android - 通过 NDK 将数据从 OpenCV Mat 复制到 Surface 会产生小错误。

Question

我正在开发一个应用程序，该应用程序将通过 native 方法处理相机帧，然后将处理后的结果发布到 Java TextureView 的 Surface 中。我曾经looking on this application作为引用并将代码实现到我的。但是，我在其中一侧看到一条奇怪的绿色条纹，我认为这是表面宽度和缓冲区步幅之间的差异。我正在尝试制定解决方案，但没有成功。有人可以帮我吗？

本地调用代码如下:

extern "C"
JNIEXPORT jstring JNICALL
Java_com_android_cols2svlc_receiver_utils_JNIHelper_surfaceTest(JNIEnv *env, jclass type, jint srcWidth, jint srcHeight, jobject srcBuffer,
                                                                jobject dstSurface, jstring path_, jint savefile) {
    const char *str = env->GetStringUTFChars(path_, 0);

    // Code

    LOGE("bob path:%s saveFile=%d", str, savefile);

    uint8_t *srcLumaPtr = reinterpret_cast<uint8_t *>(env->GetDirectBufferAddress(srcBuffer));

    if (srcLumaPtr == NULL) {
        LOGE("blit NULL pointer ERROR");
        return NULL;
    }

    int dstWidth;
    int dstHeight;

    cv::Mat mYuv(srcHeight + srcHeight / 2, srcWidth, CV_8UC1, srcLumaPtr);


    ANativeWindow *win = ANativeWindow_fromSurface(env, dstSurface);
    ANativeWindow_acquire(win);

    ANativeWindow_Buffer buf;

    dstWidth = srcHeight;
    dstHeight = srcWidth;

    ANativeWindow_setBuffersGeometry(win, dstWidth, dstHeight, 0 /*format unchanged*/);

    if (int32_t err = ANativeWindow_lock(win, &buf, NULL)) {
        LOGE("ANativeWindow_lock failed with error code %d\n", err);
        ANativeWindow_release(win);
        return NULL;
    }

    uint8_t *dstLumaPtr = reinterpret_cast<uint8_t *>(buf.bits);
    Mat dstRgba(dstHeight, buf.stride, CV_8UC4,
                dstLumaPtr);        // TextureView buffer, use stride as width
    Mat srcRgba(srcHeight, srcWidth, CV_8UC4);
    Mat flipRgba(dstHeight, dstWidth, CV_8UC4);

    // convert YUV -> RGBA
    cv::cvtColor(mYuv, flipRgba, CV_YUV2RGBA_NV21);

    // Rotate 90 degree
    // rotateMat(flipRgba, 2);

    LOGE(" ------- DATA -----------  \n dstWidth: %d   stride: %d ", dstRgba.cols, buf.stride);

    // copy to TextureView surface
    uchar *dbuf;
    uchar *sbuf;
    dbuf = dstRgba.data;
    sbuf = flipRgba.data;
    int i;
    for (i = 0; i < flipRgba.rows; i++) {
        dbuf = dstRgba.data + i * buf.stride * 4;
        memcpy(dbuf, sbuf, flipRgba.cols * 4);
        sbuf += flipRgba.cols * 4;
    }


    // Draw some rectangles
    line(dstRgba, Point(dstWidth/2, 0), Point(dstWidth/2, dstHeight-1),Scalar(255, 255, 255));
    line(dstRgba, Point(0,dstHeight-1), Point(dstWidth-1, dstHeight-1),Scalar(255,255,255 ));

    LOGE("bob dstWidth=%d height=%d", dstWidth, dstHeight);
    ANativeWindow_unlockAndPost(win);
    ANativeWindow_release(win);

    // Release
    env->ReleaseStringUTFChars(path_, str);

    //Ret
    return env->NewStringUTF("abc");
}

...这就是我得到的输出:

我还打印了所有尺寸以检查差异:

03-08 10:45:55.234 9681-9706 E/NATIVE_IMPROC:  ------- DATA -----------  
                                               dstWidth: 1152   stride: 1152    dstHeight: 1920 

Answer 1

如果 srcBuffer 来自 camera2 图像阅读器，它可能来自 YUV_420_888格式，它有一个可以指定非零步幅的标题，以及到 Y、U 和 V 平面的偏移量。实际上，Y、U、V 帧可能属于不同的 ByteBuffer，但通常相机制造商太懒了。