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FFmpeg/libavcodec/bmpenc.c

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/*
* BMP image format encoder
* Copyright (c) 2006, 2007 Michel Bardiaux
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avcodec.h"
#include "bytestream.h"
#include "bmp.h"
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;
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;
uint8_t *ptr;
unsigned char* buf0 = buf;
*p = *pict;
p->pict_type= FF_I_TYPE;
p->key_frame= 1;
n_bytes_per_row = (avctx->width*3 + 3) & ~3;
n_bytes_image = avctx->height*n_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;
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, 24); // BITMAPINFOHEADER.biBitCount
bytestream_put_le32(&buf, BMP_RGB); // 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
// 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++) {
n = 3*avctx->width;
memcpy(buf, ptr, n);
buf += n;
memset(buf, 0, n_bytes_per_row-n);
buf += n_bytes_per_row-n;
ptr -= p->linesize[0]; // ... and go back
}
return n_bytes;
}
AVCodec bmp_encoder = {
"bmp",
CODEC_TYPE_VIDEO,
CODEC_ID_BMP,
sizeof(BMPContext),
bmp_encode_init,
bmp_encode_frame,
NULL, //encode_end,
.pix_fmts= (enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("BMP image"),
};