Toward Free and Open Source Film Projection for Digital Cinema

International audienceCinema industry has chosen Digital Cinema Package (DCP) as encoding format for the distribution of digital films. DCP uses JPEG2000 for video compression. An efficient implementation of coding and decoding for this format is complex, however. Currently deployed equipment is expensive and has high maintenance costs, preventing art-house cinema theaters from acquiring it. Therefore, we conduct this research activity in cooperation with Utopia cinemas, a group of art-house cinemas, whose main requirement (besides functional ones) is to provide Free and Open Source Software (FOSS). This paper presents a solution that achieves real-time JPEG2000 decoding and DCP presentation based on widespread open source multimedia tools, namely VLC and libavcodec library. We present the improvements that were made in VLC to support the DCP packaging format, as well as details on JPEG2000 decoding inside libavcodec (optimization and lossy decoding). We also evaluate the performance of the decoding chai

Optical network technologies for future digital cinema

Digital technology has transformed the information flow and support infrastructure for numerous application domains, such as cellular communications. Cinematography, traditionally, a film based medium, has embraced digital technology leading to innovative transformations in its work flow. Digital cinema supports transmission of high resolution content enabled by the latest advancements in optical communications and video compression. In this paper we provide a survey of the optical network technologies for supporting this bandwidth intensive traffic class. We also highlight the significance and benefits of the state of the art in optical technologies that support the digital cinema work flow

Design Implementation of Next Generation Wireless LAN for Mass Digital Cinema

We have been designing an over 1.2 Gbps throughput wireless for next generation WLAN system conform with IEEE802.11TGac’s requirements. It reaches 33 meter propagation distance by using 80MHz of bandiwdth on 5GHz band. 4x5 antennas configuration contribute 2nd-order diversity gain and maintain both the high throughput and performance. The Greenfield format preamble was proposed for its high efficiency. Novel phase rotation is employed to lower the PAPR signal. Run test for transmitting 90 frames of 40961714 pixels/frame under in-door channel model proves that the proposed system shall be considered for providing an excellent performance mass digital cinema. Index Terms—Gigabit wireless LAN, IEEE802.11 TGac, digital cinema transmissio

Evaluation of GPU/CPU Co-Processing Models for JPEG 2000 Packetization

With the bottom-line goal of increasing the throughput of a GPU-accelerated JPEG 2000 encoder, this paper evaluates whether the post-compression rate control and packetization routines should be carried out on the CPU or on the GPU. Three co-processing models that differ in how the workload is split among the CPU and GPU are introduced. Both routines are discussed and algorithms for executing them in parallel are presented. Experimental results for compressing a detail-rich UHD sequence to 4 bits/sample indicate speed-ups of 200x for the rate control and 100x for the packetization compared to the single-threaded implementation in the commercial Kakadu library. These two routines executed on the CPU take 4x as long as all remaining coding steps on the GPU and therefore present a bottleneck. Even if the CPU bottleneck could be avoided with multi-threading, it is still beneficial to execute all coding steps on the GPU as this minimizes the required device-to-host transfer and thereby speeds up the critical path from 17.2 fps to 19.5 fps for 4 bits/sample and to 22.4 fps for 0.16 bits/sample

Sample-Parallel Execution of EBCOT in Fast Mode

JPEG 2000’s most computationally expensive building block is the Embedded Block Coder with Optimized Truncation (EBCOT). This paper evaluates how encoders targeting a parallel architecture such as a GPU can increase their throughput in use cases where very high data rates are used. The compression efficiency in the less significant bit-planes is then often poor and it is beneficial to enable the Selective Arithmetic Coding Bypass style (fast mode) in order to trade a small loss in compression efficiency for a reduction of the computational complexity. More importantly, this style exposes a more finely grained parallelism that can be exploited to execute the raw coding passes, including bit-stuffing, in a sample-parallel fashion. For a latency- or memory critical application that encodes one frame at a time, EBCOT’s tier-1 is sped up between 1.1x and 2.4x compared to an optimized GPU-based implementation. When a low GPU occupancy has already been addressed by encoding multiple frames in parallel, the throughput can still be improved by 5% for high-entropy images and 27% for low-entropy images. Best results are obtained when enabling the fast mode after the fourth significant bit-plane. For most of the test images the compression rate is within 1% of the original

Wavelet-based encoding for HD applications

In the past decades, most of the research on image and video compression has focused on addressing high bandwidth- constrained environments. However, for high resolution and high quality image and video compression, as in the case of High Definition Television (HDTV) or Digital Cinema (DC), the primary constraints are related to quality and flexibility. This paper presents a comparison between scalable wavelet-based video codecs and the state of the art in single point encoding and it investigates the obtainable compression efficiency when using temporal correlation with respect to pure intra coding

Lecture de DCP pour le cinéma numérique avec le lecteur multimédia VLC et libav/ffmpeg

National audienceLes salles de cinéma sont passées à l’ère numérique. Pour la distribution des copies numériques de films, la Digital Cinema Initiative (DCI) a choisi d’encoder les films au format Digital Cinema Package (DCP). Notre activité est menée en collaboration avec les cinémas Utopia, qui forment un réseau de salles indépendantes. La principale exigence d’Utopia est de fournir des logiciels libres et gratuits pour le cinéma numérique. Le format DCP utilise la compression JPEG2000 pour la vidéo, en raison de son taux de compression élevé pour les grandes images. Réaliser une implémentation efficace de codage et de décodage de ce format est complexe. Néanmoins, nous proposons une implémentation améliorée du décodage pour la projection dans les salles obscures. Les équipements actuellement déployés dans les salles sont chers à l’achat et ont un coût de maintenance élevé, ce qui empêche les petites salles indépendantes de s’équiper. Notre but est de proposer une solution logicielle adaptée à la projection des DCP. Cet article présente une solution qui réalise le décodage en temps réel et la projection, en s’appuyant sur des outils multimédia libres et standards comme le lecteur VLC et les bibliothèques libav/ffmpeg. Nous présentons les améliorations implémentées dans VLC pour supporter les DCP, qui incluent la lecture des fichiers et la synchronisation entre audio et vidéo. Nous détaillons ensuite la réalisation du décodeur JPEG2000 dans libav/ffmpeg. Pour finir, nous évaluons les performances de lecture atteintes

Layer Selection in Progressive Transmission of Motion-Compensated JPEG2000 Video

MCJ2K (Motion-Compensated JPEG2000) is a video codec based on MCTF (Motion- Compensated Temporal Filtering) and J2K (JPEG2000). MCTF analyzes a sequence of images, generating a collection of temporal sub-bands, which are compressed with J2K. The R/D (Rate-Distortion) performance in MCJ2K is better than the MJ2K (Motion JPEG2000) extension, especially if there is a high level of temporal redundancy. MCJ2K codestreams can be served by standard JPIP (J2K Interactive Protocol) servers, thanks to the use of only J2K standard file formats. In bandwidth-constrained scenarios, an important issue in MCJ2K is determining the amount of data of each temporal sub-band that must be transmitted to maximize the quality of the reconstructions at the client side. To solve this problem, we have proposed two rate-allocation algorithms which provide reconstructions that are progressive in quality. The first, OSLA (Optimized Sub-band Layers Allocation), determines the best progression of quality layers, but is computationally expensive. The second, ESLA (Estimated-Slope sub-band Layers Allocation), is sub-optimal in most cases, but much faster and more convenient for real-time streaming scenarios. An experimental comparison shows that even when a straightforward motion compensation scheme is used, the R/D performance of MCJ2K competitive is compared not only to MJ2K, but also with respect to other standard scalable video codecs