![1girl ahoge animated bare_shoulders bouncing_breasts breasts commentary_request demon_girl demon_wings gloves grey_gloves grey_legwear head_wings high_heels highleg highleg_leotard koakuma large_breasts leotard long_hair lowres mp4 necktie pixel_art red_eyes red_footwear red_hair red_neckwear shoes simple_background solo takorin thighhighs touhou very_long_hair walking wings rating:s score:13 1girl ahoge animated bare_shoulders bouncing_breasts breasts commentary_request demon_girl demon_wings gloves grey_gloves grey_legwear head_wings high_heels highleg highleg_leotard koakuma large_breasts leotard long_hair lowres mp4 necktie pixel_art red_eyes red_footwear red_hair red_neckwear shoes simple_background solo takorin thighhighs touhou very_long_hair walking wings](/cdn_image/preview/d8/67/d867dedff131e3543c175915d51e3be6.jpg)
MPEG-4 Part 14 or MP4 is a multi-purpose container format based on Apple's QuickTime format. It is an ISO standard (ISO/IEC 14496-14). It can be used for audio as well as video. It is mostly used to contain H.264 (MPEG-4 Part 10) compressed video with/and/or AAC (Advanced Audio Coding) or MP3 compressed audio. Modern browsers can directly stream MP4 files.
H.264 is the most used video format for video streaming while AAC is the successor to MP3, being more efficient than its predecessor. MP3 is still by far the most used audio format.
This tag implicates animated (learn more).