How to Merge SRT With MP4 Files
By Andrew Schrader
Updated February 10, 2017
An SRT file is a standard, text-based subtitle format that accompanies a pre-existing video track. SRT tracks can be turned on or off using your computer's media player; however, merging or hardcoding them onto MP4 video requires software that can combine both tracks into one. This is also known as multiplexing. Several free options are available for download, including Xvid4PSP and open-source software like Avidemux and TEncoder. Note that some loss in video quality can occur when re-encoding text and video tracks.
Merging SRTs and MP4s Using Xvid4PSP
Visit Xvid4PSP's online home page. Click the "Free Download" button near the top of the screen and wait for Xvid4PSP to download to your computer. Double-click the ".exe" program file and follow Xvid4PSP's installation prompts. Agree to the licensing terms and launch the program.
Click the "Open" button in the upper-left corner of the screen and locate your input MP4 video in the pop-up window. Double-click or highlight its icon and choose "Open." Your MP4's audio and video encoding elements will automatically load in the left-hand portion of the screen.
Press the "Subtitles" tab at the top of the screen and select "Add." Navigate to your input SRT file, highlight its icon and click "Add" or "Open."
Click the "Save" button near the top of the screen to choose a save location for your converted MP4 and SRT video. Name your video and click "Save" to return to the main screen.
Press the "Encode" button in the top-right portion of Xvid4PSP to begin the encoding process.
Hardcoding SRT Subtitles With Avidemux
Open your Web browser and visit the SourceForge download page for Avidemux. Scroll down the page and locate the download link that corresponds to your computer's operating system. Click the appropriate link and wait for Avidemux to download to your computer. Double-click the downloaded ".exe" file and follow the on-screen installation instructions. Agree to the licensing terms and open Avidemux.
Click the "File" tab in the top-left corner of the screen and press "Open." Browse your computer's contents, locate your input MP4 video and open it in Avidemux.
Press the "Filters" button underneath the Video tab on the left side of the screen and select "Subtitles." Click the "Subtitler" icon.
Click the "+" sign in the bottom-right corner of the window and press the "Browse" button opposite the Subtitle File field. Locate your input SRT file in the pop-up screen, highlight its icon and click "Add" or "Open."
Click the "Browse" button next to the Font (TTF) field near the top-right corner of the screen and choose a font for your subtitles with a ".ttf" file extension from your computer's directory. Check the "C:WINDOWS\Fonts" directory for fonts installed on your computer.
Press the "Set Size and Position" button in the center of the screen to enter the Subtitle Size and Position preview window. Pick a font size using the up and down arrows in the top-left corner of the screen. Set your subtitle's position by using the slide bars at the top and right sides of the screen.
Click "OK" when finished. Press the "Save" button at the top of Avidemux's main screen, choose an output location for your merged files and click "Save" to begin the encoding process.
Merging SRT and MP4 Files With TEncoder
Open your Internet browser and visit the TEncoder home page on the SourceForge Web site. Click the "Download" icon near the top of the screen and wait for the latest version of the program to download to your computer. Run the ".exe" program file when your download has finished and follow TEncoder's installation prompts, installing all VobSub, FFMPEG or VisualDub components, but make sure to use MEncoder as your primary encoding option. Agree to the program's licensing terms and open TEncoder.
Open a new Windows Explorer search screen and create a new folder. Locate your input MP4 video and drag and drop its icon into the new folder. Leave this window open.
Open a second Windows Explorer search screen and locate your input SRT file. Drag and drop the SRT file into the same folder as your MP4. Rename your SRT file so it has the same name as your MP4, but keep their individual file extensions. For example, if your MP4 is named "mpeg4video.mp4," your subtitle file should read "mpeg4video.srt."
Click back to TEncoder and press the "+ Add" button in the top-left corner. Browse your computer via the pop-up search window, locate your input MP4 and select "Add" or "Open."
Click the "Enable Subtitles" box near the bottom-right corner of the screen so a check mark appears. Your SRT subtitles will automatically load with your MP4 video.
Choose a save location for your output MP4/SRT file by clicking the "Output Path" button at the bottom of the screen. Select a folder or other location on your computer and press "Save."
Press the "Subtitle Settings" to choose any additional subtitle configurations, like font, color and size. Click the "Encode" button to automatically begin merging your MP4 and SRT files.
Change your MP4's audio or video encoding methods, if needed, by using the "Codec" or "Encoding" options in each program. For simply merging SRTs with your video, leave this options alone.
Andrew Schrader has been a professional writer and filmmaker since 2004. He works as a writer and director, holding a Bachelor of Arts in film and media studies from UC Santa Barbara. Schrader specializes in writing about technology and computer software.