Drain startup audio on END and validate Opus fixture failures

tools/chatgui/src/streamplayer_window.cpp

@@ -186,7 +186,7 @@ void StreamPlayerWindow::decode() {
     uint32_t videoRevision = 0;
     auto reset = [&] {
         avcodec_free_context(&decoder);
-        opus_codec_decoder_destroy(opus); opus = nullptr; expectedAudio = -1; waitKey = true;
+        opus_codec_decoder_destroy(opus); opus = nullptr; expectedAudio = -1; waitKey = true; prerollSamples = 0;
         std::lock_guard<std::mutex> guard(p.lock);
         p.videos.clear(); p.videoBytes = 0; p.audios.clear(); p.prefillUntil = 0; p.videoBase = p.audioPts = -1;
         emit statusChanged(text("Waiting for a key frame…"));
@@ -213,7 +213,11 @@ void StreamPlayerWindow::decode() {
                 : record.reason == STREAM_CLOSE_GROUP ? "The channel is closed" : "Could not continue the stream";
             fail(text(reason)); break;
         }
-        if (record.kind == StreamRecordKind::End) { std::lock_guard<std::mutex> guard(p.lock); p.ended = true; break; }
+        if (record.kind == StreamRecordKind::End) {
+            std::lock_guard<std::mutex> guard(p.lock); p.ended = true;
+            if (p.videoBase < 0) p.audios.clear();
+            break;
+        }
         if (record.pts > INT64_MAX) { fail(text("Invalid stream timestamp")); break; }
         if (record.kind == StreamRecordKind::Audio) {
             if (!p.audioAvailable) continue;