Adapt the stream QP ceiling from measured encoded bitrate

tools/chatgui/src/stream_publish_engine.cpp

@@ -1,6 +1,7 @@
 #include "stream_publish_engine.h"
 #include "sound_manager.h"
 #include "audio_event_queue.h"
+#include "stream_qp_control.h"
 #include "../transport/stream_bridge.h"
 #include "debug_config.h"
 #include <QGuiApplication>
@@ -111,6 +112,7 @@ struct StreamPublishEngine::Impl {
     std::atomic<uint64_t> imageFrames{0};
     std::atomic<uint64_t> convertedFrames{0}, encodedFrames{0}, deliveredFrames{0}, repeatedFrames{0};
     std::atomic<uint64_t> encodedBytes{0}, lastKeyBytes{0}; // Видео до сетевой отправки, без повторов транспорта.
+    std::atomic<int> videoMaxQp{-1};
     uint64_t bitrateBytes = 0, videoBitrate = 0;
     int64_t bitrateAt = 0;
     void videoProgress(const char* stage) {
@@ -240,6 +242,7 @@ bool StreamPublishEngine::running() const { return m->running.load(); }
 uint64_t StreamPublishEngine::group() const { return m->group; }
 StreamPublishConfig StreamPublishEngine::config() const { std::lock_guard<std::mutex> guard(m->lock); return m->wanted; }
 uint64_t StreamPublishEngine::videoBitrate() const { return active() ? m->videoBitrate : 0; }
+int StreamPublishEngine::videoMaxQp() const { return active() ? m->videoMaxQp.load() : -1; }
 QVariant StreamPublishEngine::previewFrame() const {
 #ifdef HAVE_STREAM_CAPTURE
     std::lock_guard<std::mutex> guard(m->lock); return QVariant::fromValue(m->previewFrame);
@@ -580,6 +583,10 @@ bool StreamPublishEngine::start(uint64_t group, const StreamPublishConfig& confi
         DEBUG_WARN(DEBUG_CATEGORY_VIDEO, "desktop capture/encoder unavailable codec=%d", config.video.codec);
         emit errorOccurred(text("Video capture or encoder is unavailable")); return false;
     }
+    if (config.adaptiveQp && (config.video.maxQp < 0 || config.video.codec > 2)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_VIDEO, "desktop invalid QP adaptation codec=%d max_qp=%d", config.video.codec, config.video.maxQp);
+        emit errorOccurred(text("Select a maximum QP before enabling adaptation")); return false;
+    }
     if (config.audio && !m_microphone.acquire()) {
         DEBUG_WARN(DEBUG_CATEGORY_STREAM, "desktop publication blocked: microphone owned by another operation");
         emit errorOccurred(text("The microphone is used by another operation")); return false;
@@ -590,6 +597,7 @@ bool StreamPublishEngine::start(uint64_t group, const StreamPublishConfig& confi
       m->origin = m->started = monotonicUs(); m->stats = {}; }
     m->convertedFrames = m->encodedFrames = m->deliveredFrames = m->repeatedFrames = 0;
     m->encodedBytes = m->lastKeyBytes = 0; m->bitrateBytes = m->videoBitrate = 0; m->bitrateAt = m->origin;
+    m->videoMaxQp = config.video.maxQp;
     m->videoProgress("starting"); m->captureReport = 0;
     m->captureReportRaw = m->captureReportConverted = m->captureReportEncoded = m->captureReportDelivered = 0;
     m->id = QRandomGenerator::global()->generate64(); if (!m->id) m->id = 1;
@@ -633,6 +641,10 @@ bool StreamPublishEngine::start(uint64_t group, const StreamPublishConfig& confi
 
 bool StreamPublishEngine::reconfigure(const StreamPublishConfig& config) {
     if (!m->running) return false;
+    if (config.adaptiveQp && (config.video.maxQp < 0 || config.video.codec > 2)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_VIDEO, "desktop invalid QP adaptation codec=%d max_qp=%d", config.video.codec, config.video.maxQp);
+        emit errorOccurred(text("Select a maximum QP before enabling adaptation")); return false;
+    }
     StreamPublishConfig previous = this->config();
     if (previous.source.id == "portal" && config.source.sameSource(previous.source) && config.showCursor != previous.showCursor) {
         DEBUG_WARN(DEBUG_CATEGORY_VIDEO, "Wayland capture cursor mode cannot change during a portal session");
@@ -852,6 +864,7 @@ void StreamPublishEngine::videoLoop(StreamPublishConfig initial) {
     std::unique_ptr<LiveVideoEncoder> encoder;
     StreamPublishConfig encoding;
     QImage lastImage; uint64_t current = 0; uint32_t revision = 0;
+    StreamQpControl qp; uint64_t qpGeneration = 0;
     int64_t lastPts = -1, lastKey = -1000000, next = 0, report = 0; unsigned count = 0, skipped = 0;
     while (m->running) {
         m->videoProgress("waiting-frame");
@@ -892,7 +905,8 @@ void StreamPublishEngine::videoLoop(StreamPublishConfig initial) {
         if (generation != current) {
             auto comparable = config.video; comparable.bitrate = encoding.video.bitrate;
             bool onlyBitrate = encoder && comparable == encoding.video && config.source.sameSource(encoding.source);
-            if (onlyBitrate && encoder->setBitrate(config.video.bitrate)) {
+            if (onlyBitrate && (!config.adaptiveQp || encoder->canSetMaxQp())
+                && (config.video == encoding.video || encoder->setBitrate(config.video.bitrate))) {
                 current = generation; encoding = config;
                 { std::lock_guard<std::mutex> guard(m->lock);
                   if (m->generation == generation) { m->good = config; m->hasGood = true; m->confirmedGeneration = generation; } }
@@ -936,6 +950,13 @@ void StreamPublishEngine::videoLoop(StreamPublishConfig initial) {
                     });
                     continue;
                 }
+                if (config.adaptiveQp && !candidate->canSetMaxQp()) {
+                    DEBUG_ERROR(DEBUG_CATEGORY_VIDEO, "desktop QP adaptation unavailable encoder=%s", qPrintable(candidate->name()));
+                    QMetaObject::invokeMethod(this, [this, generation] {
+                        sourceFailed(generation, text("QP adaptation is unavailable for this encoder. Disable adaptation or choose another codec."));
+                    });
+                    next = monotonicUs() + 100000; continue;
+                }
                 // Начальный формат publisher уже зарегистрирован; уточнение размера требует новой revision даже до первого KEY.
                 revision = revision ? revision + 1 : config.video == initial.video ? 1 : 2;
                 m->videoProgress("replace-encoder");
@@ -948,6 +969,17 @@ void StreamPublishEngine::videoLoop(StreamPublishConfig initial) {
                     (unsigned long long)generation, revision, qPrintable(encoder->name()));
             }
         }
+        if (qpGeneration != current) {
+            qp.reset(config.video.maxQp, config.video.bitrate, config.adaptiveQp, monotonicUs());
+            if (encoder->canSetMaxQp() && !encoder->setMaxQp(config.video.maxQp < 0 ? 51 : config.video.maxQp)) {
+                QString error = encoder->error();
+                QMetaObject::invokeMethod(this, [this, generation, error] { sourceFailed(generation, error); });
+                next = monotonicUs() + 100000; continue;
+            }
+            qpGeneration = current; m->videoMaxQp = qp.limit();
+            DEBUG_INFO(DEBUG_CATEGORY_VIDEO, "desktop QP control encoder=%s base=%d adaptive=%d target_bps=%d step=1 interval_ms=2000",
+                qPrintable(encoder->name()), config.video.maxQp, config.adaptiveQp, config.video.bitrate);
+        }
         bool screen = config.source.kind != StreamVideoSource::Camera;
         if (!frame.isNull()) {
             if (!screen && (capture <= lastPts || monotonicUs() - m->origin - capture > 250000)) { skipped++; continue; }
@@ -968,9 +1000,11 @@ void StreamPublishEngine::videoLoop(StreamPublishConfig initial) {
         }
         m->encodedFrames += output.size();
         m->videoProgress("publish-frame");
+        uint64_t frameBytes = 0;
         stream_media_format format{(uint16_t)config.video.width, (uint16_t)config.video.height, (uint16_t)config.video.rotation,
             (uint8_t)config.video.codec, (uint8_t)(config.audio ? STREAM_MEDIA_OPUS_STEREO : 0), revision};
         for (const auto& encoded : output) {
+            frameBytes += encoded.data.size();
             m->encodedBytes += encoded.data.size();
             if (encoded.key) m->lastKeyBytes = encoded.data.size();
             if (gui_stream_publish_feed(m->id, true, encoded.pts, encoded.key, encoded.data, &format) == 1) {
@@ -994,6 +1028,18 @@ void StreamPublishEngine::videoLoop(StreamPublishConfig initial) {
                 }
             } else skipped++;
         }
+        const int previousQp = qp.limit(), selectedQp = qp.update(frameBytes, monotonicUs());
+        if (selectedQp != previousQp) {
+            if (!encoder->setMaxQp(selectedQp)) {
+                QString error = encoder->error();
+                QMetaObject::invokeMethod(this, [this, generation, error] { sourceFailed(generation, error); });
+                next = monotonicUs() + 100000; continue;
+            }
+            m->videoMaxQp = selectedQp;
+            DEBUG_INFO(DEBUG_CATEGORY_VIDEO, "desktop QP adapted encoder=%s previous=%d selected=%d base=%d actual_bps=%llu target_bps=%d",
+                qPrintable(encoder->name()), previousQp, selectedQp, config.video.maxQp,
+                (unsigned long long)qp.bitrate(), config.video.bitrate);
+        }
         if (now - report >= 1000000) {
             DEBUG_DEBUG(DEBUG_CATEGORY_VIDEO, "desktop capture generation=%llu encoded=%u skipped=%u frame_age=%lldus encoder=%s",
                 (unsigned long long)generation, count, skipped, (long long)(screen ? 0 : now - m->origin - capture), qPrintable(encoder->name()));