Extracts the RTP payload and decodes it into a wav file

extract_opus_and_decode.py

import pyshark
import opuslib
import wave
import argparse

FRAME_SIZE = 960
SAMPLE_RATE = 48000
CHANNEL_COUNT = 1
SAMPLE_WIDTH = 2

def extract_opus_from_pcapng(pcapng_file):
    opus_packets = []
    cap = pyshark.FileCapture(pcapng_file)
    for pkt in cap:
        # Skip UDP header (8) and RTP header (16)
        opus_payload = bytes.fromhex(pkt.data.data[24:])
        opus_packets.append(opus_payload)
    cap.close()
    return opus_packets

def decode_opus_to_wav(opus_packets, output_file):
    opus_decoder = opuslib.Decoder(SAMPLE_RATE, CHANNEL_COUNT)
    with wave.open(output_file, 'wb') as wav_file:
        wav_file.setnchannels(CHANNEL_COUNT)
        wav_file.setsampwidth(SAMPLE_WIDTH)
        wav_file.setframerate(SAMPLE_RATE)

        for packet in opus_packets:
            decoded_pcm = opus_decoder.decode(packet, FRAME_SIZE)
            wav_file.writeframes(decoded_pcm)

def main():
    parser = argparse.ArgumentParser(description='Decode opus from pcap file into wav')
    parser.add_argument('pcap_file', type=str, help='Path to the pcap file')
    parser.add_argument('wav_file', type=str, help='Path to the wav file')

    args = parser.parse_args()

    pcap_file = args.pcap_file
    wav_file = args.wav_file

    opus_packets = extract_opus_from_pcapng(pcap_file)
    decode_opus_to_wav(opus_packets, wav_file)

if __name__ == '__main__':
    main()