Redump Sega - Mega-CD - Sega CD missing serials

It seems that the way index.js currently works at https://github.com/robloach/libretro-dats is creating issues for some games with alternate versions being misidentified/ignored.

In the case of “Sonic CD (USA)” for Sega CD, the official Redump DAT has three entries (tracklist abridged for readability) :

<game name="Sonic CD (USA)">
		<category>Games</category>
		<description>Sonic CD (USA)</description>
		<rom name="Sonic CD (USA).cue" size="3820" crc="33b99240" md5="638f1e41830319de1914772076096626" sha1="5b085f78a6904d275715dcfeb454ecc262e704e5"/>
		<rom name="Sonic CD (USA) (Track 01).bin" size="139381872" crc="a6184e05" md5="ed96420538f989e94480f810d5f90685" sha1="3c316af52cc9ee8c30976a1cdb66339545dda3bd"/>
		[...]

<game name="Sonic CD (USA) (RE125)">
		<category>Games</category>
		<description>Sonic CD (USA) (RE125)</description>
		<rom name="Sonic CD (USA) (RE125).cue" size="4100" crc="e8a15187" md5="92d0c52b29c25b21e8d0bef3e3086115" sha1="ff275b2a8bf5c301fed311addca55aee8a1a13ab"/>
		<rom name="Sonic CD (USA) (RE125) (Track 01).bin" size="139381872" crc="a6184e05" md5="ed96420538f989e94480f810d5f90685" sha1="3c316af52cc9ee8c30976a1cdb66339545dda3bd"/>
		[...]
		
<game name="Sonic CD (USA) (RE125) (Alt)">
		<category>Games</category>
		<description>Sonic CD (USA) (RE125) (Alt)</description>
		<rom name="Sonic CD (USA) (RE125) (Alt).cue" size="4310" crc="53948c76" md5="ac75d9b8331ba59da608c49e5cc03cb7" sha1="4d190b6a7cc7e2284f7c16f6afaf94ff625dfb8c"/>
		<rom name="Sonic CD (USA) (RE125) (Alt) (Track 01).bin" size="139381872" crc="a6184e05" md5="ed96420538f989e94480f810d5f90685" sha1="3c316af52cc9ee8c30976a1cdb66339545dda3bd"/>
		[...]

All versions share the same “Track 01.bin” checksums. Once parsed with the libretro-dat javascript routine, there is only one entry under “Sonic CD (USA) (RE125) (Alt)” in the libretro redump metadat:

game (
	name "Sonic CD (USA) (RE125) (Alt)"
	description "Sonic CD (USA) (RE125) (Alt)"
	rom ( name "Sonic CD (USA) (RE125) (Alt) (Track 01).bin" size 139381872 crc a6184e05 md5 ed96420538f989e94480f810d5f90685 sha1 3c316af52cc9ee8c30976a1cdb66339545dda3bd )

The difference in this case only appears in Track 13:

<rom name="Sonic CD (USA) (Track 13).bin" size="14013216" crc="c41a848e" md5="f01a263ce6475c1f43871483e5ab68f2" sha1="21dcc020dae2a0d650eed76540b54897d34ee889"/>
<rom name="Sonic CD (USA) (RE125) (Track 13).bin" size="14013216" crc="282d4f23" md5="88107ee77b536248c0b9149ac1c71ea4" sha1="5797d380e8df06f7d83a37ac55b3072f8a3dff57"/>
<rom name="Sonic CD (USA) (RE125) (Alt) (Track 13).bin" size="14013216" crc="8e9aaeaf" md5="c02b110395c9cb8a6a1066eb5c36835c" sha1="6cfbd4139d60eb7762874aa0308a01f40e0e17fc"/>

The same is true of “Layer Section (Japan) (3M)” and “Layer Section (Japan) (6M)” in the Sega Saturn set. Except the differences appear from Track 02.bin.

        <rom name="Layer Section (Japan) (6M).cue" size="2183" crc="4a838a68" md5="2f21a45ccdf5b439a35d0ad0a4b9f99a" sha1="75932d563fb498e77e0a107efca33c034a75b04c"/>
		<rom name="Layer Section (Japan) (6M) (Track 01).bin" size="16779168" crc="07e9d8da" md5="4cb2552702a5767be5b791efad43762d" sha1="d90ef75e7a8d0ff60fceb58d4e534308b85391ea"/>
		<rom name="Layer Section (Japan) (6M) (Track 02).bin" size="5644800" crc="4385448d" md5="f52bb23aaf351581cea09442d74e0981" sha1="76ee44b608700841f89a3b0c325e7ccf691562c5"/>
		

		<rom name="Layer Section (Japan) (3M).cue" size="2183" crc="6f8ecb12" md5="e6ec1fb1245f5a5ff095bfa29f9d62e1" sha1="7905e5451fbcd372905dae9c4ef2339dff271357"/>
		<rom name="Layer Section (Japan) (3M) (Track 01).bin" size="16779168" crc="07e9d8da" md5="4cb2552702a5767be5b791efad43762d" sha1="d90ef75e7a8d0ff60fceb58d4e534308b85391ea"/>
		<rom name="Layer Section (Japan) (3M) (Track 02).bin" size="5644800" crc="ccffab2f" md5="c7edd32ea27e9596546b6bf8d7148784" sha1="cce1afd9f917210cdf061bdf23982f1597e6639a"/>

Sega - Saturn Libretro MetaDAT

game (
	name "Layer Section (Japan) (6M)"
	description "Layer Section (Japan) (6M)"
	rom ( name "Layer Section (Japan) (6M) (Track 01).bin" size 16779168 crc 07e9d8da md5 4cb2552702a5767be5b791efad43762d sha1 d90ef75e7a8d0ff60fceb58d4e534308b85391ea )
)

Could the script entries be based on the cue checksums instead to make sure all versions are accounted for?

[ghost]

Hello again Rob,

Yes, with the current index.js routine, it looks like titles with similar Track01.bin checksums are overridden/assimilated under one single title. For example, in the case of Sonic it is “Sonic CD (USA) (RE125) (Alt)”. This was the main focus of my initial post above. I originally thought that having the index.js pick up the CRC of the CUE would solve the problem (and it does in a way since all 3 versions are accounted for in the libretro-DAT if you change the script to retain the CUE checksum instead of Track01), but I know understand RetroArch has another way to identify CD-based games (serial/magic number).

Perhaps when there are duplicates found, it should pick the one with the least amount of characters in its title?

This unfortunately won’t work in the case other games/sets. Case in point Layer Section (in the Saturn set). See first post – “Layer Section (Japan) (6M)” and “Layer Section (Japan) (3M)”.

Couldn’t there be a switch in RetroArch to let the user pick up the scan method? (serial or checksums).

For reference, here are the libretro-DAT files I created with CUE checksums: Sega CD Saturn

EDIT: readability, links to DAT files

[pkos]

Could the script entries be based on the cue checksums instead to make sure all versions are accounted for?

This PR updates the scanner code to check Redump serials, when it cant identify a disc a crc is generated. The logs and playlists now contain these serials. If you wish, please clone the PR and test this issue again. Also, Rob has updated the databases to contain serials.