的直播，主要使用的是camera采集的数据推流到服务器上，在客户端播放camera采集的数据。采用SurfaceView+ SurfaceTexture来显示camera数据, SurfaceTexture在接收图像流之后,可以进行二次处理，比如(加字体水印), 处理完毕后再送给另一个SurfaceView用于显示.
先说说，android端采集摄像头数据，这个网上有很多的资料，可以百度下。这里可以在回调函数OnPreviewFrame(byte[] data,Camera cma)中获取摄像头数据data. 关键是如何把data传输到服务器，要实现这个目标，我使用ffmpeg 来解决这个为题。在android 工程创建jni文件夹，使用jni调用。native函数如下:// 在OnPreviewFrame中调用
public native void push(byte[] data); // 可以在OnSurfcaeChanged(）中调用. 在jni中初始化输出路径. public native int initPush(String outputurl,int width,int height); 在jni 层的代码如下:static void ffmpeg_init() {
avcodec_register_all();
#if CONFIG_AVDEVICE
avdevice_register_all();#endif
avfilter_register_all();av_register_all();avformat_network_init();
}
static int avinit(int width, int height){/**编码开始*/int ret;if(codec==NULL){ yuv_width = width; yuv_height = height; y_length = width * height; uv_length = width * height / 4; LOGI("init start\n"); codec = avcodec_find_encoder(AV_CODEC_ID_H264); if (!codec) { LOGI("Codec not found\n"); return -1; } c = avcodec_alloc_context3(codec); if (!c) { LOGI("Could not allocate video codec context\n"); return -1; } /* put sample parameters */ c->bit_rate = 400000; /* resolution must be a multiple of two */ c->width = width; c->height = height; /* frames per second */ //c->time_base = (AVRational){1,5}; c->time_base.den = 25; c->time_base.num = 1; /* emit one intra frame every ten frames * check frame pict_type before passing frame * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I * then gop_size is ignored and the output of encoder * will always be I frame irrespective to gop_size */ if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER) c->flags |= CODEC_FLAG_GLOBAL_HEADER; c->gop_size = 10; c->max_b_frames = 10; c->pix_fmt = AV_PIX_FMT_YUV420P; //av_opt_set(c->priv_data, "preset", "slow", 0); av_opt_set(c->priv_data, "preset", "superfast", 0); av_opt_set(c->priv_data, "tune", "zerolatency", 0); /* open it */ if (avcodec_open2(c, codec, NULL) < 0) { LOGI("Could not open codec\n"); return -1; } LOGI("init end 1\n"); video_st = avformat_new_stream(ofmt_ctx, codec); if (video_st == NULL) { LOGI("video_st == NULL\n"); return -1; } video_st->time_base.num = 1; video_st->time_base.den = 25; video_st->codec = c; return 0;}/**编码结束*/ }
JNIEXPORT jint JNICALL Java_com_example_directvideo_MainActivity_initPush (JNIEnv *env, jobject obj,jstring out ,jint width, jint height){ int ret ; ffmpeg_init();const char* str = //"rtmp://192.168.1.102:1935/myapp/test1"; //"/storage/emulated/0/zsy.mp4"; (*env)->GetStringUTFChars(env, out, 0); LOGI("%s %d %d ", str,width,height); //AVOutputFormat *ofmt = NULL; //AVFormatContext *ofmt_ctx = NULL; //Output avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", str); //RTMP //avformat_alloc_output_context2(&ofmt_ctx, NULL, "mpegts", output_str);//UDP if (!ofmt_ctx) { LOGI( "Could not create output context\n"); ret = AVERROR_UNKNOWN; goto end; } ret = avinit(width, height); ofmt = ofmt_ctx->oformat; //Open output URL if (!(ofmt->flags & AVFMT_NOFILE)) { ret = avio_open(&ofmt_ctx->pb, str, AVIO_FLAG_WRITE); if (ret < 0) { LOGI( "Could not open output URL '%s'", str); goto end; } } ret = avformat_write_header(ofmt_ctx, NULL); if (ret < 0) { LOGE( "Error occurred when opening output URL\n"); goto end; } (*env)->ReleaseStringUTFChars(env, out, str); if (ret < 0 && ret != AVERROR_EOF) { LOGI( "Error occurred.\n"); return ret; } intited = 1;return 0;} 注意传输视频流时，必须使用h264编码器进行编码。初始化成功后，便可使用push()来推送每一帧的camera数据到服务器上。本人在ubuntu系统中，利用ngnix + rtmp搭建了简易的流媒体服务器。在pc机上，使用ffplay rtmp://192.168.1.102:1935/myapp/test1的命令来播放视屏.