记录下centos下 ffmpeg项目编译参数

官网下载最新的ffmpeg源文件，直接./confiure --prefix=path_to_install && make && make install ，期间没有什么问题。（但是在最后想生成动态库的时候有问题，暂时不去解决了，静态的先凑合用吧）

但是在写了一个测试文件去测试的时候，总是链接错误，不是缺少这个库就是av***未定义的引用。少的库直接加-l就行了，但是av***里面未定义引用我就郁闷了，最后发现可能是ffmpeg库的引用顺序不对造成的。

记录下ffmpeg库引用顺序，反正这个顺序在我这里是可以用的。最后附带下测试代码

#! /bin/bash
BIN_PATH=/home/mico/bin
export LD_LIBRARY_PATH=$BIN_PATH/lib:/usr/local/lib64:/usr/lib64

gcc test_ffmpeg.c -L $BIN_PATH/lib -L /usr/local/lib -L /usr/lib64 -I $BIN_PATH/include -lavfilter -lavformat -lavdevice -lavcodec -lswscale -lavutil -lswresample -llzma -lz -lbz2 -pthread -lm -g -o test_ffmpeg.out
    
echo "well done"

/*
 * Copyright (c) 2010 Nicolas George
 * Copyright (c) 2011 Stefano Sabatini
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
/**
 * @file
 * API example for decoding and filtering
 * @example filtering_video.c
 */
#define _XOPEN_SOURCE 600 /* for usleep */
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavfilter/buffersink.h>
#include <libavfilter/buffersrc.h>
#include <libavutil/opt.h>
#define ENABLE_DISPLAY 0
#define ENABLE_YUV 1
const char *filter_descr = "scale=78:24,transpose=cclock";
/* other way:
   scale=78:24 [scl]; [scl] transpose=cclock // assumes "[in]" and "[out]" to be input output pads respectively
 */
static AVFormatContext *fmt_ctx;
static AVCodecContext *dec_ctx;
AVFilterContext *buffersink_ctx;
AVFilterContext *buffersrc_ctx;
AVFilterGraph *filter_graph;
static int video_stream_index = -1;
static int64_t last_pts = AV_NOPTS_VALUE;

#if ENABLE_YUV
    FILE *fp_yuv;
#endif

static int open_input_file(const char *filename)
{    
    int ret;
    AVCodec *dec;
    
#if ENABLE_YUV
    fp_yuv=fopen("output.yuv","wb+");
#endif

    if ((ret = avformat_open_input(&fmt_ctx, filename, NULL, NULL)) < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot open input file
");
        return ret;
    }
    if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot find stream information
");
        return ret;
    }
    /* select the video stream */
    ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &dec, 0);
    if (ret < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file
");
        return ret;
    }
    video_stream_index = ret;
    /* create decoding context */
    dec_ctx = avcodec_alloc_context3(dec);
    if (!dec_ctx)
        return AVERROR(ENOMEM);
    avcodec_parameters_to_context(dec_ctx, fmt_ctx->streams[video_stream_index]->codecpar);
    /* init the video decoder */
    if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot open video decoder
");
        return ret;
    }
    return 0;
}


static int init_filters(const char *filters_descr)
{
    char args[512];
    int ret = 0;
    const AVFilter *buffersrc  = avfilter_get_by_name("buffer");
    const AVFilter *buffersink = avfilter_get_by_name("buffersink");
    AVFilterInOut *outputs = avfilter_inout_alloc();
    AVFilterInOut *inputs  = avfilter_inout_alloc();
    AVRational time_base = fmt_ctx->streams[video_stream_index]->time_base;
    enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE };
    filter_graph = avfilter_graph_alloc();
    if (!outputs || !inputs || !filter_graph) {
        ret = AVERROR(ENOMEM);
        goto end;
    }
    /* buffer video source: the decoded frames from the decoder will be inserted here. */
    snprintf(args, sizeof(args),
            "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
            dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,
            time_base.num, time_base.den,
            dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
    ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
                                       args, NULL, filter_graph);
    if (ret < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot create buffer source
");
        goto end;
    }
    /* buffer video sink: to terminate the filter chain. */
    ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",
                                       NULL, NULL, filter_graph);
    if (ret < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink
");
        goto end;
    }
    ret = av_opt_set_int_list(buffersink_ctx, "pix_fmts", pix_fmts,
                              AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN);
    if (ret < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot set output pixel format
");
        goto end;
    }
    /*
     * Set the endpoints for the filter graph. The filter_graph will
     * be linked to the graph described by filters_descr.
     */
    /*
     * The buffer source output must be connected to the input pad of
     * the first filter described by filters_descr; since the first
     * filter input label is not specified, it is set to "in" by
     * default.
     */
    outputs->name       = av_strdup("in");
    outputs->filter_ctx = buffersrc_ctx;
    outputs->pad_idx    = 0;
    outputs->next       = NULL;
    /*
     * The buffer sink input must be connected to the output pad of
     * the last filter described by filters_descr; since the last
     * filter output label is not specified, it is set to "out" by
     * default.
     */
    inputs->name       = av_strdup("out");
    inputs->filter_ctx = buffersink_ctx;
    inputs->pad_idx    = 0;
    inputs->next       = NULL;
    if ((ret = avfilter_graph_parse_ptr(filter_graph, filters_descr,
                                    &inputs, &outputs, NULL)) < 0)
        goto end;
    if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0)
        goto end;
end:
    avfilter_inout_free(&inputs);
    avfilter_inout_free(&outputs);
    return ret;
}
static void display_frame(const AVFrame *frame, AVRational time_base)
{
    int x, y;
    uint8_t *p0, *p;
    int64_t delay;
    if (frame->pts != AV_NOPTS_VALUE) {
        if (last_pts != AV_NOPTS_VALUE) {
            /* sleep roughly the right amount of time;
             * usleep is in microseconds, just like AV_TIME_BASE. */
            delay = av_rescale_q(frame->pts - last_pts,
                                 time_base, AV_TIME_BASE_Q);
            if (delay > 0 && delay < 1000000)
                usleep(delay);
        }
        last_pts = frame->pts;
    }
    /* Trivial ASCII grayscale display. */
    p0 = frame->data[0];
    puts("33c");
    for (y = 0; y < frame->height; y++) {
        p = p0;
        for (x = 0; x < frame->width; x++)
            putchar(" .-+#"[*(p++) / 52]);
        putchar('
');
        p0 += frame->linesize[0];
    }
    fflush(stdout);
}


#if ENABLE_YUV
static void save_yuv(const AVFrame *pFrame_out) 
{    
    int i=0;
    if (pFrame_out->format==AV_PIX_FMT_YUV420P) {
        //Y, U, V
        for(i=0;i<pFrame_out->height;i++){
            fwrite(pFrame_out->data[0]+pFrame_out->linesize[0]*i,1,pFrame_out->width,fp_yuv);
        }
        for(i=0;i<pFrame_out->height/2;i++){
            fwrite(pFrame_out->data[1]+pFrame_out->linesize[1]*i,1,pFrame_out->width/2,fp_yuv);
        }
        for(i=0;i<pFrame_out->height/2;i++){
            fwrite(pFrame_out->data[2]+pFrame_out->linesize[2]*i,1,pFrame_out->width/2,fp_yuv);
        }
    }    
}
#endif


int main(int argc, char **argv)
{
    int ret;
    AVPacket packet;
    AVFrame *frame;
    AVFrame *filt_frame;
    if (argc != 2) {
        fprintf(stderr, "Usage: %s file
", argv[0]);
        exit(1);
    }
    frame = av_frame_alloc();
    filt_frame = av_frame_alloc();
    if (!frame || !filt_frame) {
        perror("Could not allocate frame");
        exit(1);
    }
    if ((ret = open_input_file(argv[1])) < 0)
        goto end;
    if ((ret = init_filters(filter_descr)) < 0)
        goto end;
    /* read all packets */
    while (1) {
        if ((ret = av_read_frame(fmt_ctx, &packet)) < 0)
            break;
        if (packet.stream_index == video_stream_index) {
            ret = avcodec_send_packet(dec_ctx, &packet);
            if (ret < 0) {
                av_log(NULL, AV_LOG_ERROR, "Error while sending a packet to the decoder
");
                break;
            }
            while (ret >= 0) {
                ret = avcodec_receive_frame(dec_ctx, frame);
                if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
                    break;
                } else if (ret < 0) {
                    av_log(NULL, AV_LOG_ERROR, "Error while receiving a frame from the decoder
");
                    goto end;
                }
                frame->pts = frame->best_effort_timestamp;
                /* push the decoded frame into the filtergraph */
                if (av_buffersrc_add_frame_flags(buffersrc_ctx, frame, AV_BUFFERSRC_FLAG_KEEP_REF) < 0) {
                    av_log(NULL, AV_LOG_ERROR, "Error while feeding the filtergraph
");
                    break;
                }
                /* pull filtered frames from the filtergraph */
                while (1) {
                    ret = av_buffersink_get_frame(buffersink_ctx, filt_frame);
                    if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                        break;
                    if (ret < 0)
                        goto end;
#if ENABLE_DISPLAY
                    display_frame(filt_frame, buffersink_ctx->inputs[0]->time_base);
#endif
#if ENABLE_YUV
                    save_yuv(filt_frame);
#endif
                    av_frame_unref(filt_frame);
                }
                av_frame_unref(frame);
            }
        }
        av_packet_unref(&packet);
    }
end:
#if ENABLE_YUV
    fclose(fp_yuv);
#endif
    avfilter_graph_free(&filter_graph);
    avcodec_free_context(&dec_ctx);
    avformat_close_input(&fmt_ctx);
    av_frame_free(&frame);
    av_frame_free(&filt_frame);
    if (ret < 0 && ret != AVERROR_EOF) {
        fprintf(stderr, "Error occurred: %s
", av_err2str(ret));
        exit(1);
    }
    exit(0);
}