无法在 Qt 中将音频从麦克风录制到 QFile
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【中文标题】无法在 Qt 中将音频从麦克风录制到 QFile【英文标题】：Unable to record audio from microphone to QFile in Qt 【发布时间】：2014-01-29 11:32:57 【问题描述】：我正在尝试从桌面上的默认麦克风录制音频并将其存储在 QFile 中。 最后，我想使用 windows 媒体播放器播放录制的文件。问题是 QAudioInput 有一个方法 bytesReady() 在我的情况下它总是返回 0 。即使音频状态是 QAudio::ActiveState，bytesReady() 也会显示 0 字节，这意味着没有音频字节可以从麦克风中读取。系统麦克风工作正常。我的代码得到了完美的编译，我还在指定位置获得了一个大小为 80KB 的文件，但即使保存为 .wav，该文件也无法使用 Windows Media Player 播放，它会返回错误。 在我的情况下，输出窗口每次都将 bytesReady 显示为 0。我怀疑 QAudioInput 无法从麦克风读取音频数据。
您能帮我找出我的代码中的错误吗？
`class mikeDemoClass : public QWidget
Q_OBJECT
public:
mikeDemoClass(QWidget *parent = 0, Qt::WFlags flags = 0);
~mikeDemoClass();
public slots:
void startRecording();
void browseFiles();
void stopRecording();
void handleAudioInputState(QAudio::State);
void notified();
private:
Ui::mikeDemoWidget ui;
QAudioInput *audioInput;
QFile *recordFile;
QTimer *testTimer;
int audio_state;
;
// cpp file starts here
#include <QIODevice>
#include "mic_demo.h"
mikeDemoClass::mikeDemoClass(QWidget *parent, Qt::WFlags flags)
: QWidget(parent, flags)
ui.setupUi(this);
audioInput = NULL;
recordFile = NULL;
audio_state = -1;
connect(ui.browseButton,SIGNAL(clicked()),this,SLOT(browseFiles()));
connect(ui.recordingButton,SIGNAL(clicked()), this,SLOT(startRecording()));
mikeDemoClass::~mikeDemoClass()
if(recordFile)
delete recordFile;
recordFile = NULL;
void mikeDemoClass::browseFiles()
QString FileName = QFileDialog::getSaveFileName(this, tr("Browse Files"), "D:/", tr("Media Files (*.raw)"));
if(!FileName.isEmpty())
recordFile = new QFile(FileName);
QTextDocument *textDoc = new QTextDocument(FileName);
ui.textEdit->setDocument(textDoc);
void mikeDemoClass::startRecording()
bool status = recordFile->open(QIODevice::WriteOnly);
if(!status)
qDebug() <<"Error opening the file";
QString default_deviceName = "";
QAudioFormat preferred_format;
QList<QAudioDeviceInfo> device_list = QAudioDeviceInfo::availableDevices(QAudio::AudioInput);
int count = device_list.count();
if(device_list.empty())
qDebug() <<"The Audio Input Devices is empty";
else
foreach(QAudioDeviceInfo device_info, device_list)
QString device_name = device_info.deviceName();
qDebug() << "device_name:" << device_name.toLatin1();
QAudioDeviceInfo info = QAudioDeviceInfo::defaultInputDevice();
default_deviceName = info.deviceName();
if(!default_deviceName.isEmpty())
preferred_format = info.preferredFormat();
QString codec = preferred_format.codec();
int sampleRate = preferred_format.sampleRate();
int sampleSize = preferred_format.sampleSize();
int channelCount = preferred_format.channelCount();
int sampleType = preferred_format.sampleType();
int byteOrder = preferred_format.byteOrder();
qDebug() << "codec:" << codec.toLatin1() << "sampleRate :" << sampleRate << "sampleSize:" << sampleSize << "channel Count:" << channelCount << "sample type:" <<sampleType
<< "byteOrder:" << byteOrder;
QAudioFormat format;
format.setSampleRate(8000);
format.setChannels(1);
format.setSampleSize(8);
format.setCodec("audio/PCM");
format.setByteOrder(QAudioFormat::LittleEndian);
format.setSampleType(QAudioFormat::UnSignedInt);
QAudioDeviceInfo info = QAudioDeviceInfo::defaultInputDevice();
if(!info.isFormatSupported(format))
qDebug() <<"Default format not supported, try to use nearest format";
format = info.nearestFormat(format);
audioInput = new QAudioInput(info, format, this);
connect(audioInput, SIGNAL(notify()), this, SLOT(notified()));
connect(audioInput,SIGNAL(stateChanged(QAudio::State)),this, SLOT(handleAudioInputState(QAudio::State)));
QTimer::singleShot(10000, this, SLOT(stopRecording()));
//audioInput->setBufferSize(4096);
qDebug() << "platform buffer size:" << audioInput->bufferSize();
audioInput->start(recordFile);
void mikeDemoClass::stopRecording()
testTimer->stop();
audioInput->stop();
recordFile->close();
delete audioInput;
void mikeDemoClass::handleAudioInputState(QAudio::State state)
qDebug() << "Audio State:" << state;
audio_state = state;
if(state == QAudio::StoppedState)
qDebug() << "Error State:" << audioInput->error();
if(audioInput->error() != QAudio::NoError)
qDebug() << "QAudioInput error:" << audioInput->error();
void mikeDemoClass::notified()
if(audio_state == QAudio::ActiveState)
qDebug() << "Error State:" << audioInput->error();
qDebug() << "platform buffer size after calling QAudioInput start():" << audioInput->bufferSize();
qDebug() << "bytesReady = " << audioInput->bytesReady()
<< ", " << "elapsedUSecs = " <<audioInput->elapsedUSecs()
<< ", " << "processedUSecs = "<<audioInput->processedUSecs();
`
输出显示如下：
device_name: "Microphone (High Definition Aud"
device_name: "default"
codec: "audio/pcm" sampleRate : 11025 sampleSize: 8 channel Count: 1 sample type: 1 byteOrder: 1
Default format not supported, try to use nearest format
platform buffer size: 0
Audio State: 0
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 1003000 , processedUSecs = 1000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 1998000 , processedUSecs = 2000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 3003000 , processedUSecs = 3000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 4000000 , processedUSecs = 4000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 5006000 , processedUSecs = 5000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 6001000 , processedUSecs = 6000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 7005000 , processedUSecs = 7000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 8002000 , processedUSecs = 8000000
Error State: 0
platform buffer size after called QAudioInput start(): 1600
bytesReady = 0 , elapsedUSecs = 8997000 , processedUSecs = 9000000
Audio State: 2
Error State: 0
【问题讨论】：
上述代码的输出如图所示： 试试看例子qt-project.org/doc/qt-5.0/qtmultimedia/… 我想你忘记了音频标题。 @Samoth：我完全没有编译错误，我已经包含了所有内容。我没有显示头文件。 @jeevan_reddy 我并没有考虑 c++ 标头，而是这个：wave header 【参考方案1】：将您的代码与Qt documentation 中的示例进行比较后，您正在使用通知信号来处理 QAudio::ActiveState，而示例代码将插槽连接到 stateChanged 信号：-
void AudioInputExample::handleStateChanged(QAudio::State newState)
switch (newState)
case QAudio::StoppedState:
if (audio->error() != QAudio::NoError)
// Error handling
else
// Finished recording
break;
case QAudio::ActiveState:
// Started recording - read from IO device
break;
default:
// ... other cases as appropriate
break;
如 notify() 所述：-
在 setNotifyInterval 设置的时间间隔处理 x ms 的音频数据时发出此信号
间隔可以为零吗？
但是，我建议按照documentation 中所示的示例代码并使用 stateChanged 信号，而不是通知。
【讨论】：
setNotifyInterval 默认为 1 秒。如果未设置通知间隔，则没有问题。我的代码完美编译，我也可以执行它。 @jeevan_reddy，我从未暗示您的代码无法编译，或者您无法执行它。听起来您只阅读了答案的倒数第二行。 我阅读了您的整个 cmets，我的重点是 QAudioInput 的 bytesReady() 方法，据我所知，该方法应该返回在 QMedia::ActiveState 中从麦克风读取的音频数据。除了打印 sme 调试语句外，在 QActiveState 中我不会做任何有意义的事情。真正的问题是为什么 bytesReady() 在状态为 Active 时返回 0。我认为这不应该发生。 您是否尝试过等待 stateChanged 信号，而不是通知？ 我试过了，我在 stateChaged 信号发出时调用的插槽中打印 bytesRead() 。我检查了 QAudio::ActiveState 然后打印 bytesRead() 给出 0.【参考方案2】：将 PHDEBUG 或 PHDBG 视为 qDebug() 并查看以下内容（我认为您的缺失点是作为缓冲区的 QIODevice。）：
Reader.cpp：
#include "PhLtcReader.h"
PhLtcReader::PhLtcReader(QObject *parent) :
QObject(parent),
_input(NULL),
_position(0),
_buffer(NULL)
_decoder = ltc_decoder_create(1920, 3840);
PHDEBUG << "LTC Reader created";
bool PhLtcReader::init(QString input)
QList<QAudioDeviceInfo> list = QAudioDeviceInfo::availableDevices(QAudio::AudioInput);
if(list.isEmpty())
PHDEBUG << "No audio input device";
return false;
QAudioDeviceInfo info = QAudioDeviceInfo::defaultInputDevice();
foreach(QAudioDeviceInfo device, list)
if(device.deviceName() == input)
info = device;
PHDEBUG << "LTC input device :" << info.deviceName();
QAudioFormat format;
format.setCodec("audio/pcm");
format.setByteOrder(QAudioFormat::LittleEndian);
format.setSampleRate(48000);
format.setChannelCount(1);
format.setSampleSize(8);
format.setSampleType(QAudioFormat::SignedInt);
if(!info.isFormatSupported(format))
PHDEBUG << "Unsupported audio format";
return false;
_position = 0;
_input = new QAudioInput(info, format);
connect(_input, SIGNAL(notify()), this, SLOT(onNotify()));
_buffer = _input->start();
_input->setNotifyInterval(10);
_pauseDetector.start();
return true;
void PhLtcReader::close()
if(_input)
_input->stop();
delete _buffer;
_buffer = NULL;
delete _input;
_input = NULL;
QList<QString> PhLtcReader::inputList()
QList<QString> names;
QList<QAudioDeviceInfo> list = QAudioDeviceInfo::availableDevices(QAudio::AudioInput);
foreach(QAudioDeviceInfo device, list)
names.append(device.deviceName());
return names;
void PhLtcReader::onNotify()
QByteArray array = _buffer->readAll();
char max = 0;
for(int i = 0; i < array.count(); i++)
if(array.at(i) > max)
max = array.at(i);
ltc_decoder_write(_decoder, (ltcsnd_sample_t*)array.data(), array.count(), _position);
LTCFrameExt frame;
unsigned int *hhmmssff = new unsigned int[4];
while(ltc_decoder_read(_decoder, &frame))
PhFrame oldFrame = _clock.frame();
hhmmssff[0] = frame.ltc.hours_tens * 10 + frame.ltc.hours_units;
hhmmssff[1] = frame.ltc.mins_tens * 10 + frame.ltc.mins_units;
hhmmssff[2] = frame.ltc.secs_tens * 10 + frame.ltc.secs_units;
hhmmssff[3] = frame.ltc.frame_tens * 10 + frame.ltc.frame_units;
delete hhmmssff;
_position += array.count();
阅读器.h
class PhLtcReader : public QObject
Q_OBJECT
public:
explicit PhLtcReader(QObject *parent = 0);
bool init(QString _input="");
void close();
static QList<QString> inputList();
private slots:
void onNotify();
private:
QAudioInput *_input;
qint64 _position;
QIODevice * _buffer;
;
#endif // PHLTCREADER_H
【讨论】：
麦克风音频首先没有存储在原始文件中。 smebdy 请让我知道上面显示的代码中的错误是什么。任何帮助表示赞赏。 我无法从我的桌面录制麦克风音频并首先保存到原始文件中。我真的需要帮助，为什么 QAudioInput 没有首先执行它的工作。任何帮助表示赞赏。在我的情况下，即使音频状态为 Active，QAudioInput bytesReady() 也会显示 0。 QAudioInput 无法从桌面的麦克风读取数据。 @jeevan_reddy 编辑了我的代码，尝试修改它然后回来；）【参考方案3】：您的问题的答案可以在输出中找到。
有一句话说
Default format not supported, try to use nearest format
这是问题所在。您的平台不支持您使用的格式。尝试其他格式或安装编解码器/驱动程序以支持该格式。
【讨论】：
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