关于libyuv格式转换、图像裁剪说明

项目源代码https://github.com/liluojun/PlayVideo

关联文章https://blog.csdn.net/hjt505694246/article/details/105046233Android硬编、硬解h264

https://blog.csdn.net/hjt505694246/article/details/105047729FFmpeg解码裸H264数据

         Android相机输出的是yuv数据、yuv数据格式太多了如420p、420sp等，我们经常会需要对yuv数据做处理，最原始的使用java for循环的方式耗时太多不合算，libyuv是由google开源的一个针对yuv数据处理的库，其效率比使用java处理的方式快太多了，故比较推荐使用。

public class NativeMethod {public native void nv21ToI420(byte[] src, byte[] dst, int w, int h, byte[] y, byte[] u, byte[] v);public native void nv21ToNv12(byte[] src, byte[] dst, int w, int h, byte[] y, byte[] u, byte[] v);public native void nv21CutterToI420(byte[] src, byte[] dst, int cutter_w, int cutter_h, int w, int h, byte[] y, byte[] u, byte[] v);public native void nv21CutterToNv12(byte[] src, byte[] dst, int cutter_w, int cutter_h, int w, int h, byte[] y, byte[] u, byte[] v);
}

我在项目中提供了4个方法示例前两个是nv21转420p和420sp，后两个是转的过程中做出裁剪。

参数说明：byte[] src 源数据

                  byte[] dst转换后的输出数据

                  int cutter_w裁剪的宽度

                  int cutter_h裁剪的高度

                  int w原宽度

                  int h原高度

                 byte[] y, byte[] u, byte[] v裁剪后yuv三个分量的数据，由于我用的是yuv渲染故需要这些值，没需求的可以不用理会。

jni层代码

#define  LOGE(...) __android_log_print(ANDROID_LOG_ERROR,"ffmpeg",__VA_ARGS__)
#ifndef _Included_media_jni_NativeMethod
#define _Included_media_jni_NativeMethod
#ifdef __cplusplus
extern "C" {
#include "libyuv.h"
#include <android/log.h>
#include "media_jni_NativeMethod.h"
#endif
void releaseByteArray(JNIEnv *env, jbyteArray array, uint8_t *elems, jint mode) {env->ReleaseByteArrayElements(array, (jbyte *) elems, mode);env->DeleteLocalRef(array);
}
/** Class:     media_jni_NativeMethod* Method:    nv21ToI420* Signature: ([B[BII)V*/
JNIEXPORT void JNICALL Java_media_jni_NativeMethod_nv21ToI420(JNIEnv *env, jobject job, jbyteArray src, jbyteArray dst, jint w, jint h, jbyteArray y,jbyteArray u, jbyteArray v) {uint8_t *srcArray = (uint8_t *) env->GetByteArrayElements(src, NULL);uint8_t *dstArray = (uint8_t *) env->GetByteArrayElements(dst, NULL);uint8_t *yArray = (uint8_t *) env->GetByteArrayElements(y, NULL);uint8_t *uArray = (uint8_t *) env->GetByteArrayElements(u, NULL);uint8_t *vArray = (uint8_t *) env->GetByteArrayElements(v, NULL);jint uvW = w >> 1;jint ySize = w * h;jint uSize = (uvW) * (h >> 1);uint8_t *y_src = srcArray;uint8_t *uv_src = srcArray + ySize;uint8_t *y_dst = dstArray;uint8_t *u_dst = dstArray + ySize;uint8_t *v_dst = dstArray + ySize + uSize;libyuv::NV21ToI420(y_src, w, uv_src, w, y_dst, w, u_dst, uvW, v_dst, uvW, w, h);memcpy(yArray, y_dst, ySize);memcpy(uArray, u_dst, (w * h) >> 2);memcpy(vArray, v_dst, (w * h) >> 2);//I420旋转方法注释但不能删除
//    yuv.libyuv::I420Rotate(y_tran, w, u_tran, w >> 1, v_tran, w >> 1, y_dst, h, u_dst, h >> 1, v_dst,
//                       h >> 1, h, w, yuv.libyuv::kRotate270);releaseByteArray(env, src, srcArray, 0);releaseByteArray(env, dst, dstArray, 0);releaseByteArray(env, y, yArray, 0);releaseByteArray(env, v, vArray, 0);releaseByteArray(env, u, uArray, 0);
} ;/** Class:     media_jni_NativeMethod* Method:    nv21ToNv12* Signature: ([B[BII)V*/
JNIEXPORT void JNICALL Java_media_jni_NativeMethod_nv21ToNv12(JNIEnv *env, jobject job, jbyteArray src, jbyteArray dst, jint w, jint h, jbyteArray y,jbyteArray u, jbyteArray v) {LOGE("111");uint8_t *srcArray = (uint8_t *) env->GetByteArrayElements(src, 0);uint8_t *dstArray = (uint8_t *) env->GetByteArrayElements(dst, 0);LOGE("222");uint8_t *yArray = (uint8_t *) env->GetByteArrayElements(y, NULL);uint8_t *uArray = (uint8_t *) env->GetByteArrayElements(u, NULL);uint8_t *vArray = (uint8_t *) env->GetByteArrayElements(v, NULL);jint ySize = w * h;jint uvSize = (w >> 1) * (h >> 1);uint8_t *y_src = srcArray;uint8_t *uv_src = srcArray + ySize;uint8_t *u_src = srcArray + ySize;uint8_t *v_src = srcArray + ySize + uvSize;uint8_t *y_dst = dstArray;uint8_t *uv_dst = dstArray + ySize;libyuv::NV21ToI420(y_src, w, uv_src, w, yArray, w, uArray, w >> 1, vArray, w >> 1, w,h);libyuv::I420ToNV12(yArray, w, uArray, w >> 1, vArray, w >> 1, y_dst, w, uv_dst, w, w, h);releaseByteArray(env, src, srcArray, 0);releaseByteArray(env, dst, dstArray, 0);releaseByteArray(env, y, yArray, 0);releaseByteArray(env, v, vArray, 0);releaseByteArray(env, u, uArray, 0);
} ;
/** Class:     media_jni_NativeMethod* Method:    nv21CutterToI420* Signature: ([B[BIIII)V*/
JNIEXPORT void JNICALL Java_media_jni_NativeMethod_nv21CutterToI420(JNIEnv *env, jobject job, jbyteArray src, jbyteArray dst, jint cw, jint ch, jint w,jint h, jbyteArray y,jbyteArray u, jbyteArray v) {uint8_t *srcArray = (uint8_t *) env->GetByteArrayElements(src, 0);uint8_t *dstArray = (uint8_t *) env->GetByteArrayElements(dst, 0);jbyteArray transitJbyteArray = env->NewByteArray(w * h * 3 / 2);uint8_t *transitArray = (uint8_t *) env->GetByteArrayElements(transitJbyteArray, 0);uint8_t *yArray = (uint8_t *) env->GetByteArrayElements(y, NULL);uint8_t *uArray = (uint8_t *) env->GetByteArrayElements(u, NULL);uint8_t *vArray = (uint8_t *) env->GetByteArrayElements(v, NULL);jint ySize = w * h;jint startx = (w - cw) / 2;jint starty = (h - ch) / 2;jint uvSize = (w >> 1) * (h >> 1);uint8_t *y_src = srcArray;uint8_t *uv_src = srcArray + ySize;uint8_t *y_transit = transitArray;uint8_t *u_transit = transitArray + ySize;uint8_t *v_transit = transitArray + ySize + uvSize;uint8_t *y_dst = dstArray;uint8_t *u_dst = dstArray + (cw * ch);uint8_t *v_dst = dstArray + (cw * ch) + ((cw * ch) >> 2);libyuv::NV21ToI420(y_src, w, uv_src, w, y_transit, w, u_transit, w >> 1, v_transit, w >> 1, w,h);libyuv::ConvertToI420(transitArray, ySize + uvSize, y_dst, cw, u_dst, cw >> 1,v_dst, cw >> 1,startx, starty, w, h, cw, ch, libyuv::kRotate0, libyuv::FOURCC_I420);memcpy(yArray, y_dst, cw * ch);memcpy(uArray, u_dst, (cw * ch) >> 2);memcpy(vArray, v_dst, (cw * ch) >> 2);releaseByteArray(env, transitJbyteArray, transitArray, 0);releaseByteArray(env, src, srcArray, 0);releaseByteArray(env, dst, dstArray, 0);releaseByteArray(env, y, yArray, 0);releaseByteArray(env, v, vArray, 0);releaseByteArray(env, u, uArray, 0);
} ;/** Class:     media_jni_NativeMethod* Method:    nv21CutterToNv12* Signature: ([B[BIIII)V*/
JNIEXPORT void JNICALL Java_media_jni_NativeMethod_nv21CutterToNv12(JNIEnv *env, jobject job, jbyteArray src, jbyteArray dst, jint cw, jint ch, jint w,jint h, jbyteArray y,jbyteArray u, jbyteArray v) {uint8_t *srcArray = (uint8_t *) env->GetByteArrayElements(src, 0);uint8_t *dstArray = (uint8_t *) env->GetByteArrayElements(dst, 0);uint8_t *yArray = (uint8_t *) env->GetByteArrayElements(y, NULL);uint8_t *uArray = (uint8_t *) env->GetByteArrayElements(u, NULL);uint8_t *vArray = (uint8_t *) env->GetByteArrayElements(v, NULL);jbyteArray transitJbyteArray = env->NewByteArray(w * h * 3 / 2);uint8_t *transitArray = (uint8_t *) env->GetByteArrayElements(transitJbyteArray, 0);jint ySize = w * h;jint startx = (w - cw) / 2;jint starty = (h - ch) / 2;jint uvSize = (w >> 1) * (h >> 1);uint8_t *y_src = srcArray;uint8_t *uv_src = srcArray + ySize;uint8_t *y_transit = transitArray;uint8_t *u_transit = transitArray + ySize;uint8_t *v_transit = transitArray + ySize + uvSize;uint8_t *y_dst = dstArray;uint8_t *uv_dst = dstArray + (cw * ch);libyuv::NV21ToI420(y_src, w, uv_src, w, y_transit, w, u_transit, w >> 1, v_transit, w >> 1, w,h);libyuv::ConvertToI420(transitArray, ySize + uvSize, yArray, cw, uArray, cw >> 1,vArray, cw >> 1,startx, starty, w, h, cw, ch, libyuv::kRotate0, libyuv::FOURCC_I420);libyuv::I420ToNV12(yArray, cw, uArray, cw >> 1, vArray, cw >> 1, y_dst, cw,uv_dst, cw, cw, ch);releaseByteArray(env, transitJbyteArray, transitArray, 0);releaseByteArray(env, src, srcArray, 0);releaseByteArray(env, dst, dstArray, 0);releaseByteArray(env, y, yArray, 0);releaseByteArray(env, v, vArray, 0);releaseByteArray(env, u, uArray, 0);
} ;
#ifdef __cplusplus
}
#endif
#endif以上就是jni层全部的代码基本上只涉及到数据转换和libyuv库的调用没啥太不好理解的地方。里面有注释旋转的代码有兴趣或者需求的童鞋可以恢复过来玩一玩。

这是yuv jni的目录。