Tuesday, February 19, 2019

Media: The State of Play

Orphan gets its original media from both digital and analog sources. Digital media - DVDs, Blu-rays, streaming - are straightforward but rare for our sorts of shows. Most of our sources are analog - VHS tapes or LaserDiscs. Both present knotty problems. This blog entry provides a snapshot of the "state of play" in Orphan's media processing.


Until quite recently, all our LaserDiscs came were ripped by private collectors. The most prolific and helpful has been Erik of Piyo Piyo Productions. Erik has an extensive collection, an excellent capture capability, and deep knowledge of the encoding issues in LaserDiscs. ics- has also contributed some captures, which M74 has encoded. And finally, an anonymous friend of a friend has provided a few rare discs.

All the LaserDiscs collectors are at the mercy of the analog electronics in their players and in their capture cards. This can introduce some pretty ugly problems. LaserDisc players have been out of production for twenty years, and their electronics are, well, old. Most capture cards introduce some form of compression, which complicates software filtering of the many artifacts in the sources. Lossless capture has required insanely expensive (professional) equipment  or insanely arcane (Windows XP era) hardware and software... until now.

The Domesday86 project, which I've written about before, seeks to bypass the main sources of introduced error in LaserDisc rips by capturing the RF output of the laser directly and post-processing the results entirely in software. This sounds so promising that Orphan has created a Domesday Duplicator setup in Japan - LaserDisc player, special hardware, and software. It's been a long, frustrating, and expensive saga. Japanese anime LaserDiscs had many attributes that the Domesday project team had never seen. It's taken months to get the decoding software into usable shape. With the release of v4 of ld-decode, the project is just about there and produces usable lossless captures. ld-decode still can't handle the digital audio tracks, but those can be captured directly.

The first LaserDisc to be processed through Orphan's Domesday Duplicator will be Boyfriend. The Duplicator lossless decode still needs to be encoded down to reasonable size, but at least that's a tractable problem. Further, as ld-decode improves, the RF captures can be processed again, if the improvement in quality is sufficient.

Props to gamnark for championing the project, assembling the hardware, and doing all the hard work of capturing and decoding numerous test cases both for Orphan and for the ld-decode team. The team provided financial support for the equipment.

VHS Tapes

Tapes have been an even more frustrating story than LaserDiscs. The initial attempt at capture in Japan involved an inexpensive USB capture device and a standard S-VHS deck. The results were hit or miss, mostly miss, with dropped frames and video/audio sync problems galore. The cause of the problems varied, but one might be the presence of copy protection on some tapes. LaserDiscs couldn't be duplicated easily and had no copy protection. VHS tapes could be duped (with significant quality loss, of course), and copy protection was sometimes employed.

The next attempt was to buy a much better deck, a D-VHS deck with a built-in Time Base Correction (TBC) and digital (Firewire) output. This produced better results, but the digital output had MPEG2 compression that couldn't be bypassed. The compression tended to blend frames and muck up deinterlacing. The TBC handles only part of the dropped frame and lost sync problems, so the results were still hit or miss.

The current plan is to do lossless capture of the standard S-video output and try to clean up the results in software. This requires an ancient, XP-era AGP PC and specific versions of old ATI All in Wonder cards. The first card gamnark bought was damaged in shipment and didn't work. The second one lost its heat sink within five minutes. Fortunately, the card seems to work once the heat sink was reattached. An external TBC might still be needed.

Ultimately, we'd like to see something like a Domesday-for-tapes: a way to capture the output of the helical scan read head directly, bypassing everything else in the VHS deck. However, that's a complex problem, both in hardware and in software, and it's not clear that VHS decks have a maintenance access point for capturing the RF data.

gamnark is once again doing all the heavy lifting on this project, with financial support from the team and its anonymous benefactor.


Orphan's Domesday Duplicator for LaserDiscs is up and running, and the first encodes will show up in projects this year. VHS tapes remain a work-in-progress, and the light at the end of the tunnel is still fairly distant.

1 comment:

  1. Sounds very stressful but I look forward to the results immensely. Thank you Orphan for all your work at preserving these obscure titles