Feature

TV peripheral encompasses superset processor

Prying Eyes looks inside the Delkin eFilm Picturevision, which enables the playback of audio, still-image, and video files on a variety of memory-card formats.

By Brian Dipert, Senior Technical Editor -- EDN, 2/21/2008

Delkin Devices' eFilm Picturevision, which enables the playback of audio, still image and video files housed on a variety of memory card formats, was $159 at its September 2002 introduction. By April of 2004, when I bought it, it was down to $9.99 (after $50 rebate). What hardware building blocks enable it to work its decode-and-display magic?

The processing heart of Picturevision, I was surprised to discover after cracking open the case, is ESS Technology's ES4318 DVD processor. This 208-lead PQFP-enclosed IC tackles JPEG images, MP3 audio tracks, and MPEG-1 and MPEG-2 video clips. But of course, ESS's device is capable of supporting many more formats and features than this (PDF). Picturevision is a case study in the appeal of leveraging high volume (therefore low cost) semiconductors, even if a given chip's feature set is overkill for the target application.

View/download a PDF that relates some of the issues discussed here to the PCB.

Picturevision's memory foundation comprises a curious mix of three different technologies; Macronix's 29F080 8 Mbit flash memory, AMIC Technology's A276308 512 Kbit OTP (one-time programmable) EPROM, and two AMIC A43L0616 16 Mbit SDRAMs (PDF). Proximity and trace routing suggests that the 29F080 houses code executed by the ES4318, but what of the seemingly function-redundant A276308? Does it store overflow (i.e. not capable of fitting within the 29F080) code for the ES4318 that, by virtue of its EPROM location, isn't in-system updateable? Does it instead hold non-upgradeable system data? Or is it the nonvolatile memory partner to another system IC? And where's the EEPROM or battery-backed SRAM...or is there no need for nonvolatile, bit-alterable storage in this design?

The system design contains many elements of mystery. There are, for example, unpopulated sites for three additional SOP-enclosed ICs on the PCB, along with unused locations for numerous capacitors, inductors, and resistors. Consider, too, the mysterious QFP chip with 'DRiVE' stamped in large type on the first line of the package mark, 'Free' below it in a much smaller font, and 'PF08-2-0-0' on package mark line three. No amount of Google searching on my part uncovered the chip's identity, and the individuals at Delkin who might know the answer have long ago departed for other careers. My guess? It's an interface chip that translates between Picturevision's various memory card slots and the ATAPI interface ESS's ES4318 expects. Ideas, readers?

The PCB backside is almost completely consumed by traces, vias, through-hole solder points and passive components; it additionally contains four small-leadcount ICs, along with six surface-mount tactile switches that mate with top-panel buttons.

Delkin's product natively handles CompactFlash I and II (including MicroDrive), Memory Stick (but not higher-capacity Memory Stick PRO), Multimedia, Secure Digital (but not higher-capacity SDHC) and now-defunct SmartMedia card formats. Front-panel LEDs indicate valid system power and in-progress memory card accesses. On the other end of the front panel, you'll find an infrared receiver which partners with the supplied remote control.

The eFilm Picturevision is no longer manufactured, says Delkin, although it's still available for purchase from numerous retailers. The unfulfilled potential of its ES4318 core, along with the unpopulated IC and passive component sites on the PCB, leaves me wondering what kind of product it could have been, and whether the incremental price tag (and sales volume) of a premium variant would have been enough to justify the incremental bill-of-materials and other costs. In late 2002, for example, high-definition monitors and televisions with component video connections (which the ES4318 natively supports) weren't common, but S-Video-equipped systems were more pervasive. Should Delkin have provided multiple video output options on the device? And similarly, should the company have harnessed the ES4318's integrated S/PDIF transmitter in order to offer both analog and digital audio output capabilities?

In fairness to Delkin's engineers, the device's composite video connection wasn't the only limiter to high quality image reproduction. Several eFilm Picturevision reviewers explicitly suggested rendering downscaled 640x480 pixel versions of images prior to attempting to display them on the device; the ES4318 was apparently performance-hampered beyond standard-definition resolutions, leading to unacceptably long picture-to-picture transition delays above the 0.3 Mpixel per-image threshold. And of course, by virtue of its DVD roots, the ES4318 didn't natively support the Quicktime video 'wrapper' format that many digital cameras output, or for that matter any of the proprietary or industry-standard (i.e. Adobe DNG) RAW still image formats.