Clapr Blog
Blog
Browser-native video tips, FFmpeg internals, and Clapr product updates.
FFmpeg yuv420p for X (Twitter) Video: The Pixel Format Rule
X's media docs allow exactly one pixel format. Here is the FFmpeg command that converts 4:2:2 or 4:4:4 footage, and why a rejected upload explains nothing.
FFmpeg Faststart for YouTube: Moov Atom at the Front
YouTube's recommended settings ask for the moov atom at the front and no edit lists. Here is the FFmpeg command, and an honest read of what it fixes.
Burn a Zoom Transcript Into a Video With FFmpeg
Zoom embeds the transcript in your recording but hides it by default. Here is the ffmpeg command that renders that VTT permanently into the picture.
FFmpeg Settings to Encode Video for X (Twitter)
X's media docs list six encoding rules stated with the word "must". Here is each one quoted verbatim and mapped to the FFmpeg flag that satisfies it.
FFmpeg: Extract OBS's Second Audio Track With -map 0:a:1
OBS's Advanced Output Mode records up to 6 audio tracks, but a player plays one at a time. Here is the ffmpeg -map command that pulls track 2 out.
FFmpeg Compress Video for Telegram: The Command, Explained
Telegram allows 2 GB per file, so size is rarely the problem. Here is the FFmpeg command, and why it must output MP4, H.264, and keep an audio track.
FFmpeg GIF Palette: The High-Quality GIF Command, Explained
The two-step palettegen/paletteuse command with every flag explained from FFmpeg's own docs — including the lanczos flag that is now marked deprecated.
HandBrake RF vs FFmpeg CRF: The Same Number, Explained
HandBrake's docs call the RF slider a Constant Rate Factor, sometimes abbreviated CRF. What that means when you move a value to ffmpeg -crf.
VLC sout Transcode on the Command Line: Every Flag
The full VLC --sout transcode syntax, flag by flag, from VideoLAN's own docs — including the 96 audio bitrate default and the 48000 Hz sample rate ceiling.
Combine Zoom Recording Parts Into One File With FFmpeg
Zoom split your meeting into several MP4s because the recording was stopped and restarted. Here is the FFmpeg command that joins the parts back into one file.
How to Export Apple Lossless (ALAC) from Audacity
Audacity's manual gives a verbatim command for Apple Lossless export, plus one trap: name the file .m4a, not .alac. Here is the command, explained.
DaVinci Resolve Can't Export AIFF: the FFmpeg Way Around It
Resolve's own codec list marks AIFF as encode-unavailable on every platform. Here is what it can write, and the FFmpeg command that covers the rest.
FFmpeg and Slack: What the Official Docs Say About Video Size
Slack documents one per-file ceiling — 1GB — and never promises to shrink your upload. What its docs actually say, and where FFmpeg's own docs stop.
FFmpeg Remux to MP4 for Loom Upload (No Re-encode)
Loom recommends H.264/AAC MP4. Here is the FFmpeg remux command that swaps the container without re-encoding, and when a remux is not enough.
Convert a Zoom M4A Recording to MP3 with FFmpeg
Zoom saves meeting audio as M4A and never offers MP3. Here is the FFmpeg command, what each flag does, and why stream copy cannot do this job.
Audacity LAME Command Line Export Options, Explained
Audacity can hand your audio to LAME on a command line. Here are the official commands, what each one produces, and the only documented ID3v1 route.
DaVinci Resolve H.264 Master Preset: The FFmpeg Equivalent
Resolve's H.264 Master preset defaults to QuickTime, Auto profile, single pass and AAC 320 Kb/s. Every documented default, mapped to its FFmpeg flag.
Compress Video for Discord: What the 20MB Cap Actually Measures
Discord checks size before compression, so the file on your disk is what counts. The caps by tier and boost level, and where the encoder settings come from.
FFmpeg: Extract Audio From a Loom MP4 Without Re-Encoding
Loom downloads are always MP4. Here is the FFmpeg command that copies the audio out losslessly, what Loom says is inside the file, and what it loses.
Shotcut Command Line Export With melt: The Official Way
Shotcut's guide gives a one-line melt export command, then warns that Shotcut is not an ffmpeg front end. Here is what that means for your flags.
FFmpeg: Convert SRT to VTT for the WordPress Video Block
The WordPress Video block reads WebVTT only. Here is the FFmpeg command, and how to check the result against the .vtt example WordPress itself publishes.
Audacity Export: The (external program) FFmpeg Command
Audacity ships a default FFmpeg command for (external program) export that fails on Mac. What the placeholder means, and every variation the manual documents.
FFmpeg Instagram Reels Settings: Every Flag, Sourced
Instagram hides its Reels encoding requirements in a collapsed block. Here is every line of it mapped to an FFmpeg flag, plus which channel each applies to.
FFmpeg: Convert WebM to MP4 for WordPress Uploads
WordPress.com names .webm as an extension needing a plugin and tells you to convert before uploading. Here is the FFmpeg command, flag by flag.
Compress Video Under 25MB for Gmail With FFmpeg
Gmail's 25 MB cap counts your total attachments, and Google never says whether it is measured before or after encoding. How to pick an FFmpeg target.
FFmpeg: Extract Audio Without Re-Encoding (And Why the Extension Matters)
Copying an audio stream out of a video is lossless and near-instant — FFmpeg's own docs guarantee it. The part that trips people up is the output extension. Here is the command, the mechanism, and the one error everyone hits.
FFmpeg Faststart and WordPress: What the Docs Say
WordPress asks for Fast Start / Web Optimized by name on two official pages. What the docs state, what they leave out, and where stream copy fits.
Teams Transcript VTT to SRT: The FFmpeg Command
Teams downloads transcripts as .docx or .vtt only. Here is the FFmpeg command for SRT, and why Microsoft's own format rules make renaming fail.
FFmpeg: Compress Video for WordPress to the Official Spec
Every flag in this FFmpeg command maps to a row of WordPress.com's recommended video settings table — 1080p, h.264, 8mbps, AAC 160kbps, Fast Start.
Split a Video Into 140-Second Clips for X With FFmpeg
The FFmpeg segment command for cutting a long video into 140-second pieces for X, and what X's help centre and developer docs each publish as the limit.