Verify forced keyframes and isolate encoder probes from live timestamps

tools/chatgui/src/stream_video_encoder.cpp

@@ -79,6 +79,8 @@ bool StreamVideoEncoder::open(const StreamVideoConfig& config) {
     for (const auto& name : encoders(config.codec)) {
         const AVCodec* encoder = avcodec_find_encoder_by_name(name.constData());
         if (!encoder) continue;
+        // Проба не оставляет references/PTS в live-контексте: после двух KEY encoder открывается заново.
+        for (int pass = 0; pass < 2; pass++) {
         close(); m->config = config; m->name = QString::fromLatin1(name);
         m->codec = avcodec_alloc_context3(encoder);
         if (!m->codec) { m->error = "Video encoder allocation failed"; break; }
@@ -108,6 +110,7 @@ bool StreamVideoEncoder::open(const StreamVideoConfig& config) {
         AVDictionary* options = nullptr;
         if (name == "libx264" || name == "libx265") {
             av_dict_set(&options, "preset", "ultrafast", 0); av_dict_set(&options, "tune", "zerolatency", 0);
+            av_dict_set(&options, "forced-idr", "1", 0);
             if (name == "libx264") av_dict_set(&options, "x264-params", "scenecut=0:open-gop=0:repeat-headers=0", 0);
             else av_dict_set(&options, "x265-params", "bframes=0:rc-lookahead=0:open-gop=0:pools=1:frame-threads=1:log-level=error", 0);
         } else if (name.endsWith("_nvenc")) {
@@ -118,9 +121,12 @@ bool StreamVideoEncoder::open(const StreamVideoConfig& config) {
             av_dict_set(&options, "deadline", "realtime", 0); av_dict_set(&options, "cpu-used", "8", 0);
             av_dict_set(&options, "lag-in-frames", "0", 0); av_dict_set(&options, "row-mt", "1", 0);
         } else if (name == "libsvtav1") {
-            av_dict_set(&options, "preset", "12", 0); av_dict_set(&options, "svtav1-params", "pred-struct=1:lookahead=0:lp=2", 0);
+            c->rc_max_rate = 0;
+            av_dict_set(&options, "preset", "11", 0); av_dict_set(&options, "svtav1-params", "pred-struct=1:lookahead=0:lp=2", 0);
         } else if (name.endsWith("_qsv")) {
             av_dict_set(&options, "async_depth", "1", 0); av_dict_set(&options, "look_ahead", "0", 0);
+        } else if (name.endsWith("_vaapi")) {
+            av_dict_set(&options, "async_depth", "1", 0);
         } else if (name == "libvvenc") av_dict_set(&options, "preset", "fast", 0);
         if (result >= 0) result = avcodec_open2(c, encoder, &options);
         av_dict_free(&options);
@@ -144,17 +150,26 @@ bool StreamVideoEncoder::open(const StreamVideoConfig& config) {
         if (result < 0) {
             m->error = ffError(result);
             DEBUG_DEBUG(DEBUG_CATEGORY_VIDEO, "desktop encoder unavailable name=%s size=%dx%d error=%s",
-                name.constData(), config.width, config.height, qPrintable(m->error)); continue;
+                name.constData(), config.width, config.height, qPrintable(m->error)); break;
         }
+        if (!pass) {
         QImage probe(config.width, config.height, QImage::Format_RGB32); probe.fill(Qt::black);
         QList<StreamEncodedFrame> output;
         if (!encode(probe, 0, true, output) || output.isEmpty() || !output.front().key) {
             DEBUG_WARN(DEBUG_CATEGORY_VIDEO, "desktop encoder probe lacks immediate KEY name=%s error=%s", name.constData(), qPrintable(m->error));
-            continue;
+            break;
         }
-        DEBUG_INFO(DEBUG_CATEGORY_VIDEO, "desktop encoder ready name=%s codec=%d size=%dx%d fps=%d bitrate=%d probe_KEY=%d",
-            name.constData(), config.codec, config.width, config.height, config.fps, config.bitrate, output.front().data.size());
+        output.clear();
+        if (!encode(probe, 1000000 / config.fps, true, output) || output.isEmpty() || !output.front().key) {
+            DEBUG_WARN(DEBUG_CATEGORY_VIDEO, "desktop encoder cannot force an independent KEY name=%s error=%s", name.constData(), qPrintable(m->error));
+            break;
+        }
+        continue;
+        }
+        DEBUG_INFO(DEBUG_CATEGORY_VIDEO, "desktop encoder ready name=%s codec=%d size=%dx%d fps=%d bitrate=%d two_KEYs=verified",
+            name.constData(), config.codec, config.width, config.height, config.fps, config.bitrate);
         return true;
+        }
     }
     if (m->error.isEmpty()) m->error = "No working encoder for " + codecName(config.codec);
 #else
@@ -183,6 +198,7 @@ bool StreamVideoEncoder::encode(const QImage& image, uint64_t pts, bool key, QLi
         result = sws_scale(m->scale, input, stride, 0, canvas.height(), m->frame->data, m->frame->linesize);
     }
     m->frame->pts = static_cast<int64_t>(pts); m->frame->pict_type = key ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_NONE;
+    if (key) m->frame->flags |= AV_FRAME_FLAG_KEY; else m->frame->flags &= ~AV_FRAME_FLAG_KEY;
     AVFrame* hardware = nullptr;
     if (result >= 0 && m->codec->hw_frames_ctx) {
         hardware = av_frame_alloc();