MP4 to mkv conversion

[carlmart]

This is the first time I deal with converting an mp4 file to mkv, with as little or no re encoding as possible, and I failed.

I tried to MKV merge, different versions, and Vidcoder, and couldn't even load the file.

From Mediainfo I get the following specs for the file:

 General
  Complete name                            : C:\ file.mp4
  Format                                   : MPEG-4
  Format profile                           : Base Media / Version 2
  Codec ID                                 : mp42
  File size                                : 6.80 GiB
  Duration                                 : 56mn 38s
  Overall bit rate                         : 17.2 Mbps
  
  Video
  ID                                       : 1
  Format                                   : AVC
  Format/Info                              : Advanced Video Codec
  Format profile                           : Baseline@L4.0
  Format settings, CABAC                   : No
  Format settings, ReFrames                : 1 frame
  Format settings, GOP                     : M=1, N=30
  Codec ID                                 : avc1
  Codec ID/Info                            : Advanced Video Coding
  Duration                                 : 56mn 38s
  Source duration                          : 56mn 38s
  Bit rate mode                            : Variable
  Bit rate                                 : 16.3 Mbps
  Width                                    : 1 920 pixels
  Height                                   : 1 080 pixels
  Display aspect ratio                     : 16:9
  Frame rate mode                          : Constant
  Frame rate                               : 29.970 fps
  Color space                              : YUV
  Chroma subsampling                       : 4:2:0
  Bit depth                                : 8 bits
  Scan type                                : Progressive
  Bits/(Pixel*Frame)                       : 0.262
  Stream size                              : 6.45 GiB (95%)
  Source stream size                       : 6.72 GiB (99%)
  mdhd_Duration                            : 3398195
  
  Audio
  ID                                       : 2
  Format                                   : AAC
  Format/Info                              : Advanced Audio Codec
  Format profile                           : LC
  Codec ID                                 : 40
  Duration                                 : 56mn 38s
  Bit rate mode                            : Constant
  Bit rate                                 : 192 Kbps
  Channel(s)                               : 2 channels
  Channel positions                        : Front: L R
  Sampling rate                            : 48.0 KHz
  Compression mode                         : Lossy
  Stream size                              : 79.4 MiB (1%)
  mdhd_Duration                            : 3398229

With Vidcoder I can't even load it, and with MKVmerge I get this message:

Command line used:

"C:\Video\MKVToolNix 6.2.0\mkvmerge.exe" --output-charset UTF-8 --identify-for-mmg "C:\file.mp4"

Output:

Error: The demultiplexer for the file 'C:\file.mp4' failed to initialize:

The file could not be opened for reading, or there was not enough data to parse its headers.

What should I do?

[ozok]

You can extract streams from mp4 file and then mux them to mkv later. I don't have much time right now to write commands, but mp4box or ffmpeg can be used to extract streams and mkvmerge to mux them into mkv. I guess you can use yamb as the GUI for mp4box.