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bmpenc.c
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1 /*
2  * BMP image format encoder
3  * Copyright (c) 2006, 2007 Michel Bardiaux
4  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "libavutil/imgutils.h"
24 #include "libavutil/avassert.h"
25 #include "avcodec.h"
26 #include "bytestream.h"
27 #include "bmp.h"
28 #include "internal.h"
29 
30 static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
31 static const uint32_t rgb565_masks[] = { 0xF800, 0x07E0, 0x001F };
32 static const uint32_t rgb444_masks[] = { 0x0F00, 0x00F0, 0x000F };
33 
34 static av_cold int bmp_encode_init(AVCodecContext *avctx){
35  switch (avctx->pix_fmt) {
36  case AV_PIX_FMT_BGRA:
37  avctx->bits_per_coded_sample = 32;
38  break;
39  case AV_PIX_FMT_BGR24:
40  avctx->bits_per_coded_sample = 24;
41  break;
42  case AV_PIX_FMT_RGB555:
43  case AV_PIX_FMT_RGB565:
44  case AV_PIX_FMT_RGB444:
45  avctx->bits_per_coded_sample = 16;
46  break;
47  case AV_PIX_FMT_RGB8:
48  case AV_PIX_FMT_BGR8:
49  case AV_PIX_FMT_RGB4_BYTE:
50  case AV_PIX_FMT_BGR4_BYTE:
51  case AV_PIX_FMT_GRAY8:
52  case AV_PIX_FMT_PAL8:
53  avctx->bits_per_coded_sample = 8;
54  break;
55  case AV_PIX_FMT_MONOBLACK:
56  avctx->bits_per_coded_sample = 1;
57  break;
58  default:
59  av_log(avctx, AV_LOG_INFO, "unsupported pixel format\n");
60  return -1;
61  }
62 
63  return 0;
64 }
65 
66 static int bmp_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
67  const AVFrame *pict, int *got_packet)
68 {
69  int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize, ret;
70  const uint32_t *pal = NULL;
71  uint32_t palette256[256];
72  int pad_bytes_per_row, pal_entries = 0, compression = BMP_RGB;
73  int bit_count = avctx->bits_per_coded_sample;
74  uint8_t *ptr, *buf;
75  AVFrame * const p = (AVFrame *)pict;
76 
77  p->pict_type= AV_PICTURE_TYPE_I;
78  p->key_frame= 1;
79  switch (avctx->pix_fmt) {
80  case AV_PIX_FMT_RGB444:
81  compression = BMP_BITFIELDS;
82  pal = rgb444_masks; // abuse pal to hold color masks
83  pal_entries = 3;
84  break;
85  case AV_PIX_FMT_RGB565:
86  compression = BMP_BITFIELDS;
87  pal = rgb565_masks; // abuse pal to hold color masks
88  pal_entries = 3;
89  break;
90  case AV_PIX_FMT_RGB8:
91  case AV_PIX_FMT_BGR8:
92  case AV_PIX_FMT_RGB4_BYTE:
93  case AV_PIX_FMT_BGR4_BYTE:
94  case AV_PIX_FMT_GRAY8:
95  av_assert1(bit_count == 8);
96  avpriv_set_systematic_pal2(palette256, avctx->pix_fmt);
97  pal = palette256;
98  break;
99  case AV_PIX_FMT_PAL8:
100  pal = (uint32_t *)p->data[1];
101  break;
102  case AV_PIX_FMT_MONOBLACK:
103  pal = monoblack_pal;
104  break;
105  }
106  if (pal && !pal_entries) pal_entries = 1 << bit_count;
107  n_bytes_per_row = ((int64_t)avctx->width * (int64_t)bit_count + 7LL) >> 3LL;
108  pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
109  n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);
110 
111  // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
112  // and related pages.
113 #define SIZE_BITMAPFILEHEADER 14
114 #define SIZE_BITMAPINFOHEADER 40
115  hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);
116  n_bytes = n_bytes_image + hsize;
117  if ((ret = ff_alloc_packet2(avctx, pkt, n_bytes)) < 0)
118  return ret;
119  buf = pkt->data;
120  bytestream_put_byte(&buf, 'B'); // BITMAPFILEHEADER.bfType
121  bytestream_put_byte(&buf, 'M'); // do.
122  bytestream_put_le32(&buf, n_bytes); // BITMAPFILEHEADER.bfSize
123  bytestream_put_le16(&buf, 0); // BITMAPFILEHEADER.bfReserved1
124  bytestream_put_le16(&buf, 0); // BITMAPFILEHEADER.bfReserved2
125  bytestream_put_le32(&buf, hsize); // BITMAPFILEHEADER.bfOffBits
126  bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize
127  bytestream_put_le32(&buf, avctx->width); // BITMAPINFOHEADER.biWidth
128  bytestream_put_le32(&buf, avctx->height); // BITMAPINFOHEADER.biHeight
129  bytestream_put_le16(&buf, 1); // BITMAPINFOHEADER.biPlanes
130  bytestream_put_le16(&buf, bit_count); // BITMAPINFOHEADER.biBitCount
131  bytestream_put_le32(&buf, compression); // BITMAPINFOHEADER.biCompression
132  bytestream_put_le32(&buf, n_bytes_image); // BITMAPINFOHEADER.biSizeImage
133  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biXPelsPerMeter
134  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biYPelsPerMeter
135  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biClrUsed
136  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biClrImportant
137  for (i = 0; i < pal_entries; i++)
138  bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);
139  // BMP files are bottom-to-top so we start from the end...
140  ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
141  buf = pkt->data + hsize;
142  for(i = 0; i < avctx->height; i++) {
143  if (bit_count == 16) {
144  const uint16_t *src = (const uint16_t *) ptr;
145  uint16_t *dst = (uint16_t *) buf;
146  for(n = 0; n < avctx->width; n++)
147  AV_WL16(dst + n, src[n]);
148  } else {
149  memcpy(buf, ptr, n_bytes_per_row);
150  }
151  buf += n_bytes_per_row;
152  memset(buf, 0, pad_bytes_per_row);
153  buf += pad_bytes_per_row;
154  ptr -= p->linesize[0]; // ... and go back
155  }
156 
157  pkt->flags |= AV_PKT_FLAG_KEY;
158  *got_packet = 1;
159  return 0;
160 }
161 
162 AVCodec ff_bmp_encoder = {
163  .name = "bmp",
164  .type = AVMEDIA_TYPE_VIDEO,
165  .id = AV_CODEC_ID_BMP,
166  .init = bmp_encode_init,
167  .encode2 = bmp_encode_frame,
168  .pix_fmts = (const enum AVPixelFormat[]){
169  AV_PIX_FMT_BGRA, AV_PIX_FMT_BGR24,
170  AV_PIX_FMT_RGB565, AV_PIX_FMT_RGB555, AV_PIX_FMT_RGB444,
171  AV_PIX_FMT_RGB8, AV_PIX_FMT_BGR8, AV_PIX_FMT_RGB4_BYTE, AV_PIX_FMT_BGR4_BYTE, AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8,
172  AV_PIX_FMT_MONOBLACK,
173  AV_PIX_FMT_NONE
174  },
175  .long_name = NULL_IF_CONFIG_SMALL("BMP (Windows and OS/2 bitmap)"),
176 };
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