How to convert MP4 to closed captions with automated transcription 
Step 1
Sign up for a free Sonix trial account—includes 30 minutes of free MP4 to captions conversion.
Step 2
Upload the MPEG-4 Video File file(s) (*.MP4) from your computer, Dropbox, Google Drive, or by dragging it on the page.
Step 3
Choose the language spoken in the uploaded MP4 file. We support over 37 different languages including Russian, Chinese, Spanish, and English. Click the 'Start Transcribing Now' button.
Step 4
Sonix will then automatically transcribe the audio from your MP4 file and convert it to a simple text format. Grab a cupcake, it will take only a few minutes.
Step 5
Use the Sonix AudioText Editor to polish your transcript before we convert it to a caption file. Simply type in your browser to correct any words in your transcript.
Step 6
Click the 'Export' button. Choose either 'Subrip subtitle file (.srt)' or 'WebVTT file (.vtt)' from the dropdown to download the closed caption version of your MP4 file. You can also adjust the character length and time duration length of each caption.
That's it! Your MP4 file has now been converted to closed captioning and is ready for the next step in your workflow!
Thousands of incredible customers use SOnix to create closed captions from their MP4 files 
Convert MP4 video files to subtitle
Frequently Asked Questions for MPEG-4 Video File (*.MP4)
What is a MP4 file?
An MP4 file is also known as a MPEG-4 Part 14 multimedia container. MP4 files were developed by the Moving Picture Experts Group (MPED). WIth an MP4 File, there are separate compression algorithms for the audio and video tracks. Typically, video is compressed with the MPEG-4 codec and the audio is compressed using the AAC codec (which is the same codec used in AAC files). Most MP4 files are downloaded from Apple’s iTunes STore since most of the media downloaded from the store is downloaded in this format. The MP4 format is also used for Internet streaming video.
Does Sonix transcribe video files with a *.MP4 file extension?
Yes, Sonix does automatically transcribe video files with a .MP4 file extension. Sonix is an online video to text converter. Convert any audio (mp3, m4a, wav, ...) or video (mp4, mov, avi, ...) file to text without installing any software! Sonix quickly and accurately transcribes *.MP4 files and converts them to text in a subtitle format.
Know anyone who needs to convert MPEG-4 Video File (.MP4) to subtitle?
We'd appreciate it if you tell them about Sonix—the best way to convert MP4 to subtitle.
Other ways to convert your MP4 video files with Sonix
Create closed captions from your MPEG-4 Video File files with Sonix 
Sonix transcribes your audio and video files in over 37 languages so they are easy to search, edit, and share. Sonix is an online, fully-automated speech to text service that quickly converts MPEG-4 Video File files to captions. Sign up today and start transcribing.
Includes 30 minutes of free transcription
