Move the documentation for the --format option to the manpage

It's too big for beeing embedded in the help message and it's easier to edit in the markdown file.

README.md

@@ -5,6 +5,7 @@
 - [OPTIONS](#options)
 - [CONFIGURATION](#configuration)
 - [OUTPUT TEMPLATE](#output-template)
+- [FORMAT SELECTION](#format-selection)
 - [VIDEO SELECTION](#video-selection)
 - [FAQ](#faq)
 - [DEVELOPER INSTRUCTIONS](#developer-instructions)
@@ -184,16 +185,7 @@ ## Workarounds:
     --sleep-interval SECONDS         Number of seconds to sleep before each download.
 
 ## Video Format Options:
-    -f, --format FORMAT              Video format code, specify the order of preference using slashes, as in -f 22/17/18 .  Instead of format codes, you can select by
+    -f, --format FORMAT              Video format code, see the "FORMAT SELECTION" for all the info
-                                     extension for the extensions aac, m4a, mp3, mp4, ogg, wav, webm. You can also use the special names "best", "bestvideo", "bestaudio",
-                                     "worst".  You can filter the video results by putting a condition in brackets, as in -f "best[height=720]" (or -f "[filesize>10M]").
-                                     This works for filesize, height, width, tbr, abr, vbr, asr, and fps and the comparisons <, <=, >, >=, =, != and for ext, acodec,
-                                     vcodec, container, and protocol and the comparisons =, != . Formats for which the value is not known are excluded unless you put a
-                                     question mark (?) after the operator. You can combine format filters, so  -f "[height <=? 720][tbr>500]" selects up to 720p videos
-                                     (or videos where the height is not known) with a bitrate of at least 500 KBit/s. By default, youtube-dl will pick the best quality.
-                                     Use commas to download multiple audio formats, such as -f  136/137/mp4/bestvideo,140/m4a/bestaudio. You can merge the video and audio
-                                     of two formats into a single file using -f <video-format>+<audio-format> (requires ffmpeg or avconv), for example -f
-                                     bestvideo+bestaudio.
     --all-formats                    Download all available video formats
     --prefer-free-formats            Prefer free video formats unless a specific one is requested
     --max-quality FORMAT             Highest quality format to download
@@ -271,6 +263,13 @@ # OUTPUT TEMPLATE
 youtube-dl_test_video_.mp4          # A simple file name
 ```
 
+# FORMAT SELECTION
+
+By default youtube-dl tries to download the best quality, but sometimes you may want to download other format.
+The simplest case is requesting a specific format, for example `-f 22`. You can get the list of available formats using `--list-formats`, you can also use a file extension (currently it supports aac, m4a, mp3, mp4, ogg, wav, webm) or the special names `best`, `bestvideo`, `bestaudio` and `worst`.
+
+If you are want to download multiple videos and they don't have the same formats available, you can specify the order of preference using slashes, as in `-f 22/17/18`. You can also filter the video results by putting a condition in brackets, as in `-f "best[height=720]"` (or `-f "[filesize>10M]"`).  This works for filesize, height, width, tbr, abr, vbr, asr, and fps and the comparisons <, <=, >, >=, =, != and for ext, acodec, vcodec, container, and protocol and the comparisons =, != . Formats for which the value is not known are excluded unless you put a question mark (?) after the operator. You can combine format filters, so  `-f "[height <=? 720][tbr>500]"` selects up to 720p videos (or videos where the height is not known) with a bitrate of at least 500 KBit/s. Use commas to download multiple formats, such as `-f 136/137/mp4/bestvideo,140/m4a/bestaudio`. You can merge the video and audio of two formats into a single file using `-f <video-format>+<audio-format>` (requires ffmpeg or avconv), for example `-f bestvideo+bestaudio`.
+
 # VIDEO SELECTION
 
 Videos can be filtered by their upload date using the options `--date`, `--datebefore` or `--dateafter`, they accept dates in two formats:

youtube_dl/options.py

@@ -322,32 +322,7 @@ def _hide_login_info(opts):
     video_format.add_option(
         '-f', '--format',
         action='store', dest='format', metavar='FORMAT', default=None,
-        help=(
+        help='Video format code, see the "FORMAT SELECTION" for all the info')
-            'Video format code, specify the order of preference using'
-            ' slashes, as in -f 22/17/18 . '
-            ' Instead of format codes, you can select by extension for the '
-            'extensions aac, m4a, mp3, mp4, ogg, wav, webm. '
-            'You can also use the special names "best",'
-            ' "bestvideo", "bestaudio", "worst". '
-            ' You can filter the video results by putting a condition in'
-            ' brackets, as in -f "best[height=720]"'
-            ' (or -f "[filesize>10M]"). '
-            ' This works for filesize, height, width, tbr, abr, vbr, asr, and fps'
-            ' and the comparisons <, <=, >, >=, =, !='
-            ' and for ext, acodec, vcodec, container, and protocol'
-            ' and the comparisons =, != .'
-            ' Formats for which the value is not known are excluded unless you'
-            ' put a question mark (?) after the operator.'
-            ' You can combine format filters, so  '
-            '-f "[height <=? 720][tbr>500]" '
-            'selects up to 720p videos (or videos where the height is not '
-            'known) with a bitrate of at least 500 KBit/s.'
-            ' By default, youtube-dl will pick the best quality.'
-            ' Use commas to download multiple audio formats, such as'
-            ' -f  136/137/mp4/bestvideo,140/m4a/bestaudio.'
-            ' You can merge the video and audio of two formats into a single'
-            ' file using -f <video-format>+<audio-format> (requires ffmpeg or'
-            ' avconv), for example -f bestvideo+bestaudio.'))
     video_format.add_option(
         '--all-formats',
         action='store_const', dest='format', const='all',