how to fix or change a mp4 video timestamps (frame rate) based on available frames?

I have a video file that was created as x264, 26 fps, 20MB. command used to convert avconv -i infile.mp4 -c:v libx265 -c:a libmp3lame outfile.mp4 After converting it to x265 HEVC it gets wrong timestamps and so frame rate 1 fps, it has 1MB and the frames looks ok, just the time is messed. sample warning messages: mp4 @ 0x10e8660] Non-monotonous DTS in output stream 0:0; previous: 114400515, current: 454496; changing to 114400516. This may result in incorrect timestamps in the output file. Past duration 0.644524 too large the x264 file reports 23s duration, the new one x265 is 11 minutes 46 seconds... this wont fix it: avconv -i infile.mp4 -c:v copy -c:a copy -r 26 outfile.mp4 Obs.: the mp4 was created using "DU Recorder" on android, capturing the screen.