libavcodec/bmpenc.c

   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 "avcodec.h"
  24 #include "bytestream.h"
  25 #include "bmp.h"
  26
  27 static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
  28 static const uint32_t rgb565_masks[]  = { 0xF800, 0x07E0, 0x001F };
  29
  30 static av_cold int bmp_encode_init(AVCodecContext *avctx){
  31     BMPContext *s = avctx->priv_data;
  32
  33     avcodec_get_frame_defaults((AVFrame*)&s->picture);
  34     avctx->coded_frame = (AVFrame*)&s->picture;
  35
  36     return 0;
  37 }
  38
  39 static int bmp_encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
  40     BMPContext *s = avctx->priv_data;
  41     AVFrame *pict = data;
  42     AVFrame * const p= (AVFrame*)&s->picture;
  43     int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize;
  44     const uint32_t *pal = NULL;
  45     int pad_bytes_per_row, bit_count, pal_entries = 0, compression = BMP_RGB;
  46     uint8_t *ptr;
  47     unsigned char* buf0 = buf;
  48     *p = *pict;
  49     p->pict_type= FF_I_TYPE;
  50     p->key_frame= 1;
  51     switch (avctx->pix_fmt) {
  52     case PIX_FMT_BGR24:
  53         bit_count = 24;
  54         break;
  55     case PIX_FMT_RGB555:
  56         bit_count = 16;
  57         break;
  58     case PIX_FMT_RGB565:
  59         bit_count = 16;
  60         compression = BMP_BITFIELDS;
  61         pal = rgb565_masks; // abuse pal to hold color masks
  62         pal_entries = 3;
  63         break;
  64     case PIX_FMT_RGB8:
  65     case PIX_FMT_BGR8:
  66     case PIX_FMT_RGB4_BYTE:
  67     case PIX_FMT_BGR4_BYTE:
  68     case PIX_FMT_GRAY8:
  69     case PIX_FMT_PAL8:
  70         bit_count = 8;
  71         pal = (uint32_t *)p->data[1];
  72         break;
  73     case PIX_FMT_MONOBLACK:
  74         bit_count = 1;
  75         pal = monoblack_pal;
  76         break;
  77     default:
  78         return -1;
  79     }
  80     if (pal && !pal_entries) pal_entries = 1 << bit_count;
  81     n_bytes_per_row = ((int64_t)avctx->width * (int64_t)bit_count + 7LL) >> 3LL;
  82     pad_bytes_per_row = (4 - n_bytes_per_row) & 3;
  83     n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);
  84
  85     // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
  86     // and related pages.
  87 #define SIZE_BITMAPFILEHEADER 14
  88 #define SIZE_BITMAPINFOHEADER 40
  89     hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);
  90     n_bytes = n_bytes_image + hsize;
  91     if(n_bytes>buf_size) {
  92         av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", n_bytes, buf_size);
  93         return -1;
  94     }
  95     bytestream_put_byte(&buf, 'B');                   // BITMAPFILEHEADER.bfType
  96     bytestream_put_byte(&buf, 'M');                   // do.
  97     bytestream_put_le32(&buf, n_bytes);               // BITMAPFILEHEADER.bfSize
  98     bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved1
  99     bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved2
 100     bytestream_put_le32(&buf, hsize);                 // BITMAPFILEHEADER.bfOffBits
 101     bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize
 102     bytestream_put_le32(&buf, avctx->width);          // BITMAPINFOHEADER.biWidth
 103     bytestream_put_le32(&buf, avctx->height);         // BITMAPINFOHEADER.biHeight
 104     bytestream_put_le16(&buf, 1);                     // BITMAPINFOHEADER.biPlanes
 105     bytestream_put_le16(&buf, bit_count);             // BITMAPINFOHEADER.biBitCount
 106     bytestream_put_le32(&buf, compression);           // BITMAPINFOHEADER.biCompression
 107     bytestream_put_le32(&buf, n_bytes_image);         // BITMAPINFOHEADER.biSizeImage
 108     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biXPelsPerMeter
 109     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biYPelsPerMeter
 110     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrUsed
 111     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrImportant
 112     for (i = 0; i < pal_entries; i++)
 113         bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);
 114     // BMP files are bottom-to-top so we start from the end...
 115     ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
 116     buf = buf0 + hsize;
 117     for(i = 0; i < avctx->height; i++) {
 118         if (bit_count == 16) {
 119             const uint16_t *src = (const uint16_t *) ptr;
 120             uint16_t *dst = (uint16_t *) buf;
 121             for(n = 0; n < avctx->width; n++)
 122                 AV_WL16(dst + n, src[n]);
 123         } else {
 124             memcpy(buf, ptr, n_bytes_per_row);
 125         }
 126         buf += n_bytes_per_row;
 127         memset(buf, 0, pad_bytes_per_row);
 128         buf += pad_bytes_per_row;
 129         ptr -= p->linesize[0]; // ... and go back
 130     }
 131     return n_bytes;
 132 }
 133
 134 AVCodec bmp_encoder = {
 135     "bmp",
 136     CODEC_TYPE_VIDEO,
 137     CODEC_ID_BMP,
 138     sizeof(BMPContext),
 139     bmp_encode_init,
 140     bmp_encode_frame,
 141     NULL, //encode_end,
 142     .pix_fmts = (const enum PixelFormat[]){
 143         PIX_FMT_BGR24,
 144         PIX_FMT_RGB555, PIX_FMT_RGB565,
 145         PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
 146         PIX_FMT_MONOBLACK,
 147         PIX_FMT_NONE},
 148     .long_name = NULL_IF_CONFIG_SMALL("BMP image"),
 149 };