push an RTMP stream，and find that the channel and frequency was changed

[wwfengqi]

Question

hello ,

When I use FFmpeg to push an audio wav file to RTMP stream on MediaMTX, and set the output stream encoding to AAC, with 1 channel and a frequency of 8000Hz, but when I play the corresponding RTSP address in VLC, I find that the channels have become 2 and the frequency has become 16000Hz.Sample Bits also has become 32, Why is this happening?
For information, i'm have mediamtx1.8 on linux.

Thanks in advance.

Regards