ffmpeg-video-editing

1# FFmpeg Video Editing
2 
3## Cutting Video Segments
4 
5### Extract a portion (keep segment)
6 
7```bash
8# Extract from start_time to end_time
9ffmpeg -i input.mp4 -ss START -to END -c copy output.mp4
10 
11# With re-encoding for frame-accurate cuts
12ffmpeg -i input.mp4 -ss START -to END -c:v libx264 -c:a aac output.mp4
13```
14 
15### Remove a segment (cut out middle)
16 
17To remove a segment, split into parts and concatenate:
18 
19```bash
20# 1. Extract before the cut
21ffmpeg -i input.mp4 -to CUT_START -c copy part1.mp4
22 
23# 2. Extract after the cut  
24ffmpeg -i input.mp4 -ss CUT_END -c copy part2.mp4
25 
26# 3. Concatenate
27ffmpeg -f concat -safe 0 -i filelist.txt -c copy output.mp4
28```
29 
30## Concatenating Multiple Segments
31 
32### Using concat demuxer (recommended for same-codec files)
33 
34Create a file list (`segments.txt`):
35```
36file 'segment1.mp4'
37file 'segment2.mp4'
38file 'segment3.mp4'
39```
40 
41Then concatenate:
42```bash
43ffmpeg -f concat -safe 0 -i segments.txt -c copy output.mp4
44```
45 
46### Using filter_complex (for re-encoding)
47 
48```bash
49ffmpeg -i seg1.mp4 -i seg2.mp4 -i seg3.mp4 \
50  -filter_complex "[0:v][0:a][1:v][1:a][2:v][2:a]concat=n=3:v=1:a=1[v][a]" \
51  -map "[v]" -map "[a]" output.mp4
52```
53 
54## Removing Multiple Segments (Batch)
55 
56For removing many short segments (like filler words), the efficient approach:
57 
581. Calculate the "keep" segments (inverse of remove segments)
592. Extract each keep segment
603. Concatenate all keep segments
61 
62```python
63import subprocess
64import os
65…