# MP3

The legacy audio standard with universal support across every device and player.

## What It Is

MP3 (MPEG-1 Audio Layer III) is the audio compression format that defined digital music distribution. Developed by the Fraunhofer Society and standardized in 1993, MP3 achieves roughly 10:1 compression of CD-quality audio. While newer codecs like AAC and Opus deliver better quality at lower bitrates, MP3 remains the most universally recognized and supported audio format in existence. Every device, browser, media player, and audio chip decodes MP3. The original MP3 patents expired in 2017, making it effectively royalty-free for most practical purposes.

## When to Choose MP3

Choose MP3 when:

- You need maximum compatibility with legacy systems — MP3 plays on every device ever made with audio capability.
- Your distribution channel requires MP3 — some podcast platforms and RSS feeds still mandate MP3 format.
- File format recognition matters — end users understand “.mp3” more than any other audio extension.

Consider alternatives when:

- You are encoding audio for HLS video streams — [AAC](https://cloud.qencode.com/audio-formats-codecs/aac) is required by the HLS spec and more efficient.
- You want better quality at lower bitrates — [Opus](https://cloud.qencode.com/audio-formats-codecs/opus) achieves transparent quality at 128 kbps vs. MP3’s 256 kbps.
- You are building for WebRTC or low-latency audio — [Opus](https://cloud.qencode.com/audio-formats-codecs/opus) is the standard with configurable latency down to 2.5ms.

## Key Characteristics

|     |     |
| --- | --- |
| Standard | ISO/IEC 11172-3 (MPEG-1 Layer III), 1993 |
| Bitrate range | 32 kbps – 320 kbps (CBR); VBR also supported |
| Sweet spot bitrate | 192 kbps (high quality for music) |
| Channels | Stereo, joint stereo, dual channel, mono |
| Latency | ~26ms (algorithmic delay) |
| Sample rates | 32, 44.1, 48 kHz |
| Royalty status | Effectively royalty-free (patents expired 2017) |
| Container support | [MP4](https://cloud.qencode.com/video-formats-codecs/mp4), standalone (.mp3) |
| Browser support | All browsers — Chrome, Firefox, Safari, Edge |
| Typical use case | Legacy audio, podcast RSS feeds, maximum compatibility |

## Browser & Device Support

| Platform | MP3 | AAC | Opus | Vorbis |
| --- | --- | --- | --- | --- |
| Chrome (desktop) |  |  | 33+ |  |
| Firefox (desktop) |  |  | 15+ |  |
| Safari (macOS) |  |  | 14.1+ |  |
| Edge |  |  | 79+ |  |
| iOS Safari |  |  | 14.5+ |  |
| Android Chrome |  |  |  |  |

## How Qencode Handles MP3

Qencode encodes MP3 audio. Specify `mp3` as the audio codec with your desired bitrate and channel configuration.

Pair with Audio Normalization to ensure consistent loudness across MP3 outputs.

```json
{
  "query": {
    "source": "https://your-storage.com/video.mp4",
    "format": [
      {
        "output": "mp3",
        "audio_codec": "mp3"
      }
    ]
  }
}
```

Copy this payload and use it with your API key to encode MP3 audio from any source.

## MP3 vs. AAC

|  | MP3 | AAC |
| --- | --- | --- |
| Compression | Older, less efficient | ~30% better at same quality |
| Quality at 128 kbps | Good (transparent for most) | Better (near-transparent) |
| Quality at 64 kbps | Noticeable artifacts | Acceptable quality |
| Royalty status | Patents expired (royalty-free) | Licensed (fees absorbed by vendors) |
| Streaming support | Progressive download only | HLS, DASH, CMAF native |
| Browser support | Universal | Universal |
| Best for | Legacy compatibility, podcasts | Streaming, Apple ecosystem, modern apps |

## Related Technologies

[**AAC** 
\
The modern successor to MP3 with better compression and HLS support.](https://cloud.qencode.com/audio-formats-codecs/aac)[**Opus** 
\
The most efficient audio codec available, mandatory for WebRTC.](https://cloud.qencode.com/audio-formats-codecs/opus)

### Audio Normalization

Standardize loudness levels across your audio library.