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Direct Link: http://donkeykongforum.com/index.php?topic=2055
Read the entire post at the link above with screenshots.
If you don't understand those screenshots here is a breakdown of the issue being disputed:
Get up to speed on some back history of Donkey Kong
Below, you'll find a large collection of animated GIFs. PLEASE take the time to read this ENTIRE post before jumping to them, and please continue reading what is posted AFTER them. In summary, these GIFs show that each of the Donkey Kong world record direct feed recordings presented by Billy Mitchell and verified by TG were generated in MAME and not by original Donkey Kong hardware. These scores are: 1,047,200 (the King of Kong "tape"), 1,050,200 (the Mortgage Brokers score), and 1,062,800 (the Boomers score). In order to demonstrate this, it's necessary to understand how DK images are generated by MAME versus an original PCB.
Video emulation has changed across MAME versions, but there are basically 4 eras: 0.115 and prior, 0.116 - 0.121, 0.122 - 0.126, 0.127 and newer. Each of these groups or eras show different methods of video emulation as a result of MAMEdev making various improvements. As it currently stands, video emulation is not perfect, but it's closer than it used to be.
The important bit: prior to version 0.127, MAME generated video in essentially a "snapshot" fashion. The Z80 would run for 1 frame, then the video emulation takes the "snapshot" of that point time and displays the image. Then the Z80 runs for 1 frame, the next snapshot is taken, displayed on the monitor, etc. etc. Real DK hardware, on the other hand, generates video in a "rolling shutter" fashion: the video generator scans left-to-right/bottom-to-top, while the Z80 builds the screen in memory from the opposite direction right-to-left, top-to-bottom. Both video generation and the Z80 are running concurrently with no "snapshots". The result is that it becomes fairly easy to determine WHAT generated the image based on HOW the image has been generated.
Video emulation has changed across MAME versions, but there are basically 4 eras: 0.115 and prior, 0.116 - 0.121, 0.122 - 0.126, 0.127 and newer. Each of these groups or eras show different methods of video emulation as a result of MAMEdev making various improvements. As it currently stands, video emulation is not perfect, but it's closer than it used to be.
The important bit: prior to version 0.127, MAME generated video in essentially a "snapshot" fashion. The Z80 would run for 1 frame, then the video emulation takes the "snapshot" of that point time and displays the image. Then the Z80 runs for 1 frame, the next snapshot is taken, displayed on the monitor, etc. etc. Real DK hardware, on the other hand, generates video in a "rolling shutter" fashion: the video generator scans left-to-right/bottom-to-top, while the Z80 builds the screen in memory from the opposite direction right-to-left, top-to-bottom. Both video generation and the Z80 are running concurrently with no "snapshots". The result is that it becomes fairly easy to determine WHAT generated the image based on HOW the image has been generated.
If you don't understand those screenshots here is a breakdown of the issue being disputed:
Get up to speed on some back history of Donkey Kong
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