In other words, what are some factual, non-subjective reasons why you might choose (or avoid) a certain file format ? (For example, disk usage, audio accuracy, emulator compatibility, etc).

I'm primarily curious about the Sega and Sony CD-based consoles (SegaCD, Saturn, Dreamcast, and Playstation). Unfortunately, not many people seems to know the technical specifications of the various file formats: bin, iso, bin/cue, iso/cue, img/sub/ccd/cue, iso/cue/wav, iso/cue/mp3, cdi, gdi/bin/raw.

  • 2
    "Best" probably depends "does this particular emulated application need specifics of how data is stored on the CD": It's basically a tradeoff between size and detail. Or is the focus of the question "how does a CD work, and how do those various abbreviations fit into that, and what kind of data they represent?" If yes, please edit the question. Basically "iso" is the CD-DA high-level filesystem format, "cue" a list of tracks and their positions, "wav" and "mp3" are alternative audio formats.
    – dirkt
    May 15 '19 at 5:16
  • I remember that ISO format is unadapted for (most) Playstation games, because they store meaningful information in the sector's checksum data, and ISO format scrap this data. This is why games are (mostly) riped as bin/cue format. Only games with neither video nor streamed audio data could come without this data but I don't know if there's any.
    – Bregalad
    May 15 '19 at 6:08
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    I think for should edit your question title, because best is asking for an opinion. May 15 '19 at 6:46
  • Yes, best is asking for an opinion, BUT... "And why ?" is asking for the facts that you base your opinion on. For example, only experts are allowed to give opinionated testimony in court, however, if you question them further on the details, most competent experts should be able to explain the facts that led them to their conclusion(s). I also immediately re-worded the question ("in other words") as the first sentence in order to clarify, but I'm open to suggestions for even better wording ?
    – Nikolaii99
    May 16 '19 at 10:28

Due to the nature of optical media, the answer is probably whatever format lets you play the game as close as possible to how the original was.

Optical media can have many "out of band" features, that is things that are not part of the raw data stream encoded on the disk. Often they can only be read by specific drives, and in some cases only the special ones in the consoles themselves.

For example, the PlayStation and GameCube both used modified disks to make them difficult to copy. In the case of the PlayStation the disc has a specially encoded wobble that normal CD burners cannot replicate, and which normal CD drives don't pass on to the computer anyway so which is not easy to even read. The PlayStation itself doesn't allow software to read the wobble either, only the CD drive firmware checks for it and signals present/not present to the system. So even if a format existed for storing the wobble information, there is no practical way to read it.

So the answer to the question really is to use whatever lets you play the game. Once you have bypassed the copy protection system there is little difference between the formats, certainly in terms of how the resulting burned or emulated discs play.

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    FWIW, the groove's wobble is used to store the ATIP region normally only found on recordable media. The ATIP holds information about the physical blank, such as the length of the spiral, which isn't otherwise useful for a pressed CD. Somewhat clever to use it for copy-protection data.
    – fadden
    May 15 '19 at 14:38

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