最简单的基于FFmpeg的直播系统开发移动端例子：IOS 视频解码器

/*
* 提示：该行代码过长，系统自动注释不进行高亮。一键复制会移除系统注释 
* /** * 最简单的基于FFmpeg的视频解码器-IOS * Simplest FFmpeg IOS Decoder * * 雷霄骅 Lei Xiaohua * leixiaohua1020@126.com * 中国传媒大学/数字电视技术 * Communication University of China / Digital TV Technology * http://blog.csdn.net/leixiaohua1020 * * 本程序是IOS平台下最简单的基于FFmpeg的视频解码器。 * 它可以将输入的视频数据解码成YUV像素数据。 * * This software is the simplest decoder based on FFmpeg in IOS. * It can decode video stream to raw YUV data. * */ #import "ViewController.h"#include <libavcodec/avcodec.h>#include <libavformat/avformat.h>#include <libavutil/imgutils.h>#include <libswscale/swscale.h> @interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.} - (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.} - (IBAction)clickDecodeButton:(id)sender {    AVFormatContext	*pFormatCtx;    int				i, videoindex;    AVCodecContext	*pCodecCtx;    AVCodec			*pCodec;    AVFrame	*pFrame,*pFrameYUV;    uint8_t *out_buffer;    AVPacket *packet;    int y_size;    int ret, got_picture;    struct SwsContext *img_convert_ctx;    FILE *fp_yuv;    int frame_cnt;    clock_t time_start, time_finish;    double  time_duration = 0.0;        char input_str_full[500]={0};    char output_str_full[500]={0};    char info[1000]={0};        NSString *input_str= [NSString stringWithFormat:@"resource.bundle/%@",self.inputurl.text];    NSString *output_str= [NSString stringWithFormat:@"resource.bundle/%@",self.outputurl.text];        NSString *input_nsstr=[[[NSBundle mainBundle]resourcePath] stringByAppendingPathComponent:input_str];    NSString *output_nsstr=[[[NSBundle mainBundle]resourcePath] stringByAppendingPathComponent:output_str];        sprintf(input_str_full,"%s",[input_nsstr UTF8String]);    sprintf(output_str_full,"%s",[output_nsstr UTF8String]);        printf("Input Path:%s\n",input_str_full);    printf("Output Path:%s\n",output_str_full);        av_register_all();    avformat_network_init();    pFormatCtx = avformat_alloc_context();        if(avformat_open_input(&pFormatCtx,input_str_full,NULL,NULL)!=0){        printf("Couldn't open input stream.\n");        return ;    }    if(avformat_find_stream_info(pFormatCtx,NULL)<0){        printf("Couldn't find stream information.\n");        return;    }    videoindex=-1;    for(i=0; i<pFormatCtx->nb_streams; i++)        if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){            videoindex=i;            break;        }    if(videoindex==-1){        printf("Couldn't find a video stream.\n");        return;    }    pCodecCtx=pFormatCtx->streams[videoindex]->codec;    pCodec=avcodec_find_decoder(pCodecCtx->codec_id);    if(pCodec==NULL){        printf("Couldn't find Codec.\n");        return;    }    if(avcodec_open2(pCodecCtx, pCodec,NULL)<0){        printf("Couldn't open codec.\n");        return;    }        pFrame=av_frame_alloc();    pFrameYUV=av_frame_alloc();    out_buffer=(unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P,  pCodecCtx->width, pCodecCtx->height,1));    av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize,out_buffer,                         AV_PIX_FMT_YUV420P,pCodecCtx->width, pCodecCtx->height,1);    packet=(AVPacket *)av_malloc(sizeof(AVPacket));        img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,                                     pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);            sprintf(info,   "[Input     ]%s\n", [input_str UTF8String]);    sprintf(info, "%s[Output    ]%s\n",info,[output_str UTF8String]);    sprintf(info, "%s[Format    ]%s\n",info, pFormatCtx->iformat->name);    sprintf(info, "%s[Codec     ]%s\n",info, pCodecCtx->codec->name);    sprintf(info, "%s[Resolution]%dx%d\n",info, pCodecCtx->width,pCodecCtx->height);            fp_yuv=fopen(output_str_full,"wb+");    if(fp_yuv==NULL){        printf("Cannot open output file.\n");        return;    }        frame_cnt=0;    time_start = clock();        while(av_read_frame(pFormatCtx, packet)>=0){        if(packet->stream_index==videoindex){            ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);            if(ret < 0){                printf("Decode Error.\n");                return;            }            if(got_picture){                sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,                          pFrameYUV->data, pFrameYUV->linesize);                                y_size=pCodecCtx->width*pCodecCtx->height;                fwrite(pFrameYUV->data[0],1,y_size,fp_yuv);    //Y                fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv);  //U                fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv);  //V                //Output info                char pictype_str[10]={0};                switch(pFrame->pict_type){                    case AV_PICTURE_TYPE_I:sprintf(pictype_str,"I");break;                    case AV_PICTURE_TYPE_P:sprintf(pictype_str,"P");break;                    case AV_PICTURE_TYPE_B:sprintf(pictype_str,"B");break;                    default:sprintf(pictype_str,"Other");break;                }                printf("Frame Index: %5d. Type:%s\n",frame_cnt,pictype_str);                frame_cnt++;            }        }        av_free_packet(packet);    }    //flush decoder    //FIX: Flush Frames remained in Codec    while (1) {        ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);        if (ret < 0)            break;        if (!got_picture)            break;        sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,                  pFrameYUV->data, pFrameYUV->linesize);        int y_size=pCodecCtx->width*pCodecCtx->height;        fwrite(pFrameYUV->data[0],1,y_size,fp_yuv);    //Y        fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv);  //U        fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv);  //V        //Output info        char pictype_str[10]={0};        switch(pFrame->pict_type){            case AV_PICTURE_TYPE_I:sprintf(pictype_str,"I");break;            case AV_PICTURE_TYPE_P:sprintf(pictype_str,"P");break;            case AV_PICTURE_TYPE_B:sprintf(pictype_str,"B");break;            default:sprintf(pictype_str,"Other");break;        }        printf("Frame Index: %5d. Type:%s\n",frame_cnt,pictype_str);        frame_cnt++;    }    time_finish = clock();     time_duration=(double)(time_finish - time_start);        sprintf(info, "%s[Time      ]%fus\n",info,time_duration);    sprintf(info, "%s[Count     ]%d\n",info,frame_cnt);        sws_freeContext(img_convert_ctx);        fclose(fp_yuv);        av_frame_free(&pFrameYUV);    av_frame_free(&pFrame);    avcodec_close(pCodecCtx);    avformat_close_input(&pFormatCtx);        NSString * info_ns = [NSString stringWithFormat:@"%s", info];    self.infomation.text=info_ns; }  @end
*/