3GP (3rd Generation Partnership Project)

Overview

3GP is a multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services. It stores video and audio streams that are commonly used in 3G mobile phones and is designed for transmitting audio and video files between 3GPP-compliant mobile phones and over the Internet.

Technical Details

Container Structure

• Base Format: Based on the ISO base media file format (MP4)
• File Extension: .3gp, .3g2 (for 3GPP2)
• MIME Type: video/3gpp, audio/3gpp
• Streaming Support: Optimized for mobile network streaming

Supported Codecs

Video Codecs

• H.263: Primary video codec for 3GP
• MPEG-4 Visual: Simple Profile
• H.264/AVC: In newer versions
• VP8: Limited support

Audio Codecs

• AMR (Adaptive Multi-Rate): Primary audio codec
• AMR-WB (Wideband): Enhanced audio quality
• AAC: Advanced Audio Coding
• MP3: Limited support

File Structure

ftyp (File Type Box)
mdat (Media Data Box)
moov (Movie Box)
  ├── mvhd (Movie Header)
  ├── trak (Track Box - Video)
  │   ├── tkhd (Track Header)
  │   └── mdia (Media Box)
  └── trak (Track Box - Audio)
      ├── tkhd (Track Header)
      └── mdia (Media Box)

History and Development

3GP was developed by the 3GPP consortium in 1998 as part of the specifications for 3G mobile telecommunications. It was designed to enable multimedia messaging and streaming on mobile devices with limited bandwidth and processing power. The format has evolved through several releases, with 3GPP Release 6 introducing significant improvements.

Code Examples

FFmpeg Conversion

# Convert video to 3GP format
ffmpeg -i input.mp4 -c:v h263 -c:a amr_nb -ar 8000 -ac 1 output.3gp

# Convert with specific bitrate for mobile
ffmpeg -i input.mp4 -c:v h263 -b:v 64k -c:a amr_nb -ar 8000 -b:a 12.2k output.3gp

# Extract audio from 3GP
ffmpeg -i input.3gp -vn -c:a copy output.amr

# Convert 3GP to MP4
ffmpeg -i input.3gp -c:v libx264 -c:a aac output.mp4

Python Metadata Reading

from pymediainfo import MediaInfo

def analyze_3gp_file(filename):
    """Analyze 3GP file and extract metadata"""
    media_info = MediaInfo.parse(filename)
    
    for track in media_info.tracks:
        if track.track_type == 'General':
            print(f"Format: {track.format}")
            print(f"Duration: {track.duration} ms")
            print(f"File size: {track.file_size} bytes")
        elif track.track_type == 'Video':
            print(f"Video codec: {track.format}")
            print(f"Resolution: {track.width}x{track.height}")
            print(f"Frame rate: {track.frame_rate} fps")
        elif track.track_type == 'Audio':
            print(f"Audio codec: {track.format}")
            print(f"Sample rate: {track.sampling_rate} Hz")
            print(f"Channels: {track.channel_s}")

# Usage
analyze_3gp_file('video.3gp')

JavaScript 3GP Detection

function is3GPFile(file) {
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.onload = function(e) {
            const buffer = new Uint8Array(e.target.result);
            
            // Check for 3GP file type signature
            const signature = String.fromCharCode(...buffer.slice(4, 8));
            const brand = String.fromCharCode(...buffer.slice(8, 12));
            
            if (signature === 'ftyp' && (brand === '3gp4' || brand === '3gp5' || brand === '3gp6')) {
                resolve(true);
            } else {
                resolve(false);
            }
        };
        reader.onerror = reject;
        reader.readAsArrayBuffer(file.slice(0, 12));
    });
}

// Usage
document.getElementById('fileInput').addEventListener('change', async (e) => {
    const file = e.target.files[0];
    if (file && await is3GPFile(file)) {
        console.log('Valid 3GP file detected');
    }
});

Common Use Cases

Mobile Communications

• MMS (Multimedia Messaging): Sending video messages
• Video Calls: Recording and storing video calls
• Mobile Video Recording: Default format on many phones
• Voice Messages: Audio recording and playback

Streaming Applications

• Mobile Streaming: Low-bandwidth video streaming
• Progressive Download: Partial playback during download
• Live Broadcasting: Real-time video transmission
• Video Podcasts: Mobile-optimized content delivery

Legacy Device Support

• Older Mobile Phones: Compatibility with feature phones
• Embedded Systems: Resource-constrained devices
• Automotive Systems: In-car entertainment systems
• Security Cameras: Mobile surveillance applications

Tools and Software

Mobile Applications

• Native Camera Apps: Built-in recording on mobile devices
• WhatsApp: Video message recording
• Telegram: Voice and video message support
• VLC Mobile: Cross-platform media player

Desktop Software

• VLC Media Player: Universal media player
• FFmpeg: Command-line conversion tool
• HandBrake: GUI video converter
• MediaInfo: File analysis and metadata extraction

Development Libraries

• Android MediaRecorder: Native Android recording
• iOS AVFoundation: iOS multimedia framework
• GStreamer: Cross-platform multimedia framework
• OpenMAX: Hardware acceleration interface

Online Converters

• CloudConvert: Web-based file conversion
• Convertio: Online multimedia converter
• Online-Convert: Free conversion service
• Zamzar: Multi-format converter

Quality and Limitations

Advantages

• Small File Size: Efficient compression for mobile networks
• Low Bandwidth: Suitable for 3G/4G streaming
• Universal Support: Wide mobile device compatibility
• Fast Processing: Low computational requirements

Disadvantages

• Limited Quality: Lower video resolution and bitrate
• Codec Restrictions: Limited codec support
• Audio Quality: Compressed audio with artifacts
• Modern Alternatives: Superseded by MP4 and WebM

Mobile Network Optimization

Bitrate Recommendations

Video Quality    Resolution   Video Bitrate   Audio Bitrate
Low             176x144      64 kbps         12.2 kbps
Medium          320x240      128 kbps        12.2 kbps
High            352x288      256 kbps        23.85 kbps

Streaming Parameters

• Buffer Size: 2-5 seconds for mobile networks
• Segment Duration: 2-10 seconds per chunk
• Adaptive Bitrate: Automatic quality adjustment
• Error Resilience: Forward error correction

Modern Usage and Legacy Support

While 3GP has largely been replaced by MP4 for most modern applications, it remains important for:

• Legacy Device Support: Older mobile phones and embedded systems
• Bandwidth-Constrained Environments: Very low-speed networks
• Specific Applications: MMS and mobile messaging
• Archival Purposes: Preserving historical mobile content

The format continues to be supported by mobile platforms for backward compatibility, though most new content is created in more modern formats like MP4 with H.264 encoding.