The understanding of AVPacket in FFmpeg?

when I read the introduction to AVPacket in the FFmpeg document, I saw this sentence:

For video, it should typically contain one compressed frame. For audio it may contain several compressed frames.
for video, it contains one compressed frame; for audio, it may contain multiple compressed frames.

AVPacket (compressed packet) is decoded into AVFrame (uncompressed packet) by the decoder.

question:
what is the relationship between AVPacket, AVFrame, Frame, and frames? How to understand the sentence in the document?

Multimedia video-processing cPP c ffmpeg
Apr.09,2021

Previous: The files under the php traversal folder are incomplete

Next: How to deal with front-end JSONArray or JSONObject data in CGI

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bddd70-313b2.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bddd70-313b2.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?