FFmpeg recipe
FFmpeg: Trim an MP4 (No Re-Encoding)
Stream-copy trims an MP4 between two timestamps without re-encoding. Output is bit-identical to the source — instant on any machine.
Command
ffmpeg -ss 00:00:10 -i input.mp4 -to 00:00:30 -c copy -y output.mp4Prefer no terminal?
Use the Video Trimmer in your browser
What each flag does
| -ss | Seek to this timestamp (HH:MM:SS or seconds). Place BEFORE -i for fast keyframe seek; AFTER -i for sample-accurate seek. |
|---|---|
| -i | Input file. Can be a video, audio, or image. Repeat for multiple inputs. |
| -to | Stop at this timestamp (absolute, not duration). Use -t instead for a relative duration. |
| -c copy | Stream-copy: no re-encoding. Output is bit-identical between cut points. Fastest possible. |
| -y | Overwrite output file without confirmation. |
Notes & gotchas
- Place -ss BEFORE -i for fast keyframe seek. AFTER -i is sample-accurate but slower.
- -to is the absolute end time. Use -t 20 for "encode 20 seconds starting from -ss" instead.
- Stream-copy snaps to the nearest keyframe, which can offset the start by up to ~10 seconds in long-GOP video. Re-encode for frame-accurate cuts.
Related recipes
Trim (frame-accurate) · MP4
Frame-accurate MP4 trim with FFmpeg. Re-encodes for exact-frame precision — use when -c copy keyframe snapping is not OK.
Convert MOV → MP4 · MOV → MP4
Convert MOV to MP4 with FFmpeg using H.264 video and AAC audio. CRF 23 default keeps quality visually identical.
Convert HEVC → H.264 · HEVC → H.264
Convert HEVC (H.265) video to H.264 with FFmpeg so it plays on Windows, in Chrome, and on older Macs.
Convert MKV → MP4 · MKV → MP4
Convert MKV to MP4 with FFmpeg using stream-copy. Remuxes the H.264 / AAC streams without re-encoding.