Sunday, February 25, 2018

Super Nt - Testing and Capturing

I had not planned on publishing a second blog entry on the Super Nt, but there were one or two issues I wished to address and the first blog entry was becoming very long.  So here is another blog entry discussing testing and capturing games on this increasingly wonderful device.

Testing Games on the Super Nt

Ideally, the hardware you should have to test the Super Nt is a 3-chip SNES console with a CPU/PPU1/PPU2 revisions of 2/1/3.  This is the system Kevtris is targeting.  There are early consoles with revisions of 1/1/1, 2/1/1 and 2/1/2, but they almost all have an SHVC-CPU-01 PCB with the separate SHVC-SOUND module.  Boards SNS-CPU-GPM-01, SNS-CPU-GPM-02, SNS-CPU-RGB-01, SNS-CPU-RGB-02 & SNS-CPU-APU-01 are good boards.  Avoid the 1-chip consoles, while they output sharper graphics they also bring their own set of glitches to the table.  Do not test on any clone console, only use official Nintendo hardware.  Test PAL games on PAL consoles and NTSC games on NTSC consoles.

While it is ideal to have genuine cartridges, the sd2snes is exceptionally compatible with games and works harmoniously with the Super Nt.  The Super PowerPak and official Super EverDrive are almost as compatible.  Make sure you update to the latest firmware on your card (that includes the Ramsis firmware for the Super PowerPak).  Also, make sure your Super Nt is updated to the latest firmware.  Avoid Super Nt fimrware v4.1, it had a nasty regression that could cause random crashes in games.  Flash carts can tell you the versions of your CPU/PPU1/PPU2, as can some games.

When it comes to ROMs, use ROMs from the No-Intro set, preferably a recent compilation of the No-Intro set.  You can find a fairly recent compilation on  In order to ensure that your ROM is good, check this site :  Select Nintendo - Super Nintendo Entertainment System from the drop down menu and then click on Search to search for the game in question.  If you want to see the recent updates, choose Selected on the drop down menu Set.

When using an emulator to test games, there is only one choice.  You must use the latest version of Higan, the only SNES emulator that focuses on accuracy over playability.  Do not use SNES9x or ZSNES or a Retron 5 or a jailbroken SNES Classic.  Higan is admitted a bit more of a pain to use than other emulators because it is closer to the each-game-has-its-own-manifest system of MAME than the drag-and-drop-your-ROM system of Nestopia.  Simply Import the ROM file and then test it out.  Higan is nearly 100% accurate, but a regression can slip in from time to time with obscure behavior and edge cases.

Here is a checklist of things to do when you think you have found a bug :

  • Make sure you have updated to the latest Super Nt and flash cart firmware
  • Make sure your ROM is a good dump
  • Try all official versions and revisions, including Japanese and PAL if they exist.
  • Try the game on an original SNES, preferably with a 2/1/3 CPU/PPU1/PPU2 revision
  • Try the game in higan
  • Power down your console and do not run another game beforehand.
  • Try the game a few times in the Super Nt, pressing reset a couple of times (reset to game, not reset to flash menu)
While a 3-chip 2/1/3 console is the most compatible known console, some games can crash due to poor programming.  See my previous blog entry for more details.  

Capturing Super Nt Video

While I can only speak for my own device, the StarTech USB3HDCAP, I believe my advice will be helpful for others.  The StarTech's processing chip is also used in the Elgato HD60 and the Micomsoft XCAPTURE-1.

The dirty secret of the StarTech's chip is its inability to capture full range (0-255) RGB losslessly.  It seems to either capture using YUV 4:2:2 or 4:2:0 or limited range (15-235) RGB.  When the Super Nt was first released, it only output full range RGB (and it converted the RGB from YUV, scalers or no scalers).  Now as of v4.3, it has the option to output limited range RGB in the Scalers menu.  For the StarTech, you need to set the Limited RGB option introduced in v4.3 to get the most accurate colors from the Super Nt.

Another issue that I encountered with the StarTech is its ability to capture perfectly sharp pixels.  With the default Super Nt settings, the pixels may not be as sharp and even as they can be from a PC emulator.  But this can be fixed.  In the 1080p mode, for 5x/4x set the horizontal resolution to 1024 and the vertical resolution to 960.  For the 6x/5x, set it to 1536 and 1200, respectively.  You may need to adjust your horizontal position setting to 40.  Disable all scalers and interpolation.  In OBS set the YUV Color Space to 709 and the Color Range to Full.  I also boosted the contrast from 128 to 130.  With that, let's compare a frame from the StarTech capture to a screenshot from higan v1.06 :


Super Nt
Compared to the captures I took in my first blog entry on the Super Nt, the differences between higan and the Super Nt as captured are no longer easy to spot.  In fact, the two screenshots are nearly identical.  Some people were disappointed because the Super Nt's color reproduction did not match higan's, but kevtris' fixes (eliminating RGB to YUV to RGB conversion and linearizing the brightness levels) have squarely addressed that issue.  While you may not get perfect reference screenshots from the StarTech USB3HDCAP, you can come very close.  It is certainly good enough for Youtube and Twitch.

If you are unsure if your display supports full range RGB, run Super Metroid.  If the Limited Range RGB option is off on the Super Nt and you see a dark gray background, then your monitor is limited range.  Turn the option on to give a proper black.

The scanlines may appear misaligned in 1080p mode with the default vertical position setting, 42.  Adjust it to 40 and you will have much more nicely aligned scaline to pixel boundaries.  When using the new gamma sliders in v4.3, 1.25 is the equivalent of the old gamma boost turned on when the scanlines were off or when the scanlines were turned on and the gamma boost was off.  1.40 is the equivalent when the gamma boost and scanlines are both on.

Sunday, February 11, 2018

Super Nt Review - The Ideal FPGA Console?

In the four months since the announcement of the Super Nt, there has been a lot of anticipation over the final product.  Will it ship on time?  Will it be as good as the Nt Mini?  Is it worth the money?  Can I put my original hardware away?  Now that I have had mine for about four days by the time this blog entry posts, I can try to answer those questions and give my own impressions of the system.

Sunday, February 4, 2018

StarTech USB3HDCAP Review - A Jack of All Trades?

The StarTech USB3HDCAP (courtesy of
Capturing real hardware has always been something of a challenge, especially when it comes to retro video game consoles and computers.  I have been seeking an affordable "all-in-one" capturing solution for some time.  Recently I read about the StarTech USB3HDCAP and remarked that it could handle odd inputs like 15KHz RGB, 240p Component video and even 320x200 70Hz VGA.  I also read that the StarTech uses the same hardware as the more expensive Micomsoft X-CAPTURE 1 and the less-featured Elgato HD60 S.  I purchased a card recently and found that getting the best out of it is not quite as straightforward as I expected.  Here let me discuss what I have tried and how well it works.

Wednesday, January 24, 2018

sd2snes and MSU-1

The MSU-1 was a software memory controller (mapper) created by byuu for the bsnes/higan emulator to allow for vastly increased storage for SNES software.  The MSU-1 allows for ROMS up to 4GB in size whereas ROMs for the SNES were limited usually to 4MB without extra hardware.  FMV playback became possible due to the DVD-like storage capacity provided by the MSU-1.  In addition to the size increase, the MSU-1 allows for streaming audio in the same format provided by a CD, namely 16-bit uncompressed stereo audio at a 44.1KHz sample rate.  The ill-fated SNES CD-ROM system that Nintendo and Sony collaborated on was not nearly as powerful and would have suffered from noticeable load times.  In this blog post, let's talk about the hardware behind the MSU-1 and some of the more interesting hacks available for it.

Wednesday, January 10, 2018

Famicom & NES - Simple Tweaks to Restore Audio Balance Levels

Audio balance levels in the NES and Famicom can cause some consternation and official hardware is not always consistent.  Here I will discuss some simple modifications you can do to your console to restore the balance between internal audio channels and internal audio channels and external cartridge audio.

Sunday, January 7, 2018

Analogue Nt Mini : Audio Tweaking

The Nt Mini's audio has come under some criticism from such luminaries as the My Life in Gaming channel.  Kevtris has fixed NES audio issues in Jailbreak firmwares v1.0 (MMC5 pulse pitch), v1.3 (audio sweep bug), and v1.8 (crackling static issue).  The excellent MLiG video was using v1.2, so its statements may not hold true for the latest official or jailbroken firmware.  Even so, it is hard to diagnose and fix a problem without being able to define the problem or demonstrate it in a way that would illustrate the problem to the less-technical viewer.  The MLiG video said little more than "We feel that sound might be somewhat further removed from the original hardware experience than any other aspect of the system."  

That MLiG comment is so vague as to suggest that the Nt Mini could be outputting reversed-duty cycle pulse waves like a Famiclone or too low pitched noise as with the NES Classic Edition, which it clearly does not.  Nonetheless, a more articulate critic of kevtris' APU implementation in the Nt Mini and Hi-Def NES Mod is that in certain musical tracks, the triangle and noise channels are too quiet compared to the two pulse channels.  In order to talk about this claim, first we must discuss the mixing levels of NES APU channels.

Friday, January 5, 2018

OPL2/3 Frequency - The 1Hz-ish Difference

The nature of FM Synthesis sound is based on sine waves.  Sine waves create sound by oscillating at a certain frequency and amplitude.  So a sine wave oscillating at a frequency of 440Hz (the pitch) would sound like an A note (A4) hit above the middle C (C4) on the 4th octave of a full 88-key keyboard.  But a sine wave in and of itself is not very interesting musically, so FM synthesis modulates two or more sine waves to create a much more complex sound.  The sine wave's frequency is programmed into the FM Synthesis chip and the modulation of the two frequency, combined with other methods to shape the waveform such as ASDR envelopes, make a sound more complex and realistic than the Programmable Sound Generators that were used in computer and video game music before FM Synthesis became popular in computer music.

Monday, January 1, 2018

Hyperkin's SNES Mouse - A Curious Product out of Left Field

In the middle of 2017, one of the more prominent companies that make retro-video gaming products, Hyperkin, announced a new mouse for the SNES.  The SNES mouse was released with Mario Paint in 1992, and while some other games supported it, it was mainly associated with Mario Paint.  Needless to say this announcement came as something of a surprise, as few people were really clamoring for a replacement SNES mouse.  I was so fascinated by this product that I resolved to obtain one as soon as I could, budget permitting, and review it on this blog.  This Christmas, the budget did permit my acquisition of what Hyperkin calls the "Hyper Click Retro Style Mouse for SNES", so let us proceed to the review.