Container - .mkv and.mp4, these contain various video, audio, and subtitle streams within them. Even the exact same video can be placed in different containers. You can losslessly convert between them with ffmpeg.
Codec - This is what most people mean when they confuse it with the container. The codec is the biggest factor in compatibility with your hardware and system. HEVC(h265/x265) and AVC(h264/x264) are the main ones.
Bit depth - 8-bit/10-bit - Most high quality anime encodes are 10-bit. Converting an 8-bit source to 10-bit might seem counterintuitive if you know a little about transcoding and data loss, but it gives a better result at smaller sizes.
Frame rate - This will usually be 23.976 FPS. Many TVs use interpolation to turn this into 60 fps giving you an artificial sense of smoothness. This is not recommended for anime and should be disabled in settings. 60 FPS encodes are even worse and should be avoided.
Level/Profile - These are specifications within the h264/h265 standard which give an idea of compatibility and specify the maximum resolution and bitrate, for example h264 4.0 = 1080p 30fps 20 Mbps. Higher level/profile = lower compatibility = more processing power needed to decode.
The full information for a video will look like -
x264 High 10 .mkv
(codec) (profile) (bit depth) (container)
Codecs - Audio codecs are divided into lossless (FLAC, TrueHD, DTS-HDMA) and lossy (aac, opus, mp3). While lossless raw video will be multiple GBs per minute, audio is more manageable in size, and you'll see many options with lossless audio.
Lossless audio is unnecessary for most sound systems. Even with the best audiophile grade setup, it's nearly impossible to make out the difference. However, some exceptional music samples exist, which can be used to differentiate lower-bitrate lossy audio by listening to small extracted parts repeatedly. If you want to try, check out these online ABX tests or Foobar plugin with this guide for setting it up. This foobar plugin lets you ABX any two tracks of your choice and produces a verifiable log. If you manage to complete it with a decent probability, do join our discord for some interesting conversation.
A good benchmark for bitrates (stereo/2.0) is -
128 kbps for opus
160 kbps for aac
192 kbps for mp3
For surround audio, multiply with the number of stereo pairs.
Most anime subtitles are in the .ass format, it has better styling options compared to srt. This styling often breaks when there is incompatibility somewhere in the playback process.
Fansubs use a variety of fonts in subtitles. These are bundled within the .mkv files as attachments or provided separately in a folder. The ones given separately can be installed on windows or placed in your player's fonts folder for a quick solution. They should be muxed in for perfect compatibility.
Quality might be somewhat subjective. The best release for the purpose of this guide is an encode which fixes flaws of the raw bdmv while simultaneously not altering the original material too much. There is a difference between obvious flaws which need to be fixed and your subjective preference of how you like the encode. If something apparently looks "better" because it unnecessarily alters the video, then it's not a good indication of quality. These statements might seem too complicated or a bit vague, I'll try to explain in brief, but this is beyond the scope of a guide for beginners and more into the realm of encoding.
The official BDMV, from the blurays, is itself an encode of the actual source. It often suffers from issues like banding, blocking, noise, aliasing, etc. These might be originating from a variety of reasons. For example, a lot of anime is native 720p and is upscaled to 1080p for the bluray. Even if issues aren't present in the bdmv, they can appear in the encode because of compression. This fixing is called filtering, a step which comes before encoding. The video is filtered with Avisynth/Vapoursynth before passing it on to the encoder.
BDMV - A simple complete copy of the bluray. It's used as a source for making another release or encoding, this is not useful for watching.
These can be found on U2 (Chinese-Private), Skyeysnow (Chinese-Open) and nyaa (usually without seeds). Release groups don't matter for bdmvs because they're all the same unless the files are corrupted. JPBDs often have better quality than USBD because of more bitrate devoted to the video instead of multiple(dub) audio tracks. In some cases, blurays from Italy or other countries might have the best quality.
BDRemux - The BDMV is losslessly packaged into mkv files for ease. The sizes are huge, just like bdmvs.
BDRip - An encode made directly from the BDMV/BDRemux. This is the only kind of encode considered good quality.
Most can be found on nyaa with some rare stuff on rutracker(Russian). The direct encode is usually a raw without subtitles and is used by remuxers or fansubbers to make a release. The groups can be roughly rated as -
Excellent - Beatrice-Raws, Kawaiika-Raws, SCY
Good - Raws-Maji, VCB-Studio
Okay - Snow-raws, ANK-raws, Reinforce, LowPower-Raws, Moozzi2
Fansub groups like Coalgirls, Commie, Doki etc. also have their own encodes, but their main contribution is subtitles. These subtitles are taken by remux groups and combined with good video and multiple subtitle/audio options to make a complete release. Sometimes they use their own encodes. They'll usually mention all sources used for the release in the description.
Examples of good remux groups are - Kametsu, CTR, YURI, pog42, Arid, ARC, Mysteria, Drag, UDF, NH, KH.
WEB-DL - Until the blurays are released, this is the only source available for new airing anime. Note that this is not a WEBRip, as in a screen capture. The ones released by reliable groups are always direct WEB-DLs from sources like Crunchyroll or Funimation. The quality will be the same no matter which group releases these, however they often go down and reliability is a factor when you want airing anime in the shortest time possible. The most reliable one right now is SubsPlease.
Re-encode - Marked red on nyaa, these are usually encodes of a BDRip, WEB source or even worse. Encoding is a lossy proceess and information is lost at every stage. The same encode made from the BDMV instead of a BDRip would've been better quality. Re-encoding is considered a bad practice.
Mini encode - These are around 500mb or lower, they can be either a BDRip or a re-encode. Despite a bad reputation, the minis which are not re-encodes can be a decent option for those low on storage or bandwidth. Mini groups -
Good - Judas (new)
Decent - Akihitosubs, DB, Ember, Nep_Blanc
Bad - Judas (old), Cleo, Reaktor, Cerberus. Their video might be bad, but Cerberus and Reaktor often pick good subtitle sources.
Trash - DKB, HR, SSA, FFA, YuiSubs and any other group using NVENC.
Note that this tier list is valid only for BD sourced encodes and not airing anime. The order of quality for WEB releases is -
Subsplease/Erai 1080p > Subsplease/Erai 720p > All mini encodes.
If you're in a rush to get something, try searching on nyaa with the recommended release from -
The first one is geared more towards video quality than the best subtitles. A lot of releases were compared by various people and compiled into these sheets to make it easier for you. However, these don't cover all the anime that exists. Subtitle preferences are subjective and the author's might not match with your own or the best video might not be compatible with your setup. It's always better to have an idea about these things yourself so you can always find what you need.
The main source for finding torrents is nyaa.si, you already have a general idea about the codecs, quality and release groups from the sections above. These 3 things are what we'll use to quickly find the best release for any anime. Nyaa search is simple and limited, but it's enough for finding anything, given that the uploader correctly tags the release.
First, change the All Categories option to
Anime - English Translated. It can be set to just
Anime to include english, raws and other languages. The two useful search operators are
AND is already implicit in every search. For example -
"Attack on Titan"|"Shingeki no Kyojin" will return results that match either
- is useful when you want to exclude something. When I try to search for an anime titled just
Monster, the results are flooded by Pocket Monsters episodes. This can be solved by changing the search to
Once you have the search results, they are sorted by date (newest) by default. Sorting by seeds or completed downloads might help in finding the best release.
For a complete example, let's take KonoSuba, the long title is complicated enough to make searching hard. Suppose I want to watch this on a TV, and a compatibility check reveals that I can't play x264 10-bit(hi10p) . For the video, hevc/x265 10-bit gives me the best size/quality. And I want the superior video from a bluray, with fansubs, instead of a web release. For some reason, I also desire flac. So my search becomes
Konosuba BD 1080 hevc flac
Most releases are tagged both hevc and x265, explicitly mentioning only 265 like
Konosuba BD 265 flac will also give you some results where the uploader forgot to tag hevc. If I don't want flac, it'll be
Konosuba BD hevc -flac or
Konosuba BD hevc opus. There's still a problem in this search, we used
konosuba instead of the full name and some results are missing. Changing it to
Kono BD hevc flac matches everything. Now we can sort the results and immediately see one by kawaiika-raws. Aware of the fact that they usually have the best video and often pick good fansubs, you can safely download it.
This was just to provide a better idea of the process, most actual searches are easy and rarely need anything beyond
Anime name BD or
Anime name hevc for smaller sizes.
Older anime was subbed by a variety of fansub groups. Every good release will mention the sources used for subtitles, the edits made, and often describe their choice of subtitles. A very good resource for fansub reviews was MyAnimeList. They removed the fansub reviews section a few years ago towards their goal of legitimization, since fansubs are associated with piracy. Luckily, the data was archived and can be brought back on the MAL page itself through this. Fair warning, the reviews are mostly filled with hate and trolls but often give you an idea of which group used which script. You can also make out the kind of translation and how much it is localized.
Localization means changing cultural references and puns to fit the english context, but too often it becomes more about the American context and fansubs get riddled with memes. A degree of localization is always involved with translation to make sure the dialogue flows smoothly, but too much of it might be a problem for some. These two websites provide information and comparisons between various groups doing any anime -
Most newer fansubbed anime is some variation of edited official subs from CR or Funi. These edits are usually range between excessive localization by completely eradicating and replacing the idea of Japan with America or untranslation by changing random phrases and lines back to Japanese. Most actual fansubs lie somewhere in between these extremes. After looking at the work of a few groups, you'll be able to figure out who has a tendency to do what.
AnimeTosho is a very useful resource for grabbing just the subtitles from any release on nyaa. You search the title as it is on nyaa and after opening the page you'll see
All Attachments near the bottom. This will download all subtitles and fonts extracted from that release. It's also useful to get the mediainfo when the uploader hasn't posted it, to do this, just click on any of the mkv files in the torrent and you'll get details about it. Animetosho is also a DDL site which uploads torrents from nyaa to various hosting services. There's also an NZB option, but none of the file hosts last for long.
XDCC - Downloads over IRC offered by many groups, useful to obtain content with dead torrents.
Anichiraku (private) - Stuff from nyaa and other places mirrored to google drive for fast direct downloads.
Animetosho - Mirrors most torrents posted on TokyoTosho, Anidex and Nyaa's English translated anime category onto various file hosting services, as well as usenet. Screenshots, mediainfo, subtitles are also extracted and posted.
Anime usually has .ass subtitle styling, while the subs will show up on most TVs and players (plex, emby, jellyfin etc.), the typesetting or overlapping dialogue is sometimes broken. This is especially a problem if you're watching fansubs. Kodi is one of the few players which supports proper ass rendering. Note that the player is separate from the kodi media server and can even be used with plex.
On some releases(like coalgirls), the OP/ED are removed from the episodes and placed into separate files. These files are then linked to the appropriate position in the episodes where they are supposed to play. While this is a great idea to save space, unfortunately, it doesn't work on a lot of players and the OP/ED is never played. If you notice this while watching anime, OCs are the most probable cause.
Fix ordered chapters using UnlinkMKV
Matroska(mkv) is a very versatile container. It can contain multiple streams of video, audio, subtitles, and other attachments. The process of taking these streams, adding or removing some, and bundling them into a new mkv is called muxing. In general, you could be muxing any format, but for anime we'll mostly be dealing with mkv. It's useful when you want to use subtitles from a different release with what you already have downloaded, or to remove the extra english audio tracks to save space. Note that this is a lossless process different from encoding and takes only a few seconds.
Mkvtoolnix is the best tool for all kinds of muxing. The equivalent cli option is mkvmerge (installed with mkvtoolnix) or ffmpeg. The process can also be done in batch for a whole folder at once. Example (paste in cmd in that folder) -
FOR /F "tokens=*" %G IN ( 'dir /b *.mkv ') DO ffmpeg -n -i "%G" -map 0:v:0 -map 0:a:1 -map 0:s:2 -map 0:t? -c copy "%~nG .mkv"
This will copy the first video, second audio, third subtitle stream and all attachments, which are usually the japanese ones in dual audio releases. You can check the stream number with mediainfo. The index starts from zero so
-map 0:s:0 would select the first subtitle stream.
-map 0:t? copies the attachments(fonts) if any exist. Understanding more about the ffmpeg map option is helpful here as that is the only part you need to change.
This is used to verify that the files you have are the correct ones, or whether they match with the version released by the uploader. CRCs will change if any part of the file changes, even if you only change one letter in one tag in the file. This allows us to identify files that were changed from the original source or corrupted at some point. However, just renaming the file will not change it. Apart from the numbers included within  at the end of a filename, .sfv (CRC checksum) or .md5 (MD5 checksum) files can also be used for the same purpose. Sometimes a group makes mistakes and wants to correct them by releasing a second version(v2), in this case the changed CRC makes it easy to differentiate between multiple versions.