> For the complete documentation index, see [llms.txt](https://harsha-vallamkonda.gitbook.io/harshavallamkonda/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://harsha-vallamkonda.gitbook.io/harshavallamkonda/ffmpeg-commands/ffmpeg-commands-ultimate-guide.md).

# FFmpeg Commands Ultimate Guide

***

#### 1. Installation

**Windows (via winget):**

```bash
winget install ffmpeg
```

**macOS (via Homebrew):**

```bash
brew install ffmpeg
```

**Linux (Ubuntu/Debian):**

```bash
sudo apt update
sudo apt install ffmpeg
```

***

#### 2. Convert Video Format

Convert a video from one container or codec to another without re-encoding (if possible):

```bash
ffmpeg -i input.avi -c copy output.mp4
```

* `-i input.avi`: specifies the input file.
* `-c copy`: copies audio and video streams without re-encoding.

> **Tip:** If `-c copy` fails, re-encode with:
>
> ```bash
> ffmpeg -i input.avi -c:v libx264 -c:a aac output.mp4
> ```

***

#### 3. Compress Video

Reduce file size with controlled quality using CRF (Constant Rate Factor):

```bash
ffmpeg -i input.mp4 -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k output_compressed.mp4
```

* `-crf 23`: quality scale (0=lossless, 51=worst). 18–23 is a good range.
* `-preset medium`: tradeoff between speed and compression.
* `-b:a 128k`: sets audio bitrate.

***

#### 4. Trim Video (Extract Segment)

Cut a segment without re-encoding:

```bash
ffmpeg -i input.mp4 -ss 00:01:30 -to 00:03:00 -c copy output_trimmed.mp4
```

* `-ss 00:01:30`: start time at 1 minute 30 seconds.
* `-to 00:03:00`: end time at 3 minutes.
* `-c copy`: stream copy.

> **Note:** For frame-accurate cuts, move `-ss` before `-i` and re-encode.

***

#### 5. Split Video into Segments

Automatically split into equal-length parts with clean keyframe cuts:

```bash
ffmpeg -i input.mp4 -c copy -map 0 \
  -f segment -segment_time 90 \
  -reset_timestamps 1 \
  -force_key_frames "expr:gte(t,n_forced*90)" \
  "segment-%03d.mp4"
```

* `-segment_time 90`: target 90-second segments.
* `-force_key_frames`: ensures keyframes at split points.
* `-reset_timestamps 1`: resets timestamps per segment.

***

#### 6. Merge Videos

Concatenate multiple files without re-encoding:

1. Create `filelist.txt`:

   ```
   file 'part1.mp4'
   file 'part2.mp4'
   file 'part3.mp4'
   ```
2. Run:

   ```bash
   ffmpeg -f concat -safe 0 -i filelist.txt -c copy merged.mp4
   ```

***

#### 7. Resize Video

Change resolution:

```bash
ffmpeg -i input.mp4 -vf "scale=1280:720" output_720p.mp4
```

* `-vf "scale=width:height"`: sets new resolution.

> **Aspect-ratio preservation:** Use `-2` for height or width, e.g., `scale=1280:-2`.

***

#### 8. Crop Video

Crop a region from the video:

```bash
ffmpeg -i input.mp4 -vf "crop=640:480:100:50" cropped.mp4
```

* `crop=out_w:out_h:x:y`.

***

#### 9. Add Watermark

Overlay an image watermark:

```bash
ffmpeg -i input.mp4 -i watermark.png \
  -filter_complex "overlay=10:10" watermarked.mp4
```

* `overlay=10:10`: positions watermark at (10px,10px).

***

#### 10. Apply Filters

**Grayscale:**

```bash
ffmpeg -i input.mp4 -vf "hue=s=0" gray.mp4
```

**Brightness & Contrast:**

```bash
ffmpeg -i input.mp4 -vf "eq=brightness=0.05:contrast=1.2" adjusted.mp4
```

***

#### 11. Create GIF

From a video segment:

```bash
ffmpeg -i input.mp4 -ss 00:00:10 -t 5 \
  -vf "fps=10,scale=320:-1:flags=lanczos" \
  -c:v gif output.gif
```

* `-ss`: start; `-t`: duration.

***

#### 12. Extract Audio

Save only the audio stream:

```bash
ffmpeg -i input.mp4 -vn -c:a libmp3lame -b:a 192k output.mp3
```

* `-vn`: no video.
* `-b:a 192k`: audio bitrate.

***

#### 13. Extract Frames

Capture frames as images:

```bash
ffmpeg -i input.mp4 -vf "fps=1" frame_%04d.png
```

* `fps=1`: one frame per second.

***

#### 14. Generate Thumbnail

Export a single frame:

```bash
ffmpeg -i input.mp4 -ss 00:02:15 -vframes 1 thumbnail.jpg
```

* `-vframes 1`: capture one frame.

***

#### 15. Change Aspect Ratio

Set display aspect ratio:

```bash
ffmpeg -i input.mp4 -vf "scale=640:480,setdar=4:3" output_4_3.mp4
```

***

#### 16. Extract Subtitles

Get subtitles from a video:

```bash
ffmpeg -i input.mkv -map 0:s:0 subs.srt
```

#### 17. Add Subtitles

Embed subtitles into MP4:

```bash
ffmpeg -i input.mp4 -i subs.srt \
  -c:v copy -c:a copy -c:s mov_text output_subbed.mp4
```

***

#### 18. Fix Audio Sync

Delay audio by 0.5s:

```bash
ffmpeg -i input.mp4 -itsoffset 0.5 -i input.mp4 \
  -map 0:v -map 1:a -c copy synced.mp4
```

***

#### 19. Stream to RTMP

Live stream to Twitch/YouTube:

```bash
ffmpeg -re -i input.mp4 -c:v libx264 -c:a aac \
  -f flv rtmp://live.twitch.tv/stream_key
```

***

#### 20. Batch Convert Files

Convert all `.avi` files to `.mp4` in a folder (Windows CMD):

```bash
for %i in (*.avi) do ffmpeg -i "%i" -c copy "%~ni.mp4"
```

***

#### 21. Get File Info

Display codec, resolution, duration:

```bash
ffmpeg -i input.mp4
```

***

### Usage Tips

* Surround paths with quotes if they contain spaces.
* For frame-accurate trims, place `-ss` before `-i` and omit `-c copy`.
* Experiment with `-crf` (18–28) and `-preset` (ultrafast–veryslow) for quality vs. speed.
* Consult `ffmpeg -h` for detailed help on flags.

***

*End of FFmpeg Command Reference*


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