I have an mp4 video that I made. It has 1 audio track, an audio file (WAV file) that I imported in. That's the only audio in this video. The rest of the audio tracks are muted.

I chose my output settings for the video to be h265, mp4, 1080 pixel, (and average overall bitrate at 20,000 kbps), and the audio to be Lossless PCM, with the audio bitrate at 1536 kbps. I chose stereo for output. The original audio file is also stereo. Based on my selections, the audio in the video should be lossless. But there are a couple parts in the video where the audio sounds slightly distorted or compressed. I compared it to the original audio file just to make sure, and there is a difference between the audio file and the resulting video. Does anyone know what might be causing this?

My computer is a laptop with an i7 processor and 8GB of RAM. I'm on Windows 10.

Is it possible that this sound issue is being caused by the fact that I'm saving the file as an mp4? I am pretty new to video editing.

Update: I also produced the video as an AVI instead of an MP4. And still received the same slight audio compression in the resulting video.

Thanks for any help

additional tags: LPCM