Preface

Before, when I was engaged in Android development, I wanted to learn audio and video practice , In my mind, I think if there is one specially developed for Android FFmpeg Just a tutorial . Slowly found that this idea is very unreliable , Because there were few audio and video related tutorials at that time , If you want to target Android, it's rare .

Later, in order to learn FFmpeg, The author is also intermittent , Start with the basic data of audio and video , from FFmpeg Compile to practice , I hope that through my study, I can uncover FFmpeg The veil of mystery , Until now, I only dare to say that I am just a novice in the army of audio and video development , Although I've been groping for a long time ,
But it is still difficult to advance , I think there are two main reasons , It's a fairy's Guide , The second is intermittent , Lack of systematic learning summary .

The most important thing in learning is to master , If you want to learn in your heart , However, there is no fully targeted tutorial materials , In the end, you will find that you still think more than you do , You might as well not …

about FFmpeg This thing , You say it's difficult , In fact, it's just the same thing , You say it's simple , Countless people are forced to give up at the compilation stage , Perhaps it is not itself that is difficult , More learners have the courage to start and persevere .

In order to enable novices to get started more quickly FFmpeg, The author will start a series on FFmpeg Related articles , It mainly involves audio and video unpacking 、 Audio and video decoding 、 Audio and video coding 、 Audio resampling and other related knowledge points .

At the end of this series , It may end with a little practice , The content of this practice is generally ：

1、 Enter multiple mp3 file , Decoded into pcm, Then resampling , Splice and code into aac Audio ;
2、 Enter multiple mp4 file , Extract the video and decode it into yuv, Then splice and encode into h264;
3、 take 1 Medium aac Audio and 2 Medium h264 Merge videos into new mp4 file .

Today, we mainly set up the environment first , After all, a journey of a thousand miles begins with a single step .

Author's environment

The example environment used by the author Mac System , The development tool is CLion.

install FFmpeg

About introducing in PC Up lead in FFmpeg It's still relatively simple , It can be installed through the command line tool , Then extract and process the relevant library , Or you can directly use the source code and directly compile the relevant libraries . But if you want to FFmpeg To inherit into Android, you need to use NDK The tutorial compiled ,
For how to use NDK Tutorial compilation FFmpeg Children's shoes can go through my previous articles , Maybe I can sort out one later .

Whereas FFmpeg It's a C Language library , Born with cross platform ability , Therefore, the author suggests to study directly in PC Just practice and study , If you've learned , That's transplanted to other platforms. That's not so easy Do you .

Today, I use the command line installation method to integrate FFmpeg, stay Mac We can use Homebrew Package management tools for installation ,Linux It can be used apt.

1、 use first Homebrew install ffmpeg:

brew install ffmpeg

Then wait quietly , Generally, if you fail, it's mostly a network problem , The solution is well known …

2、 After successful installation, we use brew info Command to see where the installation went , When introducing the project later, we need to use , The order is ：

brew info ffmpeg

For example, the author's output is shown in the figure ：

To configure CLion engineering

Newly-built CLion After the project , We will FFmpeg Configure the library path and header file , To configure CMakeLists.txt：

cmake_minimum_required(VERSION 3.17)

#  Be careful  FFmpegPro It's the name of the project , This development needs to be replaced according to the actual situation 
project(FFmpegPro)

set(CMAKE_CXX_STANDARD 11)

# FFmpeg Installation directory , By command "brew info ffmpeg" obtain 
set(FFMPEG_DIR /opt/homebrew/Cellar/ffmpeg/5.0)
#  Header file search path 
include_directories(${FFMPEG_DIR}/include/)
#  Search path of dynamic link library or static link library 
link_directories(${FFMPEG_DIR}/lib/)

add_executable(FFmpegPro main.cpp)

# Link library 
target_link_libraries(FFmpegPro
        #FFmpeg  library 
        avcodec
        avfilter
        avformat
        avutil
        swresample
        swscale
        )

Simply test whether the configuration is successful , stay main Simply call some... In the code ffmpeg Library API, If it works normally, it indicates that the configuration is successful ：

#include <iostream>
extern "C"{
#include "libavcodec/avcodec.h"
#include <libavformat/avformat.h>
#include "libavutil/avutil.h"
}

int main(int arg,char **argv) {
    //  Print ffmpeg Information about 
    std::cout << "av_version_info:" << av_version_info() << std::endl;
    std::cout << "av_version_info:" << avcodec_configuration() << std::endl;
    return 0;
}

If it works normally, print out ffmpeg The version number of indicates that the environment configuration is successful .

Pay attention to me , Progress together , Life is more than coding！！！