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PianoPoet Unifying Piano Transcription and Rendering via Auto-regressive Modeling

A single-checkpoint model for neural piano transcription and rendering, built on one shared auto-regressive Transformer backbone.

Piano audio PianoPoet MIDI

01 / Overview

One backbone, both directions

PianoPoet frames transcription and rendering as sequence-to-sequence tasks with a shared MIDI tokenizer but decoupled audio representations: semantic audio frames for transcription, and acoustic tokens for rendering.

PianoPoet architecture for piano transcription and piano rendering

Joint capability

A single checkpoint at the frontier

The unified model reaches strong results in both acoustic-to-symbolic transcription and symbolic-to-acoustic rendering.

1
shared checkpoint
2
generative directions
AR
training objective
Comparison of transcription onset F1 score and rendering LPAPS across models
Figure 2. Arrows indicate the preferred direction for each metric.

Abstract

Across acoustic and symbolic music

Solo-piano transcription and rendering connect the acoustic and symbolic domains of music in opposite directions. Although pianists naturally move between these domains, recent unified models lag behind task-specific methods. To address this challenge, we present PianoPoet, a single-checkpoint auto-regressive framework that unifies both tasks with a shared Transformer backbone.

We formulate both directions as sequence-to-sequence problems and identify the construction of sequences with appropriate representations as a key challenge. PianoPoet shares a common MIDI tokenizer for both directions while decoupling audio representations: continuous semantic audio frames for fine-grained transcription, and a piano-specific discrete audio tokenizer for realistic piano rendering. Both tasks are optimized with cross-entropy loss.

PianoPoet outperforms prior unified models, achieves the best results among the evaluated generative transcription methods, and outperforms specialized rendering methods in most evaluated metrics. It supports full-band stereo rendering and stereo-position control through acoustic prompts. Ablations show that both directions can share a backbone with little interference while remaining comparable to single-task variants.

Piano rendering

Examples are drawn from the MAESTRO test set [1].

03 / Reconstruction

Piano audio codec

We compare the reconstruction performance between PianoPoet DAC and general-purpose & piano-specific neural codecs. Examples are drawn from the MAESTRO test set [1].

04 / Zero-shot transfer

Historical piano restoration

PianoPoet restores noisy historical piano recordings by composing its two learned directions, without restoration-specific training or fine-tuning.

Input Noisy piano audio
Transcribe PianoPoet to MIDI
Prompted render MIDI + clean audio prompt
Output Restored piano audio

PianoPoet, zero-shot. The noisy source is first transcribed into MIDI. That MIDI is then rendered with the shared clean piano audio prompt, using the same unified checkpoint in both directions. The five-second conditioning prompt is included in the listening comparison below.

Trained, specialized baseline. Both baseline stages are designed specifically for restoration: Moliner's supervised Two-Stage U-Net denoiser is followed by BABE-2, which uses a trained diffusion prior for generative equalization.

Output format PianoPoet 48 kHz stereo Moliner + BABE-2 22.05 kHz mono

05 / Acoustic prompting

Stereo-position control

PianoPoet changes spatial position and room character through acoustic prompting while keeping the transcribed MIDI performance fixed.

Fixed performance Noisy Chopin audio → PianoPoet transcription → MIDI
Controlled rendering Same MIDI + different acoustic prompts → stereo audio

Each five-second acoustic prompt is paired below with its aligned 30-second rendering, making the resulting left, center, and right presentations directly comparable.

L Dry / left C Wet / center R Dry / right