Media tools
Sume media tools by API: trim, filter, captions, frames, inspect, speech-to-text, upscaling, background removal, transitions, and Timeline assembly.
Start with Video editing API limits: Sume media tool caps in one table
Spotify video podcast specs: MP4, 1080p 16:9, H.264
Spotify for Creators recommends a 16:9 MP4 at 1080p or higher, H.264 and AAC-LC, 24 to 60 FPS, one video and one audio track. How to render and check it.
AI sound effects generator API: an open-weight SFX model, then Sume
Sume lists no sound-effects route. Stable Audio 3 Small SFX is open-weight, so you can run it yourself, import the files to Sume and mix them in Timeline 1.0.
Does Suno watermark songs? What you can and cannot confirm
Suno's v6 launch is on its blog, but no watermark detail was readable there. How to check Suno's terms, and what Sume's music files are as delivered.
Sync music to the beat of a short video with AI
YouTube's Gemini editing can sync music to the beat. To do it yourself on Sume, read beat times from a clip's music track and place Timeline cuts on them.
Telegram video note limits: 1 minute, square, upload only
A Telegram video note is a rounded square MPEG4 up to 1 minute, and bots cannot send it by URL. What sendVideoNote takes and how to render a square clip.
Timeline fit: cover, contain, stretch or blur?
In a Sume Timeline render, video[].fit sets how a clip fills the frame: cover crops, contain pads black, stretch distorts, blur pads with a blurred copy.
render_strategy_unsafe: Timeline render single with over 12 slots
render_strategy_unsafe means render.strategy was single with more than 12 video slots. Use auto or chunked, or send 12 or fewer slots. Sume Timeline docs.
Trim a video without re-encoding: precision keyframe in the Sume API
Sume's video trim with precision keyframe stream-copies the cut, with no re-encode. It can start a GOP early, so read actual_start_seconds in the result.
Crop a video by fractions and the out-of-bounds error
The video filter crop op takes fractions of the frame, not pixels. Rules, the 0.05 minimum, the out-of-bounds error, and a centered 9:16 crop of a 16:9 clip.
Darken a video with an API: the dim operation and its amount
The dim op multiplies a clip's brightness by amount in (0, 1]. 0.45 darkens, 1 changes nothing, 0 and above 1 are refused. Request, limits and cost.
seek fast or precise: which to use for video inspect stills
Video inspect's seek option: precise decodes the exact instant, fast snaps to the keyframe at or before it and skips the decode. What changes in the result.
Transcribe a video into sentence segments with Sume: options and cost
video inspect with transcribe true returns text, words and, with sentence segmentation, gapless caption-line segments. Options, the $0.01 per minute rate.
YouTube show artwork size: 16:9 banner and backdrop
YouTube show artwork is 16:9 JPG or PNG up to 10 MB, in two kinds: a banner with the title and a backdrop without it. Sizes from YouTube's page.
Zoom virtual background video format: MP4 or MOV, 480p to 1080p
Zoom takes an MP4 or MOV virtual background from 480x360 up to 1920x1080; images are 24-bit PNG or JPG up to 15 MB. How to render a clip in that range.
What is audio ducking? Meaning, settings, and how it works
Audio ducking automatically lowers music while a voice speaks and raises it in the pauses. How the sidechain works, and what each setting does.
SRT vs VTT: the difference between the two subtitle formats
SRT and VTT are both plain-text subtitle files. VTT adds a WEBVTT header, dot milliseconds, positioning and styling, and is what HTML5 players read.
Hormozi-style captions: what they are and how to make them
Hormozi-style captions are big uppercase words shown one at a time, timed to speech, with key words in a contrast color. How to make them by API.
WebM vs MP4: which video format to use, and when
WebM and MP4 are both video containers. Use MP4 when one file must play everywhere; add WebM (AV1 or VP9 with Opus) as an open, royalty-free option.
MOV vs MP4: which is better, and does quality differ?
MOV and MP4 are sibling containers that can hold the same H.264 video, so quality comes from the codec, not the extension. MP4 plays in more places.
Product video sound: when to add it, and how with AI
Browsers generally block autoplay with sound until a visitor interacts, so a looping product clip must work muted. Save sound for clips people play.
YouTube multi-language audio: add dubbed tracks, made with AI
YouTube multi-language audio lets one video carry dubbed tracks you upload yourself. The rules, the upload steps, and how to make each track with AI.
How to mix voice with background music into one file
Mix voice with background music: set the music below the voice, duck it under speech, fade it out, export one file. The Sume way: render, then detach.
How to fade out audio at the end of a track
To fade out audio, lower the volume to silence over the last few seconds. Use FFmpeg's afade filter, or a Sume render for a track Sume made.
WAV vs MP3: which is better, and when to use each
WAV is exact and large; MP3 is small and lossy. Keep WAV while you edit or join audio, export MP3 last, and know that MP3 to WAV restores nothing.
How to transcribe an interview and label each speaker
Transcribe an interview in two steps: speech-to-text for the words and their times, then speaker labels from separate tracks or a pass by hand.
J cut and L cut: what they are and how to make one
A J cut plays the next shot's sound before its picture; an L cut lets a shot's sound run on under the next picture. Here's how to build each one.
How to cut a video in half (or into equal parts)
To cut a video in half, split it at its length ÷ 2 into two files. For N equal parts, part i starts at i × length ÷ N. Steps, precision, and limits.
How to split a video by file size without re-encoding
Split a video by file size: scale its length by your limit ÷ its size, cut parts that long without re-encoding, then check each part's size.
How to insert a video into another video
To insert a video into another video, split the main video at the insert point and play it, the new clip, then the rest, all in one render.
How to shorten a video: trim, cut, or remove pauses
Shorten a video by cutting time: trim the start or end, remove sections from the middle, or cut the pauses. Which to pick, how, and the limits.
Types of cuts in video editing: hard, jump, J, L, and more
The main types of cuts in video editing: hard, jump, J and L, match, cutaway, cross-cut, and smash cut. What each does, and how to build them.
Dip to black transition: fade out and in between clips
A dip to black fades one clip out to black, then fades the next in from black. How to build one when a render's fade is a crossfade, and the limits.
23.976 vs 24 fps: the difference and when it matters
23.976 fps is 24000/1001, the NTSC-film version of 24 fps: 0.1% slower, one frame in 1,001. When that gap matters, and what Sume renders do with it.
Keyframe interval explained: I-frames, GOPs, and cuts
The keyframe interval is how far apart a video's whole-picture frames sit. It decides where copy cuts and fast seeks land. How to read and set it.
How to convert frames to seconds (and back) at any fps
Seconds = frames ÷ fps, and frames = seconds × fps. How to convert frames and timecode at 24, 23.976, or 29.97 fps, and why Sume takes seconds.
What codec does MP4 use? MP4 is a container, not a codec
MP4 isn't a codec: it's a container holding video and audio compressed by separate codecs, such as H.264 and AAC. How to tell them apart.
How to check a video's codec with ffprobe or an API
Check a video's codec by probing it: ffprobe prints each stream's codec_name. For a Sume-hosted file, a free probe returns video_codec and pix_fmt.
MP4 plays audio but no video? Check the video stream
An MP4 that plays sound but no picture has a video stream the player can't decode, or none at all. Probe the codec and pixel format, then re-encode.
Convert 4:3 to 16:9 video: pillarbox, crop, or stretch
Convert 4:3 video to 16:9 three ways: pillarbox it, crop 12.5% off the top and bottom, or stretch it. With FFmpeg and the Sume API.
Cinematic bars size: bar height for 2.39:1 and 2.35:1
Cinematic bars on a 1920×1080 video are 138 px each for 2.39:1 and 131 px for 2.35:1. The formula, sizes for 720p to 4K, and how to add them.
How to find the aspect ratio of a video (and calculate it)
Find a video's aspect ratio by dividing its width and height by their greatest common divisor: 1920×1080 is 16:9. Plus the traps that mislead.
Vertical video resolution: 9:16 sizes from 720p to 4K
Vertical video resolution is 1080×1920 for 1080p, 720×1280 for 720p, and 2160×3840 for 4K. How to size any 9:16 frame, and what Sume can render.
How to upscale video to 4K: scale factors and step order
To upscale video to 4K, enlarge it by 2160 ÷ its height: ×2 from 1080p, ×3 from 720p. How to do it with FFmpeg or Sume, and why to upscale last.
Video freezes but audio continues: causes and fixes
If a video freezes but the audio continues in every player, the file holds a still frame. How to check its streams, and the three Sume render causes.
How to combine photos and videos into one video
Combine photos and videos into one video on a single timeline: each photo held for a set time, each clip cut to length, one soundtrack under it all.
What is text-based video editing? How transcript cuts work
Text-based video editing cuts a video by deleting words from its transcript. How word timings become a cut list, and how to build it with Sume's API.
AI image generator with a transparent background: 2 steps
Make an AI image with a transparent background in two steps: generate it on a plain backdrop, then remove the background to get a PNG with alpha.
Can a JPG be transparent? No: make a transparent PNG instead
No. A JPG has no alpha channel, so every pixel is opaque. Cut the subject out and save it as a PNG, a format that can store transparent pixels.