Merge pull request #3389 from penguin2233/master

Rewrite compression guide

wiki/Guides/Compressing_files/en.md

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+# Compressing files
+
+Each beatmapset has a file size limit dictated by its total length. This guide will help you to get your beatmap under that limit.
+
+There are 2 types of compression. **Lossy** and **Lossless** compression.
+
+- **Lossless** implies that the quality never degrades and can be repeatedly compressed or decompressed.
+- **Lossy** is a much more powerful form of compression which sacrifices quality for space/processor demand.
+
+## Video
+
+Videos are usually where people go wrong. There are thousands of video codecs out there, and *believe it or not, YouTube is usually a terrible place to get videos*.
+
+H.264 is a good codec to use but like most video codecs, it is lossy. This means you want to avoid re-encoding the video multiple times, but instead encode from the high resolution source once.
+
+### Using Handbrake
+
+This section will show you how to remove audio from videos using [Handbrake](https://handbrake.fr/) to reduce the file size of the video file.
+
+1. Open Handbrake and import your video file. You can drag and drop your file into Handbrake or manually import by clicking the `File` option.
+
+![Importing video files in Handbrake](img/import-handbrake.jpg "Importing the video into Handbrake")
+
+2. Select the `Fast 720p30` preset.
+
+![Selecting the video preset](img/preset-handbrake.jpg "Selecting the preset")
+
+3. Select the `Audio` tab and remove all audio tracks. Do the same for any subtitles by going into the `Subtitles` tab and removing all entries.
+
+![Removing audio tracks from the audio tab in Handbrake](img/removeaudio-handbrake.jpg "Removing the audio tracks")
+
+4. Go into the `Video` tab and set the video codec as `H.264 (X264)`. Change the `Constant Quality` to between 20–25. Smaller values will produce smaller file sizes at the cost of the video's quality.
+
+![Setting the video codec and quality in Handbrake](img/codecquality-handbrake.jpg "Setting the video codec and constant quality")
+
+5. Set the framerate to `30`.
+
+![Setting the video framerate in Handbrake](img/framerate-handbrake.jpg "Setting the framerate")
+
+6. To resize the image of the video file, go to the `Dimensions` tab and change the width to `1280` and change the height to `720`.
+
+![Setting the video dimensions in Handbrake](img/dimensions-handbrake.jpg "Setting the video dimensions")
+
+7. Lastly, pick the file location you want to save your result to, then click `Start Encode`.
+
+![Encoding and saving the video](img/save-handbrake.jpg "Encoding and saving the video")
+
+## Audio
+
+The audio bitrate determines a lot about the size of the audio file. You can use [Audacity](https://www.audacityteam.org/) to change the bitrate of your audio files.
+
+The [Ranking Criteria](/wiki/Ranking_Criteria#audio) has a rule noting that anything above 192kbps is not allowed. In addition to this, anything under 128kbps is usually considered to be low quality.
+
+1. Import the audio file into Audacity.
+
+![Importing audio into Audacity](img/import-audacity.jpg "Importing audio into Audacity")
+
+2. Export the audio as MP3.
+
+![Export as MP3](img/exportmenu-audacity.jpg "Export as MP3")
+
+3. Change the export options to help compress your file. Use `Preset` and select the quality as `Medium, 145-185 kbps`. If you want, you can enter in the metadata in the next dialog. When ready, click `OK`.
+
+![Export settings](img/exportsettings-audacity.jpg "Export settings")