编码流程.txt

拿yuv编码成HEVC来举例子

变量：
AVCodec *pCodec;
AVCodecContext *pCodecCtx;
int got_output;
FILE *fp_in;
FILE *fp_out;
AVFrame *pFrame;
AVPacket pkt;
int y_size;
int framecnt = 0

char filename_in = "../ds_480x272.yuv";

#if TEST_HEVC
	AVCodecID codec_id=AV_CODEC_ID_HEVC;
	char filename_out[]="ds.hevc";
#else
	AVCodecID codec_id=AV_CODEC_ID_H264;
	char filename_out[]="ds.h264";
#endif


avcodec_register_all();
pCodec = avcodec_find_encoder(codec_id); //pCodec == 0 fail

pCodecCtx = avcodec_alloc_context3(pCodec);//pCodecCtx == 0 fail

pCodecCtx->bit_rate = 400000;
pCodecCtx->width = in_w;
pCodecCtx->height = in_h;
pCodecCtx->time_base.num=1;
pCodecCtx->time_base.den=25;
pCodecCtx->gop_size = 10;
pCodecCtx->max_b_frames = 1;
pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;	

if (codec_id == AV_CODEC_ID_H264)
        av_opt_set(pCodecCtx->priv_data, "preset", "slow", 0);

if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
        printf("Could not open codec\n");
        return -1;
    }

pFrame = av_frame_alloc();
    if (!pFrame) {
        printf("Could not allocate video frame\n");
        return -1;
    }
    pFrame->format = pCodecCtx->pix_fmt;
    pFrame->width  = pCodecCtx->width;
    pFrame->height = pCodecCtx->height;

    ret = av_image_alloc(pFrame->data, pFrame->linesize, pCodecCtx->width, pCodecCtx->height,
                         pCodecCtx->pix_fmt, 16);


fp_in = fopen(filename_in, "rb");
fp_out = fopen(filename_out, "wb");

y_size = pCodecCtx->width * pCodecCtx->height;

for (i = 0; i < framenum; i++) {
        av_init_packet(&pkt);
        pkt.data = NULL;    // packet data will be allocated by the encoder
        pkt.size = 0;
		//Read raw YUV data
		if (fread(pFrame->data[0],1,y_size,fp_in)<= 0||		// Y
			fread(pFrame->data[1],1,y_size/4,fp_in)<= 0||	// U
			fread(pFrame->data[2],1,y_size/4,fp_in)<= 0){	// V
			return -1;
		}else if(feof(fp_in)){
			break;
		}

        pFrame->pts = i;
        /* encode the image */
        ret = avcodec_encode_video2(pCodecCtx, &pkt, pFrame, &got_output);
        if (ret < 0) {
            printf("Error encoding frame\n");
            return -1;
        }
        if (got_output) {
            printf("Succeed to encode frame: %5d\tsize:%5d\n",framecnt,pkt.size);
			framecnt++;
            fwrite(pkt.data, 1, pkt.size, fp_out);
            av_free_packet(&pkt);
        }
    }
    //Flush Encoder
    for (got_output = 1; got_output; i++) {
        ret = avcodec_encode_video2(pCodecCtx, &pkt, NULL, &got_output);
        if (ret < 0) {
            printf("Error encoding frame\n");
            return -1;
        }
        if (got_output) {
            printf("Flush Encoder: Succeed to encode 1 frame!\tsize:%5d\n",pkt.size);
            fwrite(pkt.data, 1, pkt.size, fp_out);
            av_free_packet(&pkt);
        }
    }

    fclose(fp_out);
    avcodec_close(pCodecCtx);
    av_free(pCodecCtx);
    av_freep(&pFrame->data[0]);
    av_frame_free(&pFrame);