No match for digital nes games

[fekir]

For example, from below is not recognized by retroarch, even if it has an entry on no-intro.

https://mhughson.itch.io/from-below

As pointed out in the comments, the original file has a given nes header, while no-intro replaced it with a nes 2.0 header before hashing, as it is done for all nes roms.

As no-intro also provides the hashes for the roms without header, it might make more sense that retroarch calculates the hash for nes files without the header if it does not found any match, ie ignore the first 16 bytes

[RobLoach]

:+1: Feel free to submit it to https://github.com/libretro/libretro-database/blob/master/metadat/homebrew/Nintendo%20-%20Nintendo%20Entertainment%20System.dat

[fekir]

@RobLoach what should I submit? The games are already upstream (nointro in this case)

In this particular case: https://datomatic.no-intro.org/index.php?page=show_record&s=45&n=3375

[RobLoach]

If you have the full No-Intro set, it would be great to update the Headered .dat file for NES: https://github.com/libretro/libretro-database/blob/master/dat/Nintendo%20-%20Nintendo%20Entertainment%20System.dat

Makes sense that From Below isn't showing up, because that was dumped to No-Intro after that .dat file was updated. Clrmamepro's Dir2Dat or similar will do it for you.

[fekir]

There is a misunderstanding.

I have to modify the downloaded rom, otherwise retroarch does not recognize it.

Nes roms have an optional header. No-intro overrides this header.

Thus the hashes do not match.

If I adapt the header, then the rom is recognized.

As no-intro also has headerless hashes, a more robust approach would be to calculate a headerless hash.

[RobLoach]

Correct. Some people have exported some set with the headers over at https://github.com/libretro/libretro-database/blob/master/dat/Nintendo%20-%20Nintendo%20Entertainment%20System.dat

Otherwise, Manual Scan is the best option.

[fekir]

I see, but wouldn't it be better to use the data already available at no-intro instead of duplicating it?

[RobLoach]

The data provided from No-Intro lives at https://github.com/libretro/libretro-database/blob/master/metadat/no-intro/Nintendo%20-%20Nintendo%20Entertainment%20System.dat

RetroArch doesn't currently support skipping the NES header when scanning, hence our need to have a seperate one for with a common set of headered CRCs. The CRCs end up being different, so it's not duplicate.

[fekir]

RetroArch doesn't currently support skipping the NES header when scanning, hence our need [...]

My proposal/feature request was to add that support ;)

The CRCs end up being different, so it's not duplicate

Yes, but it is already possible to recognize those games, it's a duplicated effort.

But maybe this is the wrong repo for adding such feature?

[RobLoach]

Found out what's wrong...

When downloading the sets, we need to check toggle "Pirate, Homebrew, Aftermarket" :facepalm:

[RobLoach]

But even with that, I'm unsure the hashes are the same for the release vs what's in No-Intro.