M-LTW: A fast and efficient intra video codec Otoniel M. Lo ´ pez a,Ã , Miguel O. Martı ´nez-Rach a , Pablo Pin ˜ol a , Manuel Perez Malumbres a , Jose ´ Oliver b a Universidad Miguel Herna ´ndez, Avda. Universidad s/n, 03202 Elche, Spain b Universidad Polite ´cnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain article info Article history: Received 30 November 2007 Received in revised form 26 June 2008 Accepted 4 July 2008 Keywords: Intra-video coding DWT integer transform Rate control Performance evaluation abstract Intra-video coding is a common way to process video material for applications like professional video editing systems, digital cinema, video surveillance applications, multi-spectral satellite imaging, HQ video delivery, etc. Most practical intra-coding systems employ JPEG encoders due to their simplicity, low coding delay and low memory requirements. JPEG2000 is the main candidate to replace JPEG in this kind of application due to its excellent rate/distortion (R/D) performance and high coding flexibility. However, its complexity and computational resource requirements for proper operation could be a limitation for certain applications. In this work, we propose an intra-video codec, M-LTW, which is able to obtain very good R/D performance results, as good as JPEG2000 or H.264 INTRA, with faster processing and lower memory usage. & 2008 Elsevier B.V. All rights reserved. 1. Introduction A wide variety of video compression schemes have been reported in the literature. Most of them are based on the DCT transform and motion estimation and compensa- tion techniques. Nevertheless, a lot of research interest has been focused on developing still image and video wavelet coders due to the excellent properties of wavelet transform. Most wavelet-based video encoding proposals are strongly based on inter-coding approaches, which require high-complexity encoder designs as a counterpart to the excellent R/D (rate/distortion) performance bene- fits. On the other hand, some applications like professional video editing, digital cinema, video surveillance applica- tions, multi-spectral satellite imaging, HQ video delivery, etc. would rather use an intra-coding system that is able to reconstruct a specific frame of a video sequence as fast as possible and with high visual quality. The strength of an intra-video coding system relies on the ability to efficiently exploit the spatial redundancies of each video sequence frame avoiding complexity in the design of the encoding/decoding engines. There are several still image codecs that get very good R/D results. Unfortunately, most of them propose complex algorithms to achieve the pursued R/D performance. As a conse- quence of the higher computational complexity de- manded by these coders, their software (even hardware) implementations require powerful processors with en- ough computational resources to cope with the algorithm requirements. For example, the JPEG2000 [10] standard uses a large number of contexts and an iterative time- consuming optimization algorithm (called PCRD) to improve coding efficiency, increasing the complexity of the encoding engine. Something similar happens with H.264/AVC [11] INTRA coding, where a powerful spatial prediction scheme with context modeling and R/D optimization is employed in order to efficiently exploit spatial redundancies. In this paper, we propose a new lightweight and efficient intra-video coder, M-LTW (motion lower-tree wavelet), based on the LTW algorithm [15]. The main Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/image Signal Processing: Image Communication ARTICLE IN PRESS 0923-5965/$ - see front matter & 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.image.2008.07.001 Ã Corresponding author. Tel.: +34 96 665 8392. E-mail addresses: otoniel@umh.es (O.M. Lo ´ pez), mmrach@umh.es (M.O. Martı ´nez-Rach), pablop@umh.es (P. Pin ˜ol), mels@umh.es (M. Perez Malumbres), joliver@disca.upv.es (J. Oliver). Signal Processing: Image Communication 23 (2008) 637–648