[英]playing created Audio-Data has noise and periodical clicking in sound
我寫了一個應用程序,它從硬件中播放聲音(就像一個充滿特定頻率的正弦波的環形緩沖區)。 一切正常,我可以正確播放創建的聲音,除了定期點擊(可能在緩沖區的末尾?)和噪音。
我初始化並運行緩沖區:
void Audiooutput::InitializeAudioParameters()
{
Audio_DataWritten = 0;
Audio_fragments = 4;
Audio_channels = 2;
Audio_BufferSize = 256;
Audio_Samplerate = 8000;
Audio_ResamplingFactor = 1;
Audio_Framesize = 2;
// (SND_PCM_FORMAT_S16_LE / 8);
Audio_frames = Audio_BufferSize / Audio_Framesize * Audio_fragments;
snd_pcm_uframes_t size;
err = snd_pcm_hw_params_any(pcmPlaybackHandle, hw_params);
err = snd_pcm_hw_params_set_rate_resample(pcmPlaybackHandle, hw_params, 1);
// qDebug()<<a1.sprintf(" % d \t snd_pcm_hw_params_set_rate: %s",Audio_Samplerate,snd_strerror(err));
err =
snd_pcm_hw_params_set_format(pcmPlaybackHandle, hw_params,
SND_PCM_FORMAT_S16_LE);
err =
snd_pcm_hw_params_set_channels(pcmPlaybackHandle, hw_params,
Audio_channels);
err = snd_pcm_hw_params_set_rate_near(pcmPlaybackHandle, hw_params, &Audio_Samplerate, 0);
// qDebug()<<a1.sprintf(" % d \t snd_pcm_hw_params_set_rate: %s",Audio_Samplerate,snd_strerror(err));
if ((err =
snd_pcm_hw_params_set_periods_near(pcmPlaybackHandle, hw_params,
&Audio_fragments, 0)) < 0) {
qDebug() << a1.sprintf("Error setting # fragments to %d: %s\n",
Audio_fragments, snd_strerror(err));
} else
qDebug() << a1.sprintf("setting # fragments to %d: %s\n",
Audio_fragments, snd_strerror(err));
err = snd_pcm_hw_params_get_buffer_size(hw_params, &size);
if ((err =
snd_pcm_hw_params_set_buffer_size_near(pcmPlaybackHandle,
hw_params,
&Audio_frames)) < 0) {
qDebug() << a1.
sprintf("Error setting buffer_size %d frames: %s",
Audio_frames, snd_strerror(err));
} else
qDebug() << a1.sprintf("setting Buffersize to %d --> %d: %s\n",
Audio_BufferSize, Audio_frames,
snd_strerror(err));
Audio_BufferSize = Audio_frames;
if ((err = snd_pcm_hw_params(pcmPlaybackHandle, hw_params)) < 0) {
qDebug() << a1.sprintf("Error setting HW params: %s",
snd_strerror(err));
}
Q_ASSERT(err >= 0);
}
void Audiooutput::ProduceAudioOutput(int n, int mmodes, int totalMModeGates,
short *sinusValue, short *cosinusValue)
{
for (int audioSample = 0; audioSample < n;
audioSample += Audio_ResamplingFactor) {
currentposition =
(int)(m_Audio.generalPos % (Audio_BufferSize / 2));
if (currentposition == 0) {
QueueAudioBuffer();
m_Audio.currentPos = 0;
}
m_Audio.generalPos++;
AudioData[currentposition * 2] =
(short)(sinusValue[audioSample]);
AudioData[currentposition * 2 + 1] =
(short)(cosinusValue[audioSample]);
}
}
void Audiooutput::QueueAudioBuffer()
{
snd_pcm_prepare(pcmPlaybackHandle);
Audio_DataWritten +=
snd_pcm_writei(pcmPlaybackHandle, AudioData, Audio_BufferSize);
}
更改音頻緩沖區大小或片段也會更改單擊期間。 任何人都可以幫我解決這個問題嗎? 我還檢查了第一個和最后一個值。 你總是與眾不同。
更多詳情。
接收數據的計數是動態的,並且變化取決於不同的參數。 但我總是玩某個部分,例如128個值或256或512 ....
//我從硬件中獲取Audiodata(在Timerloop中)
audiobuffersize = 256;
short *AudioData = new short[256];
int generalAudioSample = 0;
void CollectDataFromHw()
{
...
int n = 0;
n = GetData(buf1,buf2);//buf1 = new short[MAX_SHRT]
if(n > 0)
FillAudioBuffer(n,buf1,buf2)
...
}
-------------------------------------------
void FillAudioBuffer(int n, short*buf1, short*buf2)
{
for(int audioSample = 0;audioSample < n; audioSample++){
iCurrentAudioSample = (int)(generalAudioSample % (audiobuffersize/2));
if(iCurrentAudioSample == 0) {
snd_pcm_writei(pcmPlaybackHandle,AudioData,audiobuffersize );
memset(AudioData,0x00,audiobuffersize*sizeof(short));
}
generalAudioSample++;
AudioData[iCurrentAudioSample * 2] = (short)(buf1[audioSample];
AudioData[iCurrentAudioSample * 2 +1] = (short)(buf2[audioSample];
}
}
我也改變了audiobuffersize。 如果我將它設置為更大的尺寸,我會點擊一些額外的Echo。
任何的想法 ? // - - - - - - - - - - - - 問題是
snd_pcm_prepare(pcmPlaybackHandle);
每次調用此功能都會產生聲音點擊!
無法測試源代碼,但我認為您聽到的高頻點擊是聲波中的不連續性。 您必須確保循環周期(或緩沖區大小)是波周期的倍數。
檢查緩沖區的第一個和最后一個值是否幾乎相同(例如+/- 1)。 它們的距離決定了不需要的咔嗒聲的幅度
已解決的緩沖區在填充數據之前已經播放了好幾次。
代碼中的愚蠢錯誤。輸入一個parantez - > audio_buffersize / 2 < - - 因此結果很頻繁,如果(iCurrentAudioSample == 0)真的!!!!!
iCurrentAudioSample = (int)(generalAudioSample % (audio_buffersize/2));
if(iCurrentAudioSample == 0)
{
writetoaudioStream(audiobuffer);
}
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