# Meeting SDK Sending Audio raw data

**URL:** <https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571>\
**Category:** Meeting SDK\
**Created:** [December 21, 2023, 5:29pm UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571 "2023-12-21T17:29:06Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![stutberidze](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/stutberidze/32/54774_2.png) [@stutberidze](https://devforum.zoom.us/u/stutberidze)\
**Post date:** [December 21, 2023, 5:29pm UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571/1 "2023-12-21T17:29:06Z")

</div>

Hello @chunsiong.zoom !

I’ve used your repositories as samples to write code for sending and receiving raw audio/video frames to the meeting room, however, the only part that is not working is the audio-sending part.

### I’ve written the ZoomSDKVirtualAudioMicEvent.h header file:

```cpp
#pragma once
#include <unistd.h>
#include <iostream>
#include <cstdint>
#include "rawdata/rawdata_audio_helper_interface.h"
#include "zoom_sdk.h"
#include "zoom_sdk_raw_data_def.h"

using namespace std;
using namespace ZOOMSDK;

class ZoomSDKVirtualAudioMicEvent :
	public IZoomSDKVirtualAudioMicEvent
{

private:
	IZoomSDKAudioRawDataSender* pSender_;

protected:

	/// \brief Callback for virtual audio mic to do some initialization.
/// \param pSender, You can send audio data based on this object, see \link IZoomSDKAudioRawDataSender \endlink.
	virtual void onMicInitialize(IZoomSDKAudioRawDataSender* pSender);

	/// \brief Callback for virtual audio mic can send raw data with 'pSender'.
	virtual void onMicStartSend();

	/// \brief Callback for virtual audio mic should stop send raw data.
	virtual void onMicStopSend();

	/// \brief Callback for virtual audio mic is uninitialized.
	virtual void onMicUninitialized();
};

```

### the ZoomSDKVirtualAudioMicEvent.cpp: (Which I copy-pasted from your code)

```cpp
#include <unistd.h>
#include <iostream>
#include <cstdint>
#include <fstream>
#include <cstring>
#include <cstdio>
#include <vector>

#include "rawdata/rawdata_audio_helper_interface.h"
#include "ZoomSDKVirtualAudioMicEvent.h"
#include "zoom_sdk_def.h" 

#include <thread>

using namespace std;
using namespace ZOOM_SDK_NAMESPACE;

int audio_play_flag = -1;

void PlayAudioFileToVirtualMic(IZoomSDKAudioRawDataSender* audio_sender, string audio_source)
{
	// execute in a thread.
	while (audio_play_flag > 0 && audio_sender) {

		// Check if the file exists
		ifstream file(audio_source, ios::binary | ios::ate);
		if (!file.is_open()) {
			std::cout << "Error: File not found. Tried to open " << audio_source << std::endl;
			return;
		}

		// Get the file size
		int file_size = file.tellg();

		// Read the file into a buffer
		vector<char> buffer(file_size);
		file.seekg(0, ios::beg);
		file.read(buffer.data(), file_size);

		// Send the audio data to the virtual camera
        std::cout << " ************ BEFORE SEND IS CALLED!";
		SDKError err = audio_sender->send(buffer.data(), buffer.size(), 44100);
        std::cout << " ***************************************************************";
		if (err != SDKERR_SUCCESS) {
			std::cout << "Error: Failed to send audio data to virtual camera. Error code: " << err << std::endl;
			return;
		}
		file.close();
		audio_play_flag = -1;
	}

}

/// \brief Callback for virtual audio mic to do some initialization.
/// \param pSender, You can send audio data based on this object, see \link IZoomSDKAudioRawDataSender \endlink.
void ZoomSDKVirtualAudioMicEvent::onMicInitialize(IZoomSDKAudioRawDataSender* pSender) {
	//pSender->send();
	pSender_ = pSender;
	printf("OnMicInitialize\n");
}

/// \brief Callback for virtual audio mic can send raw data with 'pSender'.
void ZoomSDKVirtualAudioMicEvent::onMicStartSend() {

	printf("onMicStartSend\n");

	std::cout << "onStartSend" << std::endl;
	if (pSender_ && audio_play_flag != 1) {
		while (audio_play_flag > -1) {}
		audio_play_flag = 1;
		std::string audio_source_ = "pcm1644m.wav";
		thread(PlayAudioFileToVirtualMic, pSender_, audio_source_).detach();
	}
}

/// \brief Callback for virtual audio mic should stop send raw data.
void ZoomSDKVirtualAudioMicEvent::onMicStopSend() {
	printf("onMicStopSend\n");

	audio_play_flag = 0;
}
/// \brief Callback for virtual audio mic is uninitialized.
void ZoomSDKVirtualAudioMicEvent::onMicUninitialized() {
	std::cout << "onUninitialized" << std::endl;
	pSender_ = nullptr;
}

```

and in the main.cpp file Besides all initialization I wrote the following:

```auto
void startSendRawAudio()
{
        ZoomSDKVirtualAudioMicEvent * send_audio_source = new ZoomSDKVirtualAudioMicEvent();
	IZoomSDKAudioRawDataHelper * send_audio_helper = GetAudioRawdataHelper();

	SDKError err = send_audio_helper->setExternalAudioSource(send_audio_source);
	
	if (err != SDKERR_SUCCESS)
	{
		std::cerr << "Error occured start send raw audio" << std::endl;
		return;
	}
	std::cout << "Success start send raw audio" << std::endl;
}

```

- this is just a single function which I invoke in onInMeeting() function; Everything works fine except the audio sending part. I wanna know what I am missing here.

When I join the boot to a meeting the audio is not sent and it is just so silent. (The bot is unmuted)

Would love if you help me to overcome this issue.

Big thanks to you \<3

---

<div class="post-metadata">

**Author:** ![chunsiong.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/chunsiong.zoom/32/35488_2.png) [@chunsiong.zoom](https://devforum.zoom.us/u/chunsiong.zoom)\
**Post date:** [December 22, 2023, 2:51am UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571/2 "2023-12-22T02:51:28Z")

</div>

@stutberidze there are 3 things to take note when sending raw audio.

1. You might need to call the method below, which unmutes the microphone

```auto
void turnOnSendVideoAndAudio() {
	//testing WIP
	if (SendVideoRawData) {
		IMeetingVideoController* meetingVidController = m_pMeetingService->GetMeetingVideoController();
		meetingVidController->UnmuteVideo();
	}
	//testing WIP
	if (SendAudioRawData) {
		IMeetingAudioController* meetingAudController = m_pMeetingService->GetMeetingAudioController();
		meetingAudController->JoinVoip();
		printf("Is my audio muted: %d\n", getMyself()->IsAudioMuted());
		meetingAudController->UnMuteAudio(getMyself()->GetUserID());
	}
}
void turnOffSendVideoandAudio() {
	//testing WIP
	if (SendVideoRawData) {
		IMeetingVideoController* meetingVidController = m_pMeetingService->GetMeetingVideoController();
		meetingVidController->MuteVideo();
	}
	//testing WIP
	if (SendAudioRawData) {
		IMeetingAudioController* meetingAudController = m_pMeetingService->GetMeetingAudioController();
		meetingAudController->MuteAudio(getMyself()->GetUserID(), true);

	}
}

```

1. There is noise suppression turned on for Meeting SDK, hence there is possibility some audio files might play “nothing” audible.

2. For the code above, you would need a PCM file with 16 bit signed, mono channel and little endian order. The frequency can be set when sending. In this case it is 44100hz in the sample code.

---

<div class="post-metadata">

**Author:** ![stutberidze](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/stutberidze/32/54774_2.png) [@stutberidze](https://devforum.zoom.us/u/stutberidze)\
**Post date:** [December 22, 2023, 9:03am UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571/3 "2023-12-22T09:03:59Z")

</div>

Well I saw that in your code and imported and called that function to turn on the mic, however, the problem is the virtualmicevent class’s onMicStartSend function is not been called.

---

<div class="post-metadata">

**Author:** ![stutberidze](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/stutberidze/32/54774_2.png) [@stutberidze](https://devforum.zoom.us/u/stutberidze)\
**Post date:** [December 22, 2023, 1:25pm UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571/4 "2023-12-22T13:25:48Z")

</div>

**Update: now it works but when calling the send function it results in segmentation fault**

Well Somehow I made it work and now it invokes the initialization and startSend functions, however, the problem now I am having is segmentation fault when calling the send function.

Here is the code below:

```cpp
int audio_play_flag = -1;
constexpr double PI = 3.14159265358979323846;

void generateSineWave(std::vector<char>& audioData, double frequency, double duration, int sampleRate) {
    const int numSamples = static_cast<int>(duration * sampleRate);
    for (int i = 0; i < numSamples; ++i) {
        double sample = std::sin(2.0 * PI * frequency * i / sampleRate);
        int16_t intSample = static_cast<int16_t>(sample * 32767); // Assuming 16-bit signed PCM

        audioData.push_back(intSample & 0xFF);
        audioData.push_back((intSample >> 8) & 0xFF);
    }
}

void PlayAudioToVirtualMic(IZoomSDKAudioRawDataSender* audio_sender, string audio_source)
{
	printf("PLAYAUDIOFILETOVIRTUALMIC invoked!");
	
    std::vector<char> audioData;
    generateSineWave(audioData, 444.0, 5.0, 44100);

// for (auto i : audioData)
// {
// std::cout << i << std::endl;
// }

    audio_sender->send(audioData.data(), audioData.size(), 44100);
}

```

### and this is where the thread is created to invoke the sending function:

```cpp
void ZoomSDKVirtualAudioMicEvent::onMicStartSend() 
{
	printf("onMicStartSend\n");
	std::cout << "onAudioStartSend" << std::endl;
	// if (pSender_ && audio_play_flag != 1) {
	// // while (audio_play_flag > -1) {}
	// // audio_play_flag = 1;
    thread(PlayAudioToVirtualMic, pSender_, audio_source_).detach();

	// }
}

```

---

<div class="post-metadata">

**Author:** ![stutberidze](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/stutberidze/32/54774_2.png) [@stutberidze](https://devforum.zoom.us/u/stutberidze)\
**Post date:** [December 22, 2023, 1:39pm UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571/5 "2023-12-22T13:39:00Z")

</div>

# Fix

I just have fixed it.

Needed to set the audio sender:

```cpp
void ZoomSDKVirtualAudioMicEvent::onMicInitialize(IZoomSDKAudioRawDataSender* pSender)
{
	printf("ZoomSDKVirtualAudioMicEvent OnMicInitialize, waiting for turnOn chat command\n");
    this->pSender_ = pSender; // Here this was missing
}

```

---

<div class="post-metadata">

**Author:** ![chunsiong.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/chunsiong.zoom/32/35488_2.png) [@chunsiong.zoom](https://devforum.zoom.us/u/chunsiong.zoom)\
**Post date:** [December 26, 2023, 3:43am UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571/6 "2023-12-26T03:43:31Z")

</div>

Glad to hear that @stutberidze

---

<div class="post-metadata">

**Author:** ![NAN1](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/nan1/32/53990_2.png) [@NAN1](https://devforum.zoom.us/u/NAN1)\
**Post date:** [March 18, 2025, 8:51am UTC](https://devforum.zoom.us/t/meeting-sdk-sending-audio-raw-data/100571/7 "2025-03-18T08:51:13Z")

</div>

hello, i have the same problem, ‘onMicStartSend function is not been called’, can i know what did you do to fix this, thx.