TV signal analysis

[dwight]

Given the amount of discussion about slowing down the video to create "moon video" a thought crossed my mind.

The colour TV camera on the LRV/tripod operated at 29.97 frames a second. In front of pickup tube, a colour wheel rotated creating the RGB (Red Blue Green)signal in the one video stream.

At the time conventional studio cameras employed a method of splitting the colour image into RGB via a prism and filters onto three seperate pickup tubes simultaneously.

Analogue Colour TV then recombined the 3 colour channels into a composite video signal which was then seen as a colour image.

The colour wheel camera as mentioned above created the same signal but used the single BW stream to carry the three colour channels. This reduced the amount of bandwidth necessary for a simultaneous RGB signal.

Back on the ground, the signal was sent into an array of three disc recorders which used field buffers.A tv signal is composed of frames (29.97 in NTSC) and this is made up of two fields. This then expanded the colour information from three sequential fields to three simultaneous fields. This explains why when fast motion occurs, you will see the three RGB components seperate. These recorders were developed for slow motion replay of sporting events, and where ingeniously employed in creating colour TV from the moon. The field buffer could be programmed to output a particular field for a predetermined time. In Apollo's case, 3 fields long.

Had there been a slowing down of the video at any point in the chain the RGB components would show the result of this. For example if as the argument goes, the video replay rate was halved (there by slowing down the motion ), the red signal field would occupy two fields of realtime video. That is the delay from the field buffers would cover twice as much space in the realtime stream as that would be an effect of slowing down the video. There would be no way to eliminate this effect, no matter where the hypothetical video slow-down was implemented.

If you analyse single frame information each colour channel should occupy three realtime video fields. (I dont have the precise recomposition info in front of me, so this frame rate may differ slighly). The absence of such artifacting eliminates the argument of the video being slowed down. The field RGB artifacts are exactly where they should be and are precisely as long as they should be.

BTW, if you watch the start of colour TV downlinks prior to the three recomposed colours being made into one colour signal, you can notice flickering on the, at that point BW video. The flickering diminishes when, for example two of the disc recorders kick in, and near totally vanishes when all three colours are combined.

Cheerio,
Dwight
RTL TX

[Kiwi]

dwight said:

Given the amount of discussion about slowing down the video to create "moon video" a thought crossed my mind...

Had there been a slowing down of the video at any point in the chain the RGB components would show the result of this...

I'd like to know exactly what it is that the hoax-believers are proposing was done to "fake" the video. Some seem to imply that it was filmed at half-speed on earth to make it look like the astronauts were moving in lighter gravity on the moon, and that is why the activity looks normal (for earth) when played at double speed. (This is true in selected cases, but certainly not true all the time, such as when Jack Schmitt stops running at the geophone site.)

If this is indeed what they are claiming, then firstly, how do they explain the dialogue and the few sounds (such as that from hammering a rock) that synchronise with the video?

Secondly, though, they are just plain wrong. To show things happening in slow-motion, you film them at a faster speed and then show the film at normal speed.

[PhantomWolf]

If this is indeed what they are claiming, then firstly, how do they explain the dialogue and the few sounds (such as that from hammering a rock) that synchronise with the video?

Well that just prove that they added the audio later, I mean, how could you hear the hammer hitting the rock when it's in a vacuum. Dah!. [/tinfoil cap off]

Yes I know the vibration travelled through the suit.

[Kiwi]

phantomwolf said:

I mean, how could you hear the hammer hitting the rock when it's in a vacuum. Dah!.

See, I'm psychic, because I knew someone would say that and was waiting for it. Half-expected an HB to lambast me for talking nonsense. ;D

For those who don't know, on the Spacecraft Films Apollo 17 DVDs you can occasionally hear a subtle pok, pok, pok sound as Gene Cernan hammers rocks. It is discussed in the Apollo Lunar Surface Journal, naturally, and, as PhantomWolf says, it is travelling through the spacesuit and getting picked up by his microphone. IIRC, Gene didn't hear it himself at the time.

And on the same DVDs you can see many prolonged, unedited scenes of dust and the astronauts doing things that couldn't have been filmed on earth, and as the camera pans around and up and down showing land and sky you never see shadows or tracks or other evidence of gantries or cranes carrying wires to hold them up.

[dwight]

The one thing that simply slowing down video by a factor of 2 does is double the length of whatever sequence you have shot. In the case of voice communications, you would have over the course of 30 minutes introduced a 30 minute delay. Given that information was spoken in real time one would need to preempt everything with an incresingly longer time gap, the longer the video feed would last.

If we go with a Capricorn 1 style delay which was placed at intermittent moments in their downlink, we encounter another problem which is absolutely _not_ evident on any Apollo downlink video: jump cuts. By rejoining a live feed from a delayed feed of the same scene, you will be _completely_ unable to avoid movement from the astronauts. In switching as portrayed in Capricorn 1, you would not see smooth transitions unless you were extremely luckiy in that the astros didn't change positions in the meantime.

The Capricorn 1 scenario seems very clever in a film environment where the people who are supposed to be hoodwinked are, but in real-life such tricks would be picked up within a matter of seconds, especially considering the live broadcast of the moonwalks.

In addition, the transitions between kinescoped and video material on Spacecraftfilms DVDs are a different matter entirely. The method employed to archive the downlinks were done in two formats. The first involved directly recording to 2" video tape. The second involved pointing films cameras at hi resolution video monitors ans simpßly filming the screen. The cameras were synchronised to the blanking interval of the monitors so that the scrolling "sync" bar would not appear. Anyway, the DVD material in which this occurs is simply a matter of changing between two archival formats within a scene. Similar to someone editing in a missing piece of a TV show they recorded, but using a friends super 8 filmed of the screen, rather than VHS tape.

Cheers,
Dwight
RTL TX

[Kiwi]

Ahaa! Dwight, can you please enlighten me about the changeover I mention in this post (press on the date below, if you don't already know that):

kiwi said:

At 0:10:56 the image changes to a darker one, with the lunar surface going from medium grey to dark brown. It changes back again at 0:16:02. From the booklet that comes with the DVDs, I guess that this is a changeover from videotape to kinescope or vice versa. It's not unusual and happens at other times during the flag-raising and, for one instance of a few, between 1:02:36 and 1:04:36 during the ALSEP deployment.

During these darker phases, the overall image quality is much lower and there is a type of audio tape print-through, when dialogue can be heard faintly four or five seconds before it actually occurs. Additionally, and of importance regarding "wires," there are many artefacts that appear briefly on the screen -- colour banding, random white spots, dark spots and sometimes a number of white spots that can all be seen at once. Most of these last for one to three frames.

See the entire post. Can you tell me which part is video and which is kinescope, and explain all the faults in the brownish portions? What exactly caused the flares from the sun glinting off something? Was it pixels freaking out, similar to ordinary film getting fogged?

Excuse my lack of Technobabble there -- it's all in the best Laymanspeak I could think of.

Thanks for your valuable input. This will probably be of interest to other Apollonut pedants.

[dwight]

Hi Kiwi,

I am at work at the moment, so I'll hold off on the video/kinescope rundown. However just off the top of my head: A11 is completely kinescope except for the launch video (B/W). The missions up to A14 tend to be all kinescoped. With A14 onwards, the 2" tape was robust enough to use for the most part. Mark Gray prefers tape where possible as it is the native domain of the video signal. It's similar to using a vinyl copy of a master rather than the master tape (as in the case of The Beach Boys hit "Do It Again"...you can hear the ticks and pops from the mono reference vinyl dub as they lost the master tape for that particular song!!)

Filming off a TV screen increases contrast, reduces picture quality, and doesn't reproduce colours as well as videotape does. Also, 2" tape is notorious for introducing artifacts if the replay machine is not setup correctly, or if the master tape is in bad condition. The format delivers fantastic TV results when it works correctly, but is a right headache when it doesn't!

cheers
Dwight
RTL TX

[ktesibios]

Imagine that I shoot a scene using a film camera running at 60 fps (2.5 X normal cine camera speed). I then run the film at 29.97 fps and transfer it to videotape using the same sequential-frame color system developed for Apollo.

The result would be that the action would run at a hair under half-speed and the video signal would have the same electronic artifacts as live action shot with the Apollo camera.

I don't think that the characteristics of the signal can be strong evidence of the authenticity of what was filmed. The evidence is in the content- all the shots that show things behaving consistently with being in low gravity in a vacuum, while HBers have to cherry-pick little segments of video to make the "run it at double speed" trick sorta kinda appear to work.

[dwight]

The trouble with filming and then transferring to video is that there are characteristics of film and video that are subtle, and yet very different. These would be noticeable regardless of whether flying spot telecine was used or any other method of film to video conversion. I am confident I could tell the two apart in _any_ sample given to me. One also has to develop the film first. Given the live nature of the missions, and the live interaction, it would be impossible to do. Also, while speed development is possible, it is sans colour correction and timing. This means the image quality is severely degraded due to its rushed nature. The original Apollo 9 suitup film was shown on CBS prior to launch. Compared to Mark Gray's DVD material, the news footage looks awful. In 1969 there was no method by which to record onto video at twice normal speed and have it replay in slow motion, other than the disc system. The disc system was severly limited in the length of video it could store (90 seconds as far as I can recall). The disc store needed for realtime video half speed playback for the amount of uninterrupted Apollo video was not possible on such a device. MPEG2 was a long way off, so all the fields were fully uncompressed. Also dont forget doing this introduces the creeping time delay between realtime and slowed down time.

Now onto the A17 kinescope/video

The flash at 12:10 is a tape fault. This has been transferred across to the kinescoped film record. This is a fault known as banding. On 2" video, the field is made up of four sections, and this is due to the manner in which the information is recorded on the tape. The tape was bent via vacuum suction into a semi circle as it passed over the heads. The rotating heads recorded a strip of video information onto the tape in an almost verticle manner. It took four of these passes to make up one field. Banding is most noticeable when the tape machine is not properly aligned. Essentially the field composition ciruitry doesnt put the field together properly, and so you get a sync flash. This artifact occurs on alot of older TV shows which were recorded on 2" tape.

Sorry to those who were sure this was evidence of wire support. It isn't, it is a common fault in older 2" video technology, and is more pronounced on older tapes . I have seen it on numerous 2" archival tapes (Are You Being Served GB, the Goodies GB, Young Doctors AUS, The Norman Gunston Show AUS, In Melbourne Tonight (AUS), Blankety Blanks (AUS)and can assure you it is the dread of every tape operator. This fault also became obsolete once helical scan type video machines became the accepted broadcast standard.

A good giveaway for kinescope is the film speckles and the increased contrast. Videotape when replaying video is as clear as you can get in image quality (current digital noise reduction techniques not withstanding).

Hope that helps
cheers
Dwight
RTL TX

[JayUtah]

I've always used film noise as my telltale; I'm not sure enough of my judgment to detect a kinescope purely on the basis of image appearance.

[dwight]

jayutah said:

I've always used film noise as my telltale; I'm not sure enough of my judgment to detect a kinescope purely on the basis of image appearance.

The ability to detect between the two (kinescope/video) is something that comes after years of video dubbing, and telecine transfers. (Too mnay years if you ask me!)But yes, film grain is the best telltale. Once you know what to look for it is second nature. However if I was asked to describe the differences, it would be very difficult, however I could, within a matter of seconds, tell you just by looking at a particular shot. There is a look to kinescope that just seems a bit out of place. It is not really film quality, and it is not really video quality.

The Apollo kinescoped material was 16mm, not 35mm IIRC, and thus image quality is also reduced.

Of course these days with HDTV this is not as easy. Although again certain features are a giveaway. For example an HDTV projection movie, will have rock steady static scenes. (Opening credits are a good example...on film they have a slight wobble to them, in HDTV they dont)

cheers
Dwight
RTL TX

[Kiwi]

Thanks, Dwight.

I'm still a little unsure, so which exactly is the darker "brown" portion on Spacecraft's DVD between 0:10:56 and 0:16:02 which has the colour banding, random white spots, and dark spots? Is that kinescope or video?

Also, what would cause the effect like audio tape print-through, when the dialogue can be heard faintly four or five seconds before it actually occurs? When the image quality improves at 16 min. 2 sec. and the lunar suface returns to its normal grey colour, that "print-through" also goes away.

[dwight]

Hi Kiwi,

the darker section with the speckles etc is kinescoped. All video faults were encoded into the film master. The audio print through can originate from three possible sources.

1. The 2" tape. This would imply that the kinescoped archive was made from a videotape replay, shortly after the live transmission.

2. The 16mm film, if it used a magnetic audio track. I am unsure of how audio was recorded for the kinescoped material, though.

3. If the 16mm kinescope was then transferred and stored onto video tape, print through could also occur. I tend to think this is the scenario.

Without actually inspecting the archival material, it is difficult to say. Although, the print through would have slowly developed over the decades of storage.

cheers
Dwight
RTL TX

[dwight]

OK here is a Kinescope/video breakdown of the First TV section of SCF Apollo 17 DVD:

START - 04:22 Kinescope
04:22 - 06:13 2" Video
06:13 - 06:32 kinescope
06:32 - 10:56 2" Video (between 06:32 amd 07:00 there is some severe banding visible as 4 seperate horizontal stripes)
10:56 - 32:33 Kinescope
32:33 - END 2" Video

For the most part Mark has chosen pans with little coherent visual information to do the cross-wipes between Kinesope and video source material.

Cheers
Dwight

[Kiwi]

Many thanks, Dwight.

It seems that one more conspiracy theory bites the dust. To a casual viewer of the clip Margamatix linked to, it might look as if there is a wire holding up an Apollo 17 astronaut, but a close examination of the Spacecraft Films' DVD shows there certainly isn't, by the fact that the reflection from the antenna and the random white spot at the top occur in different frames.

In addition, all the extra minutes of unedited video around that time allow us to closely inspect the astronauts and check that there is indeed nothing holding them up, nor any sign of any apparutus to which a wire could be attached. The flashes above their PLSSs are merely the sun reflecting off their antennas which are strap-like -- shaped like a carpenter's metal tape rule.