docs: added most commong use case examples to readme

README.md

@@ -4,6 +4,13 @@ files quickly and efficiently.
 
 Because it uses ffmpeg under the hood, it supports any media file processing that ffmpeg can handle.
 
+1. [Installation](#installation)
+2. [Usage](#usage)
+   - [Practical examples](#more-practical-examples)
+3. [Requirements](#requirements)
+4. [All available options](#available-options)
+5. [License](#license)
+
 ### Installation
 
 #### [Homebrew](https://brew.sh) (macOS / Linux)
@@ -75,6 +82,83 @@ changing the file extension to `.mp4` while processing 4 files in parallel.
 For more info on the `-o` syntax, run `ffzap --help`. For more ffmpeg options,
 visit [ffmpeg's documentation](https://ffmpeg.org/ffmpeg.html).
 
+#### More practical examples:
+
+<details>
+<summary>Re-encode multiple videos to H265 and the audio to opus</summary>
+
+```bash
+ffzap --input-file files.txt -f "-c:v libx265 -preset medium -crf 23 -c:a libopus -b:a 128k" -o "Output/{{name}}.mp4" -t 2
+```
+
+Keypoints:
+- use `--input-file` to pass a list of file names to process
+- re-encode the video to H265 using `-c:v libx265`
+  - `-preset medium` to balance out speed and file size
+  - `-crf 23` to achieve good quality with reasonable file size
+- re-encode the audio to opus using `-c:a libopus`
+  - `-b:a 128k` sets the audio bitrate to 128k for a good trade-off between file size and audio quality 
+- `-t 2` runs two ffmpeg processes simultaneously to re-encode two files at once
+  - adjust this number according to your system specs. Most system should be able to handle two instances comfortably
+
+</details>
+
+---
+
+<details>
+<summary>Convert PNG images to JPG</summary>
+
+```bash
+ffzap --input-file files.txt -f "-c:v mjpeg -q:v 2" -o "Output/{{name}}.jpg" -t 6
+```
+
+Keypoints:
+- use `--input-file` to pass a list of file names to process
+- convert the image to JPG using `-c:v mjpeg`
+  - `-q:v 2` to set very high quality
+- `-t 6` runs six processes in parallel, converting six files at once
+  - adjust this number according to your system specs. Six shouldn't be too taxing on a modern CPU
+
+</details>
+
+---
+
+<details>
+<summary>Add a watermark to multiple videos</summary>
+
+```bash
+ffzap --input-file files.txt -f "-i watermark.png -filter_complex [1]format=rgba,lut=a=val*0.3[watermark];[0][watermark]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2 -c:a copy" -o "{{name}}_watermark.mp4" -t 2
+```
+(Note that this command may not work in Windows Powershell as it requires a different escaping format)
+
+Keypoints:
+- use `--input-file` to pass a list of file names to process (these are the files the watermark gets added to)
+- select to watermark file with `-i watermark.png` **inside** `-f`
+- `-filter_complex` applies the watermark with 70% opacity to the center of each video
+- `-c:a copy` copies the audio
+- `-t 2` processes two files in parallel
+  - adjust this number according to your system specs. Two should be good on most modern systems
+
+</details>
+
+---
+
+<details>
+<summary>Resize multiple videos</summary>
+
+```bash
+ffzap --input-file files.txt -f "-vf scale=1280:720 -c:a copy" -o "{{name}}_resized.mp4" -t 2
+```
+
+Keypoints:
+- use `--input-file` to pass a list of file names to process
+- `-vf scale=1280:720` sets the video resolution to HD
+- `-c:a copy` copies the audio
+- `-t 2` processes two files in parallel
+  - adjust this number according to your system specs. Two should be good on most modern systems
+
+</details>
+
 ### Requirements
 
 - a working installation of [ffmpeg](https://ffmpeg.org/download.html)