Number of samples in the audio frame: samples = (int)samplesPerCall = (int)(sampleRate × sampleInterval)

Number of bytes per audio sample. For example, each PCM audio sample usually takes up 16 bits (2 bytes).

Number of audio channels.

• 1: Mono
• 2: Stereo (the data is interleaved)

Audio frame sample rate: 8000, 16000, 32000, 44100, or 48000 Hz.

Audio frame data buffer. The valid data length is: samples × channels × bytesPerSample

The timestamp of the external audio frame. It is mandatory. You can use this parameter for the following purposes:

• Restore the order of the captured audio frame.
• Synchronize audio and video frames in video-related scenarios, including scenarios where external video sources are used.