我正在使用 libjpeg 从 OpenCV Mat 转换图像缓冲区并将其写入内存位置
这是代码:
bool mat2jpeg(cv::Mat frame, unsigned char **outbuffer
, long unsigned int *outlen) {
unsigned char *outdata = frame.data;
struct jpeg_compress_struct cinfo = { 0 };
struct jpeg_error_mgr jerr;
JSAMPROW row_ptr[1];
int row_stride;
*outbuffer = NULL;
*outlen = 0;
cinfo.err = jpeg_std_error(&jerr);
jpeg_create_compress(&cinfo);
jpeg_mem_dest(&cinfo, outbuffer, outlen);
jpeg_set_quality(&cinfo, JPEG_QUALITY, TRUE);
cinfo.image_width = frame.cols;
cinfo.image_height = frame.rows;
cinfo.input_components = 1;
cinfo.in_color_space = JCS_GRAYSCALE;
jpeg_set_defaults(&cinfo);
jpeg_start_compress(&cinfo, TRUE);
row_stride = frame.cols;
while (cinfo.next_scanline < cinfo.image_height) {
row_ptr[0] = &outdata[cinfo.next_scanline * row_stride];
jpeg_write_scanlines(&cinfo, row_ptr, 1);
}
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
return true;
}
问题是我无法在任何地方释放出缓冲区。
这就是我使用该功能的方式:
long unsigned int * __size__ = nullptr;
unsigned char * _buf = nullptr;
mat2jpeg(_img, &_buf, __size__);
free(_buf) 和 free(*_buf) 都失败了,看来我正试图通过这样做来释放堆头。
并且 mat2jpeg 不接受指向 outbuffer 指针的指针。任何想法?