Android Camera getSupportedPreviewSizes失败问题
问题现象：某些相机无法获取支持的分辨率，只能获取到的一个默认的480p。
问题定位：在应用上面通常都是通过getParameters()然后相应的Parameters，再调用Parameters类里面的方法再获取的，所以首先需要跟进的getParameters()接口，如下：
/**
* Returns the current settings for this Camera service.
* If modifications are made to the returned Parameters, they must be passed
* to {@link #setParameters(Camera.Parameters)} to take effect.
*
* @see #setParameters(Camera.Parameters)
*/
public Parameters getParameters() {
Parameters p = new Parameters();
String s = native_getParameters();
p.unflatten(s);
return p;
}
在这里实际上是直接调用了native_getParameters()这个方法，继续跟进：
private native final String native_getParameters();
到JNI为：
static jstring android_hardware_Camera_getParameters(JNIEnv *env, jobject thiz)
{
ALOGV("getParameters");
sp camera = get_native_camera(env, thiz, NULL);
if (camera == 0) return 0;
String8 params8 = camera->getParameters();
if (params8.isEmpty()) {
jniThrowRuntimeException(env, "getParameters failed (empty parameters)");
return 0;
}
return env->NewStringUTF(params8.string());
}
从jni再到下一层framework/av/camera/Camera.cpp：
String8 Camera::getParameters() const
{
ALOGV("getParameters");
String8 params;
sp c = mCamera;
if (c != 0) params = mCamera->getParameters();
return params;
}
再到framework/av/camera/ICamera.cpp：
// get preview/capture parameters - key/value pairs
String8 getParameters() const
{
ALOGV("getParameters");
Parcel data, reply;
data.writeInterfaceToken(ICamera::getInterfaceDescriptor());
remote()->transact(GET_PARAMETERS, data, &reply);
return reply.readString8();
}
同时在这这里需要关注：
status_t BnCamera::onTransact(
uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
{
switch(code) {
case DISCONNECT: {
ALOGV("DISCONNECT");
CHECK_INTERFACE(ICamera, data, reply);
disconnect();
reply->writeNoException();
return NO_ERROR;
} break;
case SET_PREVIEW_TARGET: {
ALOGV("SET_PREVIEW_TARGET");
CHECK_INTERFACE(ICamera, data, reply);
sp st =
interface_cast(data.readStrongBinder());
reply->writeInt32(setPreviewTarget(st));
return NO_ERROR;
} break;
case SET_PREVIEW_CALLBACK_FLAG: {
ALOGV("SET_PREVIEW_CALLBACK_TYPE");
CHECK_INTERFACE(ICamera, data, reply);
int callback_flag = data.readInt32();
setPreviewCallbackFlag(callback_flag);
return NO_ERROR;
} break;
case SET_PREVIEW_CALLBACK_TARGET: {
ALOGV("SET_PREVIEW_CALLBACK_TARGET");
CHECK_INTERFACE(ICamera, data, reply);
sp cp =
interface_cast(data.readStrongBinder());
reply->writeInt32(setPreviewCallbackTarget(cp));
return NO_ERROR;
}
case START_PREVIEW: {
ALOGV("START_PREVIEW");
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(startPreview());
return NO_ERROR;
} break;
case START_RECORDING: {
ALOGV("START_RECORDING");
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(startRecording());
return NO_ERROR;
} break;
case STOP_PREVIEW: {
ALOGV("STOP_PREVIEW");
CHECK_INTERFACE(ICamera, data, reply);
stopPreview();
return NO_ERROR;
} break;
case STOP_RECORDING: {
ALOGV("STOP_RECORDING");
CHECK_INTERFACE(ICamera, data, reply);
stopRecording();
return NO_ERROR;
} break;
case RELEASE_RECORDING_FRAME: {
ALOGV("RELEASE_RECORDING_FRAME");
CHECK_INTERFACE(ICamera, data, reply);
sp mem = interface_cast(data.readStrongBinder());
releaseRecordingFrame(mem);
return NO_ERROR;
} break;
case STORE_META_DATA_IN_BUFFERS: {
ALOGV("STORE_META_DATA_IN_BUFFERS");
CHECK_INTERFACE(ICamera, data, reply);
bool enabled = data.readInt32();
reply->writeInt32(storeMetaDataInBuffers(enabled));
return NO_ERROR;
} break;
case PREVIEW_ENABLED: {
ALOGV("PREVIEW_ENABLED");
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(previewEnabled());
return NO_ERROR;
} break;
case RECORDING_ENABLED: {
ALOGV("RECORDING_ENABLED");
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(recordingEnabled());
return NO_ERROR;
} break;
case AUTO_FOCUS: {
ALOGV("AUTO_FOCUS");
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(autoFocus());
return NO_ERROR;
} break;
case CANCEL_AUTO_FOCUS: {
ALOGV("CANCEL_AUTO_FOCUS");
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(cancelAutoFocus());
return NO_ERROR;
} break;
case TAKE_PICTURE: {
ALOGV("TAKE_PICTURE");
CHECK_INTERFACE(ICamera, data, reply);
int msgType = data.readInt32();
reply->writeInt32(takePicture(msgType));
return NO_ERROR;
} break;
case SET_PARAMETERS: {
ALOGV("SET_PARAMETERS");
CHECK_INTERFACE(ICamera, data, reply);
String8 params(data.readString8());
reply->writeInt32(setParameters(params));
return NO_ERROR;
} break;
case GET_PARAMETERS: {
ALOGV("GET_PARAMETERS");
CHECK_INTERFACE(ICamera, data, reply);
reply->writeString8(getParameters());
return NO_ERROR;
} break;
case SEND_COMMAND: {
ALOGV("SEND_COMMAND");
CHECK_INTERFACE(ICamera, data, reply);
int command = data.readInt32();
int arg1 = data.readInt32();
int arg2 = data.readInt32();
reply->writeInt32(sendCommand(command, arg1, arg2));
return NO_ERROR;
} break;
case CONNECT: {
CHECK_INTERFACE(ICamera, data, reply);
sp cameraClient = interface_cast(data.readStrongBinder());
reply->writeInt32(connect(cameraClient));
return NO_ERROR;
} break;
case LOCK: {
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(lock());
return NO_ERROR;
} break;
case UNLOCK: {
CHECK_INTERFACE(ICamera, data, reply);
reply->writeInt32(unlock());
return NO_ERROR;
} break;
default:
return BBinder::onTransact(code, data, reply, flags);
}
}
不难发现到了这里貌似需要到client端了，即frameworks/av/services/camera/libcameraservice/api1/CameraClient.cpp:
// get preview/capture parameters - key/value pairs
String8 CameraClient::getParameters() const {
Mutex::Autolock lock(mLock);
if (checkPidAndHardware() != NO_ERROR) return String8();
String8 params(mHardware->getParameters().flatten());
LOG1("getParameters (pid %d) (%s)", getCallingPid(), params.string());
return params;
}
这里又需要确定mHardware指向哪里了，mHardware初始化代码如下：
status_t CameraClient::initialize(camera_module_t *module) {
int callingPid = getCallingPid();
status_t res;
LOG1("CameraClient::initialize E (pid %d, id %d)", callingPid, mCameraId);
// Verify ops permissions
res = startCameraOps();
if (res != OK) {
return res;
}
char camera_device_name[10];
snprintf(camera_device_name, sizeof(camera_device_name), "%d", mCameraId);
mHardware = new CameraHardwareInterface(camera_device_name);
res = mHardware->initialize(&module->common);
if (res != OK) {
ALOGE("%s: Camera %d: unable to initialize device: %s (%d)",
__FUNCTION__, mCameraId, strerror(-res), res);
mHardware.clear();
return NO_INIT;
}
mHardware->setCallbacks(notifyCallback,
dataCallback,
dataCallbackTimestamp,
(void *)mCameraId);
// Enable zoom, error, focus, and metadata messages by default
enableMsgType(CAMERA_MSG_ERROR | CAMERA_MSG_ZOOM | CAMERA_MSG_FOCUS |
CAMERA_MSG_PREVIEW_METADATA | CAMERA_MSG_FOCUS_MOVE);
LOG1("CameraClient::initialize X (pid %d, id %d)", callingPid, mCameraId);
return OK;
}
中，我们继续通过mHardware = new CameraHardwareInterface(camera_device_name)找到相应文件frameworks/av/services/camera/libcameraservice/device1/CameraHardwareInterface.h:
/** Return the camera parameters. */
CameraParameters getParameters() const
{
ALOGV("%s(%s)", __FUNCTION__, mName.string());
CameraParameters parms;
if (mDevice->ops->get_parameters) {
char *temp = mDevice->ops->get_parameters(mDevice);
String8 str_parms(temp);
if (mDevice->ops->put_parameters)
mDevice->ops->put_parameters(mDevice, temp);
else
free(temp);
parms.unflatten(str_parms);
}
return parms;
}
这里指向了mDevice->ops->get_parameters()这里，如果有了解Camera启动流程的话，应该是知道这个接口是在厂家的CameraMoudlel里面的camera_device_open()中去指定了具体功能，例如hisilicon路径为：device/hisilicon/bigfish/hardware/camera/camera_hal/CameraModule.cpp，相应代码如下：
static int camera_device_open(const hw_module_t* module, const char* name, hw_device_t** device)
{
CAMERA_HAL_LOGV("enter %s()", __FUNCTION__);
int ret = 0;
int camera_id = 0;
camera_device_t* camera_device = NULL;
camera_device_ops_t* camera_ops = NULL;
android::CameraHal* camera_hal = NULL;
if(!name || !device)
{
ALOGE("invalid parameter[name=%p, device=%p]", name, device);
return -EINVAL;
}
camera_id = atoi(name);
camera_hal = new android::CameraHal(camera_id);
if(!camera_hal || !camera_hal->mInitOK)
{
ALOGE("fail to allocate memory for CameraHal or fail to init CameraHal");
ret = -ENOMEM;
goto EXIT;
//return -EINVAL;
}
camera_device = new camera_device_t;
camera_ops = new camera_device_ops_t;
if(!camera_device || !camera_ops)
{
ALOGE("fail to allocate memory for camera_device_t or camera_device_ops_t");
ret = -ENOMEM;
goto EXIT;
}
memset(camera_device, 0x00, sizeof(*camera_device));
memset(camera_ops, 0x00, sizeof(*camera_ops));
camera_device->common.tag = HARDWARE_DEVICE_TAG;
camera_device->common.version = 0;
camera_device->common.module = const_cast(module);
camera_device->common.close = camera_device_close;
camera_device->ops = camera_ops;
camera_device->priv = camera_hal;
camera_ops->set_preview_window = set_preview_window;
camera_ops->set_callbacks = set_callbacks;
camera_ops->auto_focus = auto_focus;
camera_ops->enable_msg_type = enable_msg_type;
camera_ops->disable_msg_type = disable_msg_type;
camera_ops->msg_type_enabled = msg_type_enabled;
camera_ops->start_preview = start_preview;
camera_ops->stop_preview = stop_preview;
camera_ops->preview_enabled = preview_enabled;
camera_ops->store_meta_data_in_buffers = store_meta_data_in_buffers;
camera_ops->start_recording = start_recording;
camera_ops->stop_recording = stop_recording;
camera_ops->recording_enabled = recording_enabled;
camera_ops->release_recording_frame = release_recording_frame;
camera_ops->cancel_auto_focus = cancel_auto_focus;
camera_ops->take_picture = take_picture;
camera_ops->cancel_picture = cancel_picture;
camera_ops->set_parameters = set_parameters;
camera_ops->get_parameters = get_parameters;
camera_ops->put_parameters = put_parameters;
camera_ops->send_command = send_command;
camera_ops->release = release;
camera_ops->dump = dump;
*device = &camera_device->common;
return 0;
EXIT:
if(camera_hal)
{
delete camera_hal;
camera_hal = NULL;
}
if(camera_device)
{
delete camera_device;
camera_device = NULL;
}
if(camera_ops)
{
delete camera_ops;
camera_ops = NULL;
}
return -1;
}
其中camera_ops->get_parameters = get_parameters指向了文件中的get_parameters方法：
/*
**************************************************************************
* FunctionName: get_parameters;
* Description : NA;
* Input : NA;
* Output : NA;
* ReturnValue : NA;
* Other : NA;
**************************************************************************
*/
static char* get_parameters(struct camera_device * dev)
{
CAMERA_HAL_LOGV("enter %s()", __FUNCTION__);
android::CameraHal* hal = TO_CAMERA_HAL_INTERFACE(dev);
android::CameraParameters par;
android::String8 str_params;
char* param = NULL;
par = hal->getParameters();
str_params = par.flatten();
if(str_params.length() > 0)
{
param = (char*)malloc(str_params.length() + 1);
if(NULL == param)
{
ALOGE("fail to allocate memory for CameraHal or fail to init CameraHal");
return param;
}
}
sprintf(param, "%s", str_params.string());
return param;
}
这里又指向了CameraHal，device/hisilicon/bigfish/hardware/camera/camera_hal/CameraHal.cpp：
/*
**************************************************************************
* FunctionName: CameraHal::getParameters;
* Description : NA;
* Input : NA;
* Output : NA;
* ReturnValue : NA;
* Other : NA;
**************************************************************************
*/
CameraParameters CameraHal::getParameters() const
{
CAMERA_HAL_LOGV("enter %s()", __FUNCTION__);
Mutex::Autolock lock(mLock);
return mExtendedEnv.mParameters;
}
到了这里后，只是直接返回相应的mExtendedEnv.mParameters，所以需要我们定位哪里进行赋值的，不难发现在同一文件下有一个参数初始化函数如下：
/*
**************************************************************************
* FunctionName: CameraHal::initDefaultParameters;
* Description : NA;
* Input : NA;
* Output : NA;
* ReturnValue : NA;
* Other : NA;
**************************************************************************
*/
void CameraHal::initDefaultParameters()
{
CAMERA_HAL_LOGV("enter %s()", __FUNCTION__);
int ret = 0;
CameraParameters p;
mParameterManager->queryCap(p);
ret = mParameterManager->setParam(p);
if(ret < 0)
{
CAMERA_HAL_LOGE("fail to set parameters");
return;
}
ret = mParameterManager->commitParam();
if(ret < 0)
{
CAMERA_HAL_LOGE("fail to commit parameters");
}
mExtendedEnv.mParameters = p;
}
在参数初始化中主要需要看 mParameterManager->queryCap§，那么又需要跟进 mParameterManager->queryCap()了，在CameraHal的初始化中有 mParameterManager = new CapabilityManager(&mExtendedEnv)，所以又需要找到CapabilityManager相关地方了，device/hisilicon/bigfish/hardware/camera/capability_manager/CapabilityManager.cpp：
/*
**************************************************************************
* FunctionName: CapabilityManager::queryCap;
* Description : NA;
* Input : NA;
* Output : NA;
* ReturnValue : NA;
* Other : NA;
**************************************************************************
*/
int CapabilityManager::queryCap ( CameraParameters& p )
{
CAMERA_HAL_LOGV("enter %s()", __FUNCTION__);
uint32_t i = 0;
for(i=0; iqueryCapability(p);
}
return 0;
}
不难发现这里又指向了mParametersObjs[i]->queryCapability§的函数，具体阅读时发现mParametersObjs有很多，这里我们只需要根据自己需求来分析就可以了,在这里我们需要分析的CameraParameterPreview中的queryCapability，代码如下：
int CameraParameterPreview::queryCapability(CameraParameters& p)
{
CAMERA_HAL_LOGV("enter %s()", __FUNCTION__);
struct v4l2_frmsizeenum fsize;
String8 strPreview("");
char strTmp[64];
memset(&fsize, 0x00, sizeof(fsize));
fsize.index = 0;
fsize.pixel_format = DEFAULT_CAMERA_PREVIEW_V4L2_FORMAT;
fsize.type = V4L2_FRMSIZE_TYPE_DISCRETE;
int order[PREVIEW_SIZE_COUNT];
int supportnum =0;
bool haveone=false;
while(0 == ioctl(mCameraFd, VIDIOC_ENUM_FRAMESIZES, &fsize))
{
fsize.index++;
for(unsigned int i=0; i < PREVIEW_SIZE_COUNT; i++)
{
if( (fsize.discrete.width == previewSizes[i].width) &&
(fsize.discrete.height == previewSizes[i].height) )
{
order[supportnum++] = i;
haveone=true;
}
}
}
SortingArray(order, supportnum);
for(int i=0; i < supportnum; i++)
{
snprintf(strTmp, sizeof(strTmp), "%dx%d", previewSizes[order[i]].width, previewSizes[order[i]].height);
strPreview += strTmp;
if(i < supportnum-1){
strPreview += ",";
}
}
CAMERA_PARAM_LOGI("support preview size = %s", strPreview.string());
int maxWidth = 0, maxHeight = 0;
getMaxSize(strPreview, &maxWidth, &maxHeight);
if(haveone)
{
CAMERA_PARAM_LOGI("real support preview size = %s", strPreview.string());
p.set(CameraParameters::KEY_SUPPORTED_PREVIEW_SIZES, strPreview);
CAMERA_PARAM_LOGI("support video size = %s", strPreview.string());
p.set(CameraParameters::KEY_SUPPORTED_VIDEO_SIZES, strPreview);
snprintf(strTmp, sizeof(strTmp), "%dx%d", maxWidth, maxHeight);
String8 realMaxPreviewSize(strTmp);
CAMERA_PARAM_LOGI("set preferred-preview-size-for-video = %s", realMaxPreviewSize.string());
p.set(CameraParameters::KEY_PREFERRED_PREVIEW_SIZE_FOR_VIDEO, realMaxPreviewSize);
}
struct v4l2_fmtdesc fmt;
memset(&fmt, 0, sizeof(fmt));
fmt.index = 0;
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
while (0 == ioctl(mCameraFd, VIDIOC_ENUM_FMT, &fmt))
{
fmt.index++;
CAMERA_PARAM_LOGI("Camera support capture format: { pixelformat = '%c%c%c%c', description = '%s' }",
fmt.pixelformat & 0xFF, (fmt.pixelformat >> 8) & 0xFF,
(fmt.pixelformat >> 16) & 0xFF, (fmt.pixelformat >> 24) & 0xFF,
fmt.description);
if(strcmp((char *)fmt.description, "MJPEG")== 0 || strcmp((char *)fmt.description, "Motion-JPEG")== 0)
{
mPreviewFormat = V4L2_PIX_FMT_MJPEG;
}
}
//here we must init the preview size
p.setPreviewSize(maxWidth, maxHeight);
String8 strPreviewFmt("");
strPreviewFmt += CameraParameters::PIXEL_FORMAT_YUV420SP;
strPreviewFmt += ",";
strPreviewFmt += CameraParameters::PIXEL_FORMAT_YUV420P;
p.set(CameraParameters::KEY_SUPPORTED_PREVIEW_FORMATS, strPreviewFmt);
p.set(CameraParameters::KEY_PREVIEW_FORMAT, DEFAULT_CAMERA_PREVIEW_FORMAT);
p.set(CameraParameters::KEY_VIDEO_FRAME_FORMAT, DEFAULT_CAMERA_VIDEO_FORMAT);
return 0;
}
如果我们从打印看不难发现在这里打印出来的分辨率就只有默认的640*480，仔细阅读代码不难发现关键点在0 == ioctl(mCameraFd, VIDIOC_ENUM_FRAMESIZES, &fsize)这里，这里是直接和Camera进行了通信去获取支持的分辨率了，我们在盒子上面获取到的结果就是只有默认的，这个问题到了这里分析不动了，只好求助芯片厂家hisilicon了，得到的回复是Camera的像素格式不一样，并且提供了相关补丁，修改后的代码如下：
int CameraParameterPreview::queryCapability(CameraParameters& p)
{
CAMERA_HAL_LOGV("enter %s()", __FUNCTION__);
struct v4l2_fmtdesc fmt;
memset(&fmt, 0, sizeof(fmt));
fmt.index = 0;
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
struct v4l2_frmsizeenum fsize;
String8 strPreviewYUV("");
String8 strPreviewMJEPG("");
char strTmp[64];
bool haveone=false;
int orderYUV[PREVIEW_SIZE_COUNT];
int supportYUVnum =0;
int orderMJPEG[PREVIEW_SIZE_COUNT];
int supportMJPEGnum =0;
int maxYUVWidth = 0, maxYUVHeight = 0;
int maxMJPEGWidth = 0, maxMJPEGHeight = 0;
while(0 == ioctl(mCameraFd, VIDIOC_ENUM_FMT, &fmt))
{
fmt.index++;
CAMERA_PARAM_LOGI("CameraParameterPreview support capture format: { pixelformat = '%c%c%c%c', description = '%s' }",
fmt.pixelformat & 0xFF, (fmt.pixelformat >> 8) & 0xFF,
(fmt.pixelformat >> 16) & 0xFF, (fmt.pixelformat >> 24) & 0xFF,
fmt.description);
if(strcmp((char *)fmt.description, "MJPEG")== 0 || strcmp((char *)fmt.description, "Motion-JPEG")== 0)
{
mPreviewFormat = V4L2_PIX_FMT_MJPEG;
}
else if (strcmp((char *)fmt.description, "YUV 4:2:2 (YUYV)")== 0 || strcmp((char *)fmt.description, "YUV 4:2:0 (M420)")== 0)
{
mPreviewFormat = V4L2_PIX_FMT_YUYV;
}
else
{
mPreviewFormat = V4L2_PIX_FMT_MJPEG;
}
memset(strTmp, 0x00, sizeof(strTmp));
memset(&fsize, 0x00, sizeof(fsize));
fsize.index = 0;
fsize.pixel_format = mPreviewFormat;
fsize.type = V4L2_FRMSIZE_TYPE_DISCRETE;
if(mPreviewFormat == V4L2_PIX_FMT_YUYV)
{
while(0 == ioctl(mCameraFd, VIDIOC_ENUM_FRAMESIZES, &fsize))
{
fsize.index++;
for(unsigned int i=0; i < PREVIEW_SIZE_COUNT; i++)
{
if( (fsize.discrete.width == previewSizes[i].width) &&
(fsize.discrete.height == previewSizes[i].height) )
{
orderYUV[supportYUVnum++] = i;
haveone=true;
}
}
}
SortingArray(orderYUV, supportYUVnum);
for(int i=0; i < supportYUVnum; i++)
{
snprintf(strTmp, sizeof(strTmp), "%dx%d", previewSizes[orderYUV[i]].width, previewSizes[orderYUV[i]].height);
strPreviewYUV += strTmp;
if(i < supportYUVnum){
strPreviewYUV += ",";
}
}
CAMERA_PARAM_LOGI("support preview yuv size = %s", strPreviewYUV.string());
getMaxSize(strPreviewYUV, &maxYUVWidth, &maxYUVHeight);
}
else
{
while(0 == ioctl(mCameraFd, VIDIOC_ENUM_FRAMESIZES, &fsize))
{
fsize.index++;
for(unsigned int i=0; i < PREVIEW_SIZE_COUNT; i++)
{
if( (fsize.discrete.width == previewSizes[i].width) &&
(fsize.discrete.height == previewSizes[i].height) )
{
orderMJPEG[supportMJPEGnum++] = i;
haveone=true;
}
}
}
SortingArray(orderMJPEG, supportMJPEGnum);
for(int i=0; i < supportMJPEGnum; i++)
{
snprintf(strTmp, sizeof(strTmp), "%dx%d", previewSizes[orderMJPEG[i]].width, previewSizes[orderMJPEG[i]].height);
strPreviewMJEPG += strTmp;
if(i < supportMJPEGnum){
strPreviewMJEPG += ",";
}
}
CAMERA_PARAM_LOGI("support preview mjepg size = %s", strPreviewMJEPG.string());
getMaxSize(strPreviewMJEPG, &maxMJPEGWidth, &maxMJPEGHeight);
}
}
if(haveone)
{
if(maxYUVWidth * maxYUVHeight > maxMJPEGWidth * maxMJPEGHeight)
{
mPreviewFormat = V4L2_PIX_FMT_YUYV;
CAMERA_PARAM_LOGI("real support preview yuv size = %s", strPreviewYUV.string());
p.set(CameraParameters::KEY_SUPPORTED_PREVIEW_SIZES, strPreviewYUV);
CAMERA_PARAM_LOGI("support video yuv size = %s", strPreviewYUV.string());
p.set(CameraParameters::KEY_SUPPORTED_VIDEO_SIZES, strPreviewYUV);
snprintf(strTmp, sizeof(strTmp), "%dx%d", maxYUVWidth, maxYUVHeight);
p.setPreviewSize(maxYUVWidth, maxYUVHeight);
}
else
{
mPreviewFormat = V4L2_PIX_FMT_MJPEG;
CAMERA_PARAM_LOGI("real support preview mjepg size = %s", strPreviewMJEPG.string());
p.set(CameraParameters::KEY_SUPPORTED_PREVIEW_SIZES, strPreviewMJEPG);
CAMERA_PARAM_LOGI("support video mjepg size = %s", strPreviewMJEPG.string());
p.set(CameraParameters::KEY_SUPPORTED_VIDEO_SIZES, strPreviewMJEPG);
snprintf(strTmp, sizeof(strTmp), "%dx%d", maxMJPEGWidth, maxMJPEGHeight);
p.setPreviewSize(maxMJPEGWidth, maxMJPEGHeight);
}
String8 realMaxPreviewSize(strTmp);
CAMERA_PARAM_LOGI("set preferred-preview-size-for-video = %s", realMaxPreviewSize.string());
p.set(CameraParameters::KEY_PREFERRED_PREVIEW_SIZE_FOR_VIDEO, realMaxPreviewSize);
}
//here we must init the preview size
String8 strPreviewFmt("");
strPreviewFmt += CameraParameters::PIXEL_FORMAT_YUV420SP;
strPreviewFmt += ",";
strPreviewFmt += CameraParameters::PIXEL_FORMAT_YUV420P;
p.set(CameraParameters::KEY_SUPPORTED_PREVIEW_FORMATS, strPreviewFmt);
p.set(CameraParameters::KEY_PREVIEW_FORMAT, DEFAULT_CAMERA_PREVIEW_FORMAT);
p.set(CameraParameters::KEY_VIDEO_FRAME_FORMAT, DEFAULT_CAMERA_VIDEO_FORMAT);
return 0;
}
不难发现先去获取了支持的格式，然后针对格式获取分辨率，到此获取支持分辨率问题得以解决。