Video / Audio Codec Explained (Attention Uploaders)

Recently I've noticed many uploaders do not include video codec or put wrong codec in the title. We do not require Audio codec in the title but video codec is mandatory. So here's a brief description about all the popular codecs and how to understand which codec does your torrent have.

AVC / x264 / H.264
H.264 or MPEG-4 Part 10, Advanced Video Coding (MPEG-4 AVC) is a block-oriented motion-compensation-based video compression standard. As of 2014, it is one of the most commonly used formats for the recording, compression, and distribution of video content. It supports resolutions up to 8192×4320, including 8K UHD. (Wiki)
H.264 / AVC in the title indicates the file is untouched/not encoded. Blu-ray Remuxes / WEB-DL / WEB-HD are untouched and should contain H.264/AVC in the title.To understand if the file is untouched or not, check full mediainfo of your file, if you don't see any encoding settings/x264 Info then the file is most probably untouched. x264 indicates the file is encoded. WEBRip / BluRay Encode / Re-encode / HDRip are encoded and should contain x264 in the title. All encoded file should contain encoding settings in the mediainfo. Check that before you upload anything. Some release groups like RARBG, puts H.264 in the title on Re-encoded file, this is incorrect and you should not follow this. All MkvCage & YTS releases are x264.
Netflix WED-DL's are untouched but recently Netflix updated their settings and now their WEB-DLs contains x264 settings. So x264 / H.264 both are correct for Netflix/NF WEB-DLs

HEVC / x265 / H.265
High Efficiency Video Coding (HEVC), also known as H.265 and MPEG-H Part 2, is a video compression standard, one of several potential successors to the widely used AVC (H.264 or MPEG-4 Part 10). In comparison to AVC, HEVC offers about double the data compression ratio at the same level of video quality, or substantially improved video quality at the same bit rate. It supports resolutions up to 8192×4320, including 8K UHD. (Wiki)
Same description for H.265/HEVC too. H.265 / HEVC in the title indicates the file is untouched/not encoded. Blu-ray Remuxes / WEB-DL / WEB-HD are untouched and should contain H.265/HEVC in the title.To understand if the file is untouched or not, check full mediainfo of your file, if you don't see any encoding settings/x265 info then the file is most probably untouched. x265 indicates the file is encoded. WEBRip / BluRay Encode / Re-encode / HDRip are encoded and should contain x265 in the title. All encoded file should contain encoding settings in the mediainfo.

Xvid

Xvid (formerly "XviD") is a video codec library following the MPEG-4 video coding standard, specifically MPEG-4 Part 2 Advanced Simple Profile (ASP). It uses ASP features such as b-frames, global and quarter pixel motion compensation, lumi masking, trellis quantization, and H.263, MPEG and custom quantization matrices. (Wiki)
Xvid is mostly used to encode SD and for DVDs. To understand if your file is Xvid or not check full mediainfo. Video format should contain the info. Also Xvid videos are .avi

VP9
VP9 is an open and royalty-free video coding format developed by Google.

VP9 is the successor to VP8 and competes mainly with MPEG's High Efficiency Video Coding (HEVC/H.265). At first, VP9 was mainly used on Google's video platform YouTube. The emergence of the Alliance for Open Media, and its support for the ongoing development of the successor AV1, of which Google is a part of, led to growing interest in the format (Wiki)
To understand if the file is VP9 or not, just check the full mediainfo. VP9 can only be found on YouTube videos.

Brief information about some popular audio codecs:

AC-3 / Dolby Digital Audio (DD)
AC-3, also known as Dolby Digital , is a perceptual digital audio coding technique that reduces the amount of data needed to produce high-quality sound. Perceptual digital audio coding takes advantage of the fact that the human ear screens out a certain amount of sound that is perceived as noise. Reducing, eliminating, or masking this noise significantly reduces the amount of data that needs to be provided. Dolby Laboratories developed two other perceptual coding systems, AC-1 and AC-2. Building upon Dolby's two previous coding systems, AC-3 was the first coding system designed specifically for multichannel digital audio. AC-3 is the sound format for digital television ( DTV ), digital versatile discs ( DVD s), high definition television ( HDTV ), and digital cable and satellite transmissions.(Techtarget)
You can put either AC-3 or DD in the title. No need to put Dolby Digital.
Example: House of Cards (US) S06 NF WEB-DL DD5.1 x264-NTG

E-AC-3 / Dolby Digital Plus Audio {DD(P/+)}
Dolby Digital Plus, also known as Enhanced AC-3 (and commonly abbreviated as DD+ or E-AC-3, or EC-3) is a digital audio compression scheme developed by Dolby Labs for transport and storage of multi-channel digital audio. It is a successor to Dolby Digital (AC-3), also developed by Dolby, and has a number of improvements including support for a wider range of data rates (32 Kbit/s to 6144 Kbit/s), increased channel count and multi-program support (via substreams), and additional tools (algorithms) for representing compressed data and counteracting artifacts. While Dolby Digital (AC-3) supports up to 5 full-bandwidth audio channels at a maximum bitrate of 640 Kbit/s, E-AC-3 supports up to 15 full-bandwidth audio channels at a maximum bitrate of 6.144 Mbit/s (Wiki)
Check full mediainfo to understand if your video has AC-3 or E-AC-3. You should use either DDP or DD+ in the title for E-AC-3 audio
Example: The Little Mermaid 2018 1080p NF WEB-DL DD+5.1 H.264-NTG

AAC (Advance Audio Coding)
Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at the same bit rate. The confusingly named AAC+ (HE-AAC) does so only at low bit rates and less so at high ones.
AAC supports inclusion of 48 full-bandwidth (up to 96 kHz) audio channels in one stream plus 16 low frequency effects (LFE, limited to 120 Hz) channels, up to 16 "coupling" or dialog channels, and up to 16 data streams. The quality for stereo is satisfactory to modest requirements at 96 kbit/s in joint stereo mode; however, hi-fi transparency demands data rates of at least 128 kbit/s (VBR). Tests of MPEG-4 audio have shown that AAC meets the requirements referred to as "transparent" for the ITU at 128 kbit/s for stereo, and 320 kbit/s for 5.1 audio.
AAC is the default or standard audio format for YouTube, iPhone, iPod, iPad, Nintendo DSi, Nintendo 3DS, iTunes, DivX Plus Web Player, PlayStation 3 and various Nokia Series 40 phones. It is supported on PlayStation Vita, Wii (with the Photo Channel 1.1 update installed), Sony Walkman MP3 series and later, Android and BlackBerry. AAC is also supported by manufacturers of in-dash car audio systems.(Wiki)
Check full mediainfo of your file to see if it has AAC audio or not. Do not use DD or Dolby Digital in the title if your file has AAC audio. Some Indian Release groups puts DD or Dolby Digital Audio in the title while having AAC audio. Be careful about this while uploading.

Audio Channels
Check full mediainfo of your file. On the audio part, there should be Channel(s) info. Channel info should be posted after audio codec. Example: AAC2.0 , DD5.1 , TrueHD 5.1 etc. Here is a list of what you should put in your title according to your mediainfo:

• 1.0 if there is only one channel
• 2.0 for 2 channels
• 2.1 if there are 3 channels
• 3.1 if there are 4 channels
• 4.1 if there are 5 channels
• 5.1 if there are 6 channels
• 6.1 if there are 7 channels
• 7.1 if there are 8 channels

Video codec is mandatory for every single Movie/TV/Anime/Award/Sport content. A pack of mixed codecs, for example: x264+x265 or x265+Xvid etc are not allowed. So avoid making such packs. Upload them separately. We do not require audio codec in the title but it would be nice if you put that. Just make sure you are putting the correct one. Specially while uploading Indian Release groups content (DTone/Telly/Hon3y/TamilRockers/TMV etc)