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benasselstine
04-04-2018 at 04:32 AM
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Prolonged 1UP flashing

Quote Originally Posted by benasselstine View Post
One thing we can do while we wait for a ruling is look more closely at the evidence at hand.

While watching
"Jace Hall - Twin Galaxies - Review of Billy Mitchell's Donkey Kong tape Livestream", there was a concern about the 1UP flashing for too long.

It happened at in the video while reviewing the 1.05M tape.

I too was curious about it so I went ahead an plotted the brightness of the 1UP over time for the 1.05M and 1.04M direct-feed recordings (thank goodness they are publicly available on youtube.) Even low resolution video at 30 frames per second is plenty of data to make this type of chart.

My apologies if all this has been covered before and I'm just adding to the noise.

Executive summary: I found a few things of note, but your mileage may vary.

1. I found the prolonged flashing 1UP that we already knew about in the 1.05M video, and a close cousin to it, and
2. In the 1.04M video I found a shortened HOW HIGH CAN YOU GO screen which was quite surprising, but it's such an obvious edit point I'm guessing someone else has already seen it.
3. In the 1.05M video it starts with a credit and still has a credit when the game is over.
4. The VHS glitches seem to be concentrated at the end of the 1.04M tape.

If you're still here, you're about to dive into the minutia -- come on in, the water's warm. And if you don't want the details, skip the rest.

1. First of all, the 1.05M direct feed.

The direct feed is viewable here: https://youtu.be/Y0ZKEGZpggI

Chart of 1UP flashing: https://svgshare.com/i/673.svg
(BILLY-MITCHELL-1.05M-DK:21:4:82:15:133:Y0ZKEGZpggI.svg)

The overall brightness changes a lot over time, but the relative brightness of the flashing 1UP can be seen as a regular up and down signal in the chart.

Have a scroll through the svg and look for anything that looks out of place. It's easy to spot anything strange because of the regularity, and it's a whole lot less time-intensive than staring at a flashing 1UP.

Then to get the number of seconds into the video that a particular frame is, use this calculation:
NumberOfSeconds = FrameNumber / (30000/1001)

And to see it in youtube just add "&t=NumberOfSeconds" to the youtube link. You can do it!

The prolonged flash that was highlighted in Jace's review video can be seen just after 194400 in the chart and 1:48:02 in the direct feed video. It stands out even if you're not looking for it.

On this tape, the chart has "speed bumps" and "potholes" that show where the boards start. They all happen during a HOW HIGH CAN YOU GET. Very little else of note happens in the chart other than these events, except for general brightenings due to slow dark/bright diagonal bands, and a single VHS glitch.

Other notable events:

19900, https://youtu.be/Y0ZKEGZpggI?t=663
A typical speed bump. Some speed bumps are much bigger than others.

41500, https://youtu.be/Y0ZKEGZpggI?t=1384
A typical pothole.

111100, https://youtu.be/Y0ZKEGZpggI?t=3707
A VHS glitch on first hammer of barrel board. There could be other VHS glitches, but none that affect the flashing 1UP.

132200, https://youtu.be/Y0ZKEGZpggI?t=4411
It's similar to the event at 194400 in terms of how the chart looks, but it doesn't look the same in the video. They are both speed bumps going into pie factory boards.

See the full audit here: https://pastebin.com/aL78Qi69

Here's a chart of where the events lie in relation to each other: http://svgshare.com/s/66e

You might notice that the speed bumps and potholes are pretty consistent across the whole run except for the beginning. Are we seeing evidence of something other than the start of a board? I don't think so, but what do you think?

If you want to help out, you can edit the svg file to have arrows pointing to events provided by the full audit.

Also I noticed that the game starts with a credit and ends with a credit. Has somebody already noticed/looked-into this?


2. Second of all, the 1.04M direct feed.

The direct feed is viewable here: https://youtu.be/KYtJzRcvOzk

Chart of 1UP flashing: https://svgshare.com/i/678.svg
(BILLY-MITCHELL-1.04M-DK:19:5:90:23:133:KYtJzRcvOzk.svg)

If you think this dispute thread is a poopshow, try looking at the VHS glitches on this recording.

The 1.04M direct feed doesn't have as many speed bumps and potholes as the 1.05M tape, and the overall brightness is a lot more consistent even though it is also a recording of a TV playing a video. There are some still lots of speed bumps though. I suppose more potholes are there too, but I didn't look too closely for them.

Anyway, this video has the same framerate as 1.05M, so the calculation is the same:
NumberOfSeconds = FrameNumber / (30000/1001)

Okay, let's can through the chart and look for events.

There are no prolonged flashes of 1UP in this video, and the only events in the chart seem to be VHS glitches.

Notable events:

214000, https://youtu.be/KYtJzRcvOzk?t=7140
A shortened HOW HIGH CAN YOU GO screen, and the angle of the screen changes.
It sure looks like an edit point, and I suspect that it's been seen or explained before.

Here is the span of events for speed bumps and potholes:
http://svgshare.com/s/65C

The VHS warpings were audited separately. I don't think I captured all of them here, but if they interacted strongly with the 1UP flasher, I probably did. They really stick out as jagged lines on the chart.

First of all, there seem to be more warpings at the end than the start.
http://svgshare.com/s/667

Name:  chart.png
Views: 43
Size:  10.7 KB

More than half of all VHS glitches are on the barrel board. But is half of all gameplay on the boarrel board too? I don't know.

I don't know what makes these VHS glitches appear. Tracking is one thing, and tape fatigue is another, but I am not an expert.

Here is the full audit: https://pastebin.com/re13Hy76

3. Conclusions

If the 1UP were not being saved in a save state in MAME, and these recordings employ the restoring of save states then we would expect to have some double wide 1UPs in either the on or the off position (and everything in between, but the double wide would be easy to spot). With the possible exception of 1 or 2 events, we don't see that here.

The shortened HOW HIGH CAN YOU GO screen is a concern. Future work should go back and measure the duration of each of these screens in both videos and look for similar events... but I suspect that this particular event is well known already.

The distribution of VHS glitch events on the 1.04M recording seems normal, but I'm not sure.

Here is the script I used to make the charts: https://pastebin.com/nR3MVFhS

Sorry about the extra image on the end here. I can't delete attachments.
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