Finish decoder capability probes after first paced output and drain

tools/chatgui/tests/test_call_video_gpu.cpp

@@ -25,9 +25,10 @@ static QByteArray selected;
 static unsigned opened = 0, software = 0;
 static int depth = 1;
 static bool burst = false, badReplacement = false, badProbe = false;
-struct DecodePending { std::deque<AVFrame*> frames; bool eos = false; };
+struct DecodePending { std::deque<AVFrame*> frames; bool eos = false; unsigned inputs = 0; };
 static std::map<AVCodecContext*, DecodePending> decoderContexts;
 static bool delayedDecoder = false;
+static unsigned probeInputs = 0, probeOutputs = 0, probeMaxInputs = 0;
 
 extern "C" const AVCodec* __real_avcodec_find_encoder_by_name(const char*);
 extern "C" const AVCodec* __wrap_avcodec_find_encoder_by_name(const char* name) {
@@ -116,6 +117,9 @@ extern "C" void __wrap_avcodec_free_context(AVCodecContext** context) {
 extern "C" int __real_avcodec_send_packet(AVCodecContext*, const AVPacket*);
 extern "C" int __wrap_avcodec_send_packet(AVCodecContext* context, const AVPacket* packet) {
     int result = __real_avcodec_send_packet(context, packet);
+    if (delayedDecoder && packet && result >= 0) {
+        ++probeInputs; probeMaxInputs = std::max(probeMaxInputs, ++decoderContexts[context].inputs);
+    }
     if (delayedDecoder && !packet && result >= 0) decoderContexts[context].eos = true;
     return result;
 }
@@ -129,6 +133,7 @@ extern "C" int __wrap_avcodec_receive_frame(AVCodecContext* context, AVFrame* ou
     if (result < 0 && result != AVERROR(EAGAIN) && result != AVERROR_EOF) return result;
     if (state.frames.empty()) return result;
     if (!state.eos && state.frames.size() <= 2) return AVERROR(EAGAIN);
+    ++probeOutputs;
     av_frame_move_ref(output, state.frames.front()); av_frame_free(&state.frames.front()); state.frames.pop_front(); return 0;
 }
 
@@ -138,9 +143,26 @@ private slots:
     void initTestCase() { debug_config_init(); debug_set_level(DEBUG_LEVEL_WARN); av_log_set_level(AV_LOG_ERROR); }
     void init() {
         selected.clear(); opened = software = 0; depth = 1; burst = badReplacement = badProbe = delayedDecoder = false;
+        probeInputs = probeOutputs = probeMaxInputs = 0;
         QVERIFY(contexts.empty()); QVERIFY(decoderContexts.empty());
     }
     void cleanup() { QVERIFY(contexts.empty()); QVERIFY(decoderContexts.empty()); }
+    void capabilityProbeDrainsFirstOutput() {
+        // Реальный software decoder выдаёт первый кадр только после третьего input, затем хранит хвост до EOS.
+        delayedDecoder = true;
+        QElapsedTimer timer; timer.start();
+        const auto caps = CallVideoDecoder::capabilities();
+        for (const auto& limit : caps.decode) {
+            QCOMPARE(limit.profiles, uint8_t(3)); QCOMPARE(limit.fps, uint16_t(60));
+            QCOMPARE(limit.width, uint16_t(1920)); QCOMPARE(limit.height, uint16_t(1920));
+        }
+        QVERIFY(probeInputs > 0); QCOMPARE(probeMaxInputs, 3u); QCOMPARE(probeOutputs, probeInputs);
+        const unsigned before = probeInputs;
+        const auto cached = CallVideoDecoder::capabilities();
+        QCOMPARE(cached.decode[0].profiles, caps.decode[0].profiles); QCOMPARE(probeInputs, before);
+        qInfo("Decoder capability probe with delayed output: %lldms, inputs=%u outputs=%u max_per_mode=%u",
+            timer.elapsed(), probeInputs, probeOutputs, probeMaxInputs);
+    }
     void delayedDecodeAndGenerationDrain() {
         LiveVideoEncoder encoder; LiveVideoConfig config;
         config.width = 640; config.height = 360; config.codec = 1; config.backend = "libx264";