tbn tbc tbr

目录

• tbn
• tbc
• tbr

tbn

• tbn: the time base in AVStream that has come from the container

  

  视频流时长的精确度time_base，即1s = 90000个刻度

  视频总时长T = AVStream.duration * AVStream.time_base

tbc

• tbc: the time base in AVCodecContext for the codec used for a particular stream

​ 编解码的时间精确度time_base, 即 1s = 48个刻度，和视频的pts和dts有关。

​ 视频的显示时刻Tpts = AVFrame.pts * AVCodecContext.time_base

​ 视频的解码时刻Tdts = AVFrame.dts * AVCodecContext.time_base

tbr

• tbr: tbr is guessed from the video stream and is the value users want to see when they look for the video frame rate

​ 每秒显示图片的数量，24 tbr 也就是帧率的相同表示：24 fps