Optimal Transcoding Resolution Prediction for Efficient Per-Title
  Bitrate Ladder Estimation
Jinhai Yang Mengxi Guo Shijie Zhao Junlin Li Li Zhang
Adaptive video streaming requires efficient bitrate ladder construction to
meet heterogeneous network conditions and end-user demands. Per-title optimized
encoding typically traverses numerous encoding parameters to search the
Pareto-optimal operating points for each video. Recently, researchers have
attempted to predict the content-optimized bitrate ladder for pre-encoding
overhead reduction. However, existing methods commonly estimate the encoding
parameters on the Pareto front and still require subsequent pre-encodings. In
this paper, we propose to directly predict the optimal transcoding resolution
at each preset bitrate for efficient bitrate ladder construction. We adopt a
Temporal Attentive Gated Recurrent Network to capture spatial-temporal features
and predict transcoding resolutions as a multi-task classification problem. We
demonstrate that content-optimized bitrate ladders can thus be efficiently
determined without any pre-encoding. Our method well approximates the
ground-truth bitrate-resolution pairs with a slight Bj{\o}ntegaard Delta rate
loss of 1.21% and significantly outperforms the state-of-the-art fixed ladder.