ffmpeg - resizing .mp4 changes the timebase (tbn & tbc) I have been trying to write a script to merge multiple .mp4 videos using ffmpeg. As part of this process, while trying to alter the size found that it alters the timebase. However, for ffmpeg - concat demux all streams should be same or else after merge only the first part of the video plays well and stops abruptly.
I have tried both terminal way and also using fluent-ffmpeg. But unfortunately both gives same result.

Original video Ex, org_video_1280x720.mp4


Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 812 kb/s, 25 fps, 25 tbr, 30k tbn, 60k tbc (default)


after scaling down to 640x360 via terminal ffmpeg -i org_video_1280x720.mp4 -strict -2 -vf &quot;scale=640:360&quot; new_video_640x360.mp4


Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 256 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)


The fluent-ffmpeg way of sizing

ffmpeg(`/path/to/org_video_1280x720.mp4`).size(`640x360`). autopad().output(`/path/to/new_video_640x360.mp4`)
          .on('error', function(err, stdout, stderr) {
              console.log('Error: ' + err.message);
              console.log('STD Err: ' + stderr);
         })
         .on('end', function() {
              console.log('Split &amp; Resizing Completed!');
         }).run();


Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 253 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)

Notice the tbn &amp; tbc changes after resizing; Actually I have to merge this with other video only by changing the resolution (as they were with these 25 fps, 25 tbr, 30k tbn, 60k tbc stream values); However as it alters the time_base, I was unable to do it. Hope, I am missing something in the process, as I am bit new to audio/video process. Looking for some tips/guidance to get this done!
Add -video_track_timescale X to manually set a timescale of X.
ffmpeg -i org_video_1280x720.mp4 -strict -2 -vf &quot;scale=640:360&quot; -video_track_timescale 90k new_video_640x360.mp4