本文讲述windows 平台下ffmpeg如何利用intel media SDK 进行 h264硬编码(测试版本为3.2.2)。

ffmeg硬编编码的流程与软件编码流程相同,唯一不同的地方在初始化encoder。软件编码基本流程前文有

介绍，本文不再赘述。下面介绍硬编编码初始化encoder代码。

int InitEncoderCodec( int iWidth, int iHeight)

{

AVCodec * pH264Codec = avcodec_find_encoder_by_name("h264_qsv");

//AVCodec * pH264Codec = avcodec_find_encoder_by_name("libx264");

//AVCodec * pH264Codec = avcodec_find_encoder(AV_CODEC_ID_H264);

if(NULL == pH264Codec)

{

printf("%s", "avcodec_find_encoder failed");

return -1;

}

outPutEncContext = avcodec_alloc_context3(pH264Codec);

outPutEncContext->gop_size = 12;

//outPutEncContext->framerate = 30;

//outPutEncContext->has_b_frames = 0;

outPutEncContext->max_b_frames = 0;

//outPutEncContext = avcodec_alloc_context3(pH264Codec);

outPutEncContext->codec_id = pH264Codec->id;

outPutEncContext->time_base.num =context->streams[0]->codec->time_base.num;

outPutEncContext->time_base.den = context->streams[0]->codec->time_base.den;

outPutEncContext->pix_fmt = *pH264Codec->pix_fmts;

outPutEncContext->width = iWidth;

outPutEncContext->height = iHeight;

//outPutEncContext->bit_rate = 4* 1024 * 1024;

AVDictionary *options = nullptr;

outPutEncContext->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;;

//av_dict_set(&options,"preset","ultrafast",0); //"ultrafast"s

//av_dict_set(&options,"preset","veryfast",0);

//av_opt_set(outPutEncContext->priv_data,"tune","zerolatency",0);

//av_opt_set(outPutEncContext->priv_data,"profile","baseline",0);

int ret = avcodec_open2(outPutEncContext, pH264Codec, &options);

AVQSVContext *qsv = (AVQSVContext *)outPutEncContext->hwaccel_context;

if (ret < 0)

{

printf("%s", "open codec failed");

return ret;

}

return 1;

}

硬编码与软件编码性能对比(测试机器，I7 5500)

视频复杂度低的情况下(例如编码抓取桌面视频(桌面视频无明显变化) 1080p，25fps)：

软件编码所占CPU 在30% -40%之间。硬件编码所在的cpu在18-25左右

视频负载度高的情况下(例如编码抓取桌面视频(桌面播放高清影视视频) 1080p，25fps)

软件编码所占CPU 在50% -70%之间。硬件编码所在的cpu在18-25左右

场景复杂度对软编的影响非常大，对硬编的影响不明显。

如有交流请加流媒体/Ffmpeg/音视频 127903734 ，或QQ350197870。

原文：http://www.cnblogs.com/wanggang123/p/6354485.html