Codecs & containers: MP4 vs WebM
Codecs compress pictures (H.264, VP9, AV1); containers wrap them with audio/subtitles (MP4, WebM, MKV). 'MP4 vs WebM' is usually H.264-in-MP4 vs VP9-in-WebM — different codecs, similar job.
Ship H.264 MP4 for universal playback, VP9/AV1 WebM where bandwidth matters and browsers allow it. Keep a high-quality master; every delivery encode should come from it, never from another delivery file.
Mistakes: renaming .mp4 to .webm (the codec inside didn't change), re-encoding a 2 Mbps file 'to 1080p' (upscaling invents nothing), and 60 fps for talking heads (doubles bytes, adds nothing).
Example: master ProRes 2 GB → H.264 MP4 8 Mbps ≈ 60 MB/min universal; → VP9 WebM ≈ 35 MB/min for the web player. Same shoot, right wrapper each.
Try: MP4 Export · Video Metadata
Frames, FPS and why GIFs are huge
A GIF is a flipbook of full frames with 256 colors max and no real video compression — that is why 3 seconds at 720p weighs megabytes while the same MP4 weighs kilobytes.
Extract frames as PNG for thumbnails/analysis; convert 60→30 fps by clean decimation (drop every other frame) for talking content; reserve GIF for tiny loops, and prefer muted looping MP4/WebM under 5 s.
Mistakes: 30 fps GIFs at 1080p (tens of MB), GIF for gradients/photos (banding + dither mush), and assuming fps conversion adds smoothness (it only removes).
Example: 6-frame contact sheet from a 2-min clip = storyboard in one PNG. The 'GIF version' of that clip at 720p/15fps ≈ 8 MB; muted WebM loop ≈ 400 KB.
Try: Frame Extractor · FPS Converter (note)
Bitrate ladders for the impatient
A bitrate ladder matches bits to pixels in motion: 1080p30 ≈ 8 Mbps H.264, 720p30 ≈ 5, 480p ≈ 2.5, and halve for VP9/AV1. Resolution sets the ceiling; motion sets the need.
Compress by stepping down the ladder (1080→720 saves ~40% with modest visible cost on phones), cap frame rate to content (24/30 unless sports/gaming), and check the device verdict before batch jobs.
Mistakes: starving high-motion scenes (sports at 2 Mbps = blocks), keeping 4K for a 400px embed, and judging quality on a single paused frame instead of playing motion.
Example: 10-min 1080p60 talking video at 12 Mbps = 900 MB. Ladder to 720p30 5 Mbps = 375 MB, visually identical on phones — and it won't melt a low-end laptop.
Try: Compressor Planner · Device Check