[book club issue 13] Chapter 1 multimedia processing tools ffmpeg tools

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FFmpeg The composition of

FFmpeg The project is divided into different modules according to their functions , Include AVFormat、AVCodec、AVFilter、AVDeivce、AVUtil、swresample、swscale.

FFmpeg The development of

FFmpeg It is a multimedia open source project , Project address :https://github.com/FFmpeg/FFmpeg
FFmpeg It was first developed by brix, a talented French programmer . Bella is 2000 Year development , It has been developing rapidly since then , The latest version is 5.0
at present ,FFmpeg It has been adopted by many open source projects , Such as ijkplayer、VLC、MPlayer、Blender、Google Chrome etc. .

FFmpeg The composition of

1. AVFormat yes FFmpeg Package module of , It realizes most of the media packaging formats in the current multimedia field , Including encapsulation and unpacking , such as MP4、 FLV、MKV、 TS Wait for the file encapsulation format ,RTMP、
   RTSP、HLS And so on network protocol encapsulation format . in addition , It also supports custom packaging formats .
2. AVCodec yes FFmpeg Coding and decoding module , Among them, it has realized the vast majority of media encoding and decoding formats in the current multimedia field , Including encoding and decoding , such as MPEG4、 H264、 H265 Wait for video format ,AAC、MP3 Wait for audio format . in addition , It also supports custom encoding and decoding formats .
3. AVFilter yes FFmpeg Filter module , It realizes the current general audio 、 video 、 Subtitle and other filter processing frame .
4. AVDevice yes FFmpeg Device management module , Including audio equipment and video equipment .
5. AVUtil yes FFmpeg Tool module of .
6. swresample yes FFmpeg Audio conversion module for , Including audio resampling 、 Channel number adjustment, etc .
7. swscale yes FFmpeg Video image conversion module , Including image scaling 、 Pixel format conversion .

FFmpeg The toolset of

1. ffmpeg yes FFmpeg Codec tools in the tool set ：ffmpeg Tools are mainly used for encoding and decoding ,ffmpeg The main workflow of is relatively simple

• Read input source
• Unpack audio and video
• Decode every frame of audio and video data
• Encode every frame of audio and video data
• Rewrite and package audio and video
• Output to target

2. ffplay yes FFmpeg Player in toolset ： stay FFmpeg In common use ffplay As a player , Actually ffplay It can also be used as a graphical analysis tool for many audio and video data , adopt ffplay You can see the motion estimation direction of the video image 、 Waveform of audio data .ffplay Not just the player , It is also a test ffmpeg Of codec engine 、format engine , as well as filter Engine tools , And it can also carry out visual media parameter analysis .
3. ffprobe yes FFmpeg Multimedia analysis tools in the toolset ：ffprobe It's also FFmpeg An executable program generated after source code editing .ffprobe Is a very powerful multimedia analysis tool , You can get the media information you want to know from media files or media streams , For example, the parameters of audio , The parameters of the video , Parameter information of media container, etc .