$ ffmpeg -i 01-prestice.avi -c copy 01-prestice.mkv
ffmpeg version N-105341-g8b6d800038-g7247a6fed8+5 Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 11.2.0 (Rev7, Built by MSYS2 project)
  configuration:  --pkg-config=pkgconf --cc='ccache gcc' --cxx='ccache g++' --ld='ccache g++' --enable-amf --enable-bzlib --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-iconv --enable-lzma --enable-nvenc --enable-zlib --enable-sdl2 --enable-ffnvcodec --enable-nvdec --enable-cuda-llvm --enable-gmp --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libdav1d --disable-debug --enable-fontconfig --enable-libass --enable-libfreetype --enable-libmfx --enable-libmysofa --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libwebp --enable-libzimg --enable-gpl --enable-avisynth --enable-libxvid --enable-libaom --enable-libopenmpt --enable-version3 --enable-libcaca --enable-libflite --enable-libfribidi --enable-libilbc --enable-libsvthevc --enable-libsvtav1 --enable-libsvtvp9 --enable-libmodplug --enable-librubberband --enable-libxavs --enable-libzmq --enable-libzvbi --enable-openal --enable-libvmaf --enable-libcodec2 --enable-libsrt --enable-vapoursynth --enable-librav1e --enable-opencl --enable-opengl --enable-gnutls --extra-cflags=-DLIBTWOLAME_STATIC --extra-libs=-lstdc++ --extra-cflags=-DCACA_STATIC --extra-cflags=-DMODPLUG_STATIC --extra-cflags=-DZMQ_STATIC --disable-w32threads --extra-cflags=-DAL_LIBTYPE_STATIC --extra-cflags='-IC:/media-autobuild_suite/local64/include' --extra-cflags='-IC:/media-autobuild_suite/local64/include/AL'
  libavutil      57. 18.100 / 57. 18.100
  libavcodec     59. 20.100 / 59. 20.100
  libavformat    59. 17.101 / 59. 17.101
  libavdevice    59.  5.100 / 59.  5.100
  libavfilter     8. 26.100 /  8. 26.100
  libswscale      6.  5.100 /  6.  5.100
  libswresample   4.  4.100 /  4.  4.100
  libpostproc    56.  4.100 / 56.  4.100
Input #0, avi, from '01-prestice.avi':
  Metadata:
    software        : AVI-Mux GUI 1.17.4, Nov  5 2005  22:53:48-
    JUNK            :
  Duration: 00:00:21.80, start: 0.000000, bitrate: 2710 kb/s
  Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x576 [SAR 1:1 DAR 5:4], 2558 kb/s, 25 fps, 25 tbr, 25 tbn
  Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, fltp, 128 kb/s
    Metadata:
      title           : 01-Prestice
Output #0, matroska, to '01-prestice.mkv':
  Metadata:
    software        : AVI-Mux GUI 1.17.4, Nov  5 2005  22:53:48-
    JUNK            :
    encoder         : Lavf59.17.101
  Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x576 [SAR 1:1 DAR 5:4], q=2-31, 2558 kb/s, 25 fps, 25 tbr, 1k tbn
  Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, fltp, 128 kb/s
    Metadata:
      title           : 01-Prestice
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame=    0 fps=0.0 q=-1.0 size=       1kB time=00:00:00.02 bitrate= 245.2kbits/[matroska @ 0000027016184740] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
[matroska @ 0000027016184740] Can't write packet with unknown timestamp
av_interleaved_write_frame(): Invalid argument
frame=    1 fps=0.0 q=-1.0 Lsize=       4kB time=00:00:00.20 bitrate= 161.9kbits/s speed= 967x
video:30kB audio:3kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Conversion failed!