+By default youtube-dl tries to download the best available quality, i.e. if you want the best quality you **don't need** to pass any special options, youtube-dl will guess it for you by **default**.
+
+But sometimes you may want to download in a different format, for example when you are on a slow or intermittent connection. The key mechanism for achieving this is so called *format selection* based on which you can explicitly specify desired format, select formats based on some criterion or criteria, setup precedence and much more.
+
+The general syntax for format selection is `--format FORMAT` or shorter `-f FORMAT` where `FORMAT` is a *selector expression*, i.e. an expression that describes format or formats you would like to download.
+
+The simplest case is requesting a specific format, for example with `-f 22` you can download the format with format code equal to 22. You can get the list of available format codes for particular video using `--list-formats` or `-F`. Note that these format codes are extractor specific.
+
+You can also use a file extension (currently `3gp`, `aac`, `flv`, `m4a`, `mp3`, `mp4`, `ogg`, `wav`, `webm` are supported) to download best quality format of particular file extension served as a single file, e.g. `-f webm` will download best quality format with `webm` extension served as a single file.
+
+You can also use special names to select particular edge case format:
+ - `best`: Select best quality format represented by single file with video and audio
+ - `worst`: Select worst quality format represented by single file with video and audio
+ - `bestvideo`: Select best quality video only format (e.g. DASH video), may not be available
+ - `worstvideo`: Select worst quality video only format, may not be available
+ - `bestaudio`: Select best quality audio only format, may not be available
+ - `worstaudio`: Select worst quality audio only format, may not be available
+
+For example, to download worst quality video only format you can use `-f worstvideo`.
+
+If you want to download multiple videos and they don't have the same formats available, you can specify the order of preference using slashes. Note that slash is left-associative, i.e. formats on the left hand side are preferred, for example `-f 22/17/18` will download format 22 if it's available, otherwise it will download format 17 if it's available, otherwise it will download format 18 if it's available, otherwise it will complain that no suitable formats are available for download.
+
+If you want to download several formats of the same video use comma as a separator, e.g. `-f 22,17,18` will download all these three formats, of course if they are available. Or more sophisticated example combined with precedence feature `-f 136/137/mp4/bestvideo,140/m4a/bestaudio`.
+
+You can also filter the video formats by putting a condition in brackets, as in `-f "best[height=720]"` (or `-f "[filesize>10M]"`).
+
+The following numeric meta fields can be used with comparisons `<`, `<=`, `>`, `>=`, `=` (equals), `!=` (not equals):
+ - `filesize`: The number of bytes, if known in advance
+ - `width`: Width of the video, if known
+ - `height`: Height of the video, if known
+ - `tbr`: Average bitrate of audio and video in KBit/s
+ - `abr`: Average audio bitrate in KBit/s
+ - `vbr`: Average video bitrate in KBit/s
+ - `asr`: Audio sampling rate in Hertz
+ - `fps`: Frame rate
+
+Also filtering work for comparisons `=` (equals), `!=` (not equals), `^=` (begins with), `$=` (ends with), `*=` (contains) and following string meta fields:
+ - `ext`: File extension
+ - `acodec`: Name of the audio codec in use
+ - `vcodec`: Name of the video codec in use
+ - `container`: Name of the container format
+ - `protocol`: The protocol that will be used for the actual download, lower-case. `http`, `https`, `rtsp`, `rtmp`, `rtmpe`, `m3u8`, or `m3u8_native`