Encoder for obtaining training signals configured to train a codebook for vector quantization of a video sequence of subsequent frames, each frame being subdivided into coding blocks, and for encoding the video sequence in encoded signals, the encoder comprising: - a scalar quantization unit configured to obtain, for each coding block of one or more training frames of the video sequence, a scalar quantized signal from a prediction error (e k ), - an entropy coding unit configured to entropy code, for each coding block of each training frame of the video sequence, the scalar quantized signal into an output signal, - a data selection unit configured to select, from among the training frames of the video sequence, one or several coding blocks of the training frames depending on a cost function of their respective output signal, and to obtain, for each selected coding block, a training signal, wherein the training signal is either the prediction error (e k ) or a reconstructed prediction error (e' k ) of the selected coding block, and configured to train the codebook for vector quantization of the video sequence, wherein the cost function of the output signal is a number of bits per pixel of the output signal or a rate distortion function of the output signal; and the data selection unit is configured to select the coding blocks for which the respective output signal has a cost function above a threshold (t VQ ), and wherein the encoder is configured to add the threshold (t VQ ) in the encoded signals as side information. the encoder comprising: - a scalar quantization unit configured to obtain, for each coding block of one or more training frames of the video sequence, a scalar quantized signal from a prediction error (e k ), - an entropy coding unit configured to entropy code, for each coding block of each training frame of the video sequence, the scalar quantized signal into an output signal, - a data selection unit configured to select, from among the training frames of the video sequence, one or several coding blocks of the training frames depending on a cost function of their respective output signal, and to obtain, for each selected coding block, a training signal, wherein the training signal is either the prediction error (e k ) or a reconstructed prediction error (e' k ) of the selected coding block, and configured to train the codebook for vector quantization of the video sequence, - a scalar quantization unit configured to obtain, for each coding block of one or more training frames of the video sequence, a scalar quantized signal from a prediction error (e k ), - an entropy coding unit configured to entropy code, for each coding block of each training frame of the video sequence, the scalar quantized signal into an output signal, - a data selection unit configured to select, from among the training frames of the video sequence, one or several coding blocks of the training frames depending on a cost function of their respective output signal, and to obtain, for each selected coding block, a training signal, wherein the training signal is either the prediction error (e k ) or a reconstructed prediction error (e' k ) of the selected coding block, and configured to train the codebook for vector quantization of the video sequence, wherein the cost function of the output signal is a number of bits per pixel of the output signal or a rate distortion function of the output signal; and the data selection unit is configured to select the coding blocks for which the respective output signal has a cost function above a threshold (t VQ ), and wherein the encoder is configured to add the threshold (t VQ ) in the encoded signals as side information. <EOS>