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Data Definition

The output data structure of the AO module consists of the extra stream packet information (extData), packet size, and actual data. The data is specified by the AUDIO_RETURN_AUDIO_PLAY_DATA command word in the VmiCmd enumeration and returned to developers through callbacks.

Example:

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VmiDataType module = DATA_AUDIO;
VmiCmd cmd = AUDIO_RETURN_AUDIO_PLAY_DATA;
uint8_t audioPlayData[240];
AudioData audioData;
audioData.size = sizeof(audioPlayData);
uint8_t *data = new uint8_t[sizeof(AudioData) + sizeof(audioPlayData)];
memcpy(data, &audioData, sizeof(AudioData));
memcpy(data + sizeof(AudioData), audioPlayData, sizeof(audioPlayData))
DataCallback(module, cmd, data, sizeof(AudioData) + audioData.size);

Definition of AudioData

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struct AudioData {
    ExtDataAudio extData;               // Extra information
    uint32_t size;                      // Size
    uint8_t data[0];                    // Data
} __attribute__((packed));

Definition of ExtDataAudio

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struct ExtDataAudio {
    uint32_t audioType = OPUS;              // Encoding type: OPUS/PCM
    uint8_t channels = 2;                   // Number of audio channels. 1: MONO/2: STEREO (default)
    uint8_t audioBitDepth = 16;             // Sampling depth in bits: 8 or 16 (default)
    uint32_t sampleRate = 48000;            // Sampling rate in Hz: 48000 (default)
    uint32_t sampleInterval = 10;           // Sampling interval in ms: 10 (default)
    int64_t timestamp;                      // Audio data timestamp in ms (UTC time)
} __attribute__((packed));

Definition of AudioVolume

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struct AudioVolume {
    uint32_t leftVolume = 100;                  // Volume of the left channel
    uint32_t rightVolume = 100;                 // Volume of the right channel
} __attribute__((packed));
Parent topic: Audio Output Development