Submission #2067: nitsuja's SegaCD Sonic the Hedgehog CD in 17:27.65

Console Sega CD Emulator GENS
Game Version USA Frame Count 62859
ROM Filename Sonic CD (U).iso Frame Rate 60
Branch Rerecord Count 94290
Unknown Authors nitsuja
Game Sonic the Hedgehog CD
Submitted by nitsuja on 8/18/2008 5:31:13 AM

Submission Comments
A short run of a Sonic game that hasn't had any obsoleted movies? I haven't been too interested in doing TASes lately but I couldn't help myself from improving it. The old run was well-optimized (with solid routes) and broke the game pretty thoroughly, so this ended up being less than 40 seconds faster, but I think it's still a significant improvement considering the game.
I used Gens 10a with the Sonic CD Camhack/Speedometer/SolidityViewer/HitboxDisplay enabled to make this. Thanks to Upthorn for making and releasing such good tools for TASing this game, and also for making the first version of this run (which I used a lot of ideas from).


These are the same goals as Upthorn used. In order of highest to lowest priority:
  • No time travelling or level restarting
  • Fastest in-game time
  • Fastest real time


  • Aims for fastest (primarily in-game) time
  • Takes damage to save time
  • Abuses programming errors
  • Ignores semi-important goals in the game

Level breakdown

LevelTimeOld TimeSeconds SavedNotes
Palmtree Panic 10'20"750'21"010.26Better angle on the high jump after getting the speed shoes
Palmtree Panic 20'16"600'16"800.20Took a slightly lower route
Palmtree Panic 30'17"710'17"880.17Hit the spring faster, manipulated boss to spawn earlier
Collision Chaos 10'15"830'15"830.00Very minor changes (no improvements found)
Collision Chaos 20'22"060'24"312.25Faster speedshoe route, skipped peelout at end
Collision Chaos 30'03"350'03"350.00Very minor changes (no improvements found)
Tidal Tempest 10'21"380'22"651.27Jumped to avoid walking down a slope underwater, early peelout speed trick at end
Tidal Tempest 20'31"650'40"618.96Went through wall to skip part of the route
Tidal Tempest 30'23"900'30"136.23Zipped in a different place to reach the boss sooner
Quartz Quadrant 10'18"650'19"550.90Rolled for faster speed off the first ramp
Quartz Quadrant 20'17"910'18"860.95Zip-launched into a lower route at the end
Quartz Quadrant 30'50"860'52"061.20Saved time by not skidding on the treadmill
Wacky Workbench 10'22"030'25"383.35Similar but crazier route
Wacky Workbench 20'27"250'29"482.23Didn't let the time posts slow me down, actually they helped a little
Wacky Workbench 31'03"051'04"901.85Zipped differently to reach the boss sooner
Starlight Speedway 10'14"750'15"080.33Would have been faster but the camera got too far behind for further optimizations to make any difference
Starlight Speedway 20'17"630'18"661.03Went enough faster to skip another loop
Starlight Speedway 31'05"011'05"800.79Saved time by making the game think the race was a close call at the end (Robotnik speeds up... and gets green jets?)
Metallic Madness 10'18"710'20"581.87Got enough speed to jump through the last wall
Metallic Madness 20'23"610'26"582.97Handled the circular conveyor belts faster, zipped for a speed boost at the end
Metallic Madness 31'07"561'09"401.84Faster zip, manipulated the bug things to be closer together
Total Time 29'40"2510'18"9038.65In summary... went faster?

Emulator Settings

  • Emulator: Gens 10a
  • Bios used: v1.10 (U)
  • Sound: 44100 KhZ
  • Options: Sega CD SRAM Size = 64 KB
This movie happens to stay synchronized regardless of whether "Perfect SegaCD Synchro" is on, so if SegaCD emulation is chuggy on your computer, it might help to turn that option off for this movie. It would also help to use BIN+CUE instead of ISO+MP3, because it takes more processing power to decode MP3s than to not decode them.

Desync Issues

If you're getting desyncs, first make sure you're using the correct ROM and BIOS and emulator version and settings as described above. And don't try to load a mounted disc with "Boot CD", just use Open ROM on the file like normal.
Also make sure you have the right number of audio tracks on the CD... if you're using a cue file that means your cue file needs to have the right number of correctly indexed audio track sections, if you're using MP3s that means you need exactly 34 MP3s named properly and in the same directory as your ISO (if the ISO is "Sonic CD (U).iso" then the MP3s should be "Sonic CD (U) 02.mp3" through "Sonic CD (U) 35.mp3"). The actual contents of the audio tracks can be almost anything, but the number of audio tracks has to be correct otherwise the emulated loading times will be different enough to cause a desync.


This was made with the US version of the game, but if you prefer the music from the Japanese version, you can tell Gens to run the US game but use the music from the Japanese game. The way of doing this depends on whether you are using ISO+MP3 or BIN+CUE. If you are using MP3s, simply replace the MP3 files with the ones from the Japanese version. If you are using BIN+CUE, you can edit the CUE file of the (J) version to use the (U) version for track 01 (data) and use the (J) version starting at track 02 (audio). It should look like this, except with the filenames matching the ones you have:
FILE "Sonic CD (U).iso" BINARY
  TRACK 01 MODE1/2352
    INDEX 01 00:00:00
FILE "Sonic CD (J).iso" BINARY
    PREGAP 00:02:00
    INDEX 01 12:14:49
    INDEX 00 12:18:63
    INDEX 01 12:20:63
...and so on...
One thing those won't work for, though, is the ending music. For that, you'll have to use the actual Japanese version of the game, not only the Japanese audio tracks. You'll also have to use a different version of the movie file for it to sync and version 1.00 of the Japanese MegaCD BIOS. Be warned that Quartz Quadrant has slightly slower in-game times than in the US version (differences during lag frames) even though the movie is about 10 seconds shorter (mostly due to shorter level end music).

NesVideoAgent: Hi! I am a robot. I took a few screenshots of this movie and placed them here. I'm not sure I got the right ROM though. (I tried Sonic The Hedgehog (MP).gen, which was the closest match to what you wrote.) Well, here goes! Feel free to clean up the list.
BoltR I choose to clean them all, as that is very much the wrong ROM.

mmbossman: Impressive work. Nice to see you back nitsuja. Accepting as an improvement to the published movie.

Raiscan: Processing.

Last Edited by adelikat on 10/2/2009 2:32 AM
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