Residual Vector Quantization for Audio and Speech Embeddings

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Күн бұрын

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Residual Vector Quantization (RVQ) is a useful type of quantization that can compress a whole vector into a few integers, making it more efficient than other types of quantization. It is particularly effective for encoding speech and audio more efficiently than traditional codecs like MP3, as seen in models such as SoundStream and EnCodec. This video explains how RVQ iteratively represents vectors in terms of codebook vector entries to achieve incrementally higher fidelity representation as bitrate is increased.
0:00 - Introduction
1:10 - Encodec model architecture
2:05 - Quantization in machine learning
3:56 - Codebook quantization
5:04 - Residual vector quantization
7:54 - RVQ and bitrate in EnCodec
9:08 - EnCodec audio compression examples
10:18 - Learning codebook vectors
11:31 - Codebook updates
12:15 - Encoder commitment loss
References:
SoundStream paper (2021): arxiv.org/abs/2107.03312
EnCodec paper (2022): arxiv.org/abs/2210.13438
Blog post by Assembly AI: www.assemblyai.com/blog/what-...

Пікірлер: 15

@_XoR_ Ай бұрын

I thought about using voronoi cells nearest neighbour lookup for compressing latent spaces myself, but I also thought that some processes that generate the lantent space centroids of interest can also benefit from weighted voronoi tessellation / power diagrams, where maybe depending on density of points or other features we can weight that particular cell to make it more relevant.

@EfficientNLP Ай бұрын

That's an interesting idea, and I don't know if it's been used in speech vector compression. You would require some additional space to store the weights of Voronoi cells in a weighted Voronoi tessellation, so it may or may not be as effective as using this space to do more rounds of RVQ.

@andybrice2711 Ай бұрын

I picture this like mapping out a vector space in lower resolution by using a tree structure.

@wolpumba4099 Ай бұрын

*What is RVQ?* * RVQ is a technique to compress vectors (like audio embeddings) into a few integers for efficient storage and transmission. * It achieves higher fidelity than basic quantization methods, especially at low bitrates. *How RVQ Works:* 1. *Codebook Quantization:* A set of representative vectors called "codebook vectors" are learned. Each vector is mapped to the closest codebook vector and represented by its index. 2. *Residual Calculation:* The difference between the original vector and the chosen codebook vector is calculated (the "residual vector"). 3. *Iterative Quantization:* The residual vector is further quantized using a new codebook, and a new residual is calculated. This process repeats for multiple iterations. 4. *Representation:* The original vector is represented by a list of indices, each corresponding to a chosen codebook vector in different iterations. *RVQ in EnCodec (An Audio Compression Model):* * EnCodec uses RVQ to compress audio embeddings, achieving good quality even at low bitrates (around 6kbps). * The number of RVQ iterations controls the bitrate and quality trade-off. *Learning Codebook Vectors:* * Initially, K-means clustering can be used to find optimal codebook vectors. * For better performance, codebook vectors are fine-tuned during model training: * *Codebook Update:* Codebook vectors are slightly moved towards the encoded vectors they represent. * *Commitment Loss:* The encoder is penalized for producing vectors far from any codebook vector, encouraging it to produce easily quantizable representations. * *Random Restarts:* Unused codebook vectors are relocated to areas where the encoder frequently produces vectors. *Key Benefits & Applications:* * RVQ enables efficient audio compression with smaller file sizes than traditional formats like MP3. * It has potential applications in music streaming, voice assistants, and other audio-related technologies. i used gemini 1.5 pro to summarize the transcript

@nmstoker Ай бұрын

Another great video I have a question: is RVQ solely for compression or could one conceivably do some processing of an RVQ to operate on it as a representation of the data rather than on the uncompressed data? Eg teach a model to classify sounds based just on the RVQ.

@EfficientNLP Ай бұрын

Indeed, it is often useful to use quantized representations rather than the original vector. One example that comes to mind is wav2vec2 - it performs product quantization (not quite the same as RVQ but similar, as it learns multiple discrete codebooks). It does a masked language model self-supervised setup, where the model learns to predict the quantized targets, and this works better than predicting the vector directly.

@himsgpt 18 күн бұрын

Can you make video on grouped query attention (GQA) and sliding window optimisation?

@EfficientNLP 18 күн бұрын

Great ideas for future videos. Thanks for the suggestion!

@einsteinsapples2909 Ай бұрын

If you turn ur voice tool into an extension that can work on any web page on chrome, I would be interested. The way it is now can be helpful but I have better alternatives, like I can just use chatGPTs speech to text feature which is very good.

@EfficientNLP Ай бұрын

Great point. We are currently developing a voice writer Chrome extension, and it will be available soon!

@EkShunya Ай бұрын

:smiley: 😄

@siddharthvj1 Ай бұрын

how can i connect with you

@EfficientNLP Ай бұрын

I'm active on linkedin! Link on my profile.

@andreacacioli2612 Ай бұрын

Hey There, I am trying to reach out to you via email. Could you please check? Anyway, here is my question: why does encodec's encoder output 75 frames of 128 dimension per second? I mean, don´t convolutions always just reduce dimensionality, why do they increase? I would expect a single array with less elements in the time dimension. Could you please help. Thank you

@EfficientNLP Ай бұрын

Typically when convolution layers reduce the dimension on the temporal axis, the dimension is increased by a similar amount on the spatial axis. This way, the information is represented differently, rather than being lost.