CARD: Cross-component Audio Representation Distillation for Encoder-Free Audio Captioning
Key findingRemoves the audio encoder at inference through cross-component knowledge distillation. A 13.2M-parameter projector supports encoder-free audio captioning.
Most audio captioning systems retain a pretrained audio encoder at inference. CARD explores whether that encoder's knowledge can instead be distilled into a smaller architecture. During training, a pretrained audio teacher transfers representations into a 13.2M-parameter projector and the language model; the teacher is discarded for inference. Cross-component distillation improves CIDEr-D by 11.9 on AudioCaps and 5.0 on Clotho over LLM-only distillation. CARD reaches 55.4 CIDEr-D on AudioCaps, compared with 66.4 for an encoder-retaining reference, illustrating both the potential and remaining performance gap of encoder-free captioning.
@inproceedings{kolluri2026card,
title = {{CARD}: Cross-component Audio Representation Distillation for Encoder-Free Audio Captioning},
author = {Kolluri, Ganesh Pavan Kartikeya Bharadwaj and Zhang, Yuchen and Kampouridis, Michael and Shekhar, Ravi},
booktitle = {Proceedings of the IEEE Spoken Language Technology Workshop (SLT)},
month = dec,
year = {2026},
address = {Palermo, Italy},
note = {To appear},
eprint = {2607.04619},
archivePrefix = {arXiv},
primaryClass = {cs.SD}
}