Practical guides to cutting, retiming and converting video: lossless versus frame-accurate trimming, FFmpeg commands, per-section speed changes and what a browser can do with a large file.https://alter.video/enhttps://alter.video/blog/cut-video-on-mac-without-imovie/https://alter.video/blog/cut-video-on-mac-without-imovie/QuickTime trims the ends and can split a section out of the middle. Where that runs out, why iMovie is overkill for one cut, and what the browser does instead.Sun, 06 Sep 2026 00:00:00 GMTmacmacosquicktimetrimmingKyllianhttps://alter.video/blog/speed-up-a-video-on-your-phone/https://alter.video/blog/speed-up-a-video-on-your-phone/Neither Photos app can speed up an ordinary clip. What the exceptions are, what iMovie and the app stores cost, and how to do it in the phone's browser.Sun, 06 Sep 2026 00:00:00 GMTiphoneandroidspeedKyllianhttps://alter.video/blog/video-wont-play/https://alter.video/blog/video-wont-play/A file that will not open is usually a codec your player cannot decode, not a broken video. How to tell which, and the conversion that fixes most of them.Sun, 06 Sep 2026 00:00:00 GMTplaybackcodecstroubleshootingKyllianhttps://alter.video/blog/cut-video-on-android-without-an-app/https://alter.video/blog/cut-video-on-android-without-an-app/Google Photos and Samsung Gallery trim the ends of a clip. Why the middle is the case they dodge, and how to remove it in Chrome on the phone itself.Sat, 05 Sep 2026 00:00:00 GMTandroidtrimmingmobileKyllianhttps://alter.video/blog/cut-video-on-windows-without-installing-anything/https://alter.video/blog/cut-video-on-windows-without-installing-anything/Photos trims the ends, Clipchamp ships with Windows 11, and a browser or FFmpeg does the rest. What each can do, and which to use for a cut in the middle.Sat, 05 Sep 2026 00:00:00 GMTwindowstrimmingclipchampKyllianhttps://alter.video/blog/how-to-remove-audio-from-a-video/https://alter.video/blog/how-to-remove-audio-from-a-video/Dropping the audio stream versus silencing it, the one-line FFmpeg command that does it without touching the video, and what the browser route trades.Sat, 05 Sep 2026 00:00:00 GMTaudioffmpeghow-toKyllianhttps://alter.video/blog/make-a-timelapse-from-a-video/https://alter.video/blog/make-a-timelapse-from-a-video/A timelapse from an existing recording is an 8× to 16× speed-up with the audio dropped. The frame arithmetic, the FFmpeg command, and the browser route.Sat, 05 Sep 2026 00:00:00 GMTtimelapsespeedffmpegKyllianhttps://alter.video/blog/mp4-vs-mov-vs-mkv-vs-webm/https://alter.video/blog/mp4-vs-mov-vs-mkv-vs-webm/Containers are not codecs. What each of the four can carry, where each one plays, and why this editor exports MP4 by default and WebM more slowly.Sat, 05 Sep 2026 00:00:00 GMTformatscontainerscodecsKyllianhttps://alter.video/blog/why-converting-mov-to-mp4-re-encodes/https://alter.video/blog/why-converting-mov-to-mp4-re-encodes/MOV and MP4 share a file structure, so a lossless remux is often possible. Where it breaks — HEVC, ProRes, PCM — and what a browser converter does instead.Sat, 05 Sep 2026 00:00:00 GMTformatsmovffmpegKyllianhttps://alter.video/blog/cut-video-on-chromebook/https://alter.video/blog/cut-video-on-chromebook/Chromebooks have no real video editor. What the Gallery app can and cannot do, why Linux and Android apps are often locked down, and what to use instead.Fri, 04 Sep 2026 00:00:00 GMTchromebookchromeostrimmingKyllianhttps://alter.video/blog/cut-video-on-iphone-without-an-app/https://alter.video/blog/cut-video-on-iphone-without-an-app/The iPhone Photos app can only trim the start and end of a clip. Here is why, and how to remove a section from the middle without installing anything.Fri, 04 Sep 2026 00:00:00 GMTiphonetrimmingmobileKyllianhttps://alter.video/blog/does-an-online-video-editor-upload-your-video/https://alter.video/blog/does-an-online-video-editor-upload-your-video/Every browser tool claims to be private. You can verify the claim in about ninety seconds with the tools already in your browser. Here is exactly how.Fri, 04 Sep 2026 00:00:00 GMTprivacydevtoolshow-toKyllianhttps://alter.video/blog/ffmpeg-trim-without-re-encoding/https://alter.video/blog/ffmpeg-trim-without-re-encoding/The exact -ss, -t and -c copy commands for a lossless trim, why the flag order matters, and how to cut a section out of the middle with the concat demuxer.Fri, 04 Sep 2026 00:00:00 GMTffmpegcommand linelosslessKyllianhttps://alter.video/blog/speed-up-part-of-a-video/https://alter.video/blog/speed-up-part-of-a-video/Most editors apply one speed to the whole clip. What a per-section speed change actually does to frames and audio, and how to do it in a browser or in FFmpeg.Fri, 04 Sep 2026 00:00:00 GMTspeedffmpegeditingKyllianhttps://alter.video/blog/trim-large-video-files-online/https://alter.video/blog/trim-large-video-files-online/Server-based tools cap file size because your upload costs them money. A browser tool's ceiling is the WebAssembly heap; here is how to work within it.Fri, 04 Sep 2026 00:00:00 GMTlarge filesmemorywebassemblyKyllianhttps://alter.video/blog/trim-video-without-losing-quality/https://alter.video/blog/trim-video-without-losing-quality/Trimming only loses quality if the video gets re-encoded. Here is when that happens, when it does not, and the trade you are making either way.Fri, 04 Sep 2026 00:00:00 GMTtrimmingqualityfundamentalsKyllianhttps://alter.video/blog/why-slow-motion-looks-choppy/https://alter.video/blog/why-slow-motion-looks-choppy/Slowing footage down creates no new frames — it holds the existing ones longer. The frame-rate arithmetic, and why real slow motion has to be shot, not made.Fri, 04 Sep 2026 00:00:00 GMTslow motionframe rateeditingKyllian