Wednesday, November 19, 2008

PureCinema film mode

The Pioneer Kuro has a special film mode feature called PureCinema that engages a couple different 24 fps (frames per second) processing algorithms. One of the algorithms helps with film mode de-interlacing, while the other two algorithms produce smoother motion by performing a reverse 3:2 pull-down (inverse telecine) operation and then interpolating the in-between frames or up converting to a 72 Hz frame rate.

The Pioneer Kuro has a native progressive video refresh rate of 60 Hz. Interlaced input sources (480i, 1080i) need to have their even/odd fields reassembled (de-interlaced) first to be progressively displayed. This is called de-interlacing and it removes the teeth artifacts during fast motion and pans.

PureCinema parameters:
  • Off - deactivates PureCinema
  • Standard - only works with 480i and 1080i sources, de-interlaces
  • Smooth - produces smoother moving images by frame interpolation
  • Advance - activates 72 Hz refresh rate for 3:3 pull-down of 24 fps source material for smoother moving images
None of these modes work when the input signal is 1080p60. Speculation as to why is that there's insufficient video processing resources to handle the higher bandwidth of a 1080p60 stream. Standard setting only works with interlaced sources (480i and 1080i). Smooth and Advance settings work with 480i, 480p, 720p, and 1080i input sources.

Standard and Smooth settings display at the standard 60 Hz frame rate. The Advanced setting displays film material at a 72 Hz frame rate. Note that a 72 Hz refresh rate for 3:3 pull-down is automatically engaged whenever a 1080p24 signal is input regardless of mode setting. It doesn't hurt though to play it safe and select Advance mode anyways. Note that 24 * 3 = 72.

Like film in cinema, many prime time TV shows are also recorded at a 24 fps rate, and funnily enough sometimes with a video camcorder. So the Advance mode can be useful for more than just DVD and Blu-ray playback.

What is "dejudder" and how is it related to all of this? Judder is the 3:2 hitching that occurs when 24 fps film material is displayed at a TV's native 60 Hz frame frame. Judder creates a periodic chugging effect that is easiest to see with slow pans or during scrolling credits. Dejudder is the process of removing judder by using video processing. Removing judder, like how the Kuro does with its 72 Hz frame rate is a good thing as it preserves the natural flow of 24 fps film.

Many new LCD flat panels have a 120 Hz refresh rate feature that uses frame interpolation to create smoother motion. Interpolating frames improves the LCD panel's poor motion resolution so LCD manufacturers like this feature because it boosts their specifications. Plasma displays have a superior motion resolution and don't need this technology. Note that with 24 fps film material the LCD's 120 Hz 5:5 pull-down has a similar effect to the Kuro's 72 Hz 3:3 pulldown. Also, the Smooth mode with the Kuro's PureCinema feature does frame interpolation but displays it at 60 Hz.

So dejudder used to mean removing the 3:2 hitching of 24 fps film material by playing it back at a native frame rate multiple of 24. Unfortunately dejudder has morphed into an ambiguous, overused, and abused term that includes both native rate playback and the frame interpolation of all sources (24, 30, and 60 Hz). Some people dislike the frame interpolation feature and disable it. Some LCD HDTV's don't allow 5:5 pull-down of 24 fps film material unless interpolation is enabled and this further complicates the issue. So when you hear the term "dejudder" make sure you understand if it means interpolation, native rate playback, or both.

I keep the PureCinema option set to the Advance mode and it works fine for Blu-ray, DVD, and broadcast HDTV sources. The algorithms are smart enough to prevent odd artifacts most of the time.

Wednesday, November 12, 2008

runs Linux software inside

The Kuro 9G operating instructions manual has a licensing appendix section that lists the names and licensing restrictions of the open source software used. Below is a description of each piece of software mentioned in the licensing appendix.

The Linux kernel is an embedded Unix operating system that manages peripherals, memory, and processes. Linux also has a complete TCP/IP networking stack.

A suite of tiny UNIX utilities for handling logins, user authentication, changing passwords, and otherwise maintaining users and groups on an embedded system. It also provides shadow password support to enhance system security. TinyLogin is, as the name implies, very small, and makes an excellent addition to an embedded system. The getty program opens a tty and invokes /bin/login

A high-quality and portable font engine that is capable of supporting several font formats (be they bitmapped or scalable) through a simple and uniform interface.

A library for building control points, devices, and bridges that are compliant with Version 1.0 of the UPnP Device Architecture Specification. Used for the DLNA client.

A cross platform implementation of the Zeroconf zero configuration networking standard. It includes daemons and a client side SDK for registering, browsing, and resolving network services, and assigning link local IP addresses without a DHCP server.

The portmapper manages RPC connections, which are used by protocols such as NFS and NIS. The portmap server must be running on machines which act as servers for protocols which make use of the RPC mechanism. This portmapper supports hosts.{allow,deny} type access control.

A library which provides a packet filtering mechanism based on the BSD packet filter (BPF). Used by the packet sniffing program tcpdump.

A toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) as well as a full-strength general-purpose cryptography library.

A free implementation of Netscape's Secure Socket Layer - the software encryption protocol behind the Netscape Secure Server and the Netscape Navigator Browser.

A library for reading and writing gif images.

JPEG image compression
Generic licensing for use of JPEG image decompression.

A library for manipulating PNG format graphics files.

A library for decoding the Tag Image File Format (TIFF).

A lossless data-compression library. Used by gzip and many other compression programs.

A library for dealing with MPEG-1 streams.

A set of tools to encode, stream, and playback audio and video. It uses the MPEG-4 standards for audio and video, and the IETF standards for streaming. The included player can either playback from local MP4 file or stream from a remote server via RTP/RTSP.

The Kuro 9G runs Linux for its Home Media Gallery (HMG) function and possibly other more system critical features. Linux has driver support for Ethernet 10/100 and USB devices. TinyLogin suggests that getty is used with the RS232 rear service port. FreeType are nice anti-aliased fonts that are likely used for the Kuro's menu system and closed caption text.

The Pioneer Home Media Gallery (HMG) can use both USB and DLNA as a method for accessing audio, video, and image files. The UPnP library is a basis of DLNA support while the Howl zeroconf, also a remote discovery protocol, has an overlapping and somewhat unknown purpose.

The Secure Socket Layer (SSL) is used for accessing encrypted data with https: web servers. It is possible that SSL is used for some sort of DLNA digital right management (DRM) but that fact isn't listed in the manual or advertised. SSL's sole purpose could be for streaming MP3 from servers that use https:.

The existence of the libpcap packet filtering and port mapping libraries were surprising. It is unsure why a DLNA client would need to have any sort of packet sniffing software but this could all be part of the UPnP server discovery process.

There are codec libraries for DLNA image (GIF, JPEG, PNG, TIFF) and video (MPEG-1, MPEG-4) support. MPEG-2 video support isn't listed because the Pioneer Kuro has silicon support for this video codec. It is interesting that packages for VC-1 and all of the audio formats are missing but those likely required special proprietary licensing agreements.

Pioneer has an open source code distribution service page that has a section for the Kuro HDTV's up to the Kuro 8G series. It looks like Pioneer plasma displays have been using Linux long before the HMG function was introduced. Also of interest is that a number of debug utilities are listed such as the bash shell, gcc, gdb server, strace, and telnetd. It is unknown if these debug services are active in shipping Kuro's because an nmap scan turns up empty.

It is unfortunate that a telnet shell isn't accessible so that a Kuro owner can't login and poke around with the Linux inside. It is also unfortunate that Pioneer doesn't supply an SDK so that users could create applications that do interesting things with their Kuro. It's understandable because of obligations to protect the HDMI stream and other internal IP but think of all the amazing possibilities?

Monday, November 3, 2008


Pioneer releases it's first Kuro LCD in Europe. This LCD may be available next year in North America. The bulk of this 37" 1920x1080 TV is manufactured by Sharp. About 18 months ago Sharp invested about $400 million in Pioneer for an 18% ownership stake. The Pioneer Kuro LCD product line is joint venture with Sharp and is available in 32", 37", and 46" sizes. Pioneer color filters and some Pioneer electronics are used. The MSRP for the KRL-37V is $1721 USD. Technically this LCD HDTV isn't a ninth generation (9G) plasma panel but it is part of the current Kuro product line.

A standard Cold Cathode Florescent (CCFL) backlit as is common on Sharp LCD panels was used in the KRL-37V. This HDTV has Pioneer's PureCinema processing feature and 100 Hz processing which is common with European TVs (think 50 Hz AC power lines). PureCinema has a "smooth" option which interpolates and operates at 100 Hz and it also has a mode that detects the 2:3 pull down of 24 FPS movies. On the Kuro plasma's this detected 24 Hz film source is run at a native 72 Hz 3:3 sequence which eliminates pull down judder. It is unknown if the KRL-37V LCD does this or if it runs detected film sources at a 100 Hz frame rate. Since 100 does not evenly divide by 24 this will create some sort of frame rate mismatch. Not sure of the benefits of 100 Hz.

  • 3 HDMI 1.3a
  • 1 YPbPr
  • 1 S-Video
  • 1 composite
  • 2 SCART
  • optical Toslink ouput
There isn't a USB or Ethernet jack so no DLNA and no Home Media Guide (HMG). The remote control looks a lot like the one that comes with the 5020 and 6020. Pioneer's purple high contrast filter improves the black level while not reducing the bright white level.

  • black levels
  • accurate colors

  • heavy aluminum chassis
  • standard LCD motion blur issues
  • standard LCD off-axis viewing angle problems
  • lack of a native 24 Hz multiple frame rate

The specifications for the KRL-37V seem very similar to the Sharp Aquos LC37D64U 37-Inch 1080p LCD HDTV which is available for $857. The Sharp LCD model has DLNA but it is missing all of the Pioneer modifications. Do these additions make it worth an almost $900 premium?

The reviewer said that the KRL-37V had very good performance for an LCD but lacks having a "truly groundbreaking black level response." Unfortunately reviewer said that the KRL-37V does not live up to the Kuro name.