How to Automatically Add Subtitles to Videos with API

Did you know that 85% of videos on social media are watched on mute? And yet, millions of videos lose viewers every day not because the content isn’t engaging, but because they fail to include subtitles.

Think about it: A busy commuter or someone in a noisy café. They come across a video, but without subtitles, it’s meaningless. The result? A quick swipe, and the content is forgotten.

Subtitles aren’t just an option anymore they’re essential to make videos speak, even without sound.

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What are subtitles?

Subtitles are text versions of the spoken dialogue in a video, helping viewers follow along with the conversation in the same language as the audio. They make it easier to understand the content, especially for those who might struggle with accents or unclear speech.

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While subtitles are often confused with captions, captions offer more than just dialogue. They include descriptions of non-verbal sounds, like music or sound effects, and provide additional context. Captions are mainly designed to support viewers with hearing impairments, making sure they can experience the full audio-visual content, even without sound. To learn more about captions and subtitles, check out our blog Captions vs Subtitles.

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Why are subtitles important?

Subtitles not only make videos easier to follow, but they also improve SEO by providing searchable text for search engines, increasing the chances of your video being discovered.

They also cater to viewers who may watch in silent mode or in noisy environments, ensuring your message is still communicated effectively.

Subtitles help expand your reach by making content accessible to non-native speakers, enhancing viewer engagement, and broadening your audience.

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Why use APIs for subtitle generation?

Traditional subtitle methods, like manual transcription or basic software, are slow, tedious, and prone to errors. APIs change the game, offering a faster, smarter, and more reliable way to create subtitles.

Here’s what makes APIs better:

• AI-Powered accuracy: Subtitle APIs provide up to 95% accuracy, capturing cultural nuances and ensuring contextually correct subtitles.
• Speed & efficiency: APIs generate subtitles in real-time, saving hours compared to manual transcription—ideal for tight deadlines.
• Cost-effective: Reduce costs by up to 80%, eliminating the need for expensive software and extra manpower.
• Multilingual support: Easily add subtitles in over 100 languages, ensuring global reach with accurate translations and tone preservation.
• Accessibility features: APIs offer speaker identification, timestamp syncing, sound effect descriptions, and customizable formats.
• Easy integration: Seamlessly integrate with existing tools, making the subtitle creation process hassle-free.

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Subtitle generation using APIs

If you're looking for a subtitle generator specifically designed for video content, FastPix API is the ideal solution. Unlike general transcription tools, FastPix is built to address the unique challenges of video, such as ensuring perfect synchronization between subtitles and the video's audio.

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FastPix

FastPix API offers a powerful solution for automatically generating subtitles, providing accurate and synchronized captions for your video content. Powered by advanced AI, the system effortlessly converts spoken words into text, ensuring the subtitles align perfectly with the video's timeline.

Steps to add subtitles to videos using FastPix API

Step 1: Prepare your video

• Make sure your video has clear audio by removing unwanted sounds and reducing background noise.
• Check the volume levels to ensure voices are loud and distinct for accurate transcription.

Step 2: Upload your video to FastPix

• Log in to your FastPix account and either:
  • Upload your video directly from your device
  • Or, provide a public URL from cloud storage like Google Drive or AWS.

Step 3: Enable auto-subtitle generation

• To enable auto-generated subtitles, include the subtitles JSON object in your video request.
• This object should contain:
  • name: Specify the audio language (e.g., "english").
  • metadata: (Optional) Add any additional tags or information you want to associate with the subtitles.
  • languageCode: Provide the language code for the audio (e.g., "en" for English).

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Example JSON object for enabling subtitles

1{ 
2     "inputs": [ 
3       { 
4         "type": "video", 
5         "url": "https://static.fastpix.io/sample.mp4", 
6         "startTime": 0, 
7         "endTime": 60 
8       } 
9     ], 
10     "metadata": { 
11       "key1": "value1" 
12     }, 
13     "subtitles": { 
14       "name": "english", 
15       "metadata": { 
16         "key1": "value1" 
17       }, 
18       "languageCode": "en" 
19     }, 
20     "accessPolicy": "public", 
21     "maxResolution": "1080p" 
22   } 

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Once uploaded, FastPix will process your video and generate the subtitles.

If you're not looking for a video-specific solution and need a more general-purpose subtitle generation tool for various types of audio, there are several excellent APIs to explore. Below are some of the most popular options:

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Google Cloud Speech-to-Text API

Google Cloud Speech-to-Text is a powerful tool that converts audio into text. It supports over 125 languages, making it great for global use. Whether transcribing meetings, podcasts, or videos, it efficiently handles both real-time and batch transcriptions. It also includes features like automatic punctuation, speaker identification, and custom vocabulary for better accuracy. For the procedure on how to use it, click here.

Key features:

• Supports 125+ languages
• Real-time streaming and batch transcription
• Custom vocabulary for improved accuracy
• Automatic punctuation and speaker diarization

When to use It:

Use Google Cloud Speech-to-Text if your focus is on transcribing content in multiple languages or accents with high accuracy. This API is perfect when you need to handle diverse audio content from global teams, international conferences, or multilingual podcasts. If you're working with a variety of languages and need a tool that can transcribe in real-time or batch modes, this is the go-to solution.

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Amazon Transcribe

Amazon Transcribe is a fully managed service from AWS that provides automatic speech recognition (ASR). It transcribes audio files into text, offering useful features like speaker identification, custom vocabulary, and the ability to add timestamps for each word in the transcription. This API is particularly useful for businesses and enterprises that require scalable transcription solutions for a wide range of audio formats, including call center recordings, and interviews. It can also generate captions and subtitles for videos, making it a versatile tool for various content creators. To learn how to use it, click here.

Key features:

• Speaker identification for multi-speaker audio
• Custom vocabulary to handle domain-specific terms
• Timestamps for precise transcription alignment
• Supports multiple audio formats (MP3, MP4, etc.)

When to use It:

Opt for Amazon Transcribe if you're managing large-scale transcription needs, especially when dealing with multi-speaker conversations like meetings, interviews, or customer service call recordings. This API is great when you need speaker diarization, which helps distinguish between different speakers and provides context to your transcription.

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AssemblyAI

AssemblyAI offers a simple and developer-friendly API for speech-to-text conversion. It’s known for its speed and accuracy, making it an excellent choice for anyone needing reliable transcriptions quickly. This API provides various advanced features, including content moderation to detect inappropriate language, sentiment analysis to understand the tone of the speech, and a variety of file format supports like MP3, MP4, and WAV. AssemblyAI also makes it easy to integrate transcription into apps and websites, and it's particularly popular for creating captions for videos and podcasts. Click here for the step-by-step guide.

Key features:

• Fast and accurate transcriptions
• Content moderation to detect harmful content
• Sentiment analysis for emotional insights
• Supports multiple file formats (MP3, MP4, WAV)

When to use It:

Choose AssemblyAI when you need rapid, high-quality transcriptions along with advanced features like content moderation and sentiment analysis. This API excels when you want not just a transcript, but also insights into the emotional tone of speech or a tool to filter inappropriate content for podcasts, educational videos, or social media content.

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Why FastPix API is an ideal solution for video subtitles?

• Simple and easy to use: FastPix is easy to set up and use, allowing you to quickly generate subtitles without any hassle. Its seamless integration with your existing tools ensures a smooth process, so you can focus on your content rather than the technical details.
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• High accuracy: FastPix handles diverse speech, including accents, background noise, and technical jargon, with remarkable precision. Its ability to accurately transcribe and synchronize subtitles with video content sets it apart from other tools.
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• Multilingual capabilities: Unlike many subtitle generation APIs that focus on a limited set of languages, FastPix is trained on 680,000 hours of multilingual data, enabling it to transcribe and translate across a wide range of languages. This makes it perfect for global content creators looking to reach a diverse audience.
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• Zero-shot performance: FastPix consistently delivers better results with 50% fewer errors compared to other models, even without prior training on specific datasets. It is highly effective in generating accurate subtitles even in challenging scenarios.
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• Fast & scalable: FastPix is built for scalability, making it ideal for businesses and content creators needing to generate subtitles for large volumes of videos in a fast, reliable, and cost-efficient manner.

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Conclusion

With the FastPix API, adding subtitles to your videos is effortless. It streamlines the process, delivering accurate, synchronized subtitles in multiple languages without the technical complexity. But FastPix offers more than just subtitles; our features include speech-to-text, speaker diarization, and more. To learn more about what we offer, please check out our features section.