Android FFmpegKit merging audio with video file has problem

Question

I am using FFmpegKit to add audio to a video file. But it has a problem.

I am recording video using camera2api.

• If I add raw music resource mp3 after writing it to a file it works.
• If I do voice recording and add it to the video it also works.
• But when I add voice and then music it shows success but the video only has voice recording, not music.

Here is ffmpeg command:

StringBuilder command = new StringBuilder()
            .append("-y") // overWrite
            .append(" -i ").append(video) // video
            .append(" -i ").append(audio) // audio
            .append(" -c:v ").append("copy")
            .append(" -c:a ").append("copy")
            .append(" -shortest ") // shortest from both
            .append(" -f ").append("mp4 ")
            .append(tempFile.getAbsolutePath());

I am recording voice using MediaRecorder:

mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC)
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
mediaRecorder.setAudioEncodingBitRate(96000);
mediaRecorder.setAudioSamplingRate(96000);
mediaRecorder.setAudioChannels(2) // stereo