New Benchmark Refines Audio Codec Evaluation for AI

AudioCodecBench offers a systematic framework for assessing audio codecs in large language models.

A new paper introduces AudioCodecBench, a comprehensive benchmark for evaluating audio codecs, especially those used with Multimodal Large Language Models (MLLMs). This framework addresses current limitations in defining and assessing audio tokens, promising more accurate and fair comparisons. It evaluates codecs across four key dimensions.

Sarah Kline

By Sarah Kline

September 15, 2025

4 min read

New Benchmark Refines Audio Codec Evaluation for AI

Key Facts

  • AudioCodecBench is a new comprehensive benchmark for evaluating audio codecs.
  • It addresses limitations in defining semantic and acoustic audio tokens for MLLMs.
  • The framework evaluates codecs across four dimensions: reconstruction, codebook stability, perplexity, and downstream task performance.
  • The research provides suitable definitions for semantic and acoustic tokens.
  • The findings show correlations between various evaluation metrics.

Why You Care

Ever wonder why some AI-generated speech sounds so natural, while other attempts fall flat? The quality of AI audio, from your favorite podcast’s AI voiceover to music generation, hinges on how well AI understands and recreates sound. How crucial is this for your next creative project or business venture?

New research unveils a essential tool for improving this. It aims to standardize how we measure audio quality in artificial intelligence. This directly impacts the realism and utility of AI-generated audio for you.

What Actually Happened

A team of researchers, including Lu Wang and Hao Chen, submitted a paper titled “AudioCodecBench: A Comprehensive Benchmark for Audio Codec Evaluation” to arXiv, as detailed in the blog post. This paper introduces AudioCodecBench, a new structure designed to systematically evaluate audio codecs. These codecs are crucial components in Multimodal Large Language Models (MLLMs), which handle both speech and music data. The research highlights a current problem: existing methods for defining and evaluating audio tokens are often inconsistent or incomplete. Audio tokens are the discrete units AI uses to process sound, similar to how text tokens represent words. The team revealed that their structure provides suitable definitions for both semantic tokens (what the sound means) and acoustic tokens (the fine-grained details of the sound). This allows for a more comprehensive assessment of how well different audio codecs perform.

Why This Matters to You

This new AudioCodecBench structure directly impacts the future of AI audio applications. If you’re a content creator, musician, or developer working with AI, understanding how audio codecs are evaluated is key. It means you can expect more reliable and higher-quality AI-generated audio in the future. The research shows that current evaluations often focus on specific domains, like reconstructing audio or Automatic Speech Recognition (ASR) tasks. This prevents a truly fair comparison of different codecs, according to the announcement. Imagine trying to pick the best microphone without a standardized way to test its sound quality across various scenarios. That’s the problem AudioCodecBench aims to solve for AI audio.

Key Evaluation Dimensions of AudioCodecBench:

  • Audio Reconstruction Metric: How accurately the codec rebuilds the original sound.
  • Codebook Index (ID) Stability: How consistently the codec assigns identifiers to similar sounds.
  • Decoder-Only Transformer Perplexity: A measure of how well the codec predicts the next audio token.
  • Performance on Downstream Probe Tasks: How well the codec performs in real-world applications.

How will a standardized evaluation process change your approach to selecting AI tools for audio generation or analysis? For example, if you’re a podcaster using AI to generate intro music, you’ll want a codec that excels in reconstruction and downstream tasks. The paper states that this structure allows for a comprehensive assessment of codecs’ capabilities. This means better tools for your creative endeavors. “Our results show the correctness of the provided suitable definitions and the correlation among reconstruction metrics, codebook ID stability, downstream probe tasks and perplexity,” the team revealed. This indicates a strong, interconnected evaluation method.

The Surprising Finding

Here’s an interesting twist: the research challenges the common assumption that all audio tokens are created equal. The study finds that existing research is unsuitable in its definitions of semantic tokens and acoustic tokens. This is surprising because many might assume that an audio token simply represents a sound. However, the team revealed that audio tokens must both capture global semantic content (the meaning) and preserve fine-grained acoustic details (the sound’s texture and nuances). Think of it as the difference between understanding the word ‘cat’ and hearing the specific meow of your own cat. The paper emphasizes the need for distinct definitions. This distinction is crucial for developing MLLMs that can truly understand and generate complex audio, moving beyond just basic sound reproduction.

What Happens Next

This new benchmark is set to influence AI audio creation significantly. Developers and researchers will likely adopt AudioCodecBench in the coming months, perhaps within the next 6-12 months. This will lead to more and comparable evaluations of audio codecs. For example, AI companies could use this structure to objectively compare their audio generation models against competitors. This could accelerate the creation of more natural-sounding AI voices and realistic AI-generated music. The industry implications are clear: a standardized evaluation will foster creation and competition. Actionable advice for you is to keep an eye on AI tools that explicitly mention using comprehensive benchmarks for their audio components. As the company reports, this will ensure higher quality and more reliable performance from the AI audio you use.

Ready to start creating?

Create Voiceover

Transcribe Speech

Create Dialogues

Create Visuals

Clone a Voice