Merge branch 'ffmpeg5' into 'master'

fix hang with ffmpeg5 (ffmpeg_decoder: signal EOF/errors on readPacket)

Closes #6631

See merge request OpenMW/openmw!1941

CHANGELOG.md

@@ -109,6 +109,7 @@
     Bug #6606: Quests with multiple IDs cannot always be restarted
     Bug #6653: With default settings the in-game console doesn't fit into screen
     Bug #6655: Constant effect absorb attribute causes the game to break
+    Bug #6631: Fix ffmpeg avio API usage causing hangs in ffmpeg version 5
     Bug #6667: Pressing the Esc key while resting or waiting causes black screen.
     Bug #6670: Dialogue order is incorrect
     Bug #6680: object.cpp handles nodetree unsafely, memory access with dangling pointer

apps/openmw/mwsound/ffmpeg_decoder.cpp

@@ -18,11 +18,14 @@ int FFmpeg_Decoder::readPacket(void *user_data, uint8_t *buf, int buf_size)
         std::istream& stream = *static_cast<FFmpeg_Decoder*>(user_data)->mDataStream;
         stream.clear();
         stream.read((char*)buf, buf_size);
-        return stream.gcount();
+        std::streamsize count = stream.gcount();
+        if (count == 0)
+            return AVERROR_EOF;
+        return count;
     }
     catch (std::exception& )
     {
-        return 0;
+        return AVERROR_UNKNOWN;
     }
 }