How can I reencode a video to match another's codec exactly?

Question

When I'm on vacation, I usually use our camcorder to record videos. Since they're all the same format, I can use ffmpeg to concat them into one large, smooth video without re-encoding.

However, sometimes I will use a phone or other camera to record a video (if the camcorder ran out of space/battery or was left at a hotel).

I'd like to determine the codec, framerate, etc used by my camcorder and use those parameters to convert the phone vidoes into the same format. That way, I will be able to concatonate all the videos without re-encoding the camcorder videos.

Using ffprobe, I found my camcorder has this encoding:

  Input #0, mpegts, from 'camcorderfile.MTS':
  Duration: 00:00:09.54, start: 1.936367, bitrate: 24761 kb/s
  Program 1 
    Stream #0:0[0x1011]: Video: h264 (High) (HDPR / 0x52504448), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 59.94 fps, 59.94 tbr, 90k tbn, 119.88 tbc
    Stream #0:1[0x1100]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 256 kb/s
    Stream #0:2[0x1200]: Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090), 1920x1080

The phone (iPhone 5s) encoding is:

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'mov.MOV':
  Metadata:
    major_brand     : qt  
    minor_version   : 0
    compatible_brands: qt  
    creation_time   : 2017-01-02T03:04:05.000000Z
    com.apple.quicktime.location.ISO6709: +12.3456-789.0123+456.789/
    com.apple.quicktime.make: Apple
    com.apple.quicktime.model: iPhone 5s
    com.apple.quicktime.software: 10.2.1
    com.apple.quicktime.creationdate: 2017-01-02T03:04:05-0700
  Duration: 00:00:14.38, start: 0.000000, bitrate: 11940 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 11865 kb/s, 29.98 fps, 29.97 tbr, 600 tbn, 1200 tbc (default)
    Metadata:
      creation_time   : 2017-01-02T03:04:05.000000Z
      handler_name    : Core Media Data Handler
      encoder         : H.264
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 63 kb/s (default)
    Metadata:
      creation_time   : 2017-01-02T03:04:05.000000Z
      handler_name    : Core Media Data Handler
    Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
    Metadata:
      creation_time   : 2017-01-02T03:04:05.000000Z
      handler_name    : Core Media Data Handler
    Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
    Metadata:
      creation_time   : 2017-01-02T03:04:05.000000Z
      handler_name    : Core Media Data Handler

I'm presuming that ffmpeg will automatically take any acceptable video format, and that I only need to figure out the output settings. I think I need to use -s 1920x1080 and -pix_fmt yuv420p for the output, but what other flags do I need in order to make the phone video into the same encoding as the camcorder video?

Can I get some pointers as to how I can translate the ffprobe output into the flags I need to give to ffmpeg?

Edit: Added the entire Input #0 for both media files.

Amoebaean

In principle multi-segment mkv containers support codec and resolution switching. so that should allow you to concat different video formats sequentially. But it's a fairly niche feature, so I don't know how well supported it is by players. – Pacha

It seems all of your phone video parameters matching camcorder video except audio codec and audio sample rate. You can just use -c:a ac3 for audio compatibility. I think that is enough. – Amu

@Amu Converting the phone video so that the audio stream matched did not work. The output video didn't have a correct length, and I got a lot of warnings about Non-monotonous DTS in output stream, even after I changed the framerate to match as well. There must be more that is needed to make concat work. – Amoebaean

Anyway to provide a sample Iphone-5 video file? Even 5 seconds of filming the wall or floor is enough. You'll get a faster answer if there's testable stuff (code, files, links, etc) that we can check. Thanks. – Heikeheil

I guess the best approach is to convert both video to one common format and then easily concatenate them with ffmpeg concat – Intellect

Answer 1

Ffmpeg has a filter to use with concat that looks something like this (copied from https://trac.ffmpeg.org/wiki/Concatenate):

ffmpeg -i input1.mp4 -i input2.webm -i input3.mov \
-filter_complex "[0:v:0][0:a:0][1:v:0][1:a:0][2:v:0][2:a:0]concat=n=3:v=1:a=1[outv][outa]" \
-map "[outv]" -map "[outa]" output.mkv

The site linked explains how it all works. With this feature, you don't have to worry about the bitrate. The program adjusts it automatically. Older versions of ffmpeg had some trouble with matching bitrates, but I recently used it for concatenating a video and an animation and it worked fine. Not sure it it will work for frame rate though.

Splendor

This seems to work extremely inefficiently on the latest version of ffmpeg. I'm trying to concat 2 already identical videos with a very short video in the middle. It's re-encoding everything instead of just re-encoding the tiny one in the middle to match the surrounding 2. – Thelen

@GradynWursten did you find any way to re-encode only the small part to match the rest? – Walz