From 0017d9ad6de831384e74db14a821e4c94020c9ac Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sergey=20M=E2=80=A4?= <dstftw@gmail.com>
Date: Sun, 23 Jul 2017 00:12:01 +0700
Subject: [PATCH] [YoutubeDL] Improve default format specification (closes
 #13704)

---
 test/test_YoutubeDL.py  | 11 +++++++++++
 youtube_dl/YoutubeDL.py | 31 +++++++++++++++++++++++--------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/test/test_YoutubeDL.py b/test/test_YoutubeDL.py
index e0decb81c..4af14f9db 100644
--- a/test/test_YoutubeDL.py
+++ b/test/test_YoutubeDL.py
@@ -449,6 +449,17 @@ def test_format_filtering(self):
             pass
         self.assertEqual(ydl.downloaded_info_dicts, [])
 
+    def test_default_format_spec(self):
+        ydl = YDL({'simulate': True})
+        self.assertEqual(ydl._default_format_spec({}), 'bestvideo+bestaudio/best')
+
+        ydl = YDL({'outtmpl': '-'})
+        self.assertEqual(ydl._default_format_spec({}), 'best')
+
+        ydl = YDL({})
+        self.assertEqual(ydl._default_format_spec({}, download=False), 'bestvideo+bestaudio/best')
+        self.assertEqual(ydl._default_format_spec({'is_live': True}), 'best')
+
 
 class TestYoutubeDL(unittest.TestCase):
     def test_subtitles(self):
diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index f94836d06..367ae3533 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -1064,6 +1064,25 @@ def _filter(f):
             return op(actual_value, comparison_value)
         return _filter
 
+    def _default_format_spec(self, info_dict, download=True):
+        req_format_list = []
+
+        def can_have_partial_formats():
+            if self.params.get('simulate', False):
+                return True
+            if not download:
+                return True
+            if self.params.get('outtmpl', DEFAULT_OUTTMPL) == '-':
+                return False
+            if info_dict.get('is_live'):
+                return False
+            merger = FFmpegMergerPP(self)
+            return merger.available and merger.can_merge()
+        if can_have_partial_formats():
+            req_format_list.append('bestvideo+bestaudio')
+        req_format_list.append('best')
+        return '/'.join(req_format_list)
+
     def build_format_selector(self, format_spec):
         def syntax_error(note, start):
             message = (
@@ -1534,14 +1553,10 @@ def is_wellformed(f):
 
         req_format = self.params.get('format')
         if req_format is None:
-            req_format_list = []
-            if (self.params.get('outtmpl', DEFAULT_OUTTMPL) != '-' and
-                    not info_dict.get('is_live')):
-                merger = FFmpegMergerPP(self)
-                if merger.available and merger.can_merge():
-                    req_format_list.append('bestvideo+bestaudio')
-            req_format_list.append('best')
-            req_format = '/'.join(req_format_list)
+            req_format = self._default_format_spec(info_dict, download=download)
+            if self.params.get('verbose'):
+                self.to_stdout('[debug] Default format spec: %s' % req_format)
+
         format_selector = self.build_format_selector(req_format)
 
         # While in format selection we may need to have an access to the original