FFMPEG H264/H265 编码延迟问题

参考：http://blog.csdn.net/aoshilang2249/article/details/40397199?utm_source=tuicool&utm_medium=referral

最新使用FFmpeg进行H264的编码时，发现视频编码有延迟，不是实时编码，进过一番研究发现，只要在调用avcodec_open2函数

打开编码器时，设置AVDictionary参数即可，关键代码如下：

avcodec_open2函数：

int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);

解决方案：

//H264, 设置为编码延迟为立即编码
if(c->codec_id == AV_CODEC_ID_H264)
{
     av_dict_set(ctx->priv_data, "preset", "superfast",   0);
    av_dict_set(ctx->priv_data, "tune",   "zerolatency", 0);
}
//H.265
if(c->codec_id == AV_CODEC_ID_H265)
{
 av_dict_set(ctx->priv_data, "x265-params", "qp=20", 0);
av_dict_set(ctx->priv_data, "preset", "ultrafast", 0);
av_dict_set(ctx->priv_data, "tune", "zero-latency", 0);
}

//使用给定的AVCodec初始化AVCodecContext
ret = avcodec_open2(参数, 参数,NULL);

还有这种方式:

// Set Option
    AVDictionary *param = 0;
    //H.264
    if(pCodecCtx->codec_id == AV_CODEC_ID_H264) {
        av_dict_set(?m, "preset", "slow", 0);
        av_dict_set(?m, "tune", "zerolatency", 0);
    }
    //H.265
    if(pCodecCtx->codec_id == AV_CODEC_ID_H265){
        av_dict_set(&param, "x265-params", "qp=20", 0);
        av_dict_set(&param, "preset", "ultrafast", 0);
        av_dict_set(&param, "tune", "zero-latency", 0);
    }

    //Dump Information 输出格式信息
    av_dump_format(pFormatCtx, 0, out_file, 1);

    pCodec = avcodec_find_encoder(pCodecCtx->codec_id);
    if (!pCodec){
        printf("Can not find encoder! 没有找到合适的编码器！\n");
        return -1;
    }
    if (avcodec_open2(pCodecCtx, pCodec,&param) < 0){
        printf("Failed to open encoder! 编码器打开失败！\n");
        return -1;
    }