RK3568 android11 移植 v4l2loopback 虚拟摄像头-Toy模板网

这篇具有很好参考价值的文章主要介绍了RK3568 android11 移植 v4l2loopback 虚拟摄像头。希望对大家有所帮助。如果存在错误或未考虑完全的地方，请大家不吝赐教，您也可以点击"举报违法"按钮提交疑问。

一，v4l2loopback 简介

v4l2loopback是一个Linux内核模块，它允许用户创建虚拟视频设备。这种虚拟视频设备可以用于各种用途，例如将实际摄像头的视频流复制到虚拟设备上，或者用于视频流的处理和分析等。v4l2loopback的主要作用是创建一个虚拟的Video4Linux2设备，它可以接收来自其他应用程序的视频数据，并将这些数据提供给其他应用程序。
一旦加载了v4l2loopback模块，就可以在/dev目录下找到虚拟设备文件，通常命名为/dev/videoX（X是一个数字）。

二，驱动文件配置

1. v4l2loopback 内核模块驱动文件

RK3568 android11 移植 v4l2loopback 虚拟摄像头,RockChip平台调试记录,android,rk3568,音视频,虚拟摄像头,v4l2loopback

1> v4l2loopback.c： v4l2loopback 内核模块的 C 语言源代码文件。它包含了实现 v4l2loopback 模块功能的代码。
2> v4l2loopback.h： v4l2loopback 内核模块的头文件，通常包含一些宏定义、结构体定义、函数声明等。
3> v4l2loopback_formats.h：这个文件包含了有关视频格式的定义和处理，用于支持 v4l2loopback 模块对不同视频格式的处理和转换。

2. 移植 v4l2loopback驱动

a. 将驱动(v4l2loopback)拷贝到下面的文件夹：

./kernel/drivers/v4l2loopback

b. 在 Makefile 中添加 v4l2loopback设备

kernel/drivers/Makefile中添加：
+obj-y                           +=v4l2loopback/

c. 编译kernel后会在目录下生成对应的.o文件

~/RK3568_Android11/kernel/drivers/v4l2loopback$ ls
built-in.a  Makefile  modules.builtin  modules.order  v4l2loopback.c  v4l2loopback_formats.h  v4l2loopback.h  v4l2loopback.o

d. 验证 v4l2loopback.ko 模块是否加载成功
RK3568 android11 移植 v4l2loopback 虚拟摄像头,RockChip平台调试记录,android,rk3568,音视频,虚拟摄像头,v4l2loopback
设备 video9 就是 v4l2loopback.ko 模块驱动的设备,确认v4l2loopback.ko 模块移植成功。

三，hardware下整合v4l2loopback 虚拟摄像头设备

源码目录：hardware/interfaces/camera/
修改补丁如下：

diff --git a/camera/device/3.4/default/ExternalCameraDevice.cpp b/camera/device/3.4/default/ExternalCameraDevice.cpp
index ec3264894..c2a1f4156 100755
--- a/camera/device/3.4/default/ExternalCameraDevice.cpp
+++ b/camera/device/3.4/default/ExternalCameraDevice.cpp
@@ -22,6 +22,8 @@
 #include <array>
 #include <regex>
 #include <linux/videodev2.h>
+#include <linux/v4l2-subdev.h>
+#include <linux/videodev2.h>
 #include "android-base/macros.h"
 #include "CameraMetadata.h"
 #include "../../3.2/default/include/convert.h"
@@ -373,6 +395,7 @@ status_t ExternalCameraDevice::initDefaultCharsKeys(
     UPDATE(ANDROID_LENS_INFO_AVAILABLE_OPTICAL_STABILIZATION,
            &opticalStabilizationMode, 1);
 
+    ALOGD("=========mCameraId.c_str():%s ANDROID_LENS_FACING_EXTERNAL:%d========", mCameraId.c_str(), ANDROID_LENS_FACING_EXTERNAL);
     const uint8_t facing = ANDROID_LENS_FACING_EXTERNAL;
     UPDATE(ANDROID_LENS_FACING, &facing, 1);
 
@@ -831,6 +854,16 @@ void ExternalCameraDevice::getFrameRateList(
         }
     }
 
+    struct v4l2_capability capability_v4l2;
+    int ret_query_v4l2 = ioctl(fd, VIDIOC_QUERYCAP, &capability_v4l2);
+    if (ret_query_v4l2 < 0) {
+        ALOGE("%s v4l2 QUERYCAP %s failed: %s", __FUNCTION__, strerror(errno));
+    }
+    if(strstr((const char*)capability_v4l2.driver,"v4l2")){
+        LOGD("======%s: capability_v4l2.driver:%s ========", __func__, capability_v4l2.driver);
+        SupportedV4L2Format::FrameRate fr = {1,30}; //特定帧率（1帧每秒到30帧每秒）添加到 format->frameRates 向量中
+        format->frameRates.push_back(fr);
+    }
     if (format->frameRates.empty()) {
         ALOGE("%s: failed to get supported frame rates for format:%c%c%c%c w %d h %d",
                 __FUNCTION__,
@@ -917,6 +950,12 @@ std::vector<SupportedV4L2Format> ExternalCameraDevice::getCandidateSupportedForm
     int ret = 0;
     while (ret == 0) {
         ret = TEMP_FAILURE_RETRY(ioctl(fd, VIDIOC_ENUM_FMT, &fmtdesc));
+        if(ret < 0 && strstr((const char*)capability.driver, "v4l2")) {
+            ALOGE("driver.find :%s",capability.driver);
+            fmtdesc.pixelformat = V4L2_PIX_FMT_NV12; 
+			ret = 0;
+        }
         ALOGV("index:%d,ret:%d, format:%c%c%c%c", fmtdesc.index, ret,
                 fmtdesc.pixelformat & 0xFF,
                 (fmtdesc.pixelformat >> 8) & 0xFF,
@@ -963,6 +1002,39 @@ std::vector<SupportedV4L2Format> ExternalCameraDevice::getCandidateSupportedForm
                     }
                 }
             }
+            if(strstr((const char*)capability.driver, "v4l2")) {
+					ALOGD("driver.find :%s",capability.driver);
+					SupportedV4L2Format format_1920x1080 {
+                            .width = 1920,
+                            .height = 1080,
+                            .fourcc = V4L2_PIX_FMT_NV12
+                        };
+					updateFpsBounds(fd, cropType, fpsLimits, format_1920x1080, outFmts);//名为 updateFpsBounds 的函数，向其传递了一些参数，包括文件描述符 fd、crop 类型、帧率限制、format_1920x1080 结构和 outFmts
+					ret = -1;
+                }
         }
         fmtdesc.index++;
     }
diff --git a/camera/device/3.4/default/ExternalCameraDeviceSession.cpp b/camera/device/3.4/default/ExternalCameraDeviceSession.cpp
index e2ab4fa2f..664d7d262 100644
--- a/camera/device/3.4/default/ExternalCameraDeviceSession.cpp
+++ b/camera/device/3.4/default/ExternalCameraDeviceSession.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 #define LOG_TAG "ExtCamDevSsn@3.4"
-//#define LOG_NDEBUG 0
+#define LOG_NDEBUG 0
 #define ATRACE_TAG ATRACE_TAG_CAMERA
 #include <log/log.h>
 
@@ -3104,7 +3104,18 @@ int ExternalCameraDeviceSession::configureV4l2StreamLocked(
             ALOGE("%s: QUERYBUF %d failed: %s", __FUNCTION__, i,  strerror(errno));
             return -errno;
         }
+//fy
+        ALOGD("==========mV4L2Buffer[%d] = (char*)mmap()==========", i);
+        if (buffer.memory == V4L2_MEMORY_MMAP) {
+            mV4L2Buffer[i] = (char*)mmap(0 /* start anywhere */ ,
+                        buffer.length, PROT_READ, MAP_SHARED, mV4l2Fd.get(),
+                        buffer.m.offset);
+            if (mV4L2Buffer[i] == MAP_FAILED) {
+                LOGE("%s(%d): Unable to map buffer(length:0x%x offset:0x%x) %s(err:%d)\n",__FUNCTION__,__LINE__, buffer.length,buffer.m.offset,strerror(errno),errno);
+            }
 
+        }
+        V4l2BufferLen = buffer.length;
         if (TEMP_FAILURE_RETRY(ioctl(mV4l2Fd.get(), VIDIOC_QBUF, &buffer)) < 0) {
             ALOGE("%s: QBUF %d failed: %s", __FUNCTION__, i,  strerror(errno));
             return -errno;
@@ -3401,8 +3412,10 @@ Status ExternalCameraDeviceSession::configureStreams(
         }
     }
     // Find the smallest format that matches the desired aspect ratio and is wide/high enough
-    SupportedV4L2Format v4l2Fmt {.width = 0, .height = 0};
-    SupportedV4L2Format v4l2Fmt_tmp {.width = 0, .height = 0};
+//    SupportedV4L2Format v4l2Fmt {.width = 0, .height = 0};
+//    SupportedV4L2Format v4l2Fmt_tmp {.width = 0, .height = 0};
+//初始化宽度为 1920，高度为 1088，fourcc 值为 V4L2_PIX_FMT_NV12;
+    SupportedV4L2Format v4l2Fmt {.width = 1920, .height = 1088, .fourcc = V4L2_PIX_FMT_NV12};
+    SupportedV4L2Format v4l2Fmt_tmp {.width = 1920, .height = 1088, .fourcc = V4L2_PIX_FMT_NV12};
     for (const auto& fmt : mSupportedFormats) {
         uint32_t dim = (mCroppingType == VERTICAL) ? fmt.width : fmt.height;
         if (dim >= maxDim) {
diff --git a/camera/device/3.4/default/include/ext_device_v3_4_impl/ExternalCameraDeviceSession_3.4.h b/camera/device/3.4/default/include/ext_device_v3_4_impl/ExternalCameraDeviceSession_3.4.h
index 209c5e91e..027a27ae7 100755
--- a/camera/device/3.4/default/include/ext_device_v3_4_impl/ExternalCameraDeviceSession_3.4.h
+++ b/camera/device/3.4/default/include/ext_device_v3_4_impl/ExternalCameraDeviceSession_3.4.h
@@ -383,6 +383,9 @@ protected:
     SupportedV4L2Format mV4l2StreamingFmt;
     double mV4l2StreamingFps = 0.0;
     size_t mV4L2BufferCount = 0;
+    #define V4L2_BUFFER_MAX             32
+    char *mV4L2Buffer[V4L2_BUFFER_MAX];
+    unsigned int V4l2BufferLen = 0;
     struct v4l2_plane planes[1];
     struct v4l2_capability mCapability;
 
diff --git a/camera/device/3.4/default/include/ext_device_v3_4_impl/ExternalCameraDevice_3_4.h b/camera/device/3.4/default/include/ext_device_v3_4_impl/ExternalCameraDevice_3_4.h
index 6e0e4ebab..e085682d4 100644
diff --git a/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp b/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
index 65447421c..a5a74e380 100755
--- a/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
+++ b/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
@@ -257,6 +257,8 @@ void ExternalCameraProviderImpl_2_4::addExternalCamera(const char* devName) {
 }
 
 void ExternalCameraProviderImpl_2_4::deviceAdded(const char* devName) {
+    ALOGD("=============%s===========", __func__);
+    struct v4l2_capability capability;
     if (std::atoi(devName + kDevicePrefixLen) >= 30)
     {
         sp<device::V3_4::implementation::ExternalFakeCameraDevice> deviceImpl =
@@ -267,14 +269,15 @@ void ExternalCameraProviderImpl_2_4::deviceAdded(const char* devName) {
         }
         deviceImpl.clear();
     } else {
-    {
+        {
+        ALOGD("======fd(::open(devName, O_RDWR)) devName:%s ==========", devName);
         base::unique_fd fd(::open(devName, O_RDWR));
         if (fd.get() < 0) {
             ALOGE("%s open v4l2 device %s failed:%s", __FUNCTION__, devName, strerror(errno));
             return;
         }
 
-        struct v4l2_capability capability;
+//        struct v4l2_capability capability;
         int ret = ioctl(fd.get(), VIDIOC_QUERYCAP, &capability);
         if (ret < 0) {
             ALOGE("%s v4l2 QUERYCAP %s failed", __FUNCTION__, devName);
@@ -289,6 +292,7 @@ void ExternalCameraProviderImpl_2_4::deviceAdded(const char* devName) {
     // See if we can initialize ExternalCameraDevice correctly
     sp<device::V3_4::implementation::ExternalCameraDevice> deviceImpl =
             new device::V3_4::implementation::ExternalCameraDevice(devName, mCfg);
+    ALOGD("=========ExternalCameraDevice(devName:%s======", devName);
     if (deviceImpl == nullptr || deviceImpl->isInitFailed()) {
         ALOGW("%s: Attempt to init camera device %s failed!", __FUNCTION__, devName);
         return;
@@ -296,7 +300,15 @@ void ExternalCameraProviderImpl_2_4::deviceAdded(const char* devName) {
     deviceImpl.clear();
     }
 
-    addExternalCamera(devName);
+    //fy
+    if(capability.device_caps & V4L2_CAP_VIDEO_CAPTURE) {
+        ALOGD("===========dzp_test: devName:%s========", devName);
+        addExternalCamera(devName);
+    }
+    else addExternalCamera(devName);
     return;
 }
 
@@ -331,6 +349,7 @@ ExternalCameraProviderImpl_2_4::HotplugThread::HotplugThread(
 ExternalCameraProviderImpl_2_4::HotplugThread::~HotplugThread() {}
 
 bool ExternalCameraProviderImpl_2_4::HotplugThread::threadLoop() {
+    ALOGD("============%s kDevicePath:%s========", __func__, kDevicePath);
     // Find existing /dev/video* devices
     DIR* devdir = opendir(kDevicePath);
     if(devdir == 0) {
@@ -351,6 +370,7 @@ bool ExternalCameraProviderImpl_2_4::HotplugThread::threadLoop() {
                 snprintf(v4l2DevicePath, kMaxDevicePathLen,
                         "%s%s", kDevicePath, de->d_name);
                 mParent->deviceAdded(v4l2DevicePath);
+                ALOGD("=============v4l2DevicePath:%s ==============", v4l2DevicePath);
             }
         }
     }

添加虚拟摄像头设备接口：在 “hardware/interfaces/camera/” 目录下可能会添加或修改相机设备的接口，以便 Android 系统可以与 v4l2loopback 虚拟摄像头进行交互。
实现虚拟摄像头设备功能：可能会在该目录下实现虚拟摄像头设备的功能，包括与 Android 相机框架的集成、数据流处理等。
支持虚拟摄像头的配置：可能会对 Android 相机服务的配置进行修改，以支持虚拟摄像头设备的添加和管理。

改动的目的是将 v4l2loopback 虚拟摄像头设备整合到 Android 系统中，以便应用程序可以与虚拟摄像头进行交互，并利用其提供的视频流数据。

四，赋予虚拟摄像头注册节点权限

device/rockchip/common/ueventd.rockchip.rc中修改：

/dev/video9          0666   media      camera

虚拟摄像头注册节点设为666权限是为了确保所有用户都能够访问和使用该节点。权限数字666表示所有用户都有读写权限，这意味着任何用户都可以读取和写入该节点，从而能够对虚拟摄像头进行访问和控制。
例如，如果虚拟摄像头用于视频会议应用程序，那么所有参与会议的用户都需要能够访问虚拟摄像头节点。
需要注意的是，赋予666权限也可能存在一定的安全风险，因为这样做会允许任何用户都能够对该节点进行读写操作。因此，在实际应用中，需要仔细考虑安全性和访问控制的需求，以确定是否真的需要将虚拟摄像头节点权限设置为666。文章来源地址https://www.toymoban.com/news/detail-805121.html

到了这里，关于RK3568 android11 移植 v4l2loopback 虚拟摄像头的文章就介绍完了。如果您还想了解更多内容，请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章，希望大家以后多多支持TOY模板网！