# Upscale 1080p to 4k using ffmpeg

Just use the command below:

```
ffmpeg -i INPUT_FILE \
  -vf scale=3840x2160:flags=lanczos \
  -c:v libx264 \
  -crf 13 \
  -c:a aac -b:a 512k \
  -preset slow \
  OUTPUT_FILE
```

Where:
  - `INPUT_FILE` is the path to your input file
  - `-vf scale=3840x2160:flags=lanczos`is the new resolution using lanczos
  - `-c:v libx264` is the codec H264
  - `-crf 13` is the desired quality - From 0 to 51, the higher the number the worse. The smaller the number, the larger the file size
  - `-c:a aac -b:a 512k` is the audio codec and bitrate
  - `-preset slow` is the preset used. To go faster, use `ultrafast`
  - `OUTPUT_FILE` is the output file

Hope it helps.