ffmpeg 硬件解码

ffmpeg硬件解码可以使用最新的vulkan来做，基本上来说，不挑操作系统是比较重要的，如果直接使用cuda也是非常好的选择。

	AVPixelFormat sourcepf = AV_PIX_FMT_NV12;// AV_PIX_FMT_NV12;// AV_PIX_FMT_YUV420P;
	AVPixelFormat destpf = AV_PIX_FMT_YUV420P; //AV_PIX_FMT_BGR24
	AVBufferRef* hw_device_ctx = NULL;

下面的class 是我封装了一些功能，只是示例，读者可以自行修改，读的是rtsp 流，后面准备推流到gb28181上。

class c_AVDecoder:public TThreadRunable
{
	AVPixelFormat sourcepf = AV_PIX_FMT_NV12;// AV_PIX_FMT_NV12;// AV_PIX_FMT_YUV420P;
	AVPixelFormat destpf = AV_PIX_FMT_YUV420P; //AV_PIX_FMT_BGR24
	AVBufferRef* hw_device_ctx = NULL;

	SDLDraw v_draw;
	int hw_decoder_init(AVCodecContext* ctx, const enum AVHWDeviceType type)
	{
		int err = 0;

		if ((err = av_hwdevice_ctx_create(&hw_device_ctx, type,
			NULL, NULL, 0)) < 0) {
			fprintf(stderr, "Failed to create specified HW device.\n");
			return err;
		}
		ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);

		return err;
	}

	

	
	//SDLDraw g_draw;
	struct SwsContext* img_convert_ctx = NULL;


	AVFormatContext* input_ctx = NULL;
	int video_stream, ret;
	AVStream* video = NULL;
	AVCodecContext* decoder_ctx = NULL;
	AVCodec* decoder = NULL;
	AVPacket packet;
	enum AVHWDeviceType type;
	//转换成yuv420 或者rgb
	

	int decode_write(AVCodecContext* avctx, AVPacket* packet)
	{
		AVFrame* frame = NULL, * sw_frame = NULL;
		AVFrame* tmp_frame = NULL;
		//AVFrame* pFrameDst = NULL;
		unsigned char* out_buffer = NULL;
		int ret = 0;
		ret = avcodec_send_packet(avctx, packet);
		if (ret < 0) {
			fprintf(stderr, "Error during decoding\n");
			return ret;
		}


		if (img_convert_ctx == NULL)
		{
			img_convert_ctx = sws_getContext(avctx->width, avctx->height, sourcepf,
				WIDTH, HEIGHT, destpf, SWS_FAST_BILINEAR, NULL, NULL, NULL);
		}
		static int i = 0;
		while (1) {
			if (!(frame = av_frame_alloc()) || !(sw_frame = av_frame_alloc())) {
				fprintf(stderr, "Can not alloc frame\n");
				ret = AVERROR(ENOMEM);
				goto fail;
			}
			//avctx->get_buffer2
			ret = avcodec_receive_frame(avctx, frame);
			if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
				av_frame_free(&frame);
				av_frame_free(&sw_frame);
				return 0;
			}
			else if (ret < 0) {
				fprintf(stderr, "Error while decoding\n");
				goto fail;
			}

			if (frame->format == hw_pix_fmt) {
				/* retrieve data from GPU to CPU */
				sw_frame->format = sourcepf; // AV_PIX_FMT_NV12;// AV_PIX_FMT_YUV420P;// AV_PIX_FMT_NV12;// AV_PIX_FMT_BGR24;// AV_PIX_FMT_YUV420P;
				if ((ret = av_hwframe_transfer_data(sw_frame, frame, 0)) < 0) {
					fprintf(stderr, "Error transferring the data to system memory\n");
					goto fail;
				}
				//av_frame_copy_props(sw_frame, frame);
				tmp_frame = sw_frame;
			}
			else
				tmp_frame = frame;

			

#if 0
			if (out_buffer == NULL)
			{
				out_buffer = (unsigned char*)av_malloc(av_image_get_buffer_size(destpf,
					WIDTH,
					HEIGHT,
					1));
				//av_image_alloc()
				av_image_fill_arrays(pFrameDst.data, pFrameDst.linesize, out_buffer,
					destpf, WIDTH, HEIGHT, 1);
			}

#endif
			AVFrame* pFrameDst = av_frame_alloc();
			av_image_alloc(pFrameDst->data, pFrameDst->linesize, WIDTH, HEIGHT, destpf, 1);
#if 1
			sws_scale(img_convert_ctx, tmp_frame->data, tmp_frame->linesize,
				0, avctx->height, pFrameDst->data, pFrameDst->linesize);

#endif
			//cout << "into " << i++ << endl;

#if 1
			if (!v_draw.push(pFrameDst))
			{
				av_freep(&pFrameDst->data[0]);
				av_frame_free(&pFrameDst);
			}

#endif
#if 0
			size = av_image_get_buffer_size((AVPixelFormat)tmp_frame->format, tmp_frame->width,
				tmp_frame->height, 1);
			buffer = (uint8_t*)av_malloc(size);
			if (!buffer) {
				fprintf(stderr, "Can not alloc buffer\n");
				ret = AVERROR(ENOMEM);
				goto fail;
			}
			ret = av_image_copy_to_buffer(buffer, size,
				(const uint8_t* const*)tmp_frame->data,
				(const int*)tmp_frame->linesize, (AVPixelFormat)tmp_frame->format,
				tmp_frame->width, tmp_frame->height, 1);
			if (ret < 0) {
				fprintf(stderr, "Can not copy image to buffer\n");
				goto fail;
			}

			if ((ret = (int)fwrite(buffer, 1, size, output_file)) < 0) {
				fprintf(stderr, "Failed to dump raw data.\n");
				goto fail;
			}
#endif

		fail:
			av_frame_free(&frame);
			av_frame_free(&sw_frame);

			//av_freep(&buffer);
			if (ret < 0)
				return ret;
		}
	}

	int func_init(const char* url)
	{
		const char* stype = "dxva2";
		type = av_hwdevice_find_type_by_name(stype);
		if (type == AV_HWDEVICE_TYPE_NONE) {
			fprintf(stderr, "Device type %s is not supported.\n", stype);
			fprintf(stderr, "Available device types:");
			while ((type = av_hwdevice_iterate_types(type)) != AV_HWDEVICE_TYPE_NONE)
				fprintf(stderr, " %s", av_hwdevice_get_type_name(type));
			fprintf(stderr, "\n");
			return -1;
		}

		/* open the input file */
		//const char * filename = "h:/video/a.mp4";
		AVDictionary* opts = NULL;
		av_dict_set(&opts, "rtsp_transport", "tcp", 0);
		av_dict_set(&opts, "buffer_size", "1048576", 0);
		av_dict_set(&opts, "fpsprobesize", "5", 0);
		av_dict_set(&opts, "analyzeduration", "5000000", 0);
		if (avformat_open_input(&input_ctx, url, NULL, &opts) != 0) {
			fprintf(stderr, "Cannot open input file '%s'\n", url);
			return -1;
		}

		if (avformat_find_stream_info(input_ctx, NULL) < 0) {
			fprintf(stderr, "Cannot find input stream information.\n");
			return -1;
		}

		/* find the video stream information */
		ret = av_find_best_stream(input_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
		if (ret < 0) {
			fprintf(stderr, "Cannot find a video stream in the input file\n");
			return -1;
		}
		video_stream = ret;

		AVStream* stream = input_ctx->streams[video_stream];

		float frame_rate = stream->avg_frame_rate.num / stream->avg_frame_rate.den;//每秒多少帧
		std::cout << "frame_rate is:" << frame_rate << std::endl;

		//优化直接定死
		/*for (int i = 0;; i++) {
			const AVCodecHWConfig* config = avcodec_get_hw_config(decoder, i);
			if (!config) {
				fprintf(stderr, "Decoder %s does not support device type %s.\n",
					decoder->name, av_hwdevice_get_type_name(type));
				return -1;
			}
			if (config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX &&
				config->device_type == type) {
				hw_pix_fmt = config->pix_fmt;
				break;
			}
		}*/

		if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
			return AVERROR(ENOMEM);

		video = input_ctx->streams[video_stream];
		if (avcodec_parameters_to_context(decoder_ctx, video->codecpar) < 0)
			return -1;

		decoder_ctx->get_format = get_hw_format;

		if (hw_decoder_init(decoder_ctx, type) < 0)
			return -1;

		if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0) {
			fprintf(stderr, "Failed to open codec for stream #%u\n", video_stream);
			return -1;
		}

		/* open the file to dump raw data */
		//output_file = fopen(argv[3], "w+");

		v_draw.init(1280, 720, (int)frame_rate);
		v_draw.Start();
		/* actual decoding and dump the raw data */
		while (ret >= 0) {
			if ((ret = av_read_frame(input_ctx, &packet)) < 0)
				break;

			if (video_stream == packet.stream_index)
			{
				//这里需要更加精确的计算
				ret = decode_write(decoder_ctx, &packet);
				//SDL_Delay(1000 / frame_rate);
			}
			av_packet_unref(&packet);
			if (IsStop())
				break;
		}

		/* flush the decoder */
		packet.data = NULL;
		packet.size = 0;
		ret = decode_write(decoder_ctx, &packet);
		av_packet_unref(&packet);

		
		avcodec_free_context(&decoder_ctx);
		avformat_close_input(&input_ctx);
		av_buffer_unref(&hw_device_ctx);

		return 0;
	}

public:
	void Run()
	{
		while (1)
		{
			if(!IsStop())
				func_init(rtspurl);
		}
	}
};

使用sdl来绘制画面

首先声明，使用sdl来渲染画面并不是有多好，如果可以，可以使用新的绘制方式，比如直接使用opengl，直接使用vulkan来绘制是更好的，sdl封装了opengl，d3d等绘制方式，但是也失去了灵活性，当然，你从头到尾读遍了源码，另当别论，如果要使用均值处理函数来做消除百叶窗效果，摩尔纹，还是直接使用opengl 渲染更为简单，使用glsl语言就行了，甚至要使用非线性函数来增亮图形，最好也是直接使用opengl来绘制。

#pragma once

#include<chrono>
#define __STDC_CONSTANT_MACROS
#define SDL_MAIN_HANDLED
extern "C"
{
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavutil/pixdesc.h>
#include <libavutil/hwcontext.h>
#include <libavutil/opt.h>
#include <libavutil/avassert.h>
#include <libavutil/imgutils.h>
#include <libswscale/swscale.h>
#include "SDL2\SDL.h"
};

#include "c_ringbuffer.h"
#include "TThreadRunable.h"

#include "TYUVMerge.h"


#define SFM_REFRESH_EVENT  (SDL_USEREVENT + 1)
#define SFM_BREAK_EVENT  (SDL_USEREVENT + 2)

#define WIDTH 640
#define HEIGHT 360

typedef struct
{
	int g_fps = 40;
	int thread_exit = 0;
	int thread_pause = 0;
}s_param;
static int sfp_refresh_thread(void *opaque)
{
	s_param * param = (s_param*)opaque;
	param->thread_exit = 0;
	param->thread_pause = 0;

	while (!param->thread_exit)
	{
		if (!param->thread_pause)
		{
			SDL_Event event;
			event.type = SFM_REFRESH_EVENT;
			SDL_PushEvent(&event);
		}
		SDL_Delay(1000 / param->g_fps);
	}
	param->thread_exit = 0;
	param->thread_pause = 0;
	//Break
	SDL_Event event;
	event.type = SFM_BREAK_EVENT;
	SDL_PushEvent(&event);
	return 0;
}

class TicToc
{
public:
	TicToc()
	{
		tic();
	}

	void tic()
	{
		start = std::chrono::system_clock::now();
	}

	double toc()
	{
		end = std::chrono::system_clock::now();
		std::chrono::duration<double> elapsed_seconds = end - start;
		return elapsed_seconds.count() * 1000;
	}

private:
	std::chrono::time_point<std::chrono::system_clock> start, end;
};


class SDLDraw :public TThreadRunable//实际上这里可以编码发送出去
{

	int					m_w = 0, m_h = 0;
	SDL_Window			*screen = NULL;
	SDL_Renderer		*sdlRenderer = NULL;
	SDL_Texture			*sdlTexture = NULL;
	SDL_Rect			sdlRect;
	SDL_Thread			*video_tid;
	SDL_Event			event;
	//struct SwsContext	*img_convert_ctx = NULL;
	bool m_window_init = false;
	lfringqueue<AVFrame, 20> v_frames;
	lfringqueue<AVFrame, 20> v_frames_1;
	lfringqueue<AVFrame, 20> v_frames_2;
	s_param v_param;
	//画布
	AVFrame * v_canvas_frame = NULL;
public:
	void init(int w, int h,int fps)
	{
		if (w != m_w || h != m_h)
		{
			m_w = w;
			m_h = h;
			if (v_canvas_frame != NULL)
			{
				func_uninit();
			}
		}
		v_param.g_fps = fps;
		//这是背景画布
		if (v_canvas_frame == NULL)
		{
			v_canvas_frame = av_frame_alloc();
			av_image_alloc(v_canvas_frame->data, v_canvas_frame->linesize, 1280, 720, AV_PIX_FMT_YUV420P, 1);
		}
	}
	void func_uninit()
	{
		av_freep(&v_canvas_frame->data[0]);
		av_frame_free(&v_canvas_frame);
	}
	bool push(AVFrame * frame)
	{
		//尝试三次插入
		return v_frames.enqueue(frame,3);
	}

protected:
	int draw_init(/*HWND hWnd,*/ )
	{
		//m_w = 1280;
		//m_h = 720;
		if (m_window_init == false)
		{
			SDL_Init(SDL_INIT_VIDEO);
			SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "1");
			screen = SDL_CreateWindow("FF", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
				1920, 1000, SDL_WINDOW_SHOWN/* SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE*/);
			//screen = SDL_CreateWindowFrom((void *)(hWnd));
			for (int i = 0; i < SDL_GetNumRenderDrivers(); ++i)
			{
				SDL_RendererInfo rendererInfo = {};
				SDL_GetRenderDriverInfo(i, &rendererInfo);
				cout << i << " " << rendererInfo.name << endl;
				//if (rendererInfo.name != std::string("direct3d11"))
				//{
				//	continue;
				//}
			}

			if (screen == NULL)
			{
				//printf("Window could not be created! SDL_Error: %s\n", SDL_GetError());
				return -1;
			}
			sdlRenderer = SDL_CreateRenderer(screen,0, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
			//sdlRenderer = SDL_CreateRenderer(screen, -1, SDL_RENDERER_ACCELERATED);
			//SDL_SetHint(SDL_HINT_RENDER_DRIVER, "opengl");
			
			m_window_init = true;
			SDL_Thread	*video_tid = SDL_CreateThread(sfp_refresh_thread, NULL, &v_param);
		}
		return 0;
	}

	void draw(uint8_t *data[], int linesize[])
	{
		if (sdlTexture != NULL)
		{
			SDL_DestroyTexture(sdlTexture);
			sdlTexture = NULL;
		}

		//m_w = w;
		//m_h = h;
		if (sdlTexture == NULL)
		{
			sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV,
				SDL_TEXTUREACCESS_STREAMING, m_w, m_h);
			sdlRect.x = 0;
			sdlRect.y = 0;
			sdlRect.w = m_w;
			sdlRect.h = m_h;// nh;
		}
		SDL_UpdateYUVTexture(sdlTexture, &sdlRect,
				data[0], linesize[0],
				data[1], linesize[1],
				data[2], linesize[2]);
		
		//SDL_RenderClear(sdlRenderer);
		SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, NULL);
		SDL_RenderPresent(sdlRenderer);
		//video_tid = SDL_CreateThread(sfp_refresh_thread, NULL, NULL);

	}
public:
	void Run()
	{
		draw_init();
		AVFrame * frame = NULL;


		//while (!IsStop())
		//{
		//	//解码播放 直接播放
		//	if (v_frames.dequeue(&frame))
		//	{
		//		//播放
		//		draw(frame->data, frame->linesize,WIDTH,HEIGHT);
		//		av_frame_free(&frame);
		//		SDL_Delay(10);
		//	}
		//	else
		//	{
		//		SDL_Delay(10);
		//	}
		//}


#if 1
		/*SDL_Thread	*video_tid = SDL_CreateThread(sfp_refresh_thread, NULL, &v_param);*/
		int tick = 0;
		double x = 0.0f;
		for (;;)
		{
			if (IsStop())
			{
				v_param.thread_exit = 1;
				//break;
			}
			SDL_WaitEvent(&event);
			if (event.type == SFM_REFRESH_EVENT)
			{
				if (v_frames.dequeue(&frame))
				{
					tick++;
					TicToc tt;
					//MergeYUV(v_canvas_frame->data[0], 1280, 720,
					//	frame->data[0], WIDTH, HEIGHT, 1, 10, 10);
					MergeYUV_S(v_canvas_frame->data[0], 1280, 720,
						frame->data[0], WIDTH, HEIGHT, 10, 10);
					x += tt.toc();

					//播放
					draw(v_canvas_frame->data, v_canvas_frame->linesize);
					av_freep(&frame->data[0]);
					av_frame_free(&frame);
					
					if (tick == 10)
					{
						tick = 0;
						cout << x << endl;
						x = 0.0f;
					}
				}
			}
			else if (event.type == SDL_KEYDOWN)
			{
				if (event.key.keysym.sym == SDLK_SPACE)
					v_param.thread_pause = !v_param.thread_pause;
			}
			else if (event.type == SDL_QUIT)
			{
				v_param.thread_exit = 1;
			}
			else if (event.type == SFM_BREAK_EVENT)
			{
				break;
			}
		}
#endif
	}
	SDLDraw()
	{

	}
	~SDLDraw()
	{
		func_uninit();
	}

};

//SDL_FillRect(gScreenSurface, NULL, SDL_MapRGB(gScreenSurface->format, 0xFF, 0x00, 0x00));

ffmpeg 深度学习处理filter

    dnn_processing从2018年开始就已经是FFmpeg中的一个视频filter，支持所有基于深度学习模型的图像处理算法，即输入和输出都是AVFrame，而处理过程使用的是深度学习模型。为什么要开发这样一个filter，因为作为FFmpeg DNN模块的maintainer，dnn_processing就是一个很好的使用者入手功能，读ffmpeg的代码就可以知道，其实自己写这些功能就行了，至于支持视频分析功能的filter，先不进行编码，主要考虑如何支持异步建立流水线，如何启用batch size，从而最大化的用好系统的并行计算能力，本来ffmpeg硬件解码后，如何直接在gpu中进行swscale，其实是不支持的，这一部分要自己写代码来支持，这是另外一回话，我们先使用dnn_processing模块再说，
这个模块可以完成针对灰度图的sobel算子的调用，其输入输出的格式是grayf32。除了这个dnn_processing还可以完成sr（超分辨率）和derain（去除雨点）filter的功能，下面使用ffmpeg命令演示对yuv和rgb格式的支持

./ffmpeg -i night.jpg -vf scale=iw*2:ih*2,format=yuv420p,dnn_processing=dnn_backend=tensorflow:model=./srcnn.pb:input=x:output=y srcnn.jpg

./ffmpeg -i small.jpg -vf format=yuv420p,scale=iw*2:ih*2,dnn_processing=dnn_backend=native:model=./srcnn.model:input=x:output=y -q:v 2 small.jpgsrcnn.jpg

./ffmpeg -i small.jpg -vf format=yuv420p,dnn_processing=dnn_backend=native:model=./espcn.model:input=x:output=y small_b.jpg

./ffmpeg -i rain.jpg -vf format=rgb24,dnn_processing=dnn_backend=native:model=./can.model:input=x:output=y derain.jpg

下图可以看出放大两倍以后还是可以的，不是很模糊，其实是因为我们的训练模型很浅，还没有好好做训练，即使如此，我仔细查看过线性差值比这个图像要差。

连贯执行

后面第二篇就要进行硬件解码，到提升质量filter，到输出编码了，请等待第二篇