ffmpegdecoder: improve scaler refresh

app/codec/ffmpeg/ffmpegdecoder.cpp

@@ -173,6 +173,7 @@ void FFmpegDecoder::CloseInternal()
   }
 
   ClearFrameCache();
+  FreeScaler();
 
   instance_.Close();
 }
@@ -677,13 +678,15 @@ void FFmpegDecoder::ClearFrameCache()
     cached_frames_.clear();
     cache_at_eof_ = false;
     cache_at_zero_ = false;
-
-    // Filter graph may rely on "continuous" video frames, so we free the scaler here
-    FreeScaler();
-    InitScaler(filter_params_);
   }
 }
 
+void FFmpegDecoder::ResetScaler()
+{
+  FreeScaler();
+  InitScaler(filter_params_);
+}
+
 FramePtr FFmpegDecoder::RetrieveFrame(const rational& time, const QAtomicInt *cancelled)
 {
   int64_t target_ts = GetTimeInTimebaseUnits(time, instance_.avstream()->time_base, instance_.avstream()->start_time, filter_params_.src_interlacing);
@@ -698,6 +701,9 @@ FramePtr FFmpegDecoder::RetrieveFrame(const rational& time, const QAtomicInt *ca
         || (time < cached_frames_.front()->timestamp() || time > cached_frames_.back()->timestamp() + 2)) {
       ClearFrameCache();
 
+      // Filter graph may rely on "continuous" video frames, so we free the scaler here
+      ResetScaler();
+
       instance_.Seek(seek_ts);
       if (seek_ts == min_seek) {
         cache_at_zero_ = true;
@@ -827,6 +833,7 @@ bool FFmpegDecoder::InitScaler(const RetrieveVideoParams& params)
 
   // We need to (re)create the filter, delete current if necessary
   ClearFrameCache();
+  FreeScaler();
 
   // Set our params to this
   filter_params_ = params;