android4.0 USB Camera实例(六)ffmpeg mpeg编码

前面本来说是做h264编码的　研究了两天发现ffmpeg里的h264编码似乎是要信赖第三方库x264 还是怎么简单怎么来吧所以就整了个mpeg编码　ffmpeg移植前面我有一篇ffmpeg解码里已经给了　具体链接在这http://blog.csdn.net/hclydao/article/details/18546757

怎么使用那里面也已经说了　这里主要是通过ffmpeg将yuv422格式转换成rgb 然后就是yuv422转成mpeg格式　接前面几篇　获取到yuv422数据后　为了能显示出来　所以先转换成rgb565的数据 接口函数如下

/*
* yuv to rgb
*/
JNIEXPORT jint JNICALL Java_com_hclydao_webcam_Ffmpeg_yuvtorgb(JNIEnv * env, jclass obj,const jbyteArray yuvdata, jbyteArray rgbdata,const jint dwidth,const jint dheight)
{
	jbyte *ydata = (jbyte*)(*env)->GetByteArrayElements(env, yuvdata, 0);
	jbyte *rdata = (jbyte*)(*env)->GetByteArrayElements(env, rgbdata, 0);
	AVFrame * rpicture=NULL;
	AVFrame * ypicture=NULL;
	struct SwsContext *swsctx = NULL;
	rpicture=avcodec_alloc_frame();
	ypicture=avcodec_alloc_frame();
	avpicture_fill((AVPicture *) rpicture, (uint8_t *)rdata, PIX_FMT_RGB565,dwidth,dheight);
	avpicture_fill((AVPicture *) ypicture, (uint8_t *)ydata, AV_PIX_FMT_YUYV422,mwidth,mheight);
	swsctx = sws_getContext(mwidth,mheight, AV_PIX_FMT_YUYV422,	dwidth, dheight,PIX_FMT_RGB565, SWS_BICUBIC, NULL, NULL, NULL);
	sws_scale(swsctx,(const uint8_t* const*)ypicture->data,ypicture->linesize,0,mheight,rpicture->data,rpicture->linesize);
	sws_freeContext(swsctx);
	av_free(rpicture);
	av_free(ypicture);
	(*env)->ReleaseByteArrayElements(env, yuvdata, ydata, 0);
	(*env)->ReleaseByteArrayElements(env, rgbdata, rdata, 0);
	return 0;
}

然后就是mpeg编码了 网上说ffmpeg只能将yuv420p的编码　所以要先将yuv422转成yuv420p后在进行编码 相关接口函数如下

AVCodecContext *pCodecCtx= NULL;
AVPacket avpkt;
FILE * video_file;
unsigned char *outbuf=NULL;
unsigned char *yuv420buf=NULL;
static int outsize=0;
/*
* encording init
*/
JNIEXPORT jint JNICALL Java_com_hclydao_webcam_Ffmpeg_videoinit(JNIEnv * env, jclass obj,jbyteArray filename)
{
	LOGI("%s\n",__func__);
	AVCodec * pCodec=NULL;
	avcodec_register_all();
	pCodec=avcodec_find_encoder(AV_CODEC_ID_MPEG1VIDEO);
	if(pCodec == NULL) {
		LOGE("++++++++++++codec not found\n");
		return -1;
	} 
    pCodecCtx=avcodec_alloc_context3(pCodec);
    if (pCodecCtx == NULL) {
        LOGE("++++++Could not allocate video codec context\n");
        return -1;
    }
    /* put sample parameters */
    pCodecCtx->bit_rate = 400000;
    /* resolution must be a multiple of two */
    pCodecCtx->width = mwidth;
    pCodecCtx->height = mheight;
    /* frames per second */
    pCodecCtx->time_base= (AVRational){1,25};
    pCodecCtx->gop_size = 10; /* emit one intra frame every ten frames */
    pCodecCtx->max_b_frames=1;
    pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;//AV_PIX_FMT_YUYV422;
    /* open it */
    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
        LOGE("+++++++Could not open codec\n");
        return -1;
    }
	outsize = mwidth * mheight*2;
	outbuf = malloc(outsize*sizeof(char));
	yuv420buf = malloc(outsize*sizeof(char));
	jbyte *filedir = (jbyte*)(*env)->GetByteArrayElements(env, filename, 0);
  	if ((video_file = fopen(filedir, "wb")) == NULL) {
    	LOGE("++++++++++++open %s failed\n",filedir);
    	return -1;
  	}
	(*env)->ReleaseByteArrayElements(env, filename, filedir, 0);
	return 1;
}

JNIEXPORT jint JNICALL Java_com_hclydao_webcam_Ffmpeg_videostart(JNIEnv * env, jclass obj,jbyteArray yuvdata)
{
	int frameFinished=0,size=0;
	jbyte *ydata = (jbyte*)(*env)->GetByteArrayElements(env, yuvdata, 0);
	AVFrame * yuv420pframe=NULL;
	AVFrame * yuv422frame=NULL;
	struct SwsContext *swsctx = NULL;
	yuv420pframe=avcodec_alloc_frame();
	yuv422frame=avcodec_alloc_frame();
	avpicture_fill((AVPicture *) yuv420pframe, (uint8_t *)yuv420buf, AV_PIX_FMT_YUV420P,mwidth,mheight);
	avpicture_fill((AVPicture *) yuv422frame, (uint8_t *)ydata, AV_PIX_FMT_YUYV422,mwidth,mheight);
	swsctx = sws_getContext(mwidth,mheight, AV_PIX_FMT_YUYV422,	mwidth, mheight,AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
	sws_scale(swsctx,(const uint8_t* const*)yuv422frame->data,yuv422frame->linesize,0,mheight,yuv420pframe->data,yuv420pframe->linesize);
	av_init_packet(&avpkt);
	size = avcodec_encode_video2(pCodecCtx, &avpkt, yuv420pframe, &frameFinished);
    if (size < 0) {
    	LOGE("+++++Error encoding frame\n");
        return -1;
    }
	if(frameFinished)
		fwrite(avpkt.data,avpkt.size,1,video_file);
	av_free_packet(&avpkt);
	sws_freeContext(swsctx);
	av_free(yuv420pframe);
	av_free(yuv422frame);
	(*env)->ReleaseByteArrayElements(env, yuvdata, ydata, 0);
}

JNIEXPORT jint JNICALL Java_com_hclydao_webcam_Ffmpeg_videoclose(JNIEnv * env, jclass obj)
{
	fclose(video_file);
	avcodec_close(pCodecCtx);
	av_free(pCodecCtx);
	free(outbuf);
}

最后录下来的视频是可以用播放的　总感觉代码好像哪里写的不对 bug总是有的　过程和原理搞清楚了其它就容易了

下面是我录的 至此摄像头这块暂时就这样了

这测试我又重新新建了一个工程

整个工程下载链接　请去我的资源里找吧　我上传了没显示出来　那个有20几Ｍ的就是的了

这个bug很多　没怎么认真去写　如果原理和过程有问题的希望大家指出