Containers.

Container formats — MP4/fMP4, MPEG-TS, MKV/WebM, MOV.

May 8, 2026·10 min read·fmp4 / cmaf / container

Fragmented MP4 (fMP4) segment construction — moof, mdat, tfdt, and styp

Practical reference on fragmented MP4 segment internal structure — moof + mdat box pairs, init segment vs media segments, tfdt absolute timing, styp self-identification, sidx for byte-range fetching.

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May 8, 2026·8 min read·mp4 / faststart / container

MP4 faststart — moov at front, why it matters, and how to set it

Practical reference on MP4 faststart — moov at end vs front, ffmpeg movflags=+faststart, why progressive streaming requires it, the one-pass vs two-pass tradeoff.

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May 8, 2026·9 min read·mxf / container / broadcast

MXF — the broadcast and post-production container nobody outside the industry uses

Practical reference on MXF (Material Exchange Format) — SMPTE 377, operational patterns (OP1a, OP1b, OPAtom), codec support, broadcast and post-production use, vs MP4 / MOV.

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May 8, 2026·9 min read·mov / quicktime / apple

MOV (QuickTime) — Apple's container format and the editorial-workflow standard

Practical reference on Apple QuickTime MOV — atom-based structure, the relationship to MP4, ProRes/DNxHR delivery, edit lists and timecode, when to use MOV vs MP4.

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May 8, 2026·9 min read·mkv / webm / matroska

MKV and WebM — the open container format and its browser-friendly profile

Practical reference on Matroska and WebM containers — EBML format, segment/cluster/block structure, codec flexibility, browser support, when MKV/WebM is the right choice vs MP4.

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May 8, 2026·10 min read·mp4 / fmp4 / container

MP4 / fMP4 — the universal video container and the streaming-friendly fragmented variant

Practical reference on MP4 — ISO Base Media File Format, box structure (ftyp/moov/mdat), fragmented MP4 for streaming, codec compatibility, CMAF derivation, HLS and DASH integration.

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