To ECM or not to ECM?

[bullthorn]

Hope I don't generate a warning, but ...

About to do an upload, and I've observed that after doing an ECM, my image is only 7% smaller (or 31mb less) than before. Doesn't seem worth putting someone through the effort of UNECM'ing. Yes, no?

[Meddle]

You'll save ~31 MB on the upload. If you have small amount of data with the rest being audio tracks, you are not going to gain very much from using ecm. Same goes for iso's with a 2048 byte sector length, you will have an encoded file with exceeding little to no gain. These are usually *.iso and sometimes *.bin/.cue and the .cue can be opened with notepad or any text editor.

[freakboy]

Yeah. Ecm'ing causes more problems than its worth.

[loki1985]

.iso files should never be ECMed, cause they don't contain error correction data.

[bullthorn]

Wouldn't think to use ECM on an ISO since the utility's documentation mentions only .BIN, .CCD, .CDI, and .IMG formats.

The original question was intended to ask if experienced folks think the ECM effort is worth it for such a small saving of 31Mb?

[loki1985]

depends. if i upload 3 ISOs and could save ~50 MB per ISO, i probably would.

it is the uploaders choice mainly i think. if the uploader think it is worth it, he/she should do it.

[zobraks]

ECMing can be very useful: I remember Egon had some BIN files cut to three quarters (or something) of their original size by using ECM.

Cutting off anything bigger than 50 MB justifies the use of ECM in my opinion, specially if you have a lousy upload speed (like I do). Both uploads and downloads are faster if you make those archives smaller, obviously.

[Meddle]

FYI, it also works on Blindwrite and Alcohol 120% images. I usually don't bother unless it is going to have a significant impact on my upload time and on download time for others.