How can I use JavaCV to push an audio stream to RTMP while ensuring that the frame length is 20ms?

[wwfengqi]

need to push an audio file to an RTMP relay server. The audio file is a WAV file that I have saved. The original WAV file has the following specifications: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 16000 Hz, 1 channel, s16, 256 kb/s.

The issues I am facing are:

How can I ensure that the stream pushed by JavaCV is in PCM_16_8000_1 format with a frame length of 20ms? How can I implement this in code?
Below is my code:

`recorder.setFormat("flv");
recorder.setSampleRate(8000);
recorder.setAudioChannels(1);
recorder.start();`

I would appreciate it if someone could provide some guidance on this.