ffmpeg how to control fps tbr tbn tbc parameters

Question

RT, i have two avi file,

A.avi: fps 30 tbr 30 tbn 30 tbc 30.
B.avi: fps 2 tbr 2 tbn 2 tbc 2.

the problem is how to set the same value 30 on B.avi?

Answer 1

You can re-encode with a specified frame rate:

ffmpeg -i B.avi -codec:v mpeg4 -r 30 -qscale:v 2 -codec:a copy C.avi

What these options mean:

• -codec:v mpeg4 - Use the encoder called mpeg4 for MPEG-4 Part 2 video.
• -r 30 - Set output frame rate as 30.
• -qscale:v 2 - Set video output quality using a constant quantization parameter. Recommended range is 2-5 for mpeg4.
• -codec:a copy - Copy the audio from input to output to avoid re-encoding.

Note that ffmpeg will simply duplicate frames to achieve your desired output frame rate. If instead you were reducing your frame rate ffmpeg would drop frames.

Answer 2

You can change timebase or tbn tbc by -video_track_timescale, e. g. to change the tbn and tbc to 30:

ffmpeg -i 1.avi -c:v copy -video_track_timescale 30 1.avi

Answer 3

if you want more presice control, not only control fps. but also tbr, tbn, tbc. assume you understand what mean of it. tbc,tbn,tbr

check

ffmpeg -x264opts timebase=???

or

ffmpeg -time_base

or use format factory, default it give you same tbr, tbn, tbc.