NDK–利用Camera和AudioRecord实现直播推流

时间:2021-7-9 作者:qvyue
上次我们在Android Studio中新建了项目,集成了实现直播推流所需要的工具,分别是:
  • rtmpdump:推流
  • x264:视频编码
  • faac:音频编码
文章地址:NDK–Android Studio中直播推流框架的搭建
直播推流还需要流媒体服务器支持,我这边使用的是虚拟机,有条件的也可以使用真正的服务器,具体的流媒体服务器搭建方法可以参考我以前的文章:Nginx流媒体服务器搭建
基本工作完成后,今天我们来实现直播推流。
1.首先界面非常简单,布局文件如下:


        

        
    
一个按钮开始推流,一个按钮停止推流,一个按钮切换前后置摄像头,一个SurfaceView显示摄像头画面
NDK--利用Camera和AudioRecord实现直播推流
2.定义好native方法,用于获取Java的摄像头视频和录音音频数据,以及音视频参数
public class NativePush {
    private static final String TAG = NativePush.class.getSimpleName();

    static {
        System.loadLibrary("native-lib");
    }

    private LiveStateChangeListener mListener;

    public void setLiveStateChangeListener(LiveStateChangeListener listener) {
        mListener = listener;
    }

    /**
     * native层回调
     *
     * @param code -96:音频编码器设置失败
     *             -97:音频编码器打开失败
     *             -98:打开视频编码器失败
     *             -99:建立rtmp连接失败
     *             -100:rtmp断开
     */
    public void onPostNativeError(int code) {
        Log.e(TAG, "onPostNativeError:" + code);
        //停止推流
        stopPush();
        Log.d("NativePush", code + "");
        if (null != mListener) {
            mListener.onErrorPusher(code);
        }
    }

    /**
     * native层回调
     * 推流连接建立和线程退出
     *
     * @param state
     */
    public void onPostNativeState(int state) {
        if (state == 100) {
            mListener.onStartPusher();
        } else if (state == 101) {
            mListener.onStopPusher();
        }
    }

    //设置视频参数
    public native void setVideoParams(int width, int height, int bitrate, int fps);

    //设置音频参数
    public native void setAudioParams(int sample, int channel);

    //推视频帧
    public native void pushVideo(byte[] buffer);

    //推音频帧
    public native void pushAudio(byte[] buffer, int size);

    //开始推流线程
    public native void startPush(String url);

    //停止推流
    public native void stopPush();

    //获取音频缓冲区大小
    public native int getInputSamples();
}
3.定义视频和音频的参数类,方便后期统一管理
package com.aruba.rtmppushapplication.push.params;

/**
 * 视频参数
 * Created by aruba on 2021/1/12.
 */
public class VideoParams {
    //帧数
    private int fps;
    private int videoWidth;
    private int videoHeight;
    //码率
    private int bitrate;
    private int cameraId;

    private VideoParams(int videoWidth, int videoHeight, int cameraId) {
        this.videoWidth = videoWidth;
        this.videoHeight = videoHeight;
        this.cameraId = cameraId;
    }

    public int getFps() {
        return fps;
    }

    public void setFps(int fps) {
        this.fps = fps;
    }

    public int getVideoWidth() {
        return videoWidth;
    }

    public void setVideoWidth(int videoWidth) {
        this.videoWidth = videoWidth;
    }

    public int getVideoHeight() {
        return videoHeight;
    }

    public void setVideoHeight(int videoHeight) {
        this.videoHeight = videoHeight;
    }

    public int getBitrate() {
        return bitrate;
    }

    public void setBitrate(int bitrate) {
        this.bitrate = bitrate;
    }

    public int getCameraId() {
        return cameraId;
    }

    public void setCameraId(int cameraId) {
        this.cameraId = cameraId;
    }

    public static class Builder {
        private int fps = 25;
        private int videoWidth = -1;
        private int videoHeight = -1;
        private int bitrate = 480000;
        private int cameraId = -1;

        public Builder fps(int fps) {
            this.fps = fps;
            return this;
        }

        public Builder videoSize(int videoWidth, int videoHeight) {
            this.videoHeight = videoHeight;
            this.videoWidth = videoWidth;
            return this;
        }

        public Builder bitrate(int bitrate) {
            this.bitrate = bitrate;
            return this;
        }

        public Builder cameraId(int cameraId) {
            this.cameraId = cameraId;
            return this;
        }

        public VideoParams build() {
            if (videoWidth == -1 || videoHeight == -1 || cameraId == -1) {
                throw new RuntimeException("videoWidth,videoHeight,cameraId must be config");
            }
            VideoParams videoParams = new VideoParams(videoWidth, videoHeight, cameraId);
            videoParams.setBitrate(bitrate);
            videoParams.setFps(fps);

            return videoParams;
        }
    }
}

视频需要的参数为视频宽高、fps、比特率、摄像头id(前置还是后置)

package com.aruba.rtmppushapplication.push.params;

/**
 * 音频参数
 * Created by aruba on 2021/1/12.
 */
public class AudioParams {
    //采样率
    private int sampleRate;
    //声道数
    private int channel;

    private AudioParams() {
    }

    public int getSampleRate() {
        return sampleRate;
    }

    public void setSampleRate(int sampleRate) {
        this.sampleRate = sampleRate;
    }

    public int getChannel() {
        return channel;
    }

    public void setChannel(int channel) {
        this.channel = channel;
    }

    public static class Builder {
        //采样率
        private int sampleRate = 44100;
        //声道数
        private int channel = 1;

        public Builder sampleRate(int sampleRate) {
            this.sampleRate = sampleRate;
            return this;
        }

        public Builder channel(int channel) {
            this.channel = channel;
            return this;
        }
        
        public AudioParams build(){
            AudioParams audioParams = new AudioParams();
            audioParams.setSampleRate(sampleRate);
            audioParams.setChannel(channel);
            
            return audioParams;
        }
    }
}

音频的参数为采样率和声道数,采样位数我们统一使用16bit

4.定义统一接口,用于音视频推流实现
package com.aruba.rtmppushapplication.push;

/**
 * Created by aruba on 2020/12/30.
 */
public interface IPush {
    /**
     * 初始化
     */
    void init();

    /**
     * 开始推流
     */
    int startPush();

    /**
     * 停止推流
     */
    void stopPush();
}

5.定义统一管理类,用于管理音视频推流
package com.aruba.rtmppushapplication.push;

import android.app.Activity;
import android.hardware.Camera;
import android.view.SurfaceHolder;

import com.aruba.rtmppushapplication.push.natives.LiveStateChangeListener;
import com.aruba.rtmppushapplication.push.natives.NativePush;
import com.aruba.rtmppushapplication.push.params.AudioParams;
import com.aruba.rtmppushapplication.push.params.VideoParams;

import java.lang.ref.WeakReference;

/**
 * 直播推流工具类
 * Created by aruba on 2021/1/12.
 */
public class PushHelper {
    //显示摄像头画面的surface
    private SurfaceHolder surfaceHolder;
    //音频推流
    private AudioPush audioPush;
    //视频推流
    private VideoPush videoPush;
    private WeakReference activity;
    //native层对象
    private NativePush nativePush;

    public PushHelper(Activity activity, SurfaceHolder surfaceHolder) {
        this.activity = new WeakReference(activity);
        this.surfaceHolder = surfaceHolder;
        init();
    }

    /**
     * 初始化
     */
    private void init() {
        nativePush = new NativePush();
        //设置回调
        nativePush.setLiveStateChangeListener(new LiveStateChangeListener() {
            @Override
            public void onErrorPusher(int code) {
                videoPush.stopPush();
                audioPush.stopPush();
            }

            @Override
            public void onStartPusher() {
                //等待rtmp连接开启后,再开始推视频和音频
                videoPush.startPush();
                audioPush.startPush();
            }

            @Override
            public void onStopPusher() {
                videoPush.stopPush();
                audioPush.stopPush();
            }
        });
        
        //初始化视频参数
        VideoParams videoParams = new VideoParams.Builder()
                .videoSize(1920, 1080)
                .bitrate(960000)
                .cameraId(Camera.CameraInfo.CAMERA_FACING_BACK)
                .build();
        videoPush = new VideoPush(activity.get(), videoParams, surfaceHolder);
        videoPush.setNativePush(nativePush);
        
        //初始化音频参数
        AudioParams audioParams = new AudioParams.Builder()
                .channel(1)
                .sampleRate(44100)
                .build();
        audioPush = new AudioPush(audioParams);
        audioPush.setNativePush(nativePush);

        videoPush.init();
        audioPush.init();
    }

    /**
     * 开始推流
     *
     * @param url 服务器地址
     */
    public void startPush(String url) {
        nativePush.startPush(url);
    }

    /**
     * 停止推流
     */
    public void stopPush() {
        nativePush.stopPush();
    }

    /**
     * 切换摄像头
     */
    public void swtichCamera() {
        if (videoPush != null)
            videoPush.swtichCamera();
    }
}

到目前为止,基本框架已经构建好,接下来来分别获取摄像头数据和麦克风数据,并将数据传入native层
1.摄像头数据获取,并传入native层
package com.aruba.rtmppushapplication.push;

import android.app.Activity;
import android.graphics.ImageFormat;
import android.hardware.Camera;
import android.util.Log;
import android.view.Surface;
import android.view.SurfaceHolder;

import com.aruba.rtmppushapplication.push.natives.NativePush;
import com.aruba.rtmppushapplication.push.params.VideoParams;

import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.Iterator;
import java.util.List;

/**
 * 对应视频推流的native层
 * Created by aruba on 2021/1/12.
 */
public class VideoPush implements IPush, Camera.PreviewCallback {
    private final static String TAG = VideoPush.class.getSimpleName();
    private VideoParams videoParams;
    //摄像头
    private Camera camera;
    //显示摄像头数据
    private SurfaceHolder surfaceHolder;
    //摄像头画面数据缓冲区
    private byte[] buffers;
    private boolean isSurfaceCreate;
    private NativePush nativePush;
    private WeakReference mActivity;
    private int screen;

    private byte[] raw;
    private final static int SCREEN_PORTRAIT = 0;
    private final static int SCREEN_LANDSCAPE_LEFT = 90;
    private final static int SCREEN_LANDSCAPE_RIGHT = 270;
    private boolean isPushing;

    public VideoPush(Activity activity, VideoParams videoParams, SurfaceHolder surfaceHolder) {
        this.mActivity = new WeakReference(activity);
        this.videoParams = videoParams;
        this.surfaceHolder = surfaceHolder;
    }

    @Override
    public void init() {
        if (videoParams == null) {
            throw new NullPointerException("videoParams is null");
        }
        surfaceHolder.addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder surfaceHolder) {
                isSurfaceCreate = true;
                resetPreview(surfaceHolder);
            }

            @Override
            public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {
//                stopPreview();
//                startPreview();
            }

            @Override
            public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
                isSurfaceCreate = false;
            }
        });
    }

    /**
     * 开始预览
     */
    private synchronized void startPreview() {
        try {
            camera = Camera.open(videoParams.getCameraId());
            Camera.Parameters parameters = camera.getParameters();
            parameters.setPreviewFormat(ImageFormat.NV21);//yuv
            setPreviewSize(parameters);
            setPreviewOrientation(parameters);
//            parameters.setPreviewSize(videoParams.getVideoWidth(), videoParams.getVideoHeight());
            camera.setParameters(parameters);
            if (isSurfaceCreate)
                camera.setPreviewDisplay(surfaceHolder);

            //创建缓冲区  长 * 宽 * 一像素所占用字节
            int bytePerPixel = ImageFormat.getBitsPerPixel(ImageFormat.NV21);
            buffers = new byte[videoParams.getVideoWidth() * videoParams.getVideoHeight()
                    * bytePerPixel];
            raw = new byte[videoParams.getVideoWidth() * videoParams.getVideoHeight()
                    * bytePerPixel];
            camera.addCallbackBuffer(buffers);
            camera.setPreviewCallbackWithBuffer(this);
            camera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onPreviewFrame(byte[] bytes, Camera camera) {
        if (isPushing) {
            switch (screen) {//根据屏幕位置,旋转像素数据
                case SCREEN_PORTRAIT://竖屏
                    portraitData2Raw(buffers);
                    break;
                case SCREEN_LANDSCAPE_LEFT:
                    raw = buffers;
                    break;
                case SCREEN_LANDSCAPE_RIGHT:// 横屏 头部在右边
                    landscapeData2Raw(buffers);
                    break;
            }

            if (camera != null) {
                //每次必须再调用该方法,不然onPreviewFrame只会回调一次 注:bytes就是buffers
                camera.addCallbackBuffer(bytes);
            }

            nativePush.pushVideo(raw);
        } else {
            stopPreview();
        }
//        Log.i(TAG, "获取到了视频数据");
    }

    private synchronized void resetPreview(SurfaceHolder surfaceHolder) {
        if (camera != null) {
            try {
                camera.setPreviewDisplay(surfaceHolder);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private synchronized void stopPreview() {
        if (camera != null) {
            camera.stopPreview();
            camera.release();
            camera = null;
        }
    }

    @Override
    public int startPush() {
        synchronized (TAG) {
            if (isPushing) {
                return -1;
            }
            isPushing = true;
        }
        startPreview();
        return 0;
    }

    @Override
    public void stopPush() {
        synchronized (TAG) {
            isPushing = false;
        }
    }

    public void swtichCamera() {
        if (videoParams.getCameraId() == Camera.CameraInfo.CAMERA_FACING_BACK) {
            videoParams.setCameraId(Camera.CameraInfo.CAMERA_FACING_FRONT);
        } else {
            videoParams.setCameraId(Camera.CameraInfo.CAMERA_FACING_BACK);
        }

        stopPreview();
        startPreview();
    }

    public void setVideoParams(VideoParams videoParams) {
        this.videoParams = videoParams;
    }

    public VideoParams getVideoParams() {
        return videoParams;
    }

    public void setNativePush(NativePush nativePush) {
        this.nativePush = nativePush;
    }

    /**
     * 获取摄像头支持的分辨率,并设置最佳分辨率
     *
     * @param parameters
     */
    private void setPreviewSize(Camera.Parameters parameters) {
        List supportedPreviewFormats = parameters.getSupportedPreviewFormats();
        for (Integer integer : supportedPreviewFormats) {
            System.out.println("支持:" + integer);
        }
        List supportedPreviewSizes = parameters.getSupportedPreviewSizes();
        Camera.Size size = supportedPreviewSizes.get(0);
        Log.d(TAG, "支持 " + size.width + "x" + size.height);
        int m = Math.abs(size.height * size.width - videoParams.getVideoHeight() * videoParams.getVideoWidth());
        supportedPreviewSizes.remove(0);
        Iterator iterator = supportedPreviewSizes.iterator();
        while (iterator.hasNext()) {
            Camera.Size next = iterator.next();
            Log.d(TAG, "支持 " + next.width + "x" + next.height);
            int n = Math.abs(next.height * next.width - videoParams.getVideoHeight() * videoParams.getVideoWidth());
            if (n  -1; i--) {
            raw[k] = data[i];
            k++;
        }
        // v1 u1 v2 u2
        // v3 u3 v4 u4
        // 需要转换为:
        // v4 u4 v3 u3
        // v2 u2 v1 u1
        int maxpos = data.length - 1;
        int uv_len = y_len >> 2; // 4:1:1
        for (int i = 0; i > 1; // uv数据高为y数据高的一半
        int k = 0;
        if (videoParams.getCameraId() == Camera.CameraInfo.CAMERA_FACING_BACK) {
            for (int j = 0; j = 0; i--) {
                    raw[k++] = data[width * i + j];
                }
            }
            for (int j = 0; j = 0; i--) {
                    raw[k++] = data[y_len + width * i + j];
                    raw[k++] = data[y_len + width * i + j + 1];
                }
            }
        } else {
            for (int i = 0; i 

当rtmp连接建立后,native层会回调方法:onPostNativeState,最终在PushHelper中调用VideoPush的startPush方法,该方法开启摄像头预览,将参数传给native层,并会不断调用onPreviewFrame方法将摄像头数据传递给native层。

需要注意的是:安卓手机摄像头的特殊性,需要我们根据屏幕方向来对摄像头数据进行旋转
2.音频数据获取,并传入native层
package com.aruba.rtmppushapplication.push;

import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;

import com.aruba.rtmppushapplication.push.natives.NativePush;
import com.aruba.rtmppushapplication.push.params.AudioParams;

/**
 * 对应音频推流的native层
 * Created by aruba on 2021/1/12.
 */
public class AudioPush implements IPush {
    private final static String tag = AudioPush.class.getSimpleName();
    private AudioParams audioParams;
    //录音
    private AudioRecord audioRecord;
    private int bufferSize;
    private RecordThread recordThread;
    private NativePush nativePush;

    public AudioPush(AudioParams audioParams) {
        this.audioParams = audioParams;
    }

    @Override
    public void init() {
        if (audioParams == null) {
            throw new NullPointerException("audioParams is null");
        }

        int channel = audioParams.getChannel() == 1 ?
                AudioFormat.CHANNEL_IN_MONO : AudioFormat.CHANNEL_IN_STEREO;
        //最小缓冲区大小
        bufferSize = AudioRecord.getMinBufferSize(audioParams.getSampleRate(),
                channel, AudioFormat.ENCODING_PCM_16BIT);
        audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,//麦克风
                audioParams.getSampleRate(),
                channel,
                AudioFormat.ENCODING_PCM_16BIT,
                bufferSize
        );
    }

    @Override
    public int startPush() {
        if (recordThread != null && recordThread.isPushing) {
            return -1;
        }
        stopRecord();
        recordThread = new RecordThread();
        recordThread.start();

        return 0;
    }

    @Override
    public void stopPush() {
        stopRecord();
    }

    private synchronized void stopRecord() {
        if (recordThread != null) {
            recordThread.isPushing = false;
        }
    }

    public void setAudioParams(AudioParams audioParams) {
        this.audioParams = audioParams;
    }

    public AudioParams getAudioParams() {
        return audioParams;
    }

    public void setNativePush(NativePush nativePush) {
        this.nativePush = nativePush;
    }

    class RecordThread extends Thread {
        private boolean isPushing = true;

        @Override
        public void run() {
            audioRecord.startRecording();

            nativePush.setAudioParams(audioParams.getSampleRate(), audioRecord.getChannelCount());
            while (isPushing) {
                //采样数 *  2字节(16bit:一个采样占的比特数)
                byte[] buffer = new byte[nativePush.getInputSamples() * 2];
                int len = audioRecord.read(buffer, 0, buffer.length);
                if (len > 0) {
                    //交由native层处理
//                    Log.i(tag, "获取到了音频数据");
                    nativePush.pushAudio(buffer, len);
                }
            }

            audioRecord.stop();
        }
    }
}

初始化AudioRecord后,需要开启一个线程,不断读取数据,并传入native层

注意:一次可以读取的数据大小需要通过faac编译器获取,并不能直接使用初始化AudioRecord时的bufferSize
Java层代码到此已经完成了,接下来是重头戏:native层代码编写。
1.在Java层我们第一步是调用native方法开启推流线程:
pthread_t *pid;
pthread_mutex_t mutex;
pthread_cond_t cond;

//开始推流的时间
uint32_t start_time;
//推流地址
char *path;

//回调java
JavaVM *jvm;
jobject jPublisherObj;


JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved) {
    jvm = vm;
    JNIEnv *env = NULL;
    jint result = -1;
    if (jvm) {
        LOGD("jvm init success");
    }
    if (vm->GetEnv((void **) &env, JNI_VERSION_1_4) != JNI_OK) {
        return result;
    }
    return JNI_VERSION_1_4;
}

/**
 * 调用java方法
 * @param env 
 * @param methodId 
 * @param code 
 */
void throwNativeInfo(JNIEnv *env, jmethodID methodId, int code) {
    if (env && methodId && jPublisherObj) {
        env->CallVoidMethodA(jPublisherObj, methodId, (jvalue *) &code);
    }
}

/**
 * 开始推流线程
 */
extern "C"
JNIEXPORT void JNICALL
Java_com_aruba_rtmppushapplication_push_natives_NativePush_startPush(JNIEnv *env, jobject instance,
                                                                     jstring url_) {
    if (isPublishing)//线程在运行
        return;

    if (!jPublisherObj) {
        jPublisherObj = env->NewGlobalRef(instance);
    }

    LOGE("开始推流");
    pthread_t id;
    pthread_t *pid = &id;
    const char *url = env->GetStringUTFChars(url_, 0);

    //存放url路径
    int url_len = strlen(url) + 1;
    path = (char *) (malloc(url_len));
    memset(path, 0, url_len);
    memcpy(path, url, url_len - 1);

    pthread_cond_init(&cond, NULL);
    pthread_mutex_init(&mutex, NULL);
    start_time = RTMP_GetTime();
    pthread_create(pid, NULL, startPush, NULL);

    env->ReleaseStringUTFChars(url_, url);
}
2.编写线程执行的代码,开启rtmp连接
bool isPublishing = false;

/**
 * 推流线程 
 * @param arg 
 * @return 
 */
void *startPush(void *arg) {
    pthread_mutex_lock(&mutex);
    isPublishing = true;
    pthread_mutex_unlock(&mutex);

    JNIEnv *env;
    jvm->AttachCurrentThread(&env, 0);
    jclass clazz = env->GetObjectClass(jPublisherObj);
    jmethodID errorId = env->GetMethodID(clazz, "onPostNativeError", "(I)V");
    jmethodID stateId = env->GetMethodID(clazz, "onPostNativeState", "(I)V");

    //rtmp连接
    RTMP *connect = RTMP_Alloc();
    RTMP_Init(connect);
    connect->Link.timeout = 5;//超时时间
    RTMP_SetupURL(connect, path);//设置地址
    RTMP_EnableWrite(connect);
    if (!RTMP_Connect(connect, NULL)) {//建立socket
        //建立失败
        LOGE("建立rtmp连接失败");
        //回调java层
        throwNativeInfo(env, errorId, -99);
        pthread_mutex_lock(&mutex);

        isPublishing = false;
        RTMP_Close(connect);
        RTMP_Free(connect);
        free(path);
        path = NULL;

        pthread_mutex_unlock(&mutex);
        release(env);

        jvm->DetachCurrentThread();
        pthread_exit(0);
    }
    RTMP_ConnectStream(connect, 0);//连接流
    LOGE("推流连接建立");
    throwNativeInfo(env, stateId, 100);

    while (isPublishing) {
        RTMPPacket *packet = get();
        if (packet == NULL) {
            continue;
        }

        //推流
        packet->m_nInfoField2 = connect->m_stream_id;
        int ret = RTMP_SendPacket(connect, packet, 1);//1:使用rtmp本身的上传队列
        if (!ret) {
            LOGE("rtmp断开");
            throwNativeInfo(env, errorId, -100);
        }

        RTMPPacket_Free(packet);
        free(packet);
    }

    LOGE("结束推流");
    //释放
    RTMP_Close(connect);
    RTMP_Free(connect);
    free(path);
    path = NULL;
    throwNativeInfo(env, stateId, 101);
    release(env);
    jvm->DetachCurrentThread();
    pthread_exit(0);
}
3.编写生产者消费者模式,线程中使用生产者消费者模式进行线程同步,取出数据并推流,RTMPPacket就是封装好的编码过后的数据(音视频数据经过x264、faac编码压缩后,还需要封装成rtmp可识别的数据,实际上就是一个组包的过程,后面会详细介绍如何将x264、faac编码的数据封装成RTMPPacket)
//RTMPPacket队列
std::queue queue;

//生产者
void put(RTMPPacket *pPacket) {
    pthread_mutex_lock(&mutex);
    if (isPublishing) {
        queue.push(pPacket);
    }

    pthread_cond_signal(&cond);
    pthread_mutex_unlock(&mutex);
}

//消费者
RTMPPacket *get() {
    pthread_mutex_lock(&mutex);
    if (queue.empty()) {
        pthread_cond_wait(&cond, &mutex);
    }

    RTMPPacket *packet = NULL;
    if (!queue.empty()) {
        packet = queue.front();
        queue.pop();
    }

    pthread_mutex_unlock(&mutex);

    return packet;
}
4.设置音视频参数,初始化缓冲区
//y u v 分别所占字节
int y_len, u_len, v_len;
//裸数据
x264_picture_t *pic;
//编码后的数据
x264_picture_t *pic_out;
//编码器
x264_t *encoder;

extern "C"
JNIEXPORT void JNICALL
Java_com_aruba_rtmppushapplication_push_natives_NativePush_setVideoParams(JNIEnv *env,
                                                                          jobject instance,
                                                                          jint width, jint height,
                                                                          jint bitrate, jint fps) {
    if (pic != NULL) {
        x264_picture_clean(pic);
        free(pic);
        free(pic_out);
        pic = NULL;
        pic_out = NULL;
    }
    y_len = width * height;
    u_len = y_len / 4;
    v_len = u_len;

    //设置参数
    x264_param_t param;
    //    zerolatency预设以下内容
    //            param->rc.i_lookahead = 0;
    //            param->i_sync_lookahead = 0;
    //            param->i_bframe = 0;
    //            param->b_sliced_threads = 1;
    //            param->b_vfr_input = 0;
    //            param->rc.b_mb_tree = 0;
    x264_param_default_preset(&param, x264_preset_names[0], "zerolatency");
    //设置支持的分辨率,默认就是51
    param.i_level_idc = 51;
    //推流的格式
    param.i_csp = X264_CSP_I420;
    //视频宽高
    param.i_width = width;
    param.i_height = height;
    param.i_threads = 1;

    //1秒多少帧
    param.i_timebase_num = fps;
    param.i_timebase_den = 1;
    param.i_fps_num = fps;
    param.i_fps_den = 1;
    //关键帧最大间隔时间的帧率
    param.i_keyint_max = fps * 2;

    //ABR:平均码率  CQP:恒定质量  CRF:恒定码率 
    param.rc.i_rc_method = X264_RC_ABR;
    //码率
    param.rc.i_bitrate = bitrate / 1000;
    //最大码率
    param.rc.i_vbv_max_bitrate = bitrate / 1000 * 1.2;
    //缓冲区大小
    param.rc.i_vbv_buffer_size = bitrate / 1000;

    //0:别的客户端使用pts做同步 1:推流端计算timebase做同步
    param.b_vfr_input = 0;
    //使用sps pps
    param.b_repeat_headers = 1;
    //码流级别,baseline只提供i和p帧,降低延迟,提供很好的兼容性
    x264_param_apply_profile(&param, "baseline");

    //获取解码器
    encoder = x264_encoder_open(&param);
    if (!encoder) {
        LOGE("打开视频编码器失败");
        jmethodID errorId = env->GetMethodID(env->GetObjectClass(instance), "onPostNativeError",
                                             "(I)V");
        throwNativeInfo(env, errorId, -98);
        return;
    }

    pic = (x264_picture_t *) (malloc(sizeof(x264_picture_t)));
    //调用内置函数初始化pic,pic存放yuv420数据
    x264_picture_alloc(pic, X264_CSP_I420, width, height);
    pic_out = (x264_picture_t *) (malloc(sizeof(x264_picture_t)));
    LOGE("视频编码器打开完成");
}
//音频编码器
faacEncHandle handle;
//音频缓冲区
unsigned long inputSamples;
//缓冲区最大字节数
unsigned long maxOutputBytes;

extern "C"
JNIEXPORT void JNICALL
Java_com_aruba_rtmppushapplication_push_natives_NativePush_setAudioParams(JNIEnv *env,
                                                                          jobject instance,
                                                                          jint sample,
                                                                          jint channel) {
    handle = faacEncOpen(sample, channel, &inputSamples, &maxOutputBytes);
    if (!handle) {
        LOGE("音频编码器打开失败");
        jmethodID errorId = env->GetMethodID(env->GetObjectClass(instance), "onPostNativeError",
                                             "(I)V");
        throwNativeInfo(env, errorId, -97);
        return;
    }

    //配置
    faacEncConfigurationPtr config = faacEncGetCurrentConfiguration(handle);
    config->mpegVersion = MPEG4;
    config->allowMidside = 1;//中等压缩
    config->aacObjectType = LOW;//音质
    config->outputFormat = 0;//输出格式
    config->useTns = 1;//消除爆破声
    config->useLfe = 0;
    config->inputFormat = FAAC_INPUT_16BIT;
    config->quantqual = 100;
    config->bandWidth = 0; //频宽
    config->shortctl = SHORTCTL_NORMAL;//编码方式

    int ret = faacEncSetConfiguration(handle, config);
    if (!ret) {
        LOGE("音频编码器设置失败");
        jmethodID errorId = env->GetMethodID(env->GetObjectClass(instance), "onPostNativeError",
                                             "(I)V");
        throwNativeInfo(env, errorId, -96);
        return;
    }

    LOGE("音频编码器设置成功");
}

视频编码器和音频编码器的设置看看注释就行了,毕竟不是专业人员,这边不作过多描述,感兴趣的同学可以网上查下资料

5.编写编码代码,编码Java层传递的音视频裸数据
/**
 * 编码视频
 */
extern "C"
JNIEXPORT void JNICALL
Java_com_aruba_rtmppushapplication_push_natives_NativePush_pushVideo(JNIEnv *env, jobject instance,
                                                                     jbyteArray buffer_) {
    if (!isPublishing || !encoder || !pic) {
        return;
    }
    jbyte *buffer = env->GetByteArrayElements(buffer_, NULL);

    uint8_t *u = pic->img.plane[1];
    uint8_t *v = pic->img.plane[2];
    //将nv21转换为yuv420
    for (int i = 0; i img.plane[0], buffer, y_len);
//    pic->img.plane[0] = buffer;

    //nalu
    x264_nal_t *nal = 0;
    //nalu数量
    int pi_nal;
    int ret = x264_encoder_encode(encoder, &nal, &pi_nal, pic, pic_out);
    if (ret ReleaseByteArrayElements(buffer_, buffer, 0);
        LOGE("编码失败");
        return;
    }

    //解包,将获取的有效数据交由rtmp编码
    unsigned char sps[100];
    unsigned char pps[100];
    int sps_len = 0;
    int pps_len = 0;

    for (int i = 0; i ReleaseByteArrayElements(buffer_, buffer, 0);
}

/**
 * 编码音频
 */
extern "C"
JNIEXPORT void JNICALL
Java_com_aruba_rtmppushapplication_push_natives_NativePush_pushAudio(JNIEnv *env, jobject instance,
                                                                     jbyteArray buffer_,
                                                                     jint size) {

    if (!isPublishing || !handle)
        return;

    jbyte *buffer = env->GetByteArrayElements(buffer_, NULL);

    unsigned char *outputBuffer = (unsigned char *) (malloc(
            sizeof(unsigned char) * maxOutputBytes));
    //编码
    int len = faacEncEncode(handle, (int32_t *) buffer, inputSamples, outputBuffer,
                            maxOutputBytes);
    if (len > 0) {
//        LOGE("rtmp音频推流");
        send_aac_body(outputBuffer, len);
    }

    env->ReleaseByteArrayElements(buffer_, buffer, 0);

    if (outputBuffer)
        free(outputBuffer);
}

比较难理解的是视频编码,之前介绍说h264主要是i帧,b帧,p帧,他们承载着像素数据,由于进行了压缩,可以这样理解:压缩后数据显然没有原数据的大小,所以原始数据的大小(画面的宽高),压缩比例等信息也要存储,他们就存储在sps和pps中,类似于http的headers,播放时也需要用到这些信息(毕竟解码时起码要知道画面的宽高吧),sps和pps的数据呢,又有4个字节作为分隔符,我们不需要这4个没用数据,所以要去掉它们

接下来就是将编码后的音视频数据进行组包,成为RTMPPacket
先来组包视频数据,我们组包时参考下面的文档
NDK--利用Camera和AudioRecord实现直播推流
NDK--利用Camera和AudioRecord实现直播推流
1.先是sps和pps,第一个字节为0x17,具体组包代码如下:
/**
 * rtmp发送头信息
 * @param sps 
 * @param pps 
 * @param len 
 * @param pps_len 
 */
void send_264_header(unsigned char *sps, unsigned char *pps, int sps_len, int pps_len) {
    int size = sps_len + pps_len + 16;//组包rtmp头信息需要额外16个字节
    RTMPPacket *packet = static_cast(malloc(sizeof(RTMPPacket)));
    //初始化内部缓冲区
    RTMPPacket_Alloc(packet, size);

    //组包
    unsigned char *body = reinterpret_cast(packet->m_body);
    int i = 0;
    body[i++] = 0x17;
    body[i++] = 0x00;
    body[i++] = 0x00;
    body[i++] = 0x00;
    body[i++] = 0x00;
    //版本号
    body[i++] = 0x01;
    //profile
    body[i++] = sps[1];
    //兼容性
    body[i++] = sps[2];
    //profile_level baseline
    body[i++] = sps[3];
    body[i++] = 0xff;
    body[i++] = 0xe1;
    //sps长度
    body[i++] = (sps_len >> 8) & 0xff;
    body[i++] = sps_len & 0xff;
    //sps内容
    memcpy(&body[i], sps, sps_len);
    i += sps_len;//指针偏移长度

    //pps
    body[i++] = 0x01;
    //pps长度
    body[i++] = (pps_len >> 8) & 0xff;
    body[i++] = pps_len & 0xff;
    memcpy(&body[i], pps, pps_len);

    //packet参数设置
    packet->m_packetType = RTMP_PACKET_TYPE_VIDEO;//视频类型
    packet->m_nBodySize = size;
    //客户端通过pts自己做同步
    packet->m_nTimeStamp = 0;
    packet->m_hasAbsTimestamp = 0;
    //指定通道
    packet->m_nChannel = 4;
    packet->m_headerType = RTMP_PACKET_SIZE_MEDIUM;

    //放入队列
    put(packet);
}
2.然后是关键帧和非关键帧:
/**
 * RTMP发送关键帧和非关键帧
 * @param payload 
 * @param i_payload 
 */
void send_264_body(uint8_t *payload, int i_payload) {
    if (payload[2] == 0x00) {//第三位为0x00的情况,无用信息为前4位:0000 0001
        payload += 4;
        i_payload -= 4;
    } else if (payload[2] == 0x01) {//第三位为0x01的情况,无用信息为前3位:0000 01
        payload += 3;
        i_payload -= 3;
    }

    //组包
    int size = i_payload + 9;//组包rtmp帧数据需要额外的9个字节
    RTMPPacket *packet = static_cast(malloc(sizeof(RTMPPacket)));
    //初始化内部缓冲区
    RTMPPacket_Alloc(packet, size);

    char *body = packet->m_body;
    int type = payload[0] & 0x1f;
    int index = 0;
    if (type == NAL_SLICE_IDR) {//关键帧
        body[index++] = 0x17;
    } else {//非关键帧
        body[index++] = 0x27;
    }

    body[index++] = 0x01;
    body[index++] = 0x00;
    body[index++] = 0x00;
    body[index++] = 0x00;

    //长度,占4个字节
    body[index++] = (i_payload >> 24) & 0xff;
    body[index++] = (i_payload >> 16) & 0xff;
    body[index++] = (i_payload >> 8) & 0xff;
    body[index++] = i_payload & 0xff;

    //存放数据
    memcpy(&body[index], payload, i_payload);

    //packet参数设置
    packet->m_packetType = RTMP_PACKET_TYPE_VIDEO;//视频类型
    packet->m_nBodySize = size;
    //客户端通过pts自己做同步
    packet->m_nTimeStamp = RTMP_GetTime() - start_time;//为了让客户端知道播放进度
    packet->m_hasAbsTimestamp = 0;
    //指定通道
    packet->m_nChannel = 0x04;
    packet->m_headerType = RTMP_PACKET_SIZE_LARGE;

    put(packet);
}
最后组包音频数据,先看下音频数据的文档:
NDK--利用Camera和AudioRecord实现直播推流
音频组包很简单,代码如下:
/**
 * 组包音频packet
 * @param buffer 
 * @param len 
 */
void send_aac_body(unsigned char *buffer, int len) {
    int size = len + 2;

    RTMPPacket *packet = static_cast(malloc(sizeof(RTMPPacket)));
    //初始化内部缓冲区
    RTMPPacket_Alloc(packet, size);

    char *body = packet->m_body;
    body[0] = 0xAF;
    body[1] = 0x01;
    memcpy(&body[2], buffer, len);

    //packet参数设置
    packet->m_packetType = RTMP_PACKET_TYPE_AUDIO;//音频类型
    packet->m_nBodySize = size;
    //客户端通过pts自己做同步
    packet->m_nTimeStamp = RTMP_GetTime() - start_time;//为了让客户端知道播放进度
    packet->m_hasAbsTimestamp = 0;
    //指定通道
    packet->m_nChannel = 0x04;
    packet->m_headerType = RTMP_PACKET_SIZE_MEDIUM;
    put(packet);
}
终于,直播推流代码完成了,赶紧跑下看下效果吧
NDK--利用Camera和AudioRecord实现直播推流
项目地址:https://gitee.com/aruba/rtmp-push-application.git
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