#include "ffvideo.h"

void ffvideo::initH264() {
	AVDictionary* options = nullptr;
	av_dict_set(&options, "preset", "superfast", 0);
	av_dict_set(&options, "tune", "zerolatency", 0);
	AVCodec* encoder = avcodec_find_encoder(AV_CODEC_ID_H264);
	encoder_ctx = avcodec_alloc_context3(encoder);
	encoder_ctx->codec_id = AV_CODEC_ID_H264;
	encoder_ctx->codec_type = AVMEDIA_TYPE_VIDEO;
	encoder_ctx->pix_fmt = AV_PIX_FMT_YUV420P;
	encoder_ctx->width = info.dst_width;
	encoder_ctx->height = info.dst_height;
	encoder_ctx->time_base.num = 1;
	encoder_ctx->time_base.den = info.frame_rate; //时间基
	encoder_ctx->framerate = { info.frame_rate,1 };//帧率
	encoder_ctx->bit_rate = info.bit_rate;//重要，最终视频的码率
	encoder_ctx->gop_size = info.gop_size;//关键帧间隔
	encoder_ctx->qmin = 30;//最小压缩质量
	encoder_ctx->qmax = 35;//最大压缩质量，与最小质量一起控制压缩后的图像质量
	encoder_ctx->max_b_frames = 0;//不输出B帧，输出B帧后的时间戳控制较为繁琐
	encoder_ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;//设置后通过extradata获取sps、pps
	avcodec_open2(encoder_ctx, encoder, &options);
	dst_packet = av_packet_alloc();
}

void ffvideo::initSws() {
	line_size = new int[4];
	src_size = av_image_get_buffer_size(info.src_fmt, info.src_width, info.src_height, 1);
	dst_size = av_image_get_buffer_size(info.dst_fmt, info.dst_width, info.dst_height, 1);
	src_buffer = new uint8_t[src_size];
	dst_buffer = new uint8_t[dst_size];
	dst_frame = av_frame_alloc();
	dst_frame->format = info.dst_fmt;
	dst_frame->width = info.dst_width;
	dst_frame->height = info.dst_height;
	av_image_fill_arrays(dst_frame->data, dst_frame->linesize, dst_buffer, info.dst_fmt, info.dst_width, info.dst_height, 1);

	sws_ctx = sws_getContext(info.src_width, info.src_height, info.src_fmt,
		info.dst_width, info.dst_height, info.dst_fmt,
		SWS_BICUBIC, nullptr, nullptr, nullptr);
	sws_init_context(sws_ctx, nullptr, nullptr);
}

void ffvideo::process_data(int dts, int pts, void(*cb)(ffvideo*)) {
	sws_scale(sws_ctx, static_cast<const uint8_t* const*>(&src_buffer), line_size, 0,
		info.src_height, dst_frame->data, dst_frame->linesize);
	dst_frame->pkt_dts = dts;
	dst_frame->pts = pts;

	int ret = avcodec_send_frame(encoder_ctx, dst_frame);
	if (ret < 0) {
		if (ret == AVERROR(EAGAIN)) {
			return;
		}
		return;
	}
	while (ret >= 0) {
		ret = avcodec_receive_packet(encoder_ctx, dst_packet);
		if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
			break;
		}
		if (ret < 0) {
			return;
		}
		if (cb) cb(this);
		av_packet_unref(dst_packet);
	}
}

//FILE* f = nullptr;
//
//void output2(FFplay* ctx) {
//	if (f == nullptr) {
//		f = fopen("a.h264", "wb");
//		fwrite(ctx->encoder_ctx->extradata, sizeof(uint8_t), ctx->encoder_ctx->extradata_size, f);
//	}
//
//	fwrite(ctx->dst_packet->data, sizeof(uint8_t), ctx->dst_packet->size, f);
//
//	cout << "ENCODE_SUCCESS: size = " << ctx->dst_packet->size << endl;
//}
//
//int main_test() {
//
//	FFplay play{};
//
//	play.info = {
//		1920, 1080, AV_PIX_FMT_BGRA,
//		1920, 1080, AV_PIX_FMT_YUV420P,
//		30, 2 * 1024 * 1024, 30
//	};
//
//	play.initSws();
//	play.initH264();
//
//	int count = 0;
//	while (true) {
//		if (count == 10 * 30) break;
//		count++;
//		//fake_data(count);
//		play.process_data(count, count, output2);
//	}
//	fflush(f);
//	fclose(f);
//	return 0;
//}