libavcodec/bmpenc.c

   1 /*
   2  * BMP image format encoder
   3  * Copyright (c) 2006, 2007 Michel Bardiaux
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "avcodec.h"
  23 #include "bytestream.h"
  24 #include "bmp.h"
  25
  26 static av_cold int bmp_encode_init(AVCodecContext *avctx){
  27     BMPContext *s = avctx->priv_data;
  28
  29     avcodec_get_frame_defaults((AVFrame*)&s->picture);
  30     avctx->coded_frame = (AVFrame*)&s->picture;
  31
  32     return 0;
  33 }
  34
  35 static int bmp_encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
  36     BMPContext *s = avctx->priv_data;
  37     AVFrame *pict = data;
  38     AVFrame * const p= (AVFrame*)&s->picture;
  39     int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize;
  40     uint8_t *ptr;
  41     unsigned char* buf0 = buf;
  42     *p = *pict;
  43     p->pict_type= FF_I_TYPE;
  44     p->key_frame= 1;
  45     n_bytes_per_row = (avctx->width*3 + 3) & ~3;
  46     n_bytes_image = avctx->height*n_bytes_per_row;
  47
  48     // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER
  49     // and related pages.
  50 #define SIZE_BITMAPFILEHEADER 14
  51 #define SIZE_BITMAPINFOHEADER 40
  52     hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER;
  53     n_bytes = n_bytes_image + hsize;
  54     if(n_bytes>buf_size) {
  55         av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", n_bytes, buf_size);
  56         return -1;
  57     }
  58     bytestream_put_byte(&buf, 'B');                   // BITMAPFILEHEADER.bfType
  59     bytestream_put_byte(&buf, 'M');                   // do.
  60     bytestream_put_le32(&buf, n_bytes);               // BITMAPFILEHEADER.bfSize
  61     bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved1
  62     bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved2
  63     bytestream_put_le32(&buf, hsize);                 // BITMAPFILEHEADER.bfOffBits
  64     bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize
  65     bytestream_put_le32(&buf, avctx->width);          // BITMAPINFOHEADER.biWidth
  66     bytestream_put_le32(&buf, avctx->height);         // BITMAPINFOHEADER.biHeight
  67     bytestream_put_le16(&buf, 1);                     // BITMAPINFOHEADER.biPlanes
  68     bytestream_put_le16(&buf, 24);                    // BITMAPINFOHEADER.biBitCount
  69     bytestream_put_le32(&buf, BMP_RGB);               // BITMAPINFOHEADER.biCompression
  70     bytestream_put_le32(&buf, n_bytes_image);         // BITMAPINFOHEADER.biSizeImage
  71     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biXPelsPerMeter
  72     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biYPelsPerMeter
  73     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrUsed
  74     bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrImportant
  75     // BMP files are bottom-to-top so we start from the end...
  76     ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
  77     buf = buf0 + hsize;
  78     for(i = 0; i < avctx->height; i++) {
  79         n = 3*avctx->width;
  80         memcpy(buf, ptr, n);
  81         buf += n;
  82         memset(buf, 0, n_bytes_per_row-n);
  83         buf += n_bytes_per_row-n;
  84         ptr -= p->linesize[0]; // ... and go back
  85     }
  86     return n_bytes;
  87 }
  88
  89 AVCodec bmp_encoder = {
  90     "bmp",
  91     CODEC_TYPE_VIDEO,
  92     CODEC_ID_BMP,
  93     sizeof(BMPContext),
  94     bmp_encode_init,
  95     bmp_encode_frame,
  96     NULL, //encode_end,
  97     .pix_fmts= (enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE},
  98     .long_name = "BMP image",
  99 };