# Python and FFmpeg Guide

FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. Python is often used to automate FFmpeg commands for batch processing video and audio.

## Prerequisites

1.  **Install FFmpeg**: You must have the `ffmpeg` executable installed on your system and added to your PATH.
    *   **Windows**: Download from ffmpeg.org or use `winget install ffmpeg`.
    *   **macOS**: `brew install ffmpeg`.
    *   **Linux**: `sudo apt install ffmpeg`.

## Method 1: Using `subprocess` (Standard Library)

The most direct way to use FFmpeg is by calling the command line tool using Python's built-in `subprocess` module.

### Basic Conversion

```python
import subprocess

# Convert input.mp4 to output.avi
command = ['ffmpeg', '-i', 'input.mp4', 'output.avi']

subprocess.run(command)
```

### Suppressing Output

FFmpeg is very verbose. You can suppress the output using `subprocess.DEVNULL`.

```python
import subprocess

subprocess.run(['ffmpeg', '-i', 'input.mp4', 'output.mp3'], 
               stdout=subprocess.DEVNULL, 
               stderr=subprocess.DEVNULL)
```

## Method 2: Using `ffmpeg-python` (Wrapper Library)

For complex filters and pipelines, constructing command line strings can be error-prone. The `ffmpeg-python` library provides a Pythonic interface.

### Installation

```bash
pip install ffmpeg-python
```

### Basic Usage

```python
import ffmpeg

stream = ffmpeg.input('input.mp4')
stream = ffmpeg.output(stream, 'output.mp4')
ffmpeg.run(stream)
```

### Complex Filters (Flip and Resize)

```python
import ffmpeg

(
    ffmpeg
    .input('input.mp4')
    .hflip()              # Horizontal flip
    .filter('scale', size='1280:720') # Resize
    .output('output.mp4')
    .run()
)
```

## Common Tasks

### Extract Audio from Video

```python
import subprocess

# -vn disables video recording
cmd = ['ffmpeg', '-i', 'video.mp4', '-vn', 'audio.mp3']
subprocess.run(cmd)
```

### Get Video Metadata (ffprobe)

You can use `ffprobe` to get JSON metadata about a file.

```python
import ffmpeg

try:
    probe = ffmpeg.probe('video.mp4')
    video_stream = next((stream for stream in probe['streams'] if stream['codec_type'] == 'video'), None)
    width = int(video_stream['width'])
    height = int(video_stream['height'])
    print(f"Resolution: {width}x{height}")
except ffmpeg.Error as e:
    print(e.stderr)
```

[[programming/python/python]]