diff --git a/youtube_dl/downloader/external.py b/youtube_dl/downloader/external.py
index 7fc864e85..afef40c82 100644
--- a/youtube_dl/downloader/external.py
+++ b/youtube_dl/downloader/external.py
@@ -468,7 +468,7 @@ class FFmpegFD(ExternalFD):
                 args += ['-f', 'mpegts']
             else:
                 args += ['-f', 'mp4']
-                if (ffpp.basename == 'ffmpeg' and is_outdated_version(ffpp._versions['ffmpeg'], '3.2', False)) and (not info_dict.get('acodec') or info_dict['acodec'].split('.')[0] in ('aac', 'mp4a')):
+                if (ffpp.basename == 'ffmpeg' and is_outdated_version(ffpp._lavf_version.get('runtime'), '57.56.100', False)) and (not info_dict.get('acodec') or info_dict['acodec'].split('.')[0] in ('aac', 'mp4a')):
                     args += ['-bsf:a', 'aac_adtstoasc']
         elif protocol == 'rtmp':
             args += ['-f', 'flv']
diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
index 801160e6c..b4797b9cc 100644
--- a/youtube_dl/postprocessor/ffmpeg.py
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -78,7 +78,22 @@ class FFmpegPostProcessor(PostProcessor):
         prefer_ffmpeg = True
 
         def get_ffmpeg_version(path):
-            ver = get_exe_version(path, args=['-version'])
+            if os.path.basename(path) == 'ffmpeg':
+                # get ffmpeg and libavformat runtime versions
+                vers = get_exe_version(
+                    path, args=['-version'],
+                    version_re=r'(?s)version\s+([-0-9._a-zA-Z]+)(?:.*?libavformat\s+([0-9. ]+)\s+/\s+([0-9. ]+))?')
+                if isinstance(vers, (list, tuple)):
+                    ver = vers[0]
+                    if len(vers) > 2 and vers[1] and vers[2]:
+                        self._lavf_version = {
+                            'build': vers[1].replace(' ', ''),
+                            'runtime': vers[2].replace(' ', '')
+                        }
+                else:
+                    ver = vers
+            else:
+                ver = get_exe_version(path, args=['-version'])
             if ver:
                 regexs = [
                     r'(?:\d+:)?([0-9.]+)-[0-9]+ubuntu[0-9.]+$',  # Ubuntu, see [1]
@@ -96,6 +111,7 @@ class FFmpegPostProcessor(PostProcessor):
 
         self._paths = None
         self._versions = None
+        self._lavf_version = {}
         if self._downloader:
             prefer_ffmpeg = self._downloader.params.get('prefer_ffmpeg', True)
             location = self._downloader.params.get('ffmpeg_location')
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 443d2609c..599d4552b 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -3993,7 +3993,10 @@ def detect_exe_version(output, version_re=None, unrecognized='present'):
         version_re = r'version\s+([-0-9._a-zA-Z]+)'
     m = re.search(version_re, output)
     if m:
-        return m.group(1)
+        if len(m.groups()) == 1:
+            return m.group(1)
+        else:
+            return m.groups()
     else:
         return unrecognized