[whowatch] Add extractor #292

closes #223

Authored by: nao20010128nao 
Modified from: https://github.com/nao20010128nao/ytdl-patched/blob/9e4a0e061a558cdb05a618e27f47ca0ac56ece94/youtube_dl/extractor/whowatch.py

yt_dlp/downloader/__init__.py

@@ -31,6 +31,7 @@ from .external import (
 
 PROTOCOL_MAP = {
     'rtmp': RtmpFD,
+    'rtmp_ffmpeg': FFmpegFD,
     'm3u8_native': HlsFD,
     'm3u8': FFmpegFD,
     'mms': RtspFD,
@@ -46,6 +47,7 @@ PROTOCOL_MAP = {
 def shorten_protocol_name(proto, simplify=False):
     short_protocol_names = {
         'm3u8_native': 'm3u8_n',
+        'rtmp_ffmpeg': 'rtmp_f',
         'http_dash_segments': 'dash',
         'niconico_dmc': 'dmc',
     }
@@ -54,6 +56,7 @@ def shorten_protocol_name(proto, simplify=False):
             'https': 'http',
             'ftps': 'ftp',
             'm3u8_native': 'm3u8',
+            'rtmp_ffmpeg': 'rtmp',
             'm3u8_frag_urls': 'm3u8',
             'dash_frag_urls': 'dash',
         })