Android音頻流 - 在AudioTrack上獲取靜態噪音

Question

我有一個在localhost上運行的流服務器。 當我嘗試從我的Android應用程序流式傳輸音頻時。 我大部分時間都是靜電噪音（你收音機的那種）。 有時完整的音頻是靜態噪音，有時是它的一部分，有時音頻播放得很好，所以我不確定出了什么問題。

這是我的Android應用程序的流代碼：

new Thread(
                new Runnable() {
                    @Override
                    public void run() {
                        try {
                            URI uri = URI.create("http://192.168.1.6:5000/api/tts");
                            HttpURLConnection urlConnection = (HttpURLConnection) uri.toURL().openConnection();
                            urlConnection.setRequestMethod("POST");
                            urlConnection.setRequestProperty("Content-Type", "application/json");
                            urlConnection.setRequestProperty("x-access-token", credentials.getAccessToken());
                            urlConnection.setRequestProperty("Accept", "*");
                            urlConnection.setDoInput(true);
                            urlConnection.setDoOutput(true);
                            urlConnection.connect();
                            OutputStreamWriter osw = new OutputStreamWriter(urlConnection.getOutputStream());
                            String body = "{\"text\": \"" + text + "\", \"ttsLang\": \"" + language + "\"}";
                            Log.d("TTS_HTTP", body);
                            osw.write(body);
                            osw.flush();
                            osw.close();
                            Log.d("TTS_OUT", credentials.getAccessToken());
                            Log.d("TTS_OUT", urlConnection.getResponseCode() + " " + urlConnection.getResponseMessage());

                            // define the buffer size for audio track
                            int SAMPLE_RATE = 16000;
                            int bufferSize = AudioTrack.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO,
                                    AudioFormat.ENCODING_PCM_16BIT);
                            if (bufferSize == AudioTrack.ERROR || bufferSize == AudioTrack.ERROR_BAD_VALUE) {
                                bufferSize = SAMPLE_RATE * 2;
                            }
                            bufferSize *= 2;

                            AudioTrack audioTrack = new AudioTrack(
                                    AudioManager.STREAM_MUSIC,
                                    SAMPLE_RATE,
                                    AudioFormat.CHANNEL_OUT_MONO,
                                    AudioFormat.ENCODING_PCM_16BIT,
                                    bufferSize*2,
                                    AudioTrack.MODE_STREAM);
                            byte[] buffer = new byte[bufferSize];
                            InputStream is = urlConnection.getInputStream();
                            int count;

                            audioTrack.play();
                            while ((count = is.read(buffer, 0, bufferSize)) > -1) {
                                Log.d("TTS_COUNT", count + "");
                                audioTrack.write(buffer, 0, count);
                            }
                            is.close();
                            audioTrack.stop();
                            audioTrack.release();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
        ).start();

請幫我修復代碼來解決問題。 我沒能像前面所描述的那樣正確地聽到聲音。

此外，服務器響應很好，因為我可以使用Python代碼將其保存到文件中。 保存的文件播放得很好。

>>> import requests
>>> import wave
>>> with wave.open("output.wav", "wb") as f:
...   f.setframerate(16000)  # 16khz
...   f.setnchannels(1)  # mono channel
...   f.setsampwidth(2)  # 16-bit audio
...   res = requests.post("http://192.168.1.6:5000/api/tts", headers={"x-access-token": token}, json={"text": "Hello, would you like to have some tea", "ttsLang": "en-us"}, stream=True)
...   for i in res.iter_content(chunk_size=16*1024):
...     f.writeframes(i)
...

更新：將輸入流寫入文件，然后從文件播放到audiotrack工作正常...

Answer 1

最后，我解決了這個問題。 事實證明， AudioTrack不喜歡寫入不一致的數據量並導致靜態噪聲。 這是正在寫入的字節數序列AudioTrack之前，這是造成問題的1248 ， 3439 ， 5152 ， 5152 ， 3834 ，...， 823 （不一致）。 所以，我查看了DataInputStream的readFully方法並使用它並修復了靜態噪聲問題。 字節計數順序現在看起來像5152 ， 5152 ， 5152 ，...， 5152 （一致）。 但現在問題是要讀取由於EOFException而被跳過的剩余字節。 所以我必須實現自己的方法來解決這個問題。

public class TTSInputStream extends DataInputStream {
    public TTSInputStream(InputStream in) {
        super(in);
    }

    public final int readFullyUntilEof(byte b[]) throws IOException {
        return readFullyUntilEof(b, 0, b.length);
    }

    public final int readFullyUntilEof(byte b[], int off, int len) throws IOException {
        if (len < 0)
            throw new IndexOutOfBoundsException();
        int n = 0;
        while (n < len) {
            int count = in.read(b, off + n, len - n);
            if (count < 0)
                break;
            n += count;
        }
        return n;
    }
}

我的最終代碼現在看起來像這樣：

new Thread(
                new Runnable() {
                    @Override
                    public void run() {
                        try {
                            URI uri = URI.create("http://192.168.1.6:5000/api/tts");
                            HttpURLConnection urlConnection = (HttpURLConnection) uri.toURL().openConnection();
                            urlConnection.setRequestMethod("POST");
                            urlConnection.setRequestProperty("Content-Type", "application/json");
                            urlConnection.setRequestProperty("x-access-token", credentials.getAccessToken());
                            urlConnection.setRequestProperty("Accept", "*");
                            urlConnection.setChunkedStreamingMode(bufferSize);
                            urlConnection.setDoInput(true);
                            urlConnection.setDoOutput(true);
                            urlConnection.connect();
                            OutputStreamWriter osw = new OutputStreamWriter(urlConnection.getOutputStream());
                            String body = "{\"text\": \"" + text + "\", \"ttsLang\": \"" + language + "\"}";
                            Log.d("TTS_HTTP", body);
                            osw.write(body);
                            osw.flush();
                            osw.close();
                            Log.d("TTS_OUT", credentials.getAccessToken());
                            Log.d("TTS_OUT", urlConnection.getResponseCode() + " " + urlConnection.getResponseMessage());

                            // define the buffer size for audio track
                            int SAMPLE_RATE = 16000;
                            int bufferSize = AudioTrack.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO,
                                    AudioFormat.ENCODING_PCM_16BIT);
                            if (bufferSize == AudioTrack.ERROR || bufferSize == AudioTrack.ERROR_BAD_VALUE) {
                                bufferSize = SAMPLE_RATE * 2;
                            }
                            bufferSize *= 2;
                            TTSInputStream bis = new TTSInputStream(urlConnection.getInputStream());
                            AudioTrack audioTrack = new AudioTrack(
                                    AudioManager.STREAM_MUSIC,
                                    SAMPLE_RATE,
                                    AudioFormat.CHANNEL_OUT_MONO,
                                    AudioFormat.ENCODING_PCM_16BIT,
                                    bufferSize * 2,
                                    AudioTrack.MODE_STREAM);
                            byte[] buffer = new byte[bufferSize];
                            audioTrack.play();
                            int count;
                            while ((count = bis.readFullyUntilEof(buffer)) > 0) {
                                Log.d("TTS_COUNT", "Read " + count + " bytes.");
                                audioTrack.write(buffer, 0, buffer.length);
                            }
                            bis.close();
                            audioTrack.stop();
                            audioTrack.release();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
        ).start();

現在我的音頻播放效果不錯，沒有靜音。 希望這可以幫助其他人和我有同樣的問題。