ffmpeg入门系列教程（新API）示例 02

环境搭建传送门：http://blog.csdn.net/DaveBobo/article/details/51123890

教程原文：http://dranger.com/ffmpeg/tutorial02.html

工具：

VS 2013 社区版

FFmpeg version: 20170321-db7a05d（3.2.4以上）

SDL2（需要在官网下载库和头文件并引入到工程）

新API实现教程示例 02

linux下编译命令：

gcc -o tutorial02 test2.c -lavformat -lavcodec -lswscale -lavutil -lSDL2 -lz -lm

以下代码在http://dranger.com/ffmpeg/提供的示例代码的基础上修改而来。 使用了最新的ffmpeg api代替废弃的api，并通过编译验证的可用代码。

// testffmpeg.cpp : Defines the entry point for the console application.//#include "stdafx.h"// tutorial01.c// Code based on a tutorial by Martin Bohme ([e-mail])// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1// With updates from https://github.com/chelyaev/ffmpeg-tutorial// Updates tested on:// LAVC 54.59.100, LAVF 54.29.104, LSWS 2.1.101 // on GCC 4.7.2 in Debian February 2015// A small sample program that shows how to use libavformat and libavcodec to// read video from a file.//// Use//// gcc -o tutorial01 tutorial01.c -lavformat -lavcodec -lswscale -lz//// to build (assuming libavformat and libavcodec are correctly installed// your system).//// Run using//// tutorial01 myvideofile.mpg//// to write the first five frames from "myvideofile.mpg" to disk in PPM// format.extern "C"{#include <libavcodec/avcodec.h>#include <libavformat/avformat.h>#include <libswscale/swscale.h>#include <libavutil/imgutils.h>#include <stdio.h>#include "include\libsdl\SDL.h"#include "include\libsdl\SDL_thread.h"}int main(int argc, char *argv[]) {    // Initalizing these to NULL prevents segfaults!    AVFormatContext   *pFormatCtx = NULL;    int               i, videoStream;    AVCodecParameters    *pCodecpar = NULL;    AVCodecContext    *pCodecCtx = NULL;    AVCodec           *pCodec = NULL;    AVFrame           *pFrame = NULL;    AVFrame           *pFrameYUV = NULL;    AVPacket          packet;    int               frameFinished;    int               numBytes;    uint8_t           *buffer = NULL;    struct SwsContext *sws_ctx = NULL;    SDL_Rect rect;    SDL_Event event;    // Register all formats and codecs    av_register_all();    //debug程序需要将test.flv放在对应的project目录下，跟引用的ffmpeg的dll库同一目录    char filepath[] = "test.flv";    // Open video file    if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0)        return -1; // Couldn't open file    // Retrieve stream information    if (avformat_find_stream_info(pFormatCtx, NULL) < 0)        return -1; // Couldn't find stream information    // Dump information about file onto standard error    av_dump_format(pFormatCtx, 0, filepath, 0);    // Find the first video stream    videoStream = -1;    for (i = 0; i < pFormatCtx->nb_streams; i++)        if (pFormatCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {            videoStream = i;            break;        }    if (videoStream == -1)        return -1; // Didn't find a video stream    // Get a pointer to the codec context for the video stream    pCodecpar = pFormatCtx->streams[videoStream]->codecpar;    // Find the decoder for the video stream    pCodec = avcodec_find_decoder(pFormatCtx->streams[videoStream]->codecpar->codec_id);    if (pCodec == NULL) {        fprintf(stderr, "Unsupported codec!\n");        return -1; // Codec not found    }    // Copy context    pCodecCtx = avcodec_alloc_context3(pCodec);    if (avcodec_parameters_to_context(pCodecCtx, pCodecpar) != 0) {        fprintf(stderr, "Couldn't copy codec context");        return -1; // Error copying codec context    }    // Open codec    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)        return -1; // Could not open codec    // Allocate video frame    pFrame = av_frame_alloc();    // Allocate an AVFrame structure    pFrameYUV = av_frame_alloc();    if (pFrameYUV == NULL)        return -1;    // Determine required buffer size and allocate buffer    numBytes = av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pCodecCtx->width,        pCodecCtx->height, 1);    buffer = (uint8_t *)av_malloc(numBytes*sizeof(uint8_t));    // Assign appropriate parts of buffer to image planes in pFrameYUV    // Note that pFrameYUV is an AVFrame, but AVFrame is a superset    // of AVPicture    av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize, buffer, AV_PIX_FMT_YUV420P,        pCodecCtx->width, pCodecCtx->height, 1);    // initialize SWS context for software scaling    sws_ctx = sws_getContext(pCodecCtx->width,        pCodecCtx->height,        pCodecCtx->pix_fmt,        pCodecCtx->width,        pCodecCtx->height,        AV_PIX_FMT_YUV420P,        SWS_BILINEAR,        NULL,        NULL,        NULL);    SDL_Window *sdlWindow = SDL_CreateWindow("test2",        SDL_WINDOWPOS_UNDEFINED,        SDL_WINDOWPOS_UNDEFINED,        pCodecCtx->width, pCodecCtx->height,        SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL);    SDL_Renderer *sdlRenderer = SDL_CreateRenderer(sdlWindow, -1, 0);    SDL_Texture* sdlTexture = SDL_CreateTexture(        sdlRenderer,        SDL_PIXELFORMAT_IYUV,        SDL_TEXTUREACCESS_STREAMING,        pCodecCtx->width,        pCodecCtx->height);    // Read frames and display it    i = 0;    while (av_read_frame(pFormatCtx, &packet) >= 0) {        // Is this a packet from the video stream?        if (packet.stream_index == videoStream) {            // Decode video frame            avcodec_send_packet(pCodecCtx, &packet);            if (avcodec_receive_frame(pCodecCtx, pFrame) != 0)                continue;            // Convert the image from its native format to YUV            sws_scale(sws_ctx, (uint8_t const * const *)pFrame->data,                pFrame->linesize, 0, pCodecCtx->height,                pFrameYUV->data, pFrameYUV->linesize);            // display the frame to screen            rect.x = 0;            rect.y = 0;            rect.w = pCodecCtx->width;            rect.h = pCodecCtx->height;            SDL_UpdateTexture(sdlTexture, &rect,                pFrameYUV->data[0],                pFrameYUV->linesize[0]);            SDL_RenderClear(sdlRenderer);            SDL_RenderCopy(sdlRenderer, sdlTexture, &rect, &rect);            SDL_RenderPresent(sdlRenderer);            SDL_Delay(20);        }        // Free the packet that was allocated by av_read_frame        av_packet_unref(&packet);        SDL_PollEvent(&event);        switch (event.type) {        case SDL_QUIT:            SDL_Quit();            exit(0);            break;        default:            break;        }    }    SDL_DestroyTexture(sdlTexture);    // Free the RGB image    av_free(buffer);    av_frame_free(&pFrameYUV);    // Free the YUV frame    av_frame_free(&pFrame);    // Close the codecs    avcodec_close(pCodecCtx);    // Close the video file    avformat_close_input(&pFormatCtx);    return 0;}