
        ptr -= p->linesize[0]; // ... and go back
    }
    return n_bytes;
}

AVCodec ff_bmp_encoder = {
    "bmp",
    AVMEDIA_TYPE_VIDEO,
    CODEC_ID_BMP,
    sizeof(BMPContext),
    bmp_encode_init,
    bmp_encode_frame,
    NULL, //encode_end,
    .pix_fmts = (const enum PixelFormat[]){
        PIX_FMT_BGR24,
        PIX_FMT_RGB555, PIX_FMT_RGB565,
        PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
        PIX_FMT_MONOBLACK,
        PIX_FMT_NONE},
    .long_name = NULL_IF_CONFIG_SMALL("BMP image"),
};