For every fansubbed anime episode that has been released by a group, the episode must come from some electronic source, whether it is from a television broadcast that has been captured onto a hard drive or a DVD source that has either been purchased or ripped into an ISO file format. Without the raw video, there is no anime release. That video must be obtained somehow, and that's where the raw provider (RP) comes in. For DVD ISOs, the role is pretty simple: just download the DVD image of the anime or movie that will be subbed, which will go to the encoder for processing. However, for television captures, however, there are many different cappers (people who capture the anime video straight from broadcast) in Japan who use different hardware, different codecs, and different filters on the raws before they make the episode available for download. Because the episode from different cappers are essentially different and can vary greatly, raw providers must download from different cappers/sources to choose the best video quality. This choice is usually made in collaboration with the encoder. However, several main things to notice with raws is whether the image has been over-sharpened (or warp-sharped), over-blurred, and if there are any nasty artifacting, shadowing, interlaced frames and the like. It usually the encoder's call on what raw to use, however. The RP just narrows down the selection for the encoder.
There are a few sources for obtaining raws. Since the episodes are Japanese, raws will not be found on American or English-based p2p and other file distribution networks like e-mule and the like. The raws will only be found on Japanese distribution programs like Share and Winny. There have also been .torrent sources from "raw groups." These groups have been generally discouraged by many veteran groups, but they are still used by smaller groups that look for quick workable raws, but not necessarily the best. Another requirement for raw hunting is high download bandwidth since so many version of an episode need to be downloaded. As an example, I hunted for Kanon (2006) episode 01 downloads when the anime first came out, and I easily downloaded 4GB of different raws from different sources. Pretty high bandwidth is required for uploading the final few raws to the encoder or group FTP for a final decision on the raw. At times, the encoder is also the raw hunter, which cuts out an upload step to the FTP, but there's still the step of uploading the work raw to the FTP, which still requires a fairly high upload speed. The encoder will be discussed in detail in a later post, which will explain this part of the process a little more.
All in all, raw hunting isn't difficult, though I've only been able to get Winny to work and it's generally enough, but it isn't a trivial, either. The RP needs to provide good workable raws to the encoder. There's a limit to what the encoder can do to fix up bad raws, so if the RP gives crappy raws to the encoder, the final video will still look bad regardless of what the encoder does.
Required applications: Winny, Share
Required knowledge: knowledge of quality encoding, eg. the ability to spot encoding problems with raws
Other requirements: high bandwidth download and upload to send the raw to the group ftp or encoder. Probably has the highest bandwidth requirement of all staff