feat(linux): async_depth configuration for VA-API

docs/configuration.md

@@ -2891,6 +2891,35 @@ editing the `conf` file in a text editor. Use the examples as reference.
     </tr>
 </table>
 
+### vaapi_async_depth
+
+<table>
+    <tr>
+        <td>Description</td>
+        <td colspan="2">
+            Number of frames to queue in the GPU.
+            @warning{Higher values help FPS stability under GPU load,
+            but may slightly increase latency.}
+        </td>
+    </tr>
+    <tr>
+        <td>Default</td>
+        <td colspan="2">@code{}
+            1
+            @endcode</td>
+    </tr>
+    <tr>
+        <td>Range</td>
+        <td colspan="2">1-64</td>
+    </tr>
+    <tr>
+        <td>Example</td>
+        <td colspan="2">@code{}
+            vaapi_async_depth = 4
+            @endcode</td>
+    </tr>
+</table>
+
 ## Software Encoder
 
 ### sw_preset

src/config.cpp

@@ -484,6 +484,7 @@ namespace config {
 
     {
       false,  // strict_rc_buffer
+      1,  // async_depth
     },  // vaapi
 
     {},  // capture
@@ -1115,6 +1116,7 @@ namespace config {
     int_f(vars, "vt_realtime", video.vt.vt_realtime, vt::rt_from_view);
 
     bool_f(vars, "vaapi_strict_rc_buffer", video.vaapi.strict_rc_buffer);
+    int_f(vars, "vaapi_async_depth", video.vaapi.async_depth);
 
     string_f(vars, "capture", video.capture);
     string_f(vars, "encoder", video.encoder);

src/config.h

@@ -78,6 +78,7 @@ namespace config {
 
     struct {
       bool strict_rc_buffer;
+      int async_depth;
     } vaapi;
 
     std::string capture;

src/platform/linux/vaapi.cpp

@@ -251,6 +251,8 @@ namespace va {
         BOOST_LOG(info) << "Using normal encoding mode"sv;
       }
 
+      av_dict_set_int(options, "async_depth", config::video.vaapi.async_depth, 0);
+
       VAConfigAttrib rc_attr = {VAConfigAttribRateControl};
       auto status = vaGetConfigAttributes(va_display, va_profile, va_entrypoint, &rc_attr, 1);
       if (status != VA_STATUS_SUCCESS) {

src_assets/common/assets/web/config.html

@@ -327,6 +327,7 @@ <h1 class="my-4">{{ $t('config.configuration') }}</h1>
             id: "vaapi",
             name: "VA-API Encoder",
             options: {
+              "vaapi_async_depth": "1",    
               "vaapi_strict_rc_buffer": "disabled",
             },
           },

src_assets/common/assets/web/configs/tabs/encoders/VAAPIEncoder.vue

@@ -19,6 +19,16 @@ const config = ref(props.config)
               v-model="config.vaapi_strict_rc_buffer"
               default="false"
     ></Checkbox>
+
+    <!-- Async Depth -->
+    <div class="mb-3">
+      <label for="vaapi_async_depth" class="form-label">{{ $t('config.vaapi_async_depth') }}</label>
+      <input type="number" min="1" max="64" class="form-control" id="vaapi_async_depth" placeholder="1"
+             v-model="config.vaapi_async_depth" />
+      <div class="form-text">
+        {{ $t('config.vaapi_async_depth_desc') }}
+      </div>
+    </div>
   </div>
 </template>
 

src_assets/common/assets/web/public/assets/locale/en.json

@@ -371,6 +371,8 @@
     "touchpad_as_ds4_desc": "If disabled, touchpad presence will not be taken into account during gamepad type selection.",
     "upnp": "UPnP",
     "upnp_desc": "Automatically configure port forwarding for streaming over the Internet",
+    "vaapi_async_depth": "VA-API Async Depth",
+    "vaapi_async_depth_desc": "Number of frames to queue in the GPU. Higher values help FPS stability under GPU load, but may slightly increase latency.",
     "vaapi_strict_rc_buffer": "Strictly enforce frame bitrate limits for H.264/HEVC on AMD GPUs",
     "vaapi_strict_rc_buffer_desc": "Enabling this option can avoid dropped frames over the network during scene changes, but video quality may be reduced during motion.",
     "virtual_sink": "Virtual Sink",