Clarify desktop demand reader ownership and preparation bounds

tools/chatgui/src/streamplayer_window.h

@@ -1,4 +1,4 @@
-/* Просмотр одной live-трансляции: FFmpeg/Opus в worker, ограниченные очереди PCM/кадров.
+/* Просмотр одной live-трансляции: запас остаётся в RS-кольце, worker готовит ближайшие FFmpeg/Opus кадры.
  * GUI владеет output device и окном; audio callback публикует часы физического воспроизведения.
  * Закрытие останавливает worker и снимает reader. Публикация и общий транспорт не закрываются. */
 #pragma once

tools/chatgui/transport/stream_bridge.cpp

@@ -103,36 +103,36 @@ void process(void*) {
         bridge.stopping = false;
     }
     if (bridge.opening) {
-    bridge.opening = false; bridge.viewer = bridge.requested; bridge.requested = {};
-    bridge.status = {}; bridge.statusId = bridge.viewer.id; bridge.position = -1; bridge.waiting = false;
-    stream_member_state member{};
-    int reason = STREAM_CLOSE_FAILED;
-    int result = stream_member_load(bridge.inst, bridge.viewer.group, bridge.viewer.source, &member, nullptr);
-    if (result == STREAM_OK && (!member.published || member.source.source_epoch != bridge.viewer.epoch)) {
-        DEBUG_WARN(DEBUG_CATEGORY_STREAM, "desktop selected source changed source=%llx expected=%llx actual=%llx",
-                   (unsigned long long)bridge.viewer.source, (unsigned long long)bridge.viewer.epoch,
-                   (unsigned long long)(member.published ? member.source.source_epoch : 0));
-        result = STREAM_ERR_CONFLICT; reason = STREAM_CLOSE_SOURCE_CHANGED;
-    }
-    if (result == STREAM_OK) result = stream_subscribe_open(bridge.inst, bridge.viewer.group, bridge.viewer.source, &bridge.handle);
-    stream_info info{};
-    if (result == STREAM_OK) result = stream_get_info(bridge.handle, &info);
-    if (result == STREAM_OK && info.descriptor.source_epoch != bridge.viewer.epoch) {
-        DEBUG_WARN(DEBUG_CATEGORY_STREAM, "desktop reader encountered stale local epoch");
-        result = STREAM_ERR_CONFLICT; reason = STREAM_CLOSE_SOURCE_CHANGED;
-    }
-    if (result == STREAM_OK) result = stream_media_enable(bridge.handle, STREAM_MEDIA_TRACK_VIDEO | STREAM_MEDIA_TRACK_AUDIO);
-    if (result != STREAM_OK) {
-        DEBUG_ERROR(DEBUG_CATEGORY_STREAM, "desktop viewer open failed id=%llu group=%llx source=%llx result=%d",
+        bridge.opening = false; bridge.viewer = bridge.requested; bridge.requested = {};
+        bridge.status = {}; bridge.statusId = bridge.viewer.id; bridge.position = -1; bridge.waiting = false;
+        stream_member_state member{};
+        int reason = STREAM_CLOSE_FAILED;
+        int result = stream_member_load(bridge.inst, bridge.viewer.group, bridge.viewer.source, &member, nullptr);
+        if (result == STREAM_OK && (!member.published || member.source.source_epoch != bridge.viewer.epoch)) {
+            DEBUG_WARN(DEBUG_CATEGORY_STREAM, "desktop selected source changed source=%llx expected=%llx actual=%llx",
+                       (unsigned long long)bridge.viewer.source, (unsigned long long)bridge.viewer.epoch,
+                       (unsigned long long)(member.published ? member.source.source_epoch : 0));
+            result = STREAM_ERR_CONFLICT; reason = STREAM_CLOSE_SOURCE_CHANGED;
+        }
+        if (result == STREAM_OK) result = stream_subscribe_open(bridge.inst, bridge.viewer.group, bridge.viewer.source, &bridge.handle);
+        stream_info info{};
+        if (result == STREAM_OK) result = stream_get_info(bridge.handle, &info);
+        if (result == STREAM_OK && info.descriptor.source_epoch != bridge.viewer.epoch) {
+            DEBUG_WARN(DEBUG_CATEGORY_STREAM, "desktop reader encountered stale local epoch");
+            result = STREAM_ERR_CONFLICT; reason = STREAM_CLOSE_SOURCE_CHANGED;
+        }
+        if (result == STREAM_OK) result = stream_media_enable(bridge.handle, STREAM_MEDIA_TRACK_VIDEO | STREAM_MEDIA_TRACK_AUDIO);
+        if (result != STREAM_OK) {
+            DEBUG_ERROR(DEBUG_CATEGORY_STREAM, "desktop viewer open failed id=%llu group=%llx source=%llx result=%d",
+                       (unsigned long long)bridge.viewer.id, (unsigned long long)bridge.viewer.group,
+                       (unsigned long long)bridge.viewer.source, result);
+            closeViewer(StreamRecordKind::Closed, reason); return;
+        }
+        output({bridge.viewer.id, 0, StreamRecordKind::Opened});
+        DEBUG_INFO(DEBUG_CATEGORY_STREAM, "desktop viewer opened id=%llu group=%llx source=%llx epoch=%llx",
                    (unsigned long long)bridge.viewer.id, (unsigned long long)bridge.viewer.group,
-                   (unsigned long long)bridge.viewer.source, result);
-        closeViewer(StreamRecordKind::Closed, reason); return;
-    }
-    output({bridge.viewer.id, 0, StreamRecordKind::Opened});
-    DEBUG_INFO(DEBUG_CATEGORY_STREAM, "desktop viewer opened id=%llu group=%llx source=%llx epoch=%llx",
-               (unsigned long long)bridge.viewer.id, (unsigned long long)bridge.viewer.group,
-               (unsigned long long)bridge.viewer.source, (unsigned long long)bridge.viewer.epoch);
-    bridge.wantRead = true;
+                   (unsigned long long)bridge.viewer.source, (unsigned long long)bridge.viewer.epoch);
+        bridge.wantRead = true;
     }
     if (!bridge.handle) return;
     if (bridge.resync) {

tools/chatgui/transport/stream_bridge.h

@@ -1,7 +1,7 @@
 /* Desktop live viewer: attach/detach в uasync до destroy ядра; остальные вызовы потокобезопасны.
- * Один viewer, команды содержат IDs; RX ограничен 4MB/256 записей, borrowed данные копируются.
+ * Один viewer, команды содержат IDs; подготовлено не более двух media records, общий предел RX 4MiB/16 записей.
  * Watch до attach запоминает выбранную группу. Каталог идёт через CHAT_EVT_STREAM_SOURCES,
- * медиаданные — через отдельную очередь pull. */
+ * media pull читает ближайшие кадры из общего RS-кольца; копия нужна только для передачи между потоками. */
 #pragma once
 
 #include <QByteArray>