Friday, November 17, 2023

Doctor Who DVD and Blu-ray Frame Rate & Resolution Issues

Doctor Who has had a very lengthy history on optical media.  From the first release of The Five Doctors in 1999 to Series 13 2022 Specials, many, many discs have been stamped of Doctor Who-related content. Not all discs have been error free, and some errors have come down to more subtle issues than a missing shot or misspelt credit.  Frame rate and resolution issues tend to plague the line, and these will be the focus of this blog entry.

Relevant Broadcast Standards

405-line B&W video, 50i, ~377 lines visible

525-line NTSC B&W and Color video, 59.94i, ~480 lines visible

625-line B&W and PAL Color video, 50i, ~576 lines visible

1080-line High Definition digital video, 50i or 59.94i

Original Standards - Classic Series

1963-1969 

The classic series was shot on videotape and originally broadcast from videotape with rare exceptions.  405-line B&W video was used from The Pilot Episode (An Unearthly Child) to The Enemy of the World Episode 2. 625-line B&W video was used from The Enemy of the World Episode 3 until The War Games Episode 10.

From the 1960s Hartnell and Troughton seasons what survives, if it survives at all, is a mixture of 16 and 35mm black and white film telecines.  

Tele-snaps was a business name of John Cura who provided photographic services to preserve a visual representation of a TV program. They exist for several missing stories from Marco Polo to The Wheel in Space.  These are still camera pictures taken of a TV screen.  Generally about 60-80 images of a 25 minute episode would be taken.  He did not take photos of much of season 3 due to a lack of commission from the BBC or any of season 6.

There are several 8mm home video clips taken by fans of their TV screen while broadcasting an episode.  These clips are short. 

Off-the-air audio recordings, originating from fans, exist of every missing episode.  Certain stories have been reconstructed with these recordings and either telesnaps and production photos or animation.

1970-1974 

The Pertwee half of the 1970s is very complicated in what material survives.  The initial serial, Spearhead from Space, was filmed on 16mm color film stock at 25 frames per second and survives in its entirety.  

For the Pertwee stories from The Silurians Episode 1 to The Invasion of the Dinosaurs Episode 1, there are several sources available, depending on the episode.  A visual and audio record of all episodes survives, but many episodes have had to be recolorized through several techniques. All episodes from Season 10 and 11 survive on their 625-line PAL color except for Planet of the Daleks Episode 3 and Invasion of the Dinosaurs Episode 1.   What survives and how those episodes have been restored is due to a combination of 16mm B&W telecines, professional B&W PAL monochrome videotape and NTSC color videotape recordings from professional and fan sources.

1975-1989

The normal format for recording Doctor Who after Spearhead from Space in 1970 until the end of the classic series in 1989 was to use 625-line PAL color broadcast TV cameras to shoot studio scenes onto videotape and 16mm color film to shoot location footage and model effects. Off and on from the mid 1970s to the early 1980s Outside Broadcast video cameras would be used on location to give the production a more uniform look.  From The Trial of a Timelord to Survival, video cameras would be used for all action outside of model work. The 16mm film would be transferred to tape and the resulting footage would be edited onto a master tape.  Some earlier episode edits survive on videotape.

All episodes from Season 12 through 26 survive on their master tapes.  Some episodes have their original location and model film work survived, and when available this film has been scanned in HD and presented instead of the original poorer quality telecines originally included on the broadcast master tapes on later DVDs and the Blu-ray Collections

1996 

Doctor Who - The Movie was a U.S. production, so it was mastered as 525-line 59.94i digital video, (principal photography shot on 35mm color film, 24 frames per second)

Original Standards - New Series

Series 1-4 and The Next Doctor - 625-line, 50i digital video filmized except for scrolling credits.

Tennant Specials (excluding above), Series 5-13, Torchwood Series 1-3, The Sarah Jane Adventures, K9, Class - 1080/50i digital video filmized except for scrolling credits

Torchwood Series 4 - Another U.S. production, this used the 1080/24p digital video standard.

VHS and DVD Standards Conversion Generally

Doctor Who has been engaging in standards conversion since The Pilot Episode was recorded.  The show had been telerecorded from The Pilot Episode to the end of the Pertwee era, partly for economic purposes (so the videotape could be wiped and reused) and partly to allow for overseas sales.  Telerecording an episode of a TV program involved using a film camera to record the images that were being broadcast from a special TV tube.  The film stock would usually be 16mm, although at times 35mm might be used, and the recording would always be made in black and white, even if the production was broadcast in color.

It was cheaper to use 16mm film stock rather than duplicate a videotape and using film ensured that the program could be viewed anywhere in the world.  If the show was sold to Canada, the local Canadian company could show the film as slowed down to 24fps using their normal equipment designed to transfer film to video or broadcast it like a film chain.  If the show was sold to Australia, then the film would be shown at 25fps.  

Doctor Who first began offering episodes on videotape for overseas broadcast in the 1970s, and in these cases the BBC had to duplicate the episodes onto color videotape.  Doctor Who was first sold in the USA in the early 1970s and the BBC had to perform a standards conversion from PAL to NTSC.  Standards conversion has improved by leaps and bounds over time.  In the early days, the process was similar to telerecording where a video camera was pointed at a color video monitor displaying the program and recording to tape.  The resulting image looked rather unimpressive.  By the 1980s they used more sophisticated methods, methods which have improved with computational power to the present day.  Newer machines could drop fields, repeat fields and blend fields and apply 3:2 pulldown with slowdown to make up the difference between 50i and 59.97i.  

VHS and CRTs were quite good at hiding conversion artifacts but DVDs and LCDs can make them appear even to the eyes of an untrained viewer.  By the 2000s more sophisticated techniques were available that would generate new frames on the basis of existing frames through adaptive motion interpolation, block matching and phase correlation.  Each of these methods is more computationally intense than the last, but give increasingly better results and fewer motion artifacts.   According to Steve Roberts, head of the Doctor Who Restoration Team, "All of the Classic DW NTSC DVD releases in the US (with the exception of The Moonbase which was done incorrectly) are motion-estimated standards conversion from 50 fields per second to 60 fields per second. This process does not repeat fields, rather it estimates where objects in the picture will have moved to at the point in time when a new field needs to be added. This process retains the running time and audio pitch of the PAL master."

In the PAL and NTSC days the line count was different, requiring conversion from 525 lines to 625 lines and vice versa.  This is no longer an issue in the HD-era and UHD-era, as all video systems use the same resolutions (720, 1080 or 2160 lines) regardless of the country of origin or destination.  Also there is no longer any need to convert NTSC color encoding to PAL color encoding, but converting color encoding was trivial for professional video studios.  Color has been encoded digitally in TV production since the 1990s.  DVDs encode color in the YUV format and rely on the player's hardware to convert that signal into an NTSC or PAL signal.  Most DVD players can convert YUV to Component Video with no discernable loss in color accuracy.

Most of the 1960s stories have been given a VIDFire treatment to restore the high field rate "soap opera effect" that would have been observable when these stories were broadcast as an interlaced video source (except for sequences originally shot on film).  The high frame rate "soap opera effect" is lost when the episodes were telecined.

Classic Series

Classic Series Doctor Who does not have any significant issues generally as presented in the US on VHS and DVD compared to the UK.  The video is standards converted on DVD from 720x576 at 50i to 720x480 at 59.94i.  There are a few specific issues, however: 

The Crusade Episode 1 & The Time Meddler - The Time Meddler was the only 1960s serial not given the VIDFire treatment on DVD.  The Crusade Episode 1, "The Lion", was also not given the VIDFire treatment when it was released on DVD.  At the time the Doctor Who Restoration Team believed that the film prints were too badly damaged for the process to give a believable video effect.  Both have been given the VIDFire process for Doctor Who - The Collection Season 2 Blu-ray.

The Moonbase - Those episodes which have been VIDFired for R2 DVD lost that look for the surviving episodes (2, 4) for the R1 DVD release.  In addition they slowed it down to 23.98p and then performed 3:2 pulldown to get to 59.94i instead of interpolating frames as was typically done.

Spearhead from Space - Because this story was shot completely on color 16mm film stock shot at 25fps due to a strike by the video camera operators during the serial's scheduled production and the negatives survive it was given a standalone Blu-ray release.  A new interpositive taken from the original camera negatives was scanned and used as the basis for the Blu-ray release.  In the UK the Blu-ray uses 1080/50i, but as a single frame is broken up into a pair of interlaced fields, the presentation is not truly interlaced and no weave or combining artifacts should be seen when watching the disc.  In practice, the frame rate is 25p.  For the US Blu-ray the film was slowed down to 23.98 fps, which is a standard supported by all US players and TVs, and the audio was pitch shifted to adjust for the pitch caused due to the slowdown.  

Shada - The 2017 Animated DVD has issues unique to the disc.  First, the existing videotape footage shot in 1979 has lost its high frame rate, giving it a 25p look that it should not have.  Second, the DVD was erroneously mastered so the image on the main feature will be windowboxed on all four sides on a 4:3 display.  It should not show any borders.  The 2017 R1 DVD also plays the audio 4% too slow.  The 2017 standalone Blu-ray only has the animated reconstruction as a movie, The Collection - Season 17 has it in episodic format.  

Doctor Who - The Movie - Instead of film being rescanned for the Blu-ray release, the 625-line video master was used and upscaled.  The picture quality is slightly better than the DVD but nowhere as good as it would be if the lost 35mm film was located and rescanned.  The effects were done at standard definition on video, so those would need to be redone or upscaled for high definition.  The VHS, LaserDisc, the first and Special Edition DVDs and the Blu-ray are all are based on the 625-line master, which has the audio pitched up by 4% because it runs at 25fps and has never been officially corrected.  The US Special Edition DVD, which is the only release of The Movie in North America, has been converted to 59.94i from the 625-line master, so it also runs too fast and has the higher pitch audio.

The Collections Replacement Discs

The releases of Seasons 12, 18 and 19 have had discs replaced due to mastering errors. While newer pressings of these Seasons have corrected discs out of the box, I include this information for historical purposes.

Season 12 had errors on Discs 3 (The Sontaran Experiment) and Disc 5 (Revenge of the Cybermen).  The Sontaran Experiment had one audio channel out of phase in relation to the other, Revenge of the Cybermen had a credit misspelling. These affect the U.K., U.S. and Australian versions. Later pressings of Season 12 have the discs corrected.

Season 18 had errors on Disc 1 (The Leisure Hive) and Disc 6 (The Keeper of Traken). The Leisure Hive used downmixed 5.1 audio instead of the regular stereo audio. The Keeper of Traken used an incorrect frame rate. These affect the U.K. and U.S. versions.

Season 19 had errors on Disc 1 (Castrovalva). The audio for Castrovalva Part 1 out of sync with the video for a significant portion of the episode.

New Series & Spinoffs Blu-ray

If you wish to obtain episodes of the new series in their original 50i (official) / 25p (effective) frame rate on Blu-ray, buy the U.K. releases.  There are some issues here however :

Series 1-4 - On Blu-ray all releases have been slowed down to 24p with pitch correction to allow for discs to be sold anywhere in the world.  These Series were shot on SD, so these are upscales.

Tennant Specials - On Blu-ray, the standalone release of Planet of the Dead and The Complete Specials have used blended and repeated frames to convert them from 50i/25p to 60i.  The German Complete Specials Blu-ray (which has translated German credits) has these episodes in 50i/25p.  Note that The Next Doctor was shot on SD, any appearance of that special on Blu-ray is an upscale (on the German Complete Specials Blu-ray, it is included as a DVD).  On The Ten Christmas Specials release and the 2019 The Complete Specials Steelbook release, the Tennant Specials have been slowed down to 24p with pitch correction.

Series 5 - The original Blu-ray had the "Next Time" trailers shown at the end of the broadcasts not included, the Steelbook has the trailers but has been slowed down to 24p with pitch correction.

The Day of the Doctor - The 3D Version has been slowed down to 24p with pitch correction because the Blu-ray 3D standard only supports 24fps.  3D as 2D playback is supported but it just shows you the image from one eye and the footage is still slowed down.  The 50th Anniversary Collection has a Blu-ray of this story with 50i/25p but initial releases had to be corrected with a replacement disc.

Twice Upon a Time - Ultra HD 4K Blu-ray has been slowed down to 24p with pitch correction to allow for discs to be sold anywhere in the world.  Buy the U.K. Blu-ray release for a 50i/25p Blu-ray.

Torchwood Series 1-3 - On Blu-ray, these have used blended and repeated frames to convert them from 50i/25p to 60i on all releases.

Torchwood Series 4 - UK Blu-ray has been sped up from 24fps to 25fps without pitch correction, US Blu-ray plays back at correct speed.  Torchwood Series 4 (Miracle Day), like Doctor Who - The Movie, was a US-based production.

Sarah Jane Adventures 3 - Shot in HD, no Blu-ray release available.

It should be noted that the Doctor Who Restoration Team has little, if any involvement in the mastering of New Series material for disc sales.  Any mistakes or issues should not be attributed to them.  

3 comments:

  1. I purchased the limited edition complete series 1-13 boxset that just came out in November 2023 US Version, And so far(I haven't checked all of the newly upscaled episodes) the next doctor special seems to have audio syncing issues, you can notice it after the opening credits and while the monster is climbing up the wall. Both doctors dialogue seems repeated and slightly out of sync making it seem like an echo. I have the original upscale as well and it doesn't have this issue.

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  2. Where can I find Series 1-4 in 576i50(25p effective)? Ideally not upscaled but I could downscale if needed. There doesn't seem to be a copy like this anywhere?

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    Replies
    1. Region 2 and 4 DVDs are your friends.

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