.IDX

Introduction

VobSub stores DVD subtitles outside the disc as a pair of files with the same name: a text index with the extension .idx and a binary .sub file holding the subtitle pictures. It was created by the VobSub tools for Windows to rip subtitles from DVDs without converting them to text.

DVD subtitles are small images with four colours, so like Blu-ray PGS they cannot be edited as text without optical character recognition. The binary .sub file should not be confused with the text MicroDVD format, which uses the same extension.

Structure

The .idx file is text. It begins with a comment line naming the VobSub index version, then settings such as the picture size, the 16-colour palette in hexadecimal and the language of each track (id: en, index: 0). Each subtitle then has a line giving its time and its byte position in the .sub file.

The .sub file is an MPEG-2 program stream holding only the DVD subpicture packets, in private stream 1, as they were stored in the disc’s VOB files.

# VobSub index file, v7 (do not modify this line!)
size: 720x576
palette: 000000, f0f0f0, cccccc, 999999, …
id: en, index: 0
timestamp: 00:00:01:000, filepos: 000000000
timestamp: 00:00:04:000, filepos: 000000800

Also used for

• MicroDVD subtitles .sub

Links