[Matroska-users] Matroska file decoding - Question on seekhead

Austin Einter austin.einter at gmail.com
Sun Sep 3 15:08:27 CEST 2017


First of all a BIG THANKS to Matroska, for providing a open source media
file container.

I have a requirement, where I need to parse a matroska file. Initial few
bytes of file is given as below.

0x1a 0x45 0xdf 0xa3 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x23 0x42 0x86 0x81
0x01
0x42 0xf7 0x81 0x01 0x42 0xf2 0x81 0x04 0x42 0xf3 0x81 0x08 0x42 0x82 0x88
0x6d
0x61 0x74 0x72 0x6f 0x73 0x6b 0x61 0x42 0x87 0x81 0x04 0x42 0x85 0x81 0x02
0x18
0x53 0x80 0x67 0x01 0x00 0x00 0x00 0x00 0x33 0xdb 0x10 *0x11 0x4d 0x9b 0x74*
0x40
0x42 0xbf 0x84 0x11 0xac 0x83 0x8a 0x4d 0xbb 0x8b 0x53 0xab 0x84 0x15 0x49
0xa9
0x66 0x53 0xac 0x81 0xe5 0x4d 0xbb 0x8c 0x53 0xab 0x84 0x16 0x54 0xae 0x6b
0x53
0xac 0x82 0x01 0x56 0x4d 0xbb 0x8c 0x53 0xab 0x84 0x12 0x54 0xc3 0x67 0x53
0xac
0x82 0x11 0x5c 0x4d 0xbb 0x8d 0x53 0xab 0x84 0x1c 0x53 0xbb 0x6b 0x53 0xac
0x83
0x33 0xd9 0x1c 0xec 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x94 0x00 0x00 0x00
0x00
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x00
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x00

I am trying to parse this file. I have parsed first 59 bytes successfully.
Now I am at 60th byte. From 6th byte bytes are 0x11 0x4d 0x9b 0x74, so it
means seekhead is starting.

I used mkvinfo to view parsed data. As per mkvinfo as shown below, seekhead
starts at 59 which is fine.

 [image: Inline image 2]


Looks the first seek entry starts at 71. Now from 59th to 71st position
what is there. This part I am not able to understand.

Can somebody please help me to understand this part.

Best Regards,
Kamal
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.matroska.org/pipermail/matroska-users/attachments/20170903/e47cc347/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 19581 bytes
Desc: not available
URL: <http://lists.matroska.org/pipermail/matroska-users/attachments/20170903/e47cc347/attachment-0001.png>


More information about the Matroska-users mailing list