1.前言
我们在做eis算法集成的时候，preview流或者video流需要经过算法的异步处理，在hal1框架上实现就稍微有些难度，hal3或者camX相对要容易一些。
如何去优雅的实现异步回调数据呢？
- 异步：前面几帧，比如5帧video数据需要先给算法处理，当第6帧数据过来时，算法处理好第1帧返回给系统，以此类推。
- **同步：**一帧数据过来，算法处理完，直接返回给系统。
2.获取video数据的接口
hardware/qcom/camera/QCamera2/HAL/QCamera2HWICallbacks.cpp
void QCamera2HardwareInterface::video_stream_cb_routine(mm_camera_super_buf_t *super_frame,
QCameraStream *stream,
void *userdata)
{
//1.拿到 QCamera2HardwareInterface指针
QCamera2HardwareInterface *pme = (QCamera2HardwareInterface *)userdata;
//2.拿到视频帧
mm_camera_buf_def_t *frame = super_frame->bufs[0];
//3.视频帧的一些处理
if (frame->buf_type == CAM_STREAM_BUF_TYPE_MPLANE) {
if (pme->mParameters.getVideoBatchSize() == 0) {
//一定会跑到这里面
//计算视频帧的时间戳
timeStamp = nsecs_t(frame->ts.tv_sec) * 1000000000LL + frame->ts.tv_nsec;
pme->dumpFrameToFile(stream, frame, QCAMERA_DUMP_FRM_VIDEO);
videoMemObj = (QCameraVideoMemory *)frame->mem_info;
video_mem = NULL;
if (NULL != videoMemObj && !(pme->m_bNeedVideoCb)) {
video_mem = videoMemObj->getMemory(frame->buf_idx,
(pme->mStoreMetaDataInFrame > 0)? true : false);
triggerTCB = TRUE;
LOGH("Video frame TimeStamp : %lld batch = 0 idx = %d",
timeStamp, frame->frame_idx);
}
if (pme->m_bNeedVideoCb) {
video_mem = pme->videoMemFb->getMemory(frame->buf_idx,
(pme->mStoreMetaDataInFrame > 0)? true : false);
triggerTCB = TRUE;
}
}else{
···
}
}else{
···
}
//4.把数据传递给 视频编码器 处理
if ((NULL != video_mem) && (triggerTCB == TRUE)) {
if ((pme->mDataCbTimestamp != NULL) &&
pme->msgTypeEnabledWithLock(CAMERA_MSG_VIDEO_FRAME) > 0) {
qcamera_callback_argm_t cbArg;
memset(&cbArg, 0, sizeof(qcamera_callback_argm_t));
cbArg.cb_type = QCAMERA_DATA_TIMESTAMP_CALLBACK;
cbArg.msg_type = CAMERA_MSG_VIDEO_FRAME;
cbArg.data = video_mem;
// For VT usecase, ISP uses AVtimer not CLOCK_BOOTTIME as time source.
// So do not change video timestamp.
if (!pme->mParameters.isAVTimerEnabled()) {
// Convert Boottime from camera to Monotime for video if needed.
// Otherwise, mBootToMonoTimestampOffset value will be 0.
timeStamp = timeStamp - pme->mBootToMonoTimestampOffset;
}
LOGD("Final video buffer TimeStamp : %lld ", timeStamp);
cbArg.timestamp = timeStamp;
int32_t rc = pme->m_cbNotifier.notifyCallback(cbArg);
if (rc != NO_ERROR) {
LOGE("fail sending data notify");
stream->bufDone(frame->buf_idx);
}
}
}
if (!pme->mParameters.isVideoFaceBeautification()) {
free(super_frame);
}
}
函数作用：处理视频流中的视频帧
视频帧将被发送到视频编码器。一旦视频编码器完成了视频帧的处理，它将调用另一个API (release_recording_frame)来返回帧，需要注意释放super_frame。
3.异步回调的实现
想要优雅的实现异步回调，那就需要利用c++ 11的新特性，简直好用到哭！
这里我们编写一个简单的demo，完成异步回调的实现。
3.1 编写Demo类
3.1.1 DemoCamera.h
#ifndef DEMOCAMETA_H_
#define DEMOCAMETA_H_
#include <functional>
#include <queue>
#include <pthread.h>
#include "QCamera2HWI.h"
#include "QCameraStream.h"
//自定义命名空间
namespace democamera {
namespace hal1 {
//封装video数据
struct VideoData{
mm_camera_super_buf_t *super_frame;
qcamera::QCameraStream *stream;
qcamera::QCamera2HardwareInterface *pme;
std::function<void(int)> cbHandler;
};
//demo类
class DemoCamera{
public:
DemoCamera(int);//构造函数
virtual ~DemoCamera();//析构函数
//模拟算法数据处理
void processVideo(
mm_camera_super_buf_t *super_frame,
qcamera::QCameraStream *stream,
qcamera::QCamera2HardwareInterface *pme,
std::function<void(int)> cbHandler);
void callBack(void);
public:
int videoFrame_Size;//需要的video帧数
std::queue<VideoData> videoDataQ;//缓存video的队列
bool isStartVideo;//开始录制
bool isStopVideo;//停止录制
};
}
}
#endif
3.1.2 DemoCamera.cpp
#define LOG_TAG "DemoCamera"
#include "DemoCamera.h"
extern "C" {
#include "mm_camera_dbg.h"
}
using namespace qcamera;
namespace democamera {
namespace hal1 {
DemoCamera::DemoCamera(int size)
{
videoFrame_Size = size;//算法需要的video帧数量
isStartVideo = 0;//是否开始录制视频
isStopVideo = 0;//是否停止录制视频
LOGE("videoFrame_Size =%d ",videoFrame_Size );
}
DemoCamera::~DemoCamera()
{
video_Size = 0;//这里取释放一些资源
LOGE("video_Size=%d ",video_Size);
}
void DemoCamera::processVideo(mm_camera_super_buf_t *super_frame,QCameraStream *stream,
QCamera2HardwareInterface *pme,std::function<void(int)> cbHandler)
{
VideoData d;
d.super_frame = super_frame;
d.stream = stream;
d.pme = pme;
d.cbHandler = cbHandler;
videoDataQ.push(d);//把video的数据存储到队列里
//调用算法处理
//xxx算法处理视频帧
//调用回调函数
callBack();
}
void DemoCamera::callBack()
{
if(!videoDataQ.empty())
{
//如果开始录制了视频，并且收到的视频帧达到算法需要的帧数
if(isStartVideo && (videoFrame_Size == videoDataQ.size())){
VideoData d = videoDataQ.front();
mm_camera_buf_def_t *frame = d.super_frame->bufs[0];
LOGE("zcf_cb:call cbHandler！videoDataQ.size = %d frame->idx=%d ",videoDataQ.size(),frame->frame_idx);
std::function<void(int)> cbHandler = d.cbHandler;//拿出回调函数
cbHandler(0);//回调给系统
videoDataQ.pop();//将数据弹出队列
}
//停止录制时,回调所有数据
if(isStopVideo){
LOGE("zcf_cb:录像停止 吐出所有数据 ");
while(!videoDataQ.empty()){
VideoData d = videoDataQ.front();
mm_camera_buf_def_t *frame = d.super_frame->bufs[0];
LOGE("zcf_cb:call cbHandler！videoDataQ.size = %d frame->idx=%d ",videoDataQ.size(),frame->frame_idx);
std::function<void(int)> cbHandler = d.cbHandler;
cbHandler(0);
videoDataQ.pop();
}
}
}
}
}
}
3.2 DemoCamera加入编译
hardware/qcom/camera/QCamera2/Android.mk
-LOCAL_CFLAGS := -Wall -Wextra -Werror
+LOCAL_CFLAGS := -Wall -Wextra//防止 定义的变量不使用时会报错，
LOCAL_SRC_FILES += \
util/QCameraExtZoomTranslator.cpp \
util/QCameraPprocManager.cpp \
util/QCameraBokeh.cpp \
util/QCameraClearSight.cpp \
+ HAL/DemoCamera.cpp
3.3 初始化 DemoCamera
hardware/qcom/camera/QCamera2/HAL/QCamera2HWI.h
#include "QCameraTrace.h"
//前置声明DemoCamera类
+namespace democamera {
+namespace hal1 {
+ class DemoCamera;
+}
+}
namespace qcamera {
···
private:
//使用智能指针 防止内存泄漏
+ std::unique_ptr<xtccamera::hal1::DemoCamera> mDemoCamera;
camera_device_t mCameraDevice;
uint32_t mCameraId;
mm_camera_vtbl_t *mCameraHandle;
hardware/qcom/camera/QCamera2/HAL/QCamera2HWI.cpp
#include "QCameraTrace.h"
#include "QCameraDisplay.h"
+#include "DemoCamera.h"
int QCamera2HardwareInterface::start_recording(struct camera_device *device)
{
+ hw->mDemoCamera->isStartVideo = 1;
+ hw->mDemoCamera->isStopVideo = 0;
}
int QCamera2HardwareInterface::stop_recording(struct camera_device *device)
{
+ hw->mDemoCamera->isStartVideo = 0;
+ hw->mDemoCamera->isStopVideo = 1;
}
int QCamera2HardwareInterface::openCamera(struct hw_device_t **hw_device)
{
//初始化智能指针mDemoCamera
+ mDemoCamera.reset(new democamera::hal1::DemoCamera(5));//这里设置算法需要的帧数为5
// Init params in the background
// 1. It's safe to queue init job, even if alloc job is not yet complete.
// It will be queued to the same thread, so the alloc is guaranteed to
// finish first.
// 2. However, it is not safe to begin param init until after camera is
// open. That is why we wait until after camera open completes to schedule
// this task.
memset(&args, 0, sizeof(args));
mParamInitJob = queueDeferredWork(CMD_DEF_PARAM_INIT, args);
}
3.4 调用算法处理Video流
hardware/qcom/camera/QCamera2/HAL/QCamera2HWICallbacks.cpp
#include <stdlib.h>
+#include <functional>
···
+#include "DemoCamera.h"
void QCamera2HardwareInterface::video_stream_cb_routine(mm_camera_super_buf_t *super_frame,
QCameraStream *stream,
void *userdata)
{
···
//1.拿到 QCamera2HardwareInterface指针
QCamera2HardwareInterface *pme = (QCamera2HardwareInterface *)userdata;
//2.拿到视频帧
mm_camera_buf_def_t *frame = super_frame->bufs[0];
···
//打印帧信息
++ LOGE("zcf_c:Stream(%d), Timestamp: %ld %ld frame->idx=%d frame->buf_type=%d,getVideoBatchSize=%d",
frame->stream_id,
frame->ts.tv_sec,
frame->ts.tv_nsec,
frame->frame_idx,
frame->buf_type,
pme->mParameters.getVideoBatchSize());
//3.视频帧的一些处理
if (frame->buf_type == CAM_STREAM_BUF_TYPE_MPLANE) {
if (pme->mParameters.getVideoBatchSize() == 0) {
//这里使用lamda表达式封装callBackHandler，然后赋值给包装器std::function<void(int)>
++ std::function<void(int)> callBackHandler = [=](int result)mutable{
timeStamp = nsecs_t(frame->ts.tv_sec) * 1000000000LL
+ frame->ts.tv_nsec;
pme->dumpFrameToFile(stream, frame, QCAMERA_DUMP_FRM_VIDEO);
videoMemObj = (QCameraVideoMemory *)frame->mem_info;
video_mem = NULL;
if (NULL != videoMemObj && !(pme->m_bNeedVideoCb)) {
video_mem = videoMemObj->getMemory(frame->buf_idx,
(pme->mStoreMetaDataInFrame > 0)? true : false);
triggerTCB = TRUE;
LOGH("ideo frame TimeStamp : %lld batch = 0 idx = %d",
timeStamp, frame->frame_idx);
}
if (pme->m_bNeedVideoCb) {
video_mem = pme->videoMemFb->getMemory(frame->buf_idx,
(pme->mStoreMetaDataInFrame > 0)? true : false);
triggerTCB = TRUE;
}
//4.把数据传递给 视频编码器 处理，这个直接封装在callBackHandler里面
if (!result) {
/**
Code is copied from bottom of the outer function (QCamera2HardwareInterface::video_stream_cb_routine)
so the code will be executed here in this callback instead
*/
LOGE("zcf_cf: result =%d frame->idx=%d video_mem=%p triggerTCB=%d",
result,frame->frame_idx,video_mem,triggerTCB);
if ((NULL != video_mem) && (triggerTCB == TRUE)) {
if ((pme->mDataCbTimestamp != NULL) && pme->msgTypeEnabledWithLock(CAMERA_MSG_VIDEO_FRAME) > 0) {
qcamera_callback_argm_t cbArg;
memset(&cbArg, 0, sizeof(qcamera_callback_argm_t));
cbArg.cb_type = QCAMERA_DATA_TIMESTAMP_CALLBACK;
cbArg.msg_type = CAMERA_MSG_VIDEO_FRAME;
cbArg.data = video_mem;
// For VT usecase, ISP uses AVtimer not CLOCK_BOOTTIME as time source.
// So do not change video timestamp.
if (!pme->mParameters.isAVTimerEnabled()) {
// Convert Boottime from camera to Monotime for video if needed.
// Otherwise, mBootToMonoTimestampOffset value will be 0.
timeStamp = timeStamp - pme->mBootToMonoTimestampOffset;
}
LOGE("zcf_cf: Final video buffer TimeStamp : %lld frame->idx=%d", timeStamp,frame->frame_idx);
cbArg.timestamp = timeStamp;
int32_t rc = pme->m_cbNotifier.notifyCallback(cbArg);
if (rc != NO_ERROR) {
LOGE("fail sending data notify");
stream->bufDone(frame->buf_idx);
}
}
}
}
free(super_frame);//释放资源
};
pme->mXTCCamera->processVideo(super_frame,stream,pme,callBackHandler);
return;//这里return掉 不去调用步骤4 把数据传递给 视频编码器 处理
}
}
3.5 编译运行
- mmm hardware/qcom/camera/QCamera2/
在out/···/vendor/lib/下会生成camera.msm8937.so - adb push camera.msm8937.so vendor/lib
- 重启验证 或者杀掉camera provider
log如下：
从log中可以看到，前面累计的5帧数据都没有直接回调给系统，而是等算法处理后，第3帧数据才回调给系统。
3.6 问题：最后几帧没有正确回调
//步骤4：把数据传递给 视频编码器 处理
if ((NULL != video_mem) && (triggerTCB == TRUE)) {
if ((pme->mDataCbTimestamp != NULL) && pme->msgTypeEnabledWithLock(CAMERA_MSG_VIDEO_FRAME) > 0) {
···
}
}
添加log 重新编译分析：
最后几帧数据
pme->msgTypeEnabledWithLock(CAMERA_MSG_VIDEO_FRAME) =0
因此没有正确回调
解决办法
最简单的办法就是去掉判断pme->msgTypeEnabledWithLock(CAMERA_MSG_VIDEO_FRAME) > 0
可以看到log正常回调了。
当然这种解法不一定是最好的，毕竟修改了系统原有的逻辑。
那么还有更好的解决方案吗？
- Stay hungry，Stay foolish！