I need to convert a flac file to a wav file without changing sample rate and bit depth. As far as I know changing these properties may distort the audio, so how do i specify them not to be changed?
Also, is there any way to prevent metadata to be written to the output file?
As rogerdpack commented, the command line:
ffmpeg -i inputfile.flac output.wav should do exactly what you want.
Addressing your concerns about keeping the resulting audio intact, FLAC is a lossless format and decoding it to raw PCM stored in a WAV file will keep perfect fidelity. The only thing you might have to be concerned about is if your FLAC file is a higher than normal bit depth like 24, 32 or 64 bits per sample, or has a crazy multichannel configuration. I haven't kept up on whether FFmpeg supports all those combinations. However, most FLAC files are just 16-bit, 44.1 kHz audio files, so this shouldn't be an issue.
About scrubbing metadata, check this Superuser question.
sox infile.flac outfile.wav should do exactly that, without copying metadata.
I used it to convert back a sound that grip converted from wav to flac and got exactly the same file as the original wav.