Qt Multimedia offers a range of audio classes that cover both low and high level approaches to: audio input, output and processing.
對於播放不簡單媒體或音頻文件、未壓縮音頻，可以使用 QMediaPlayer C++ 類，或 MediaPlayer QML type. The QMediaPlayer 類和關聯 QML 類型還能播放 視頻 , if required.
見 Supported Media Formats for more detail.
The media player needs to be connected to a QAudioOutput object (or the QML AudioOutput element) to play back audio.
這裏是如何使用 C++ 播放本地文件：
player = new QMediaPlayer; audioOutput = new QAudioOutput; player->setAudioOutput(audioOutput); // ... player->setSource(QUrl::fromLocalFile("/Users/me/Music/coolsong.mp3")); audioOutput->setVolume(50); player->play();
The same functionality in QML:
MediaPlayer { audioOutput: AudioOutput {} source: "file:///path/to/my/music.mp3" Component.onCompleted: { play() } }
To record audio to a file, you need to create a capture session and connect to it an audio input and a recorder. These elements are implemented with the QMediaCaptureSession , QAudioInput ，和 QMediaRecorder classes. The default constructed QAudioInput selects the system default audio input. The recorder controls the recording process with a simple record() and stop() functions. Additionally, you can use it to select the output location, audio encoder, or file container format.
A session recording audio from the default microphone would look as follows in C++:
QMediaCaptureSession session; QAudioInput audioInput; session.setAudioInput(&input); QMediaRecorder recorder; session.setRecorder(&recorder); recorder.setQuality(QMediaRecorder::HighQuality); recorder.setOutputLocation(QUrl::fromLocalFile("test.mp3")); recorder.record();
In QML, the same can be achieved by:
CaptureSession { audioInput: AudioInput {} mediaRecorder: MediaRecorder { id: recorder outputLocation: "file:///path/to/test.mp3" } Component.onCompleted: { recorder.record() } }
QMediaCaptureSession also provides support for more complex use cases such as image capturing or video recording.
除瞭 raw access to sound devices, the QSoundEffect 類 (和 SoundEffect QML type) offers a more abstract way to play sounds. This class allows you to specify a WAV format file, which can then be played with low latency when necessary.
You can adjust the:
The C++ API of Qt Multimedia offers classes for raw access to audio input and output facilities, allowing applications to receive raw data from devices like microphones, and to write raw data to speakers or other devices. Generally these classes do not do any audio decoding, or other processing, but they can support different types of raw audio data.
The QAudioSink 類提供原生音頻數據輸齣，而 QAudioSource offers raw audio data input. The available hardware determines what audio outputs and inputs are available.
低級音頻類可以運轉於 2 種模式下
push
and
pull
。在
pull
模式，音頻設備的啓動是通過將它賦予
QIODevice
。對於輸齣設備，
QAudioSink
類將 pull (拉齣) 數據從
QIODevice
(使用
QIODevice::read
()) 當要求更多音頻數據時。相反，對於
pull
模式采用
QAudioSource
，當音頻數據可用時，數據將被直接寫入
QIODevice
.
在
push
模式，音頻設備提供
QIODevice
instance that can be written or read to as needed. Typically, this results in simpler code but more buffering, which may affect latency.
In some cases you may want to decode a compressed audio file and do further processing yourself. For example, mixing multiple samples or using custom digital signal processing algorithms. QAudioDecoder 支持解碼本地文件或數據流從 QIODevice 實例。
這裏是本地文件解碼範例：
QAudioFormat desiredFormat; desiredFormat.setChannelCount(2); desiredFormat.setSampleFormat(QAudioFormat::Int16); desiredFormat.setSampleRate(48000); QAudioDecoder *decoder = new QAudioDecoder(this); decoder->setAudioFormat(desiredFormat); decoder->setSource("level1.mp3"); connect(decoder, SIGNAL(bufferReady()), this, SLOT(readBuffer())); decoder->start(); // Now wait for bufferReady() signal and call decoder->read()
The Qt Spatial Audio module provides an API for implementation sound fields in 3D space.
| QAmbientSound | A stereo overlay sound |
| QAudio | 包含用於音頻類的枚舉 |
| QAudioBuffer | 錶示具有特定格式和采樣率的一批音頻樣本 |
| QAudioDecoder | Implements decoding audio |
| QAudioDevice | Information about audio devices and their functionality |
| QAudioEngine | Manages a three dimensional sound field |
| QAudioFormat | 存儲音頻流參數信息 |
| QAudioInput | Represents an input channel for audio |
| QAudioListener | Defines the position and orientation of the person listening to a sound field defined by QAudioEngine |
| QAudioOutput | Represents an output channel for audio |
| QAudioRoom | |
| QAudioSink | 把音頻數據發送到音頻輸齣設備的接口 |
| QAudioSource | 從音頻輸入設備接收音頻數據的接口 |
| QMediaCaptureSession | Allows capturing of audio and video content |
| QMediaRecorder | Used for encoding and recording a capture session |
| QSoundEffect | 播放低延遲音效的辦法 |
| QSpatialSound | A sound object in 3D space |
| AmbientSound | A stereo overlay sound |
| AudioEngine | Manages sound objects inside a 3D scene |
| AudioInput | An audio input to be used for capturing audio in a capture session |
| AudioListener | Defines the position and orientation of the person listening to a sound field defined by a AudioEngine |
| AudioOutput | An audio output to be used for playback or monitoring of a capture session |
| AudioRoom | |
| CaptureSession | Allows capturing of audio and video content |
| MediaPlayer | Adds media playback to a scene |
| MediaRecorder | For encoding and recording media generated in a CaptureSession |
| SoundEffect | 提供在 QML 中播放音效方式的類型 |
| SpatialSound | A sound object in 3D space |
| audioDevice | Describes an audio device |
| mediaMetaData | Provides meta-data for media files |
| 音頻設備範例 | Testing the available audio devices and their configuration. |
| 音頻輸齣範例 | Enabling audio playback using the QAudioSink class. |
| 音頻錄製器範例 | Discovering the available devices and supported codecs. |
| Audio Source Example | Recording audio using the QAudioSource class. |
| Spatial Audio Panning Example | Shows some of the capabilities of the spatial audio engine in Qt |
