output stream frame rate can't match input stream frame rate in example api2-decode-encode-video

[naiixeel]

Thanks for this excellent work.

When I use example api2-decode-encode-video to do a test, I found output stream frame rate can't match input stream rate. Output stream always has framerate with fraction. The following is an example. The video stream information is got from ffmpeg.

input video stream:
Stream #0:0(und): Video: hevc (Main) (hev1 / 0x31766568), yuvj420p(pc, bt709), 3840x2160, 30011 kb/s, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1000k tbn, 1000k tbc (default)

output video stream:
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc), 3840x2160, 1465 kb/s, 25.37 fps, 25 tbr, 90k tbn, 2k tbc (default)

Any idea about this problem?

[mmomtchev]

Check the timebases, maybe your input stream has a very unusual timebase. I guess it does not happen with every file?

[naiixeel]

I have tested several different videos, they all have the same problem.

[mmomtchev]

Yes, but are the videos coming from the same encoder? Check the timebases.

https://stackoverflow.com/questions/3199489/meaning-of-ffmpeg-output-tbc-tbn-tbr

Anyway, your tbr is correct, so I guess that your video is also correct.