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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 AVERROR(EINVAL);
61  }
62 
63  avctx->coded_frame = av_frame_alloc();
64  if (!avctx->coded_frame)
65  return AVERROR(ENOMEM);
66 
67  return 0;
68 }
69 
70 static int bmp_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
71  const AVFrame *pict, int *got_packet)
72 {
73  const AVFrame * const p = pict;
74  int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize, ret;
75  const uint32_t *pal = NULL;
76  uint32_t palette256[256];
77  int pad_bytes_per_row, pal_entries = 0, compression = BMP_RGB;
78  int bit_count = avctx->bits_per_coded_sample;
79  uint8_t *ptr, *buf;
80 
81  avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
82  avctx->coded_frame->key_frame = 1;
83  switch (avctx->pix_fmt) {
84  case AV_PIX_FMT_RGB444:
85  compression = BMP_BITFIELDS;
86  pal = rgb444_masks; // abuse pal to hold color masks
87  pal_entries = 3;
88  break;
89  case AV_PIX_FMT_RGB565:
90  compression = BMP_BITFIELDS;
91  pal = rgb565_masks; // abuse pal to hold color masks
92  pal_entries = 3;
93  break;
94  case AV_PIX_FMT_RGB8:
95  case AV_PIX_FMT_BGR8:
96  case AV_PIX_FMT_RGB4_BYTE:
97  case AV_PIX_FMT_BGR4_BYTE:
98  case AV_PIX_FMT_GRAY8:
99  av_assert1(bit_count == 8);
100  avpriv_set_systematic_pal2(palette256, avctx->pix_fmt);
101  pal = palette256;
102  break;
103  case AV_PIX_FMT_PAL8:
104  pal = (uint32_t *)p->data[1];
105  break;
106  case AV_PIX_FMT_MONOBLACK:
107  pal = monoblack_pal;
108  break;
109  }
110  if (pal && !pal_entries) pal_entries = 1 << bit_count;
111  n_bytes_per_row = ((int64_t)avctx->width * (int64_t)bit_count + 7LL) >> 3LL;
112  pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
113  n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);
114 
115  // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
116  // and related pages.
117 #define SIZE_BITMAPFILEHEADER 14
118 #define SIZE_BITMAPINFOHEADER 40
119  hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);
120  n_bytes = n_bytes_image + hsize;
121  if ((ret = ff_alloc_packet2(avctx, pkt, n_bytes)) < 0)
122  return ret;
123  buf = pkt->data;
124  bytestream_put_byte(&buf, 'B'); // BITMAPFILEHEADER.bfType
125  bytestream_put_byte(&buf, 'M'); // do.
126  bytestream_put_le32(&buf, n_bytes); // BITMAPFILEHEADER.bfSize
127  bytestream_put_le16(&buf, 0); // BITMAPFILEHEADER.bfReserved1
128  bytestream_put_le16(&buf, 0); // BITMAPFILEHEADER.bfReserved2
129  bytestream_put_le32(&buf, hsize); // BITMAPFILEHEADER.bfOffBits
130  bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize
131  bytestream_put_le32(&buf, avctx->width); // BITMAPINFOHEADER.biWidth
132  bytestream_put_le32(&buf, avctx->height); // BITMAPINFOHEADER.biHeight
133  bytestream_put_le16(&buf, 1); // BITMAPINFOHEADER.biPlanes
134  bytestream_put_le16(&buf, bit_count); // BITMAPINFOHEADER.biBitCount
135  bytestream_put_le32(&buf, compression); // BITMAPINFOHEADER.biCompression
136  bytestream_put_le32(&buf, n_bytes_image); // BITMAPINFOHEADER.biSizeImage
137  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biXPelsPerMeter
138  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biYPelsPerMeter
139  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biClrUsed
140  bytestream_put_le32(&buf, 0); // BITMAPINFOHEADER.biClrImportant
141  for (i = 0; i < pal_entries; i++)
142  bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);
143  // BMP files are bottom-to-top so we start from the end...
144  ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
145  buf = pkt->data + hsize;
146  for(i = 0; i < avctx->height; i++) {
147  if (bit_count == 16) {
148  const uint16_t *src = (const uint16_t *) ptr;
149  uint16_t *dst = (uint16_t *) buf;
150  for(n = 0; n < avctx->width; n++)
151  AV_WL16(dst + n, src[n]);
152  } else {
153  memcpy(buf, ptr, n_bytes_per_row);
154  }
155  buf += n_bytes_per_row;
156  memset(buf, 0, pad_bytes_per_row);
157  buf += pad_bytes_per_row;
158  ptr -= p->linesize[0]; // ... and go back
159  }
160 
161  pkt->flags |= AV_PKT_FLAG_KEY;
162  *got_packet = 1;
163  return 0;
164 }
165 
166 static av_cold int bmp_encode_close(AVCodecContext *avctx)
167 {
168  av_frame_free(&avctx->coded_frame);
169  return 0;
170 }
171 
172 AVCodec ff_bmp_encoder = {
173  .name = "bmp",
174  .long_name = NULL_IF_CONFIG_SMALL("BMP (Windows and OS/2 bitmap)"),
175  .type = AVMEDIA_TYPE_VIDEO,
176  .id = AV_CODEC_ID_BMP,
177  .init = bmp_encode_init,
178  .encode2 = bmp_encode_frame,
179  .close = bmp_encode_close,
180  .pix_fmts = (const enum AVPixelFormat[]){
181  AV_PIX_FMT_BGRA, AV_PIX_FMT_BGR24,
182  AV_PIX_FMT_RGB565, AV_PIX_FMT_RGB555, AV_PIX_FMT_RGB444,
183  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,
184  AV_PIX_FMT_MONOBLACK,
185  AV_PIX_FMT_NONE
186  },
187 };
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