raija@Tumbleweed:~> mediainfo Video-by-Tumbleweed.webm 
General
Complete name                            : Video-by-Tumbleweed.webm
Format                                   : WebM
Format version                           : Version 2
File size                                : 1.07 MiB
Duration                                 : 3 s 900 ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 2 295 kb/s
Writing application                      : Lavf58.76.100
Writing library                          : Lavf58.76.100

Video
ID                                       : 1
Format                                   : VP8
Codec ID                                 : V_VP8
Bit rate                                 : 2 067 kb/s
Width                                    : 640 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Variable
Compression mode                         : Lossy
Default                                  : Yes
Forced                                   : No
DURATION                                 : 00:00:03,900000000

Audio
ID                                       : 2
Format                                   : Vorbis
Format settings, Floor                   : 1
Codec ID                                 : A_VORBIS
Duration                                 : 3 s 900 ms
Bit rate mode                            : Variable
Bit rate                                 : 128 kb/s
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 kHz
Compression mode                         : Lossy
Stream size                              : 60.9 KiB (6%)
Writing application                      : Lavc58.134.100
Writing library                          : libVorbis (Reducing Environment) (20200704 (Reducing Environment))
Default                                  : Yes
Forced                                   : No
DURATION                                 : 00:00:00,000000000 <--- häh???

=====================================

raija@Tumbleweed:~> mediainfo Video-by-Mageia.webm 
General
Complete name                            : Video-by-Mageia.webm
Format                                   : WebM
Format version                           : Version 2
File size                                : 9.36 MiB
Duration                                 : 31 s 936 ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 2 458 kb/s
Writing application                      : Lavf58.29.100
Writing library                          : Lavf58.29.100

Video
ID                                       : 1
Format                                   : VP8
Codec ID                                 : V_VP8
Bit rate                                 : 2 224 kb/s
Width                                    : 640 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Variable
Compression mode                         : Lossy
Default                                  : Yes
Forced                                   : No
DURATION                                 : 00:00:31,936000000

Audio
ID                                       : 2
Format                                   : Vorbis
Format settings, Floor                   : 1
Codec ID                                 : A_VORBIS
Duration                                 : 31 s 936 ms
Bit rate mode                            : Variable
Bit rate                                 : 128 kb/s
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 kHz
Compression mode                         : Lossy
Delay relative to video                  : -3 ms
Stream size                              : 499 KiB (5%)
Writing application                      : Lavc58.54.100
Writing library                          : libVorbis (Now 100% fewer shells) (20180316 (Now 100% fewer shells))
Default                                  : Yes
Forced                                   : No
DURATION                                 : 00:00:31,912000000