MP4, MOV, MKV, Codec — What They Actually Are (Finally Explained Simply)
This video explains how digital video files actually work, including what codecs are, what container formats do, and why the difference between the two matters for anyone who watches, uploads, or edits video.
Digital video is made up of millions of individual frames played back in rapid sequence to create the appearance of motion. Because storing all of those frames in raw form would consume enormous amounts of storage — up to 15 gigabytes per minute for basic HD footage — video files rely on compression systems called codecs to reduce file size while preserving visual quality. A codec, short for coder-decoder, uses mathematical rules to remove redundant visual data both within individual frames and across frames over time. On top of that compression layer, a container format bundles the compressed video, audio tracks, subtitles, metadata, and other elements together into a single file.
The video walks through the most widely used codecs, including H.264, H.265 (also called HEVC), VP9, AV1, and ProRes, explaining what each one is designed to do and where it is commonly used. It also covers the most common container formats — MP4, MOV, MKV, AVI, WebM, WMV, and FLV — describing the practical differences between them and which formats work best in which situations. A key point addressed in the video is the widespread confusion between codecs and containers: the two are entirely separate components, and understanding the distinction helps explain why some video files fail to play on certain devices or applications. The video also explains why professional video editors often work in less-compressed editing codecs like ProRes or DNxHD before exporting a finished file to a distribution codec like H.264, and why AV1 is becoming the dominant codec across major streaming platforms.
What is covered in this video:
How digital video is constructed from individual frames played back at speeds between 24 and 60 frames per second
Why raw uncompressed HD video can consume up to 15 gigabytes per minute and why compression is necessary
How codecs use temporal compression and spatial compression to reduce file size without visible quality loss
What H.264 is and why it remains the most widely used video codec on the internet today
How H.265 (HEVC) achieves the same visual quality as H.264 at approximately half the file size
What VP9 is and how Google uses it extensively across YouTube
Why AV1, backed by Google, Netflix, Apple, and Amazon, is considered the next dominant codec for streaming
What ProRes and DNxHD are and why professional video editors rely on them during the editing process
What a container format is and how MP4, MOV, MKV, AVI, WebM, WMV, and FLV differ from one another
Why the file extension on a video file does not guarantee what codec or data is actually stored inside it
Why VLC Media Player can open nearly any video file regardless of format or codec
The recommended export settings for uploading video to YouTube, including MP4 container with H.264 video and AAC audio
How AI-based video compression is beginning to outperform traditional rules-based codecs by predicting frame content
Mentioned in this video: H.264, H.265, HEVC, VP9, AV1, ProRes, DNxHD, AAC, MP4, MOV, MKV, AVI, WebM, WMV, FLV, MPEG-4, Matroska, YouTube, Netflix, Amazon, Apple, Google, Microsoft, Adobe Flash, VLC Media Player, QuickTime, Final Cut Pro, Windows Media Video, temporal compression, spatial compression, frames per second, bitrate, video codec, video container, video encoding, video transcoding, file extension, codec decoder, video compression, digital video format