Customer Review

63 of 73 people found the following review helpful
5.0 out of 5 stars Why a Special Edition release?, 26 Feb 2013
This review is from: Doctor Who: Inferno - Special Edition [DVD] (DVD)
Well, to answer the question in the title: apart from the opportunity to add new special features, the restoration team have devised a new remastering technique that gives better results.

To explain briefly: all of the original European-standard (PAL) videotapes for this story were lost or wiped, leaving only black-and-white film recordings (shot off a TV monitor), and North American-standard (NTSC) tapes converted using analogue equipment for the Canadian market.

The previous version of this story used a technique called reverse standards conversion to restore the converted NTSC video to PAL while preserving as much of the original picture quality as possible. Unfortunately, "as much as possible" is still a lot less sharp than the original pictures, and there are little annoyances, like wobbling on any horizontal lines in the picture.

The new restoration technique, first used on The Claws of Axos special edition, combines the picture detail from the remastered black and white films with just the colour from the reverse standards converted video. A technique called VidFIRE is also applied, as on most of the black and white DVDs, to restore smooth video-like motion to the film image. The result is a much sharper-looking image. It looked great on Axos, and I'm looking forward to seeing it on Inferno.
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Showing 1-9 of 9 posts in this discussion
Initial post: 4 Mar 2013 05:08:13 GMT
Last edited by the author on 4 Mar 2013 05:33:20 GMT
Re this new 'special edition' :

I thought they used 'colour dot recovery' (it might be called 'chroma dot recovery') - its used to restore colour from information stored in black & white film prints;
in this case the UK b&w film print :

ie the same process that was used on 'Planet Of The Daleks' episode 3 for its DVD release
& some other Dr Who releases since - eg for some of 'The Ambassadors Of Death';

& that it was the previous DVD edition which had the colour reversed fom the NTSC tapes & then laid over the (restored) black & white UK film print which you mention

& it was only on the vhs edition that just the reversed NTSC tape ( ie reversed back to PAL ) was used & the b&w film print not used at all.

However I may well be mistaken - ? ( And apologies to you if indeed I am )

In reply to an earlier post on 6 Mar 2013 19:39:03 GMT
Lee R says:
You're wrong about everything apart from Ambassadors of Death! Though it can get quite confusing.

This release is B&W film print remastered and overlaid with the Reverse Standards Conversion (RSC) colour.

Planet of the Daleks was a unique combination of computer colourisation and chroma dot recovery.

The previous DVD edition was the NTSC tape restored using RSC.

The VHS release was a bog standard NTSC to PAL conversion from an original PAL to NTSC conversion.

In reply to an earlier post on 7 Mar 2013 01:16:55 GMT
vey interesting;

it makes you wonder why they didn't use the present process for the previous dvd release -
surely 7 or so years ago it was possible to isolate the colour signal in the NTSC tape (? )

& presumably they also had the UK b&W film print back then.

Do you know if the Inferno b&w film print contains the 'hidden' colour information ?
( I hear not all prints do - it depends upon how they were transferred from the original broadcast tapes )

if the b&w film print does have the colour info
( & the colour isn't near-mint this time around on the new 2013 DVD edition ),
then no doubt they'll do one using chroma dot recovery eventually -
which if so is ok but it would have been better to have done it now.

In reply to an earlier post on 7 Mar 2013 16:14:23 GMT
feline1 says:
for first Inferno DVD< they'd just "perfected" a technique to de-NTSC-ify tapes and make them look more like the original PAL, so they got carried away with that, rather than noticing that it didn't look as good as putting NTSC colour on top of b&w film.
They also rather egregiously failed spot the honking great yellow bands from quad-head-misalignment.

But it's such a terrible shame that the original location film got thrown in the bin :(

In reply to an earlier post on 25 Mar 2013 02:09:34 GMT
They could have used chroma-dot recovery on Claws of Axos - apparently the film quality was good enough - but it's still not 100% accurate and is probably more expensive and time-consuming than combining the RSC colour with the film. Incidentally, they DO use the chroma-dots to match the geometry of the two pictures accurately.

In reply to an earlier post on 3 Apr 2013 18:04:39 BDT
Last edited by the author on 3 Apr 2013 18:07:14 BDT
Mr. Lee C. Mendham -
thanks for your comment; interesting & helpful.

With reference to Claws of Axos:

Then surely they should have done both the Chroma Dot Recovery and overlaying the RSC colour on the black & white film
& then used a combination of the results ?! :

ie alternating when necessary between the results of those 2 methods -
ie using whichever process came out best during the various sequences of the story.

And the same for all the other relevant Pertwee storys when such a dual processing is likely to achieve the best result.

And - wouldn't it be better to have done this now
( eg for Inferno etc ) rather than for a probable 3rd re-issue later?!

In reply to an earlier post on 15 May 2013 16:53:52 BDT
Gary L says:
Chroma Dot recovery isn't always possible for all Black-and-White film telerecordings. It relies on someone having made a mistake in the original telerecordings (the chroma dots aren't supposed to be there ... they are an "unwanted side-effect" of the transfer process that just happens to be useful 40 years down the track). Anyway, they only used Chroma Dot recovery on "Planet of the Daleks" and "Ambassadors of Death" because they didn't have any other choice (ie. no suitable NTSC color tape). Also, some early DVD releases didn't have a lot of restoration work done on them compared to the VHS releases, eg. no VIDFire on "Tomb of the Cybermen". Perhaps it was decided that a Reverse NTSC to PAL conversion was a lot easier to do (and much cheaper) than overlaying NTSC color onto a Black-and-White telerecording.

In reply to an earlier post on 16 May 2013 19:10:06 BDT
Last edited by the author on 16 May 2013 19:16:29 BDT
P. Kennard says:
Okay, let's see if we can get into the confusion here:
The RSC process used on the previous Inferno first appeared on the original Axos (lovely documentary on there about it) and produced more fluid results than previous PAL-NTSC-PAL conversions had, primarily as it 'reversed' the NTSC conversion. However, as the image had a reduced number of lines, the resulting image was softer than the original PAL. This was a massive step forward in quality, but obviously not perfect.
Overlaying colour signal from a converted version onto a black-and-white film version previously had the issue that the two didn't match: the film version suffered from various distortions caused by the original recording/transfer process, which require the colour signal to be manually distorted to match (see the Tomorrow's World piece on the original Daemons recolorisation). This led to an expensive and frequently imperfect result, no better then the RSC.
Chroma-dot colour recovery is a semi-magic bullet for lots of old material. IF the signal is there and lots of other factors are right, the colour signal can be regenerated from the chroma-dot. However, this is a process that requires extensive manual intervention and a whole range of technical issues can make it suffer and fail for reasons beyond the process's ability to recover. It also struggles with areas of heavily mixing colours and detail (plaid jackets can really upset it!). To date, no episode has used this process solely to provide a colour version. Planet of the Daleks used a mixture of Chroma-dot recovery and colorisation to produce a stunning result. Subsequent releases have used it where necessary (I.e. no better colour source available), with extensive manual colorisation and tweaking. This is an expensive and sometimes impractical way of recolourising episodes and this has to be used judiciously.
The NEW overlaying technique takes advantage of the chroma dots in a whole new way: while they may not be usable/ideal for pulling a colour signal from, they CAN be used to identify the warped geometry of the black-and-white image, allowing for a geometry map to be created and used to either correct the black-and-white image"s warped image, or warp the unwarped colour signal to match, whichever produces the better results (I'm led to believe the former is used where possible, as this would produce the 'correct' or 'original' image). This means that a much greater degree of accuracy in matching is possible, with a good degree of automation (the quality of the chroma-dot is highly variable), meaning the process is now relatively affordable.

Over the decades (they did start in the early nineties) since the Restoration Team first formed to recolour classic Pertwee, technology has changed beyond all recognition. They will always use the best available processes to produce the best possible results for us fans, frequently driving the CREATION of the processes they use. This benefits the industry and the classic TV market as a whole, but it must be pointed out that the Team have virtually NO MONEY to achieve these magical results and have to temper their work with what can be achieved on the budget they do have. With an unlimited budget, they could sit down and use ALL the differing processes and spend unlimited amounts of time picking the best parts of each frame and carefully putting together the ultimate jigsaw for our enjoyment, but that would be in a world even more fictional than our good Doctor's. They do everything they can with what they can. The work they DO achieve is massively undervalued and if they were to be paid what they should be, the discs would have to be three to five times their price!

In reply to an earlier post on 4 Jun 2013 18:53:54 BDT
P. Kennard's pretty much hit the nail on the head there. Hopefully this process can someday be used on the NTSC episodes of The Sea Devils as well - then there'll be no more wobbly horizontal lines on the shutters covering the Master's big-screen TV!

To compare the quality of the two processes, just take a look at Inferno's Deleted Scene, which only exists on the NTSC tape and therefore could only be presented in RSC quakity.
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