Use Subly to merge SRT with MP4 online. If you already have an SRT file, you can add this to a video (.MOV or MP4) that you have uploaded to Subly. Once uploaded you can edit if needed, or just use it as it is. Just look for the tool icon in the editor screen to find the option to upload your own SRT file.
Once you download your video, it will have your SRT file burned into it unless you choose a different download option. Learn more about Subly's caption generator.
