从Android视频图像获取的帧

本文介绍了从Android视频图像获取的帧的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我已经实现了一个简单的应用程序，它显示在屏幕上的摄像机图像。我想现在要做的就是抢单的帧并处理它作为位图。 从我能找到这点就不是一件容易的事。

I've implemented a simple application which shows the camera picture on the screen. What I like to do now is grab a single frame and process it as bitmap. From what I could find out to this point it is not an easy thing to do.

我已经使用与你得到的当前帧字节数组上previewFrame方法试了又试脱code它与BitmapFactory类，但它返回null。 帧的格式是一个无头YUV它可以被转换为位图，但它需要太长时间在手机上。我也读过，上previewFrame方法约束上在运行时，如果时间过长的应用程序可能会崩溃。

I've tried using the onPreviewFrame method with which you get the current frame as a byte array and tried to decode it with the BitmapFactory class but it returns null. The format of the frame is a headerless YUV which could be translated to bitmap but it takes too long on a phone. Also I've read that the onPreviewFrame method has contraints on the runtime, if it takes too long the application could crash.

那么，什么是正确的方式做到这一点？

So what is the right way to do this?

推荐答案

确定我们最终做的是使用在previewFrame方法和在一个单独的线程中的数据进行解码使用一种方法，它可以在Android中找到帮组。

Ok what we ended up doing is using the onPreviewFrame method and decoding the data in a seperate Thread using a method which can be found in the android help group.

decodeYUV(argb8888, data, camSize.width, camSize.height); Bitmap bitmap = Bitmap.createBitmap(argb8888, camSize.width, camSize.height, Config.ARGB_8888);

...

// decode Y, U, and V values on the YUV 420 buffer described as YCbCr_422_SP by Android // David Manpearl 081201 public void decodeYUV(int[] out, byte[] fg, int width, int height) throws NullPointerException, IllegalArgumentException { int sz = width * height; if (out == null) throw new NullPointerException("buffer out is null"); if (out.length < sz) throw new IllegalArgumentException("buffer out size " + out.length + " < minimum " + sz); if (fg == null) throw new NullPointerException("buffer 'fg' is null"); if (fg.length < sz) throw new IllegalArgumentException("buffer fg size " + fg.length + " < minimum " + sz * 3 / 2); int i, j; int Y, Cr = 0, Cb = 0; for (j = 0; j < height; j++) { int pixPtr = j * width; final int jDiv2 = j >> 1; for (i = 0; i < width; i++) { Y = fg[pixPtr]; if (Y < 0) Y += 255; if ((i & 0x1) != 1) { final int cOff = sz + jDiv2 * width + (i >> 1) * 2; Cb = fg[cOff]; if (Cb < 0) Cb += 127; else Cb -= 128; Cr = fg[cOff + 1]; if (Cr < 0) Cr += 127; else Cr -= 128; } int R = Y + Cr + (Cr >> 2) + (Cr >> 3) + (Cr >> 5); if (R < 0) R = 0; else if (R > 255) R = 255; int G = Y - (Cb >> 2) + (Cb >> 4) + (Cb >> 5) - (Cr >> 1) + (Cr >> 3) + (Cr >> 4) + (Cr >> 5); if (G < 0) G = 0; else if (G > 255) G = 255; int B = Y + Cb + (Cb >> 1) + (Cb >> 2) + (Cb >> 6); if (B < 0) B = 0; else if (B > 255) B = 255; out[pixPtr++] = 0xff000000 + (B << 16) + (G << 8) + R; } } }

链接：groups.google/group/android-developers/browse_thread/thread/c85e829ab209ceea/3f180a16a4872b58?lnk=gst&q=on$p$pviewframe#3f180a16a4872b58