[ffmpeg] Cache version data

Related: https://github.com/dasl-/pifi/issues/9

yt_dlp/postprocessor/ffmpeg.py

@@ -86,13 +86,18 @@ class FFmpegPostProcessor(PostProcessor):
 
     @staticmethod
     def get_versions(downloader=None):
-        return FFmpegPostProcessor.get_version_and_features(downloader)[0]
+        return FFmpegPostProcessor.get_versions_and_features(downloader)[0]
+
+    _version_cache, _features_cache = {}, {}
 
     def _determine_executables(self):
         programs = ['avprobe', 'avconv', 'ffmpeg', 'ffprobe']
 
         def get_ffmpeg_version(path, prog):
-            out = _get_exe_version_output(path, ['-bsfs'])
+            if path in self._version_cache:
+                self._versions[path], self._features = self._version_cache[path], self._features_cache.get(path, {})
+                return
+            out = _get_exe_version_output(path, ['-bsfs'], to_screen=self.write_debug)
             ver = detect_exe_version(out) if out else False
             if ver:
                 regexs = [
@@ -104,13 +109,13 @@ class FFmpegPostProcessor(PostProcessor):
                     mobj = re.match(regex, ver)
                     if mobj:
                         ver = mobj.group(1)
-            self._versions[prog] = ver
+            self._versions[prog] = self._version_cache[path] = ver
             if prog != 'ffmpeg' or not out:
                 return
 
             mobj = re.search(r'(?m)^\s+libavformat\s+(?:[0-9. ]+)\s+/\s+(?P<runtime>[0-9. ]+)', out)
             lavf_runtime_version = mobj.group('runtime').replace(' ', '') if mobj else None
-            self._features = {
+            self._features = self._features_cache[path] = {
                 'fdk': '--enable-libfdk-aac' in out,
                 'setts': 'setts' in out.splitlines(),
                 'needs_adtstoasc': is_outdated_version(lavf_runtime_version, '57.56.100', False),
@@ -148,26 +153,15 @@ class FFmpegPostProcessor(PostProcessor):
                 self._paths[basename] = location
 
         self._versions = {}
-        for p in programs:
-            get_ffmpeg_version(self._paths[p], p)
-
+        executables = {'basename': ('ffmpeg', 'avconv'), 'probe_basename': ('ffprobe', 'avprobe')}
         if prefer_ffmpeg is False:
-            prefs = ('avconv', 'ffmpeg')
-        else:
-            prefs = ('ffmpeg', 'avconv')
-        for p in prefs:
-            if self._versions[p]:
-                self.basename = p
-                break
-
-        if prefer_ffmpeg is False:
-            prefs = ('avprobe', 'ffprobe')
-        else:
-            prefs = ('ffprobe', 'avprobe')
-        for p in prefs:
-            if self._versions[p]:
-                self.probe_basename = p
-                break
+            executables = {k: v[::-1] for k, v in executables.items()}
+        for var, prefs in executables.items():
+            for p in prefs:
+                get_ffmpeg_version(self._paths[p], p)
+                if self._versions[p]:
+                    setattr(self, var, p)
+                    break
 
         if self.basename == 'avconv':
             self.deprecation_warning(

yt_dlp/utils.py

@@ -2713,7 +2713,9 @@ def check_executable(exe, args=[]):
     return exe
 
 
-def _get_exe_version_output(exe, args):
+def _get_exe_version_output(exe, args, *, to_screen=None):
+    if to_screen:
+        to_screen(f'Checking exe version: {shell_quote([exe] + args)}')
     try:
         # STDIN should be redirected too. On UNIX-like systems, ffmpeg triggers
         # SIGTTOU if yt-dlp is run in the background.