camera小結

今年這兩個月，一直都在搞camera。android的camera模塊應該是比較熟悉了，剛好項目搞完，這裏做一下總結。

camera是相機或平板必備的一個功能模塊，拍照，錄像確實很實用。

android 的 camera 分驅動層，HAL層，APP層。

底層一般都用V4L2封裝，這樣HAL可以通過V4L2標準接口對底層進行調用，讀取數據。然後傳給APP。

USB接口的camera module 一般都會支持UVC標準，UVC- USB Video Class。這種模塊一般都由一個感光sensor + controller 組成。這個controller 一般都會自帶firmware。

拍照和錄像裏面有很多parameter setting. white balance， color effect， picture quality， video quality 等等。這些都可以通過V4L2的標準IOCTL接口實現。

previewthread() 這個線程最重要，所有的功能都圍繞這個線程工作。

camera模塊不算太難，也不深，感覺還是挺簡單的。這是我做android的第一個模塊，下個項目要搞PMIC了，這模塊會比較難，也比較深，涉及東西很多，搞懂了應該就成牛人了~

take picture 過程分析

這兩天一直在調拍照，由於之前拍照照片的格式只支持VGA以下的，我拿我的pad一看，居然可以支持5M和1.3M，也就是前後攝像頭的最大分辨率。這讓我想到肯定是軟件沒做好，有待改善，然後這兩天有空，就調了調。終於調出來了，一直卡在死鎖狀態。
由於軟件功底不夠，對於鎖，沒什麼概念，還好最後還是搞出來了，過程真是痛苦啊。。

流程如下：
首先cameraservice 會調用 takepicture（）。

[cpp] view plain copy print ?

status_t CameraHardwareStub::takePicture()
{
disableMsgType(CAMERA_MSG_PREVIEW_FRAME);
if (createThread(beginPictureThread, this) == false)
return UNKNOWN_ERROR;
return NO_ERROR;
}

status_t CameraHardwareStub::takePicture()
{
    disableMsgType(CAMERA_MSG_PREVIEW_FRAME);
    if (createThread(beginPictureThread, this) == false)
        return UNKNOWN_ERROR;
    return NO_ERROR;
}

[cpp] view plain copy print ?

/*static*/ int CameraHardwareStub::beginPictureThread(void *cookie)
{
CameraHardwareStub *c = (CameraHardwareStub *)cookie;
return c->pictureThread();
}

/*static*/ int CameraHardwareStub::beginPictureThread(void *cookie)
{
    CameraHardwareStub *c = (CameraHardwareStub *)cookie;
    return c->pictureThread();
}

[cpp] view plain copy print ?

int CameraHardwareStub::pictureThread()
{
int picture_width, picture_height;
mParameters.getPictureSize(&picture_width, &picture_height);
LOGD("picture size=%dx%d", picture_width, picture_height);
if (mMsgEnabled & CAMERA_MSG_COMPRESSED_IMAGE) {
LOGE("Take Picture COMPRESSED IMAGE");
/*
* The takePicture() function called by the CameraService
* must return synchronously without attempting to wait
* for any locks, to prevent circular deadlocking in
* attempting to call CameraService callbacks to deliver
* frames. This includes waiting for the preview thread
* to finish cleanly. So stopping the preview thread
* is done in this separate pictureThread
*/
sp<PreviewThread> previewThread;
{
Mutex::Autolock lock(mLock);
previewThread = mPreviewThread;
}
if (previewThread != 0) {
previewThread->requestExitAndWait();
Mutex::Autolock lock(mLock);
mPreviewThread.clear();
}
mFakeCamera->Uninit();
mFakeCamera->StopStreaming(); //卸載掉preview 內存。
{
mPictureLock.lock();
mDataCb(CAMERA_MSG_COMPRESSED_IMAGE, mFakeCamera->GrabJpegFrame(picture_width, picture_height), mCallbackCookie);
mPictureLock.unlock();
}
}
return NO_ERROR;
}

int CameraHardwareStub::pictureThread()
{
    int picture_width, picture_height;
    mParameters.getPictureSize(&picture_width, &picture_height);
    LOGD("picture size=%dx%d", picture_width, picture_height);

    if (mMsgEnabled & CAMERA_MSG_COMPRESSED_IMAGE) {
        LOGE("Take Picture COMPRESSED IMAGE");

        /*
         * The takePicture() function called by the CameraService
         * must return synchronously without attempting to wait
         * for any locks, to prevent circular deadlocking in
         * attempting to call CameraService callbacks to deliver
         * frames. This includes waiting for the preview thread
         * to finish cleanly. So stopping the preview thread
         * is done in this separate pictureThread
         */

        sp<PreviewThread> previewThread;

        {
            Mutex::Autolock lock(mLock);
            previewThread = mPreviewThread;
        }

        if (previewThread != 0) {
            previewThread->requestExitAndWait();
            Mutex::Autolock lock(mLock);
            mPreviewThread.clear();
        }
        
        mFakeCamera->Uninit();
        mFakeCamera->StopStreaming(); //卸載掉preview 內存。
        
        {
            mPictureLock.lock();
            mDataCb(CAMERA_MSG_COMPRESSED_IMAGE, mFakeCamera->GrabJpegFrame(picture_width, picture_height), mCallbackCookie);
            mPictureLock.unlock();
        }
    }
    return NO_ERROR;
}

GrabJpegFrame 會具體執行拍照功能。

[cpp] view plain copy print ?

sp<IMemory> V4L2Camera::GrabJpegFrame (int pic_width, int pic_height)
{
FILE *output;
FILE *input;
int fileSize;
int ret, i;
int w, h;
struct v4l2_buffer v4l2_buf_picture;
struct v4l2_format format;
struct v4l2_streamparm parm;
struct v4l2_requestbuffers reqbuf;
sp<MemoryHeapBase> rawPictureHeap;
sp<MemoryHeapBase> mjpegPictureHeap;
sp<MemoryBase> jpegMemBase;
/* VIDIOC_S_FMT */
memset(&format, 0, sizeof(format));
format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
format.fmt.pix.width = pic_width;
format.fmt.pix.height = pic_height;
format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
if (ioctl(fd, VIDIOC_S_FMT, &format) < 0)
{
LOGE("Error: VIDIOC_S_FMT");
goto done;
}
/* VIDIOC_S_PARM */
memset(&parm, 0, sizeof(parm));
parm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
parm.parm.capture.timeperframe.numerator = 2;
parm.parm.capture.timeperframe.denominator = 15;
if (ioctl(fd, VIDIOC_S_PARM, &parm) < 0)
{
LOGE("Error: VIDIOC_S_PARM");
goto done;
}
/* VIDIOC_REQBUFS */
memset(&reqbuf, 0, sizeof(reqbuf));
reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
reqbuf.memory = V4L2_MEMORY_MMAP;
reqbuf.count = 1;
if (ioctl(fd, VIDIOC_REQBUFS, &reqbuf) < 0)
{
LOGE ("Error: VIDIOC_REQBUFS");
goto done;
}
memset(&v4l2_buf_picture, 0, sizeof(v4l2_buf_picture));
v4l2_buf_picture.index = 0;
v4l2_buf_picture.type = reqbuf.type;
if (ioctl(fd, VIDIOC_QUERYBUF, &v4l2_buf_picture) < 0)
{
LOGE("Error: VIDIOC_QUERYBUF");
goto done;
}
/* use MemoryHeapBase to do mmap */
rawPictureHeap = new MemoryHeapBase(fd,
v4l2_buf_picture.length, 0, v4l2_buf_picture.m.offset);
if (rawPictureHeap == NULL)
{
LOGE("Error: Cannot create rawPictureHeap");
goto done;
}
/* VIDIOC_QBUF */
if (ioctl(fd, VIDIOC_QBUF, &v4l2_buf_picture) < 0)
{
LOGE("Error: VIDIOC_QBUF");
}
StartStreaming();
for(i = 0; i < PICTURE_FRAME_GRAB_COUNT; i++){
/* get one frame from camera */
if (ioctl(fd, VIDIOC_DQBUF, &v4l2_buf_picture) < 0){
LOGE("Error: VIDIOC_DQBUF");
goto done;
}
if((ioctl(fd, VIDIOC_QBUF, &v4l2_buf_picture)) < 0){
LOGE("Error: VIDIOC_QBUF = %d:%d", ret, errno);
}
usleep(50*1000);
}
output = fopen("/data/tmp.jpg", "wb");
if (output == NULL) {
LOGE("GrabJpegFrame: Ouput file == NULL");
return NULL;
}
fileSize = saveYUYVtoJPEG((unsigned char *)rawPictureHeap->getBase(), pic_width, pic_height, output, 85);
fclose(output);
input = fopen("/data/tmp.jpg", "rb");
if (input == NULL)
LOGE("GrabJpegFrame: Input file == NULL");
else {
mjpegPictureHeap = new MemoryHeapBase(fileSize);
jpegMemBase = new MemoryBase(mjpegPictureHeap, 0, fileSize);
fread((uint8_t *)mjpegPictureHeap->base(), 1, fileSize, input);
fclose(input);
rawPictureHeap.clear();
StopStreaming();
return jpegMemBase;
}
done:
rawPictureHeap.clear();
StopStreaming();
return NULL;
}
int V4L2Camera::saveYUYVtoJPEG (unsigned char *inputBuffer, int width, int height, FILE *file, int quality)
{
struct jpeg_compress_struct cinfo;
struct jpeg_error_mgr jerr;
JSAMPROW row_pointer[1];
unsigned char *line_buffer, *yuyv;
int z;
int fileSize;
line_buffer = (unsigned char *) calloc (width * 3, 1);
yuyv = inputBuffer;
cinfo.err = jpeg_std_error (&jerr);
jpeg_create_compress (&cinfo);
jpeg_stdio_dest (&cinfo, file);
LOGI("JPEG PICTURE WIDTH AND HEIGHT: %dx%d", width, height);
cinfo.image_width = width;
cinfo.image_height = height;
cinfo.input_components = 3;
cinfo.in_color_space = JCS_RGB;
jpeg_set_defaults (&cinfo);
jpeg_set_quality (&cinfo, quality, TRUE);
jpeg_start_compress (&cinfo, TRUE);
z = 0;
while (cinfo.next_scanline < cinfo.image_height) {
int x;
unsigned char *ptr = line_buffer;
for (x = 0; x < width; x++) {
int r, g, b;
int y, u, v;
if (!z)
y = yuyv[0] << 8;
else
y = yuyv[2] << 8;
u = yuyv[1] - 128;
v = yuyv[3] - 128;
r = (y + (359 * v)) >> 8;
g = (y - (88 * u) - (183 * v)) >> 8;
b = (y + (454 * u)) >> 8;
*(ptr++) = (r > 255) ? 255 : ((r < 0) ? 0 : r);
*(ptr++) = (g > 255) ? 255 : ((g < 0) ? 0 : g);
*(ptr++) = (b > 255) ? 255 : ((b < 0) ? 0 : b);
if (z++) {
z = 0;
yuyv += 4;
}
}
row_pointer[0] = line_buffer;
jpeg_write_scanlines (&cinfo, row_pointer, 1);
}
jpeg_finish_compress (&cinfo);
fileSize = ftell(file);
jpeg_destroy_compress (&cinfo);
free (line_buffer);
return fileSize;
}

sp<IMemory> V4L2Camera::GrabJpegFrame (int pic_width, int pic_height)
{
    FILE *output;
    FILE *input;
    int fileSize;
    int ret, i;

    int w, h;
    struct v4l2_buffer v4l2_buf_picture;
    struct v4l2_format format;
    struct v4l2_streamparm parm;
    struct v4l2_requestbuffers reqbuf;
    sp<MemoryHeapBase> rawPictureHeap;
    sp<MemoryHeapBase> mjpegPictureHeap;
    sp<MemoryBase> jpegMemBase;

    /* VIDIOC_S_FMT */
    memset(&format, 0, sizeof(format));
    format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    format.fmt.pix.width = pic_width;
    format.fmt.pix.height = pic_height;
    format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
    if (ioctl(fd, VIDIOC_S_FMT, &format) < 0)
    {
        LOGE("Error: VIDIOC_S_FMT");
        goto done;
    }

    /* VIDIOC_S_PARM */
    memset(&parm, 0, sizeof(parm));
    parm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    parm.parm.capture.timeperframe.numerator = 2;
    parm.parm.capture.timeperframe.denominator = 15;
    if (ioctl(fd, VIDIOC_S_PARM, &parm) < 0)
    {
        LOGE("Error: VIDIOC_S_PARM");
        goto done;
    }

    /* VIDIOC_REQBUFS */
    memset(&reqbuf, 0, sizeof(reqbuf));
    reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    reqbuf.memory = V4L2_MEMORY_MMAP;
    reqbuf.count = 1;
    if (ioctl(fd, VIDIOC_REQBUFS, &reqbuf) < 0)
    {
        LOGE ("Error: VIDIOC_REQBUFS");
        goto done;
    }

    memset(&v4l2_buf_picture, 0, sizeof(v4l2_buf_picture));
    v4l2_buf_picture.index = 0;
    v4l2_buf_picture.type = reqbuf.type;
    if (ioctl(fd, VIDIOC_QUERYBUF, &v4l2_buf_picture) < 0)
    {
        LOGE("Error: VIDIOC_QUERYBUF");
        goto done;
    }

    /* use MemoryHeapBase to do mmap */
    rawPictureHeap = new MemoryHeapBase(fd,
            v4l2_buf_picture.length, 0, v4l2_buf_picture.m.offset);
    if (rawPictureHeap == NULL)
    {
        LOGE("Error: Cannot create rawPictureHeap");
        goto done;
    }

    /* VIDIOC_QBUF */
    if (ioctl(fd, VIDIOC_QBUF, &v4l2_buf_picture) < 0)
    {
        LOGE("Error: VIDIOC_QBUF");
    }
    StartStreaming();

    for(i = 0; i < PICTURE_FRAME_GRAB_COUNT; i++){
        /* get one frame from camera */
        if (ioctl(fd, VIDIOC_DQBUF, &v4l2_buf_picture) < 0){
            LOGE("Error: VIDIOC_DQBUF");
            goto done;
        }
        if((ioctl(fd, VIDIOC_QBUF, &v4l2_buf_picture)) < 0){
            LOGE("Error: VIDIOC_QBUF = %d:%d", ret, errno);
        }
        usleep(50*1000);
    }
    
    output = fopen("/data/tmp.jpg", "wb");

    if (output == NULL) {
        LOGE("GrabJpegFrame: Ouput file == NULL");
        return NULL;
    }

    fileSize = saveYUYVtoJPEG((unsigned char *)rawPictureHeap->getBase(), pic_width, pic_height, output, 85);

    fclose(output);

    input = fopen("/data/tmp.jpg", "rb");

    if (input == NULL)
        LOGE("GrabJpegFrame: Input file == NULL");
    else {
        mjpegPictureHeap = new MemoryHeapBase(fileSize);
        jpegMemBase = new MemoryBase(mjpegPictureHeap, 0, fileSize);

        fread((uint8_t *)mjpegPictureHeap->base(), 1, fileSize, input);
        fclose(input);

        rawPictureHeap.clear();
        StopStreaming();
        return jpegMemBase;
    }

done:
    rawPictureHeap.clear();
    StopStreaming();
    return NULL;
}

int V4L2Camera::saveYUYVtoJPEG (unsigned char *inputBuffer, int width, int height, FILE *file, int quality)
{
    struct jpeg_compress_struct cinfo;
    struct jpeg_error_mgr jerr;
    JSAMPROW row_pointer[1];
    unsigned char *line_buffer, *yuyv;
    int z;
    int fileSize;

    line_buffer = (unsigned char *) calloc (width * 3, 1);
    yuyv = inputBuffer;

    cinfo.err = jpeg_std_error (&jerr);
    jpeg_create_compress (&cinfo);
    jpeg_stdio_dest (&cinfo, file);

    LOGI("JPEG PICTURE WIDTH AND HEIGHT: %dx%d", width, height);

    cinfo.image_width = width;
    cinfo.image_height = height;
    cinfo.input_components = 3;
    cinfo.in_color_space = JCS_RGB;

    jpeg_set_defaults (&cinfo);
    jpeg_set_quality (&cinfo, quality, TRUE);

    jpeg_start_compress (&cinfo, TRUE);

    z = 0;
    while (cinfo.next_scanline < cinfo.image_height) {
        int x;
        unsigned char *ptr = line_buffer;

        for (x = 0; x < width; x++) {
            int r, g, b;
            int y, u, v;

            if (!z)
                y = yuyv[0] << 8;
            else
                y = yuyv[2] << 8;

            u = yuyv[1] - 128;
            v = yuyv[3] - 128;

            r = (y + (359 * v)) >> 8;
            g = (y - (88 * u) - (183 * v)) >> 8;
            b = (y + (454 * u)) >> 8;

            *(ptr++) = (r > 255) ? 255 : ((r < 0) ? 0 : r);
            *(ptr++) = (g > 255) ? 255 : ((g < 0) ? 0 : g);
            *(ptr++) = (b > 255) ? 255 : ((b < 0) ? 0 : b);

            if (z++) {
                z = 0;
                yuyv += 4;
            }
        }

        row_pointer[0] = line_buffer;
        jpeg_write_scanlines (&cinfo, row_pointer, 1);
    }

    jpeg_finish_compress (&cinfo);
    fileSize = ftell(file);
    jpeg_destroy_compress (&cinfo);

    free (line_buffer);

    return fileSize;
}

下面這個函數，可以查詢攝像頭模塊支持哪些照片的尺寸：

[cpp] view plain copy print ?

String8 V4L2Camera::GetSupportPictureSize(int fd, int pixelformat, int &w, int &h)
{
LOGD("%s", __func__);
String8 size_list;
struct v4l2_frmsizeenum framesize_enum;
memset(&framesize_enum, 0, sizeof(framesize_enum));
framesize_enum.index = 0;
framesize_enum.pixel_format = pixelformat;
int ret = ioctl(fd, VIDIOC_ENUM_FRAMESIZES, &framesize_enum);
if (ret < 0) {
LOGE("Error: VIDIOC_ENUM_FRAMESIZES - %s", strerror(errno));
return size_list;
}
switch(framesize_enum.type)
{
case V4L2_FRMSIZE_TYPE_DISCRETE:
do {
if (framesize_enum.index) {
w = framesize_enum.discrete.width;
h = framesize_enum.discrete.height;
}
size_list.appendFormat(
framesize_enum.index ? ",%dx%d" : "%dx%d",
framesize_enum.discrete.width,
framesize_enum.discrete.height);
framesize_enum.index++;
ret = ioctl(fd, VIDIOC_ENUM_FRAMESIZES, &framesize_enum);
} while (ret >= 0);
LOGD("Supported sizes string: %s", size_list.string());
break;
case V4L2_FRMSIZE_TYPE_STEPWISE:
case V4L2_FRMSIZE_TYPE_CONTINUOUS:
LOGD("STEPWISE/CONTINUOUS ignored: %dx%d-%dx%d/%dx%d",
framesize_enum.stepwise.min_width,
framesize_enum.stepwise.min_height,
framesize_enum.stepwise.max_width,
framesize_enum.stepwise.max_height,
framesize_enum.stepwise.step_width,
framesize_enum.stepwise.step_height);
break;
default:
LOGE("Unknown format type: %d!!!", framesize_enum.type);
}
return size_list;
}

camera recording流程

分類： Camera 2012-07-03 10:24 140人閱讀評論(0) 收藏舉報

開始app調用到cameraservices

[cpp] view plain copy print ?

// start recording mode
status_t CameraService::Client::startRecording() {
LOG1("startRecording (pid %d)", getCallingPid());
return startCameraMode(CAMERA_RECORDING_MODE);
}
// start preview or recording
status_t CameraService::Client::startCameraMode(camera_mode mode) {
LOG1("startCameraMode(%d)", mode);
Mutex::Autolock lock(mLock);
status_t result = checkPidAndHardware();
if (result != NO_ERROR) return result;
switch(mode) {
case CAMERA_PREVIEW_MODE:
if (mSurface == 0) {
LOG1("mSurface is not set yet.");
// still able to start preview in this case.
}
return startPreviewMode();
case CAMERA_RECORDING_MODE:
if (mSurface == 0) {
LOGE("mSurface must be set before startRecordingMode.");
return INVALID_OPERATION;
}
return startRecordingMode();
default:
return UNKNOWN_ERROR;
}
}

// start recording mode

status_t CameraService::Client::startRecording() {
    LOG1("startRecording (pid %d)", getCallingPid());
    return startCameraMode(CAMERA_RECORDING_MODE);
}

// start preview or recording

status_t CameraService::Client::startCameraMode(camera_mode mode) {
    LOG1("startCameraMode(%d)", mode);
    Mutex::Autolock lock(mLock);
    status_t result = checkPidAndHardware();
    if (result != NO_ERROR) return result;

    switch(mode) {
        case CAMERA_PREVIEW_MODE:
            if (mSurface == 0) {
                LOG1("mSurface is not set yet.");
                // still able to start preview in this case.

            }
            return startPreviewMode();
        case CAMERA_RECORDING_MODE:
            if (mSurface == 0) {
                LOGE("mSurface must be set before startRecordingMode.");
                return INVALID_OPERATION;
            }
            return startRecordingMode();
        default:
            return UNKNOWN_ERROR;
    }
}

[cpp] view plain copy print ?

status_t CameraService::Client::startRecordingMode() {
LOG1("startRecordingMode");
status_t result = NO_ERROR;
// if recording has been enabled, nothing needs to be done
if (mHardware->recordingEnabled()) {
return NO_ERROR;
}
// if preview has not been started, start preview first
if (!mHardware->previewEnabled()) {
result = startPreviewMode();
if (result != NO_ERROR) {
return result;
}
}
// start recording mode
enableMsgType(CAMERA_MSG_VIDEO_FRAME);
mCameraService->playSound(SOUND_RECORDING);
result = mHardware->startRecording(); //調用hal recording.
if (result != NO_ERROR) {
LOGE("mHardware->startRecording() failed with status %d", result);
}
return result;
}

status_t CameraService::Client::startRecordingMode() {
    LOG1("startRecordingMode");
    status_t result = NO_ERROR;

    // if recording has been enabled, nothing needs to be done

    if (mHardware->recordingEnabled()) {
        return NO_ERROR;
    }

    // if preview has not been started, start preview first

    if (!mHardware->previewEnabled()) {
        result = startPreviewMode();
        if (result != NO_ERROR) {
            return result;
        }
    }

    // start recording mode

    enableMsgType(CAMERA_MSG_VIDEO_FRAME);
    mCameraService->playSound(SOUND_RECORDING);
    result = mHardware->startRecording();  //調用hal recording.
    if (result != NO_ERROR) {
        LOGE("mHardware->startRecording() failed with status %d", result);
    }
    return result;
}

調用HAL 層的 previewthread 線程:

[cpp] view plain copy print ?

if (mRecordRunning == true && mMsgEnabled & CAMERA_MSG_VIDEO_FRAME) {
263 yuyv422_to_yuv420sp((unsigned char *)rawFramePointer,
264 (unsigned char *)mRecordingHeap->getBase(),
265 preview_width, preview_height);
266 LOGE(" ------- mRecordRunning --------");
267 mDataCbTimestamp(systemTime(SYSTEM_TIME_MONOTONIC), CAMERA_MSG_VIDEO_FRAME, mRecordingBuffer, mCallbackCookie);
268 }

if (mRecordRunning == true && mMsgEnabled & CAMERA_MSG_VIDEO_FRAME) {
263 yuyv422_to_yuv420sp((unsigned char *)rawFramePointer,
264 (unsigned char *)mRecordingHeap->getBase(),
265 preview_width, preview_height);
266 LOGE(" ------- mRecordRunning --------");
267 mDataCbTimestamp(systemTime(SYSTEM_TIME_MONOTONIC), CAMERA_MSG_VIDEO_FRAME, mRecordingBuffer, mCallbackCookie);
268 }

使用回調函數：回調到cameraservices .

[cpp] view plain copy print ?

void CameraService::Client::dataCallbackTimestamp(nsecs_t timestamp,
int32_t msgType, const sp<IMemory>& dataPtr, void* user) {
LOG2("dataCallbackTimestamp(%d)", msgType);
sp<Client> client = getClientFromCookie(user);
if (client == 0) return;
if (!client->lockIfMessageWanted(msgType)) return;
if (dataPtr == 0) {
LOGE("Null data returned in data with timestamp callback");
client->handleGenericNotify(CAMERA_MSG_ERROR, UNKNOWN_ERROR, 0);
return;
}
client->handleGenericDataTimestamp(timestamp, msgType, dataPtr);
}

void CameraService::Client::dataCallbackTimestamp(nsecs_t timestamp,
        int32_t msgType, const sp<IMemory>& dataPtr, void* user) {
    LOG2("dataCallbackTimestamp(%d)", msgType);

    sp<Client> client = getClientFromCookie(user);
    if (client == 0) return;
    if (!client->lockIfMessageWanted(msgType)) return;

    if (dataPtr == 0) {
        LOGE("Null data returned in data with timestamp callback");
        client->handleGenericNotify(CAMERA_MSG_ERROR, UNKNOWN_ERROR, 0);
        return;
    }

    client->handleGenericDataTimestamp(timestamp, msgType, dataPtr);
}

數據傳給client->handleGenericDataTimestamp(timestamp, msgType, dataPtr)

[cpp] view plain copy print ?

void CameraService::Client::handleGenericDataTimestamp(nsecs_t timestamp,
int32_t msgType, const sp<IMemory>& dataPtr) {
sp<ICameraClient> c = mCameraClient;
mLock.unlock();
if (c != 0) {
c->dataCallbackTimestamp(timestamp, msgType, dataPtr);
}
}

void CameraService::Client::handleGenericDataTimestamp(nsecs_t timestamp,
    int32_t msgType, const sp<IMemory>& dataPtr) {
    sp<ICameraClient> c = mCameraClient;
    mLock.unlock();
    if (c != 0) {
        c->dataCallbackTimestamp(timestamp, msgType, dataPtr);
    }
}

傳給 frameworks/base/libs/camera/Camera.cpp

[cpp] view plain copy print ?

// callback from camera service when timestamped frame is ready
void Camera::dataCallbackTimestamp(nsecs_t timestamp, int32_t msgType, const sp<IMemory>& dataPtr)
{
sp<CameraListener> listener;
{
Mutex::Autolock _l(mLock);
listener = mListener;
}
if (listener != NULL) {
listener->postDataTimestamp(timestamp, msgType, dataPtr);
}
}

// callback from camera service when timestamped frame is ready

void Camera::dataCallbackTimestamp(nsecs_t timestamp, int32_t msgType, const sp<IMemory>& dataPtr)
{
    sp<CameraListener> listener;
    {
        Mutex::Autolock _l(mLock);
        listener = mListener;
    }
    if (listener != NULL) {
        listener->postDataTimestamp(timestamp, msgType, dataPtr);
    }
}

調用到 frameworks/base/media/libstagefright/CameraSource.cpp
frameworks/base/libs/camera/ICameraClient.cpp

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