Video Formats

Video Formats — The Complete Guide (2026)

Everything you need to know about MP4, WebM, MOV, AVI, MKV, WMV, and FLV — codecs, file size, compatibility, and the right format for every use case.

Quick answer: MP4 (H.264) for universal compatibility — plays on every device and platform without additional software. WebM for web video (smaller files, browser-native). MOV for Apple and Final Cut Pro editing. MKV for home theater and media servers. AVI is a legacy Windows format. WMV for older Windows systems. MP4 is the safe default for sharing video anywhere.

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Container vs Codec — The Key Distinction

Understanding video formats requires separating two concepts: the container (the file format) and the codec (the compression algorithm used on the video data inside).

Container: MP4, MOV, MKV, AVI — these define the file structure and what metadata/audio tracks are supported.
Codec: H.264, H.265/HEVC, VP9, AV1 — these define how the video is compressed. Same codec can live inside different containers.

This is why a MOV file from an iPhone and an MP4 from a camera can both use H.264 inside — and why "converting MOV to MP4" sometimes only changes the container without re-encoding the video at all.

Format Comparison at a Glance

Format	Container / Codec	Best For	File Size	Compatibility
MP4	MPEG-4 / H.264 or H.265	Universal sharing, streaming, social media	Medium	Universal
WebM	WebM / VP8, VP9, or AV1	Web video, HTML5 player	Small	Browsers, Android
MOV	QuickTime / H.264 or ProRes	Apple devices, Final Cut Pro editing	Medium–Large	Apple-native, Win with codec
AVI	AVI / Various (Xvid, DivX, H.264)	Legacy Windows, older software	Large	Windows-native, limited mobile
MKV	Matroska / Any codec	Home theater, media servers, archiving	Varies	Desktop players, Plex/Jellyfin
WMV	ASF / Windows Media Video	Older Windows environments	Medium	Windows only (largely obsolete)
FLV	Flash Video / VP6, H.264	Legacy web (Flash era, pre-2015)	Small	Obsolete — Flash is dead

Format Deep-Dive

MP4 — The Universal Standard

MP4 (MPEG-4 Part 14) paired with H.264 video is the closest thing to a universal video format. It plays on every smartphone, smart TV, browser, and social media platform. At H.264 CRF 23, a 1080p video is typically 1–3 GB per hour — manageable for most uses. H.265 (HEVC) doubles the compression efficiency but has less hardware support, especially on older devices. For sharing, MP4/H.264 is always the safe choice.

WebM — The Web-Native Format

WebM was created by Google specifically for HTML5 video. It uses the VP8, VP9, or AV1 codec — all royalty-free — and is designed for efficient streaming in browsers. VP9 WebM is about 20–30% smaller than H.264 MP4 at comparable quality. WebM is the preferred format for web video if you control the delivery environment. It does not play natively on older iOS or Windows systems without additional software.

MOV — Apple's Professional Format

MOV (QuickTime Movie) is the native format for Apple's Final Cut Pro and is the default recording format on older iPhones (newer iPhones record HEVC by default). MOV files typically contain H.264 or ProRes video — ProRes is a high-bitrate production codec used in professional video editing. On Windows, MOV requires QuickTime or codec packs. For sharing, convert MOV to MP4; for editing on Apple hardware, MOV is fine as-is.

MKV — The Flexible Archive Format

MKV (Matroska) is an open container that supports unlimited audio tracks, subtitle streams, chapter markers, and virtually any video codec. It is the dominant format for high-quality movie rips and home theater archives. Media server software (Plex, Jellyfin, Kodi) handles MKV natively. The downside: most smartphones and online platforms do not accept MKV uploads. For distribution, convert to MP4; for local archiving, MKV is excellent.

AVI — Windows Legacy

AVI (Audio Video Interleave) is a 1992 Microsoft format. It remains in use because of its universal Windows compatibility, but it is technically outdated — limited container features, large file sizes, and no native support for chapters or multiple audio streams. If you receive an AVI file, convert it to MP4 for modern use. Do not produce new content in AVI unless specifically required by legacy software.

WMV — The Declining Windows Format

WMV (Windows Media Video) was Microsoft's proprietary answer to MP4 in the early 2000s. It plays natively on Windows but has virtually no support on macOS, iOS, or Android. The format offers no advantages over MP4/H.264 today. Convert any WMV files you receive to MP4 for wider compatibility.

FLV — The Flash Relic

FLV (Flash Video) was the dominant web video format from roughly 2005–2015 when Adobe Flash was ubiquitous. Adobe officially killed Flash support in 2020. FLV files from that era can still be converted and played in desktop video players, but the format is completely obsolete for new content. Convert to MP4 immediately.

Convert Between Video Formats

All conversions run in your browser using FFmpeg.wasm — no upload, no account required.

MP4 → WebM→ WebM → MP4→ MOV → MP4→ AVI → MP4→ MKV → MP4→ WMV → MP4→ FLV → MP4→ MP4 → GIF→ GIF → MP4→ MP4 → MP3→ MP4 → AVI→ MOV → GIF→

Convert any video format

MP4, WebM, MOV, AVI, MKV, WMV, FLV — all conversions run entirely in your browser. No software download required.

Open Video Converter → All Tools →

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Frequently Asked Questions

MP4 with H.264 encoding is the safest format for sharing. It plays on every device, browser, and platform — Windows, macOS, iOS, Android, YouTube, TikTok, Instagram, and Twitter all accept MP4. For web embedding, WebM with VP9 is slightly more efficient. For maximum compatibility, stick to MP4/H.264 at 1080p and you will never have a playback issue.

MP4 and MOV are both container formats that can hold the same H.264 or H.265 video codec inside. MOV was developed by Apple and is the native format for Final Cut Pro and older iPhones. MP4 has broader compatibility across Windows, Android, and non-Apple software. A MOV file from an iPhone often contains H.264 video — identical to what is inside an MP4 — so "converting" MOV to MP4 sometimes just renames the container without touching the video data.

MKV supports more features than MP4 — multiple audio tracks in different languages, embedded subtitle files, chapter markers, and virtually any video codec. For home theater and media server use (Plex, Jellyfin, Kodi), MKV is preferred. For sharing video online or uploading to social media, MP4 has far better compatibility. The video quality inside both containers depends on the codec and encoding settings, not the container itself.

To minimize quality loss: use the same codec as the original (or H.264/H.265 for broad compatibility), set a low CRF value (18–23 for H.264 — lower means better quality), and avoid unnecessary re-encoding. When just changing the container (e.g., MOV to MP4 when both contain H.264 inside), a lossless stream copy changes the container without touching the video data at all — zero quality loss. Convertlo's video converters automatically detect when stream copy is possible.