HarmonyOS 鸿蒙Next：基于Camera Kit，获取相机流数据传递给native，进行压缩编码

示例场景：ATS侧启动相机，使用摄像头采集视频流数据，获取相机视频流数据传递到native侧，通过buffer模式将视频编码成MP4文件保存到沙箱路径。

方案描述：具体实现步骤可分为：

Step1：申请权限，启动相机。

Step2: 启动录制，获取视频流数据，获取一帧图像转成JPG格式保存到沙箱路径。

Step3: 视频流数据传递到native侧，进行压缩编码，生成文件保存。

步骤一: 申请权限，启动相机。需要相机、麦克风、媒体位置、写入媒体和读取媒体权限。

“requestPermissions”: [

{
“name”: “ohos.permission.CAMERA”,
“reason”: “$string:app_name”,
“usedScene”: {
“abilities”: [
“FormAbility”
],
“when”: “always”
}
},
{
“name”: “ohos.permission.MICROPHONE”,
“reason”: “$string:app_name”,
“usedScene”: {
“abilities”: [
“FormAbility”
],
“when”: “always”
}
},
{
“name”: “ohos.permission.MEDIA_LOCATION”,
“reason”: “$string:app_name”,
“usedScene”: {
“abilities”: [
“FormAbility”
],
“when”: “always”
}
},
{
“name”: “ohos.permission.WRITE_MEDIA”,
“reason”: “$string:app_name”,
“usedScene”: {
“abilities”: [
“FormAbility”
],
“when”: “always”
}
},
{
“name”: “ohos.permission.READ_MEDIA”,
“reason”: “$string:app_name”,
“usedScene”: {
“abilities”: [
“FormAbility”
],
“when”: “always”
}
}
]<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

2：启动相机，预览实现。导入camera接口，创建双路预览流通道，使用XComponent组件和ImageReceiver组件创建Surface用来显示和获取预览图像。

async function createDualChannelPreview(cameraManager: camera.CameraManager, XComponentSurfaceId: string, receiver: image.ImageReceiver): Promise<void> {

// 获取支持的相机设备对象
let camerasDevices: Array<camera.CameraDevice> = cameraManager.getSupportedCameras();
// 获取支持的模式类型
let sceneModes: Array<camera.SceneMode> = cameraManager.getSupportedSceneModes(camerasDevices[0]);
let isSupportPhotoMode: boolean = sceneModes.indexOf(camera.SceneMode.NORMAL_PHOTO) >= 0;
if (!isSupportPhotoMode) {
console.error(‘photo mode not support’);
return;
}
// 获取profile对象
let profiles: camera.CameraOutputCapability = cameraManager.getSupportedOutputCapability(camerasDevices[0], camera.SceneMode.NORMAL_PHOTO); // 获取对应相机设备profiles
let previewProfiles: Array<camera.Profile> = profiles.previewProfiles;
// 预览流1
let previewProfilesObj: camera.Profile = previewProfiles[0];
// 预览流2
let previewProfilesObj2: camera.Profile = previewProfiles[0];
// 创建 预览流1 输出对象
let previewOutput: camera.PreviewOutput = cameraManager.createPreviewOutput(previewProfilesObj, XComponentSurfaceId);
// 创建 预览流2 输出对象
let imageReceiverSurfaceId: string = await receiver.getReceivingSurfaceId();
let previewOutput2: camera.PreviewOutput = cameraManager.createPreviewOutput(previewProfilesObj2, imageReceiverSurfaceId);
// 创建cameraInput对象
let cameraInput: camera.CameraInput = cameraManager.createCameraInput(camerasDevices[0]);
// 打开相机
await cameraInput.open();
// 会话流程
let photoSession: camera.CaptureSession = cameraManager.createCaptureSession();
// 开始配置会话
photoSession.beginConfig();
// 把CameraInput加入到会话
photoSession.addInput(cameraInput);
// 把 预览流1 加入到会话
photoSession.addOutput(previewOutput);
// 把 预览流2 加入到会话
photoSession.addOutput(previewOutput2);
// 提交配置信息
await photoSession.commitConfig();
// 会话开始
await photoSession.start();
}
步骤二：启动录制，获取相机视频流数据。
1：生成相机视频流数据：视频流数据是通过在onPageShow里面启动本地录制生成，当页面显示时，会调用 startRecord()方法开始录制，在页面隐藏时，调用 stopRecorder()函数停止录制视频，并释放相机资源。
async onPageShow() {
this.startRecord();
await grantPermission().then(res => {
console.info(TAG, 权限申请成功 ${<span class="hljs-built_in"><span class="hljs-built_in">JSON</span></span>.stringify(res)});
if (res) {
createDualChannelPreview(this.surfaceId, this.receiver);
}
})
}
private startRecord() {
videoCompressor.startRecorder(getContext(), cameraWidth, cameraHeight)
.then((data) => {
if (data.code == CompressorResponseCode.SUCCESS) {
Logger.debug(“videoCompressor-- record success”);
} else {
Logger.debug(“videoCompressor code:” + data.code + “–error message:” + data.message);
}
}).catch((err: Error) => {
Logger.debug(“videoCompressor error message” + err.message);
});
}
onPageHide() {
videoCompressor.stopRecorder(); // 测试停止录制
Logger.debug(“onPageHide-- stopRecorder”);
releaseCamera()
}
2: 获取相机视频流数据通过imageReceiver获取相机流数据，Videocompressor.pushoneframedata(buffer) 接收buffer数据。
function createImageReceiver(): image.ImageReceiver {
let receiver: image.ImageReceiver = image.createImageReceiver(cameraWidth, cameraHeight, 4, 8);
receiver.on(‘imageArrival’, () => {
receiver.readNextImage((err: BusinessError, nextImage: image.Image) => {
if (err || nextImage === undefined) {
Logger.error(“receiveImage -error:” + err + " nextImage:" + nextImage);
return;
}
nextImage.getComponent(image.ComponentType.JPEG, (err: BusinessError, imgComponent: image.Component) => {
if (err || imgComponent === undefined) {
Logger.error(“receiveImage–getComponent -error:” + err + " imgComponent:" + imgComponent);
return;
}
if (imgComponent.byteBuffer as ArrayBuffer) {
let buffer = imgComponent.byteBuffer;
Logger.debug(“receiveImage–byteBuffer -success:” + " buffer:" + buffer);
recordedFrameCount++;
videoCompressor.pushOneFrameData(buffer)
Logger.debug(“receiveImage-- record >>pushOneFrameData with no.” + recordedFrameCount + " frame");
nextImage.release()
} else {
Logger.debug(“receiveImage–byteBuffer -error:” + " imgComponent.byteBuffer:" + imgComponent.byteBuffer);
return;
}
});
});
});
return receiver;
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3：再此基础上获取一帧图像转成JPG格式保存到沙箱路径。

获取图像数据，使用imagePackerApi接口将图像数据打包成JPG格式。

nextImage.getComponent(image.ComponentType.JPEG, async (err, imgComponent: image.Component) => {

if (err || imgComponent === undefined) {
return;
}
if (imgComponent.byteBuffer as ArrayBuffer) {
let sourceOptions: image.SourceOptions = {
sourceDensity: 120,
sourcePixelFormat: 8, // NV21
sourceSize: {
height: this.previewProfilesObj2!.size.height,
width: this.previewProfilesObj2!.size.width
},
}
let imageResource = image.createImageSource(imgComponent.byteBuffer, sourceOptions);
let imagePackerApi = image.createImagePacker();
let packOpts: image.PackingOption = { format: “image/jpeg”, quality: 98 };
const filePath: string = getContext().cacheDir + “/image.jpg”;
let file = fs.openSync(filePath, fs.OpenMode.CREATE | fs.OpenMode.READ_WRITE);
imagePackerApi.packToFile(imageResource, file.fd, packOpts).then(() => {
console.error('pack success: ’ + filePath);
}).catch((error: BusinessError) => {
console.error('Failed to pack the image. And the error is: ’ + error);
})
imageResource.createPixelMap({}).then((res)=>{
this.imgUrl = res;
});
} else {
return;
}
nextImage.release();
})<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

步骤三：视频流数据传递到native侧，进行压缩编码。

1：native侧和JS侧交互实现，创建一个VideoCompressor类实例绑定到JS对象中。

napi_value VideoCompressor::JsConstructor(napi_env env, napi_callback_info info) {

napi_value targetObj = nullptr;
void *data = nullptr;
size_t argsNum = 0;
napi_value args[2] = {nullptr};
napi_get_cb_info(env, info, &argsNum, args, &targetObj, &data);
auto classBind = std::make_unique<VideoCompressor>();
napi_wrap(
env, nullptr, classBind.get(),
[](napi_env env, void *data, void *hint) {
VideoCompressor *bind = (VideoCompressor *)data;
delete bind;
bind = nullptr;
},
nullptr, nullptr);
return targetObj;
}
Videocompressor在JS侧自定义封装的对象，里面包含启动本地录制方法。
declare class VideoCompressor {
startRecordNative: (
outputFileFd: number,
width:number,
height:number,
outPutFilePath: string,
) => Promise<CompressorResponse>;
pushOneFrameDataNative: (
byteBuffer: ArrayBuffer
)=> Promise<CompressorResponse>;
stopRecordNative: (
)=> Promise<CompressorResponse>;
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

native侧自定义封装一个视频录制管理器类，包含启动本地录制方法。

class VideoRecordManager {

bool videoRecorderIsReady = false;
int32_t CreateVideoEncode();
int32_t CreateMutex();
void VideoCompressorWaitEos();
void NativeRecordStart(); // 启动本地录制
void SetCallBackResult(int32_t code, std::string str);
void Release();
public:
std::unique_ptr<VideoRecordBean> videoRecordBean_;
static VideoRecordManager &getInstance() {
static VideoRecordManager instance;
return instance;
}
void startRecord(); // 开始录制
void pushOneFrameData(void *data); // 推送一帧视频数据
void stopRecord(); // 停止录制视频
};<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

2：接收JS侧数据。

napi_value VideoCompressor::pushOneFrameDataNative(napi_env env,napi_callback_info info) {

// 从js中获取传递的参数
napi_value args[1] = {nullptr};
size_t argc = 1;
napi_get_cb_info(env, info, &argc, args, nullptr, nullptr);
void *arrayBufferPtr = nullptr;
size_t arrayBufferSize = 0;
napi_get_arraybuffer_info(env, args[0], &arrayBufferPtr, &arrayBufferSize); // 获取到输入的帧数据
auto &videoRecorder = VideoRecordManager::getInstance();
videoRecorder.pushOneFrameData(arrayBufferPtr);
return 0;
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

成功推送一帧视频数据后，pushOneFrameData函数会将一帧数据推送到编码器中进行编码。

void VideoRecordManager::pushOneFrameData(void *data){

// 判断是否已经可以推数据了（编码器是否准备好了）
if (!videoRecorderIsReady) {
OH_LOG_ERROR(LOG_APP, “videoRecorderIsNotReady”);
return;
}
videoRecordBean_->vEncSample->get()->pushFrameData(data);
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3：编码使用的是buffer模式，编码过程分为创建编码器实例对象 --> 设置编码器回调函数 --> 启动编码器，开始编码 --> 写入编码码流 -->将数据推入编码器的输入队列中进行编码 --> 编码完成通知编码器码流结束 --> 输出编码帧 --> 销毁编码器实例，释放资源。

3.1： 创建编码器实例对象，创建回调函数。

static void VencError(OH_AVCodec *codec, int32_t errorCode, void *userData) {

OH_LOG_ERROR(LOG_APP, “VideoEnc - VencError:%d”, errorCode);
}
static void VencFormatChanged(OH_AVCodec *codec, OH_AVFormat *format, void *userData) {
OH_LOG_ERROR(LOG_APP, “VideoEnc - VencFormatChanged”);
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3.2 设置回调函数SetVideoEncoderCallback，可以通过处理该回调报告的信息，确保编码器正常运转。

int32_t VideoEnc::SetVideoEncoderCallback() {

signal_ = make_unique<VEncSignal>();
if (signal_ == nullptr) {
OH_LOG_ERROR(LOG_APP, “Failed to new VencSignal”);
return AV_ERR_UNKNOWN;
}
signal_->arrayBufferSize = width * height * 3 / 2;
signal_->stopInput.store(false);
cb_.onError = VencError;
cb_.onStreamChanged = VencFormatChanged;
cb_.onNeedOutputData = VencOutputDataReady;
cb_.onNeedInputData = VencNeedInputData;
return OH_VideoEncoder_SetCallback(venc_, cb_, static_cast<void *>(signal_.get()));
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3.3：编码器就绪，开始编码。

int32_t VideoEnc::StartVideoEncoder() {

outputIsRunning_.store(true);
// 启动编码器，开始编码
int ret = OH_VideoEncoder_Start(venc_);
if (ret != AV_ERR_OK) {
OH_LOG_ERROR(LOG_APP, “Failed to start video codec”);
outputIsRunning_.store(false);
signal_->outCond_.notify_all();
Release();
return ret;
}
outputLoop_ = make_unique<thread>(&VideoEnc::OutputFunc, this);
if (outputLoop_ == nullptr) {
OH_LOG_ERROR(LOG_APP, “Failed to cteate output video outputLoop”);
outputIsRunning_.store(false);
Release();
return AV_ERR_UNKNOWN;
}
return AV_ERR_OK;
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3.4：写入编码码流。

void VideoEnc::pushFrameData(void *arrayBufferPtr) {

unique_lock<mutex> lock(signal_->inputMutex_);
if (signal_->stopInput)
return;
size_t dataSize = signal_->arrayBufferSize; // nv21的图像数据
void *copyBuffer = std::malloc(dataSize);
if (copyBuffer == nullptr) {
OH_LOG_ERROR(LOG_APP, “pushFrameData: failed with malloc error”);
return;
}
OH_LOG_ERROR(LOG_APP, “VideoEnc -pushFrameData --start”);
std::memcpy(copyBuffer, arrayBufferPtr, dataSize);
// 将 copyBuffer 添加到队列中
signal_.get()->inputBufferQueue_.push(copyBuffer);
OH_LOG_ERROR(LOG_APP, “VideoEnc -pushFrameData:%{public}zu”, signal_.get()->arrayBufferSize);
signal_->inputCond_.notify_one();
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3.5 将数据推入编码器的输入队列中进行编码。

static void VencNeedInputData(OH_AVCodec *codec, uint32_t index, OH_AVMemory *data, void *userData) {

VEncSignal *signal = static_cast<VEncSignal *>(userData);
unique_lock<mutex> lock(signal->inputMutex_);
signal->inputCond_.wait(lock, [&signal] { return !signal->inputBufferQueue_.empty() || signal->stopInput; });
OH_LOG_ERROR(LOG_APP, “VideoEnc -VencNeedInputData inputBufferQueue_ has data :%{public}zu”,
signal->arrayBufferSize);
auto now = std::chrono::system_clock::now();
auto timestamp = std::chrono::duration_cast<std::chrono::nanoseconds>(now.time_since_epoch()).count() / 1000;
// 配置buffer info信息
OH_AVCodecBufferAttr attr;
attr.size = 0;
attr.offset = 0;
attr.pts = 1000000 / 24 * num;
num++;
// attr.pts =timestamp;
if (signal->stopInput) {
attr.flags = AVCODEC_BUFFER_FLAGS_EOS;
/**

写入编码码流

*/
int32_t ret = OH_VideoEncoder_PushInputData(codec, index, attr);
if (ret != AV_ERR_OK) {
OH_LOG_ERROR(LOG_APP, “Failed to OH_VideoEncoder_PushInputData”);
}
OH_LOG_ERROR(LOG_APP, “StopInput --VencNeedInputData >>PushInputData-EOS”);
return;
}
if (signal->inputBufferQueue_.empty()) {
return;
}
attr.size = signal->arrayBufferSize;
attr.flags = AVCODEC_BUFFER_FLAGS_CODEC_DATA;
auto &arrayBuffer = signal->inputBufferQueue_.front();
// 输入帧buffer对应的index，送入InIndexQueue队列
// 输入帧的数据mem送入InBufferQueue队列
OH_LOG_ERROR(LOG_APP, “VideoEnc -VencNeedInputData --before memcpy”);
uint8_t *dataAddr = OH_AVMemory_GetAddr(data);
int32_t dataSize = OH_AVMemory_GetSize(data);
OH_LOG_ERROR(LOG_APP, “VideoEnc -VencNeedInputData data size :%{public}zu”, dataSize);
OH_LOG_ERROR(LOG_APP, “VideoEnc -arrayBuffer data size :%{public}zu”, signal->arrayBufferSize);
std::memcpy(dataAddr, arrayBuffer, signal->arrayBufferSize);
OH_LOG_ERROR(LOG_APP, “VideoEnc -VencNeedInputData --after memcpy”);
// 送入编码输入队列进行编码，index为对应输入队列的下标
int32_t ret = OH_VideoEncoder_PushInputData(codec, index, attr);
OH_LOG_ERROR(LOG_APP, “VencNeedInputData OH_VideoEncoder_PushInputData”);
if (ret != AV_ERR_OK) {
OH_LOG_ERROR(LOG_APP, “Failed to OH_VideoEncoder_PushInputData”);
}
signal->inputBufferQueue_.pop();
std::free(arrayBuffer); // 释放内存
};<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3.6：编码完成通知编码器码流结束。

if (signal->stopInput) {

attr.flags = AVCODEC_BUFFER_FLAGS_EOS;
int32_t ret = OH_VideoEncoder_PushInputData(codec, index, attr);
if (ret != AV_ERR_OK) {
OH_LOG_ERROR(LOG_APP, “Failed to OH_VideoEncoder_PushInputData”);
}
OH_LOG_ERROR(LOG_APP, “StopInput --VencNeedInputData >>PushInputData-EOS”);
return;
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3.7：输出编码帧，拿到编码后的数据。

void VideoEnc::OutputFunc() {

uint32_t errCount = 0;
int64_t enCount = 0;
while (true) {
if (!outputIsRunning_.load()) {
break;
}
unique_lock<mutex> lock(signal_->outMutex_);
signal_->outCond_.wait(lock,
this { return (signal_->outIdxQueue_.size() > 0 || !outputIsRunning_.load()); });
if (!outputIsRunning_.load()) {
break;
}
uint32_t index = signal_->outIdxQueue_.front();
OH_AVCodecBufferAttr attr = signal_->outputAttrQueue.front();
if (attr.flags == AVCODEC_BUFFER_FLAGS_EOS) {
outputIsRunning_.store(false);
signal_->outCond_.notify_all();
OH_LOG_ERROR(LOG_APP, “StopInput --OutputFunc ENCODE EOS %{public}lld”, enCount);
break;
}
OH_AVMemory *buffer = signal_->outBufferQueue_.front();
if (OH_AVMuxer_WriteSample(muxer->muxer, muxer->vTrackId, buffer, attr) != AV_ERR_OK) {
OH_LOG_ERROR(LOG_APP, “input video track data failed”);
}
if (OH_VideoEncoder_FreeOutputData(venc_, index) != AV_ERR_OK) {
OH_LOG_ERROR(LOG_APP, “videoEncode FreeOutputDat error”);
errCount = errCount + 1;
}
if (errCount > 0) {
OH_LOG_ERROR(LOG_APP, “videoEncode errCount > 0”);
outputIsRunning_.store(false);
signal_->outCond_.notify_all();
Release();
break;
}
signal_->outIdxQueue_.pop();
signal_->outputAttrQueue.pop();
signal_->outBufferQueue_.pop();
enCount++;
}
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

3.8：数据写入到输出文件中保存。

startRecorder(context: Context, width: number, height: number): Promise<CompressorResponse> {

try {
let date = new Date();
this.outPutFilePath = context.filesDir + “/” + date.getTime() + “.mp4”; //创建输出文件
let outputFile = fs.openSync(this.outPutFilePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
if (!outputFile) {
console.info(“videoCompressor outputFile create error”);
return new Promise((resolve, reject) => {
fs.unlink(this.outPutFilePath);
reject(new Error(“videoCompressor outputFile create error”));
});
}
return this.object.startRecordNative(outputFile.fd, width, height, this.outPutFilePath)
} catch (err) {
return new Promise((resolve, reject) => {
fs.unlink(this.outPutFilePath);
reject(err);
});
}
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>