8,350 research outputs found
Constructing a no-reference H.264/AVC bitstream-based video quality metric using genetic programming-based symbolic regression
In order to ensure optimal quality of experience toward end users during video streaming, automatic video quality assessment becomes an important field-of-interest to video service providers. Objective video quality metrics try to estimate perceived quality with high accuracy and in an automated manner. In traditional approaches, these metrics model the complex properties of the human visual system. More recently, however, it has been shown that machine learning approaches can also yield competitive results. In this paper, we present a novel no-reference bitstream-based objective video quality metric that is constructed by genetic programming-based symbolic regression. A key benefit of this approach is that it calculates reliable white-box models that allow us to determine the importance of the parameters. Additionally, these models can provide human insight into the underlying principles of subjective video quality assessment. Numerical results show that perceived quality can be modeled with high accuracy using only parameters extracted from the received video bitstream
Folded Recurrent Neural Networks for Future Video Prediction
Future video prediction is an ill-posed Computer Vision problem that recently
received much attention. Its main challenges are the high variability in video
content, the propagation of errors through time, and the non-specificity of the
future frames: given a sequence of past frames there is a continuous
distribution of possible futures. This work introduces bijective Gated
Recurrent Units, a double mapping between the input and output of a GRU layer.
This allows for recurrent auto-encoders with state sharing between encoder and
decoder, stratifying the sequence representation and helping to prevent
capacity problems. We show how with this topology only the encoder or decoder
needs to be applied for input encoding and prediction, respectively. This
reduces the computational cost and avoids re-encoding the predictions when
generating a sequence of frames, mitigating the propagation of errors.
Furthermore, it is possible to remove layers from an already trained model,
giving an insight to the role performed by each layer and making the model more
explainable. We evaluate our approach on three video datasets, outperforming
state of the art prediction results on MMNIST and UCF101, and obtaining
competitive results on KTH with 2 and 3 times less memory usage and
computational cost than the best scored approach.Comment: Submitted to European Conference on Computer Visio
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