How to convert srt to sub and idx format

Before getting in a deep discussion about how to convert srt to sub and idx subtitle format, let’s discuss them first. The common subtitle file SUB (having .sub as the file extension) is an image-based subtitle format that contains pictures of text and is usually extracted from Digital Versatile Discs (DVDs) or Blu-ray discs. SUB file format is of type – Micro DVD sub and SubViewer sub.

The Micro DVD subformat is used by the Micro DVD players. It uses the frame rate for marking the timing of subtitles while the SubViewer format is used by DivX media players and it is also supported on YouTube. The SUB format is also regarded as sub or IDX or VobSub format subtitle.

These subtitle formats are always in a pair. The subfile contains the images of the subtitle text and the IDX file contains information of when each picture is to be shown on the screen of the device. Both the subfile and the IDX file are needed for them to be used, the subtitles become useless if you only have one of the two.

The sub or IDX subtitles make use of text images to display subtitles on the device screen, this process is effective if you want the subtitles to work on every TV, irrespective of the text or font encoding being utilized by the TV.

However, using pictures or images to display texts also has some disadvantages, such as the subtitle files are relatively big, trying to edit the text is very hard and there is every possibility that the subtitle display quality would be low especially on large screens.

The SUB subtitle file is not supported on some devices such as smartphones, smart TVs, casting devices, etc. since it brings about display issues during playback on these devices. For the subtitle file to work with these devices, it needs to be converted into an SRT file having a .srt file extension. But, how to convert srt to sub and idx subtitle format?

Subtitle in media enables the user to access the information most conveniently. The conversion of media from one form to another enables the user to interpret the information in the forms appropriate to them.

Language can be translated into different forms by use of different platforms. The media from the DVD contains the translations in the form of IDX which contain the sub-files of the initial form.

When using the computer to play videos the IDX needs to convert to SRT format. SRT converts the subtitles to suit the person speaking, background music and can display the captions in different colors.

The SRT converts the speech of the subtitle and in the most appropriate language. The conversion of IDX TO SRT is done to make the user understand the flow of the media of different languages.

The SRT file is just a text-based subtitle format generated by the Sub Rip software, it can be compatible with any device which gives it an advantage over the SUB format. There are two basic methods by which you can convert srt to sub and idx subtitle format, those methods are as discussed below with easy to follow steps.

Converting SUB files to SRT with the Subtitle Edit software

Subtitle Edit is application software that can convert srt to sub and idx subtitle format, it is easy-to-use, open-source and clean. Subtitle Edit makes use of OCR (Optical Character Recognition) as a means of image-to-text conversion. OCR (Optical Character Recognition) is simply the process of capturing characters from bitmap and exporting it as plain text. The procedures to convert the file are discussed below for your convenience.

Step 1: To start with the conversion, you need to first download the latest version of “Subtitle Edit” online.

You can also download it from

After downloading it, install the software into your system by following the instructions and then launch it once installed.

Step 2: On the software interface, navigate to the File tab at the top-left corner, click on Open VobSub(sub or IDX) to import the SUB subtitle files.

Step 3: Click on Start OCR to start the OCR (Optical Character Recognition) process which will act transcribing the image-based subtitles into text. You have the opportunity to edit any incorrect transcription at the blank box located on the left side of the OCR dialog box. Once, you have scanned through, you can proceed to the next step by clicking on the OK button.

Step 4: After clicking OK, you will be redirected to the main interface of the software. Locate the Format option from the top-right side of the interface, and then select the SubRip (.srt) format and customize the subtitle encoding if it is required.

Step 5: Go to the File tab once again and select Save As. Before saving make sure to choose the output file format as SRT format and then save it. The SRT file will perfectly be synchronized as the time codes are taken from the DVD subtitle itself and ready to be used on any device.

Convert srt to sub and idx subtitle format using Online Converters

Another method you can use to convert srt to sub and idx subtitle format is through the aid of online converters. There is a couple of free converters available online for this purpose such as Subtitle converter, SUB to SRT converter,, etc.

All you need to do on these online converters is to upload your SUB subtitle format on the website, wait for some time for the OCR to carry out the conversion and then download your converted SRT subtitle format.

This method of conversion has some cons, however, for instance, if the website is too busy i.e. when many users are converting files at a time, your file will have to be in a queue and this will take more of your time.

Another constraint is that the OCR (Optical Character Recognition) process of converting the images to text is hard work for the server and this, therefore, implies that when multiple files are to be converted, they will have to be uploaded one by one on the website.

Also, most of the downloaded SRT files from these online converters are not perfectly synced i.e. the subtitle won’t be perfect. Another limitation is that the ongoing conversion process is not seen and any transcription can’t be corrected.

These constraints, therefore, make the online conversion method less reliable and less efficient. However, in cases where you have a small subtitle file to be converted, using an online converter may just be the perfect option for you.

Also, access to online converters is not limited to having a PC alone, you can easily convert a SUB subtitle format to an SRT subtitle format with your tablet or a smartphone and then use the converted file to watch a movie directly on your phone or tablet. The converted file can then be transferred to your PC if need be unlike the Subtitle Edit software which can only be used on PCs.


These types of programs operate by converting subtitles. They make use of the internet illustrations and the conversion of pictures into the subtitle. It is mainly applicable for anyone with the MAC computer and can be integrated to perform other functions.

The Sub-IDX format subtitles are usually extracted from DVDs. The files are mainly formed by two sub-files. One of them contains a picture of the subtitle text, and the other contains information about when to show each picture. You need both the sub-file and the IDX file to use them, the subtitles are unusable if you only have one.

These types of programs operate by converting the subtitles by using internet illustrations. The provision of synonyms to the subtitle is common with this format. This tool uses Pictures of the media and builds up an SRT file with the results from the pictures of the media. The conversion is so quick which makes it among the most commonly used program.

Step 1: To convert load the program and open the SRT option. Click on the convert option.

Step 2: Select the languages of the character. Select done option illustrated run.

Step 3: Save the file at the end of the process.

Step 4: The subtitles will appear in the media on the computer.


The Sub/IDX files can contain multiple languages. The languages can be converted to any language in their SRT formats. Once you load the OCR, the options will appear on the toolbar. Select the languages you want to extract. The IDX can contain multiple languages since the media can contain characters of different languages.

The program is widely used, in that it contains the format convenient for interpretation by the deaf people. This is ensured by the illustrations that show the pitch and environmental conditions of the media settings. The user can see which one is which, so it is easiest to extract all of them and then choose the one you want to keep.

This tool might not work if you have a .sub file and no .IDX file. But there is a chance that your .sub file is a Micro DVD file because they share the same file extension. To find out if it is a Micro DVD file, you can try converting it using the Support.

Wrapping up

In conclusion, using the Subtitle Edit software is the best and efficient method of converting SUB subtitle files into SRT subtitle files, its conversion is faster than online converters, the user sees the ongoing conversion process, has the opportunity to correct any transcription error in conversion from the image subtitle format to the text format, the SRT file is perfectly synced and suitable for use on any device.

There are many platforms available to convert the information subtitles either by use of Windows or MAC computers. The access of subtitles can be converted into as many languages as the user prefers. The conversion is very fast. It is important to gain the most out of the media file. The conversion of the IDX to SRT enables the disadvantage to understand the information from the Media.

Experiencing difficulties with your Device, check out our “How To” page on how to resolve some of these issues.


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