fix(xmf): emit the first frame immediately to avoid near-empty recordings

libxmf/XmfWebM.cpp

@@ -32,6 +32,7 @@ struct xmf_webm
     uint32_t frame_rate;
     uint64_t frame_count;
     uint64_t frame_time;
+    uint64_t pending_frame_start_time;
     uint64_t first_encode_time;
     uint64_t last_encode_time;
     vpx_codec_pts_t pts;
@@ -206,21 +207,26 @@ int XmfWebM_EncodeImage(XmfWebM* ctx, vpx_image_t* img, vpx_codec_pts_t start, u
     return got_pkts;
 }
 
-int XmfWebM_EncodeInternal(XmfWebM* ctx, bool force)
+int XmfWebM_EncodePendingFrame(XmfWebM* ctx, bool force)
 {
     uint32_t ms_per_frame;
+    uint64_t now;
     uint64_t ms_since_last_encode;
+    uint64_t duration;
 
     ms_per_frame = 1000 / ctx->frame_rate;
-    ms_since_last_encode = XmfTimeSource_Get(&ctx->ts) - ctx->last_encode_time;
+    now = XmfTimeSource_Get(&ctx->ts);
+    ms_since_last_encode = now - ctx->last_encode_time;
 
     if (!force && ms_since_last_encode < ms_per_frame)
         return 0;
 
-    if (ctx->pts == 0)
-        ms_since_last_encode = XmfTimeSource_Get(&ctx->ts) - ctx->frame_time;
+    duration = now - ctx->pending_frame_start_time;
 
-    XmfWebM_EncodeImage(ctx, ctx->img, ctx->pts, ms_since_last_encode);
+    if (XmfWebM_EncodeImage(ctx, ctx->img, ctx->pts, duration) < 0)
+        return -1;
+
+    ctx->pending_frame = false;
 
     return 1;
 }
@@ -234,15 +240,11 @@ int XMF_API XmfWebM_EncodeXRGB(XmfWebM* ctx, const uint8_t* srcData, uint32_t sr
 {
     uint32_t step[3];
 
-    if (!ctx->pending_frame)
+    if (ctx->pending_frame)
     {
-        ctx->first_encode_time = XmfTimeSource_Get(&ctx->ts);
-        goto convert_frame;
+        XmfWebM_EncodePendingFrame(ctx, !srcData);
     }
 
-    XmfWebM_EncodeInternal(ctx, !srcData);
-
-convert_frame:
     if (!srcData)
         return 0;
 
@@ -252,7 +254,21 @@ int XMF_API XmfWebM_EncodeXRGB(XmfWebM* ctx, const uint8_t* srcData, uint32_t sr
 
     Xpp_RGBToYCbCr420_8u_P3AC4R(srcData, srcStep, ctx->img->planes, step, width, height);
     ctx->frame_time = XmfTimeSource_Get(&ctx->ts);
-    ctx->pending_frame = true;
+
+    if (ctx->frame_count == 0)
+    {
+        /* Eagerly emit the first frame so the Gateway receives a frame even on a static recording, preventing a recording policy violation. */
+        ctx->first_encode_time = ctx->frame_time;
+        XmfWebM_EncodeImage(ctx, ctx->img, ctx->pts, 1000 / ctx->frame_rate);
+        ctx->pending_frame = false;
+    }
+    else
+    {
+        if (!ctx->pending_frame)
+            ctx->pending_frame_start_time = ctx->frame_time;
+
+        ctx->pending_frame = true;
+    }
 
     return 1;
 }