clear stream errors before attempting the read

apps/openmw/mwsound/ffmpeg_decoder.cpp

@@ -31,8 +31,8 @@ int FFmpeg_Decoder::readPacket(void *user_data, uint8_t *buf, int buf_size)
     try
     {
         std::istream& stream = *static_cast<FFmpeg_Decoder*>(user_data)->mDataStream;
-        stream.read((char*)buf, buf_size);
         stream.clear();
+        stream.read((char*)buf, buf_size);
         return stream.gcount();
     }
     catch (std::exception& )
@@ -52,6 +52,8 @@ int64_t FFmpeg_Decoder::seek(void *user_data, int64_t offset, int whence)
 
     whence &= ~AVSEEK_FORCE;
 
+    stream.clear();
+
     if(whence == AVSEEK_SIZE)
     {
         size_t prev = stream.tellg();

extern/osg-ffmpeg-videoplayer/videostate.cpp

@@ -173,8 +173,8 @@ int VideoState::istream_read(void *user_data, uint8_t *buf, int buf_size)
     try
     {
         std::istream& stream = *static_cast<VideoState*>(user_data)->stream;
-        stream.read((char*)buf, buf_size);
         stream.clear();
+        stream.read((char*)buf, buf_size);
         return stream.gcount();
     }
     catch (std::exception& )
@@ -194,6 +194,8 @@ int64_t VideoState::istream_seek(void *user_data, int64_t offset, int whence)
 
     whence &= ~AVSEEK_FORCE;
 
+    stream.clear();
+
     if(whence == AVSEEK_SIZE)
     {
         size_t prev = stream.tellg();