How to manually change duration field in matroska/mkv

Question

I have one mkv file that doesn't have valid duration. I want to change this duration parameter manually. I gone through this matroska specification defined at http://www.matroska.org/technical/specs/index.html

Looking at specification for matroska this contains only identification magic numbers, but this doesn't specify length for data.

How to parse this matroska header so that i get duration field and change this field?

How is this question related to c? – 404 Nov 01 '14 at 09:23 — 404, Nov 01 '14 at 09:23

score 2 · Accepted Answer · answered Nov 01 '14 at 09:24

The type of the Duration field is float. According to the documentation it can be either 4 or 8 octets. To know which size it is, you have to look at the data size part of the field. The data size part uses an UTF-8 like system. It's explained here.

score -1 · Answer 2 · answered May 14 '18 at 15:09

-1

You can use ffprobe to get duration of .mkv file :

$ ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 input.mkv
5012.640000

See : https://trac.ffmpeg.org/wiki/FFprobeTips#Duration

answered May 14 '18 at 15:09

Calumah

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Although your answer will properly show the duration, the question is about how to manually change the duration. – llogan May 14 '18 at 18:27
For your information, question title before editing was : "Parse mkv file to get duration" .... – Calumah May 19 '20 at 07:13

How to manually change duration field in matroska/mkv

2 Answers2