Rémi Bernon : winegstreamer: Implement MF_LOW_LATENCY attribute and latency query.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 226f8b7c28408762bc54c32406d57377b19f0866
URL:    https://gitlab.winehq.org/wine/wine/-/commit/226f8b7c28408762bc54c32406d5737...

Author: Rémi Bernon 
Date:   Thu May 25 14:15:43 2023 +0200

winegstreamer: Implement MF_LOW_LATENCY attribute and latency query.

---

dlls/winegstreamer/h264_decoder.c |  4 ++++
 dlls/winegstreamer/unixlib.h      |  1 +
 dlls/winegstreamer/wg_transform.c | 23 +++++++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/dlls/winegstreamer/h264_decoder.c b/dlls/winegstreamer/h264_decoder.c
index 8795d12169f..c6e817df6b0 100644
--- a/dlls/winegstreamer/h264_decoder.c
+++ b/dlls/winegstreamer/h264_decoder.c
@@ -88,6 +88,7 @@ static HRESULT try_create_wg_transform(struct h264_decoder *decoder)
     };
     struct wg_format input_format;
     struct wg_format output_format;
+    UINT32 low_latency;

if (decoder->wg_transform)
         wg_transform_destroy(decoder->wg_transform);
@@ -109,6 +110,9 @@ static HRESULT try_create_wg_transform(struct h264_decoder *decoder)
     output_format.u.video.fps_d = 0;
     output_format.u.video.fps_n = 0;

+    if (SUCCEEDED(IMFAttributes_GetUINT32(decoder->attributes, &MF_LOW_LATENCY, &low_latency)))
+        attrs.low_latency = !!low_latency;
+
     if (!(decoder->wg_transform = wg_transform_create(&input_format, &output_format, &attrs)))
         return E_FAIL;

diff --git a/dlls/winegstreamer/unixlib.h b/dlls/winegstreamer/unixlib.h
index 938319faea7..a9892bf9d4f 100644
--- a/dlls/winegstreamer/unixlib.h
+++ b/dlls/winegstreamer/unixlib.h
@@ -309,6 +309,7 @@ struct wg_transform_attrs
 {
     UINT32 output_plane_align;
     UINT32 input_queue_length;
+    BOOL low_latency;
 };

struct wg_transform_create_params
diff --git a/dlls/winegstreamer/wg_transform.c b/dlls/winegstreamer/wg_transform.c
index f21914b4086..d6218af04b9 100644
--- a/dlls/winegstreamer/wg_transform.c
+++ b/dlls/winegstreamer/wg_transform.c
@@ -101,6 +101,26 @@ static GstFlowReturn transform_sink_chain_cb(GstPad *pad, GstObject *parent, Gst
     return GST_FLOW_OK;
 }

+static gboolean transform_src_query_latency(struct wg_transform *transform, GstQuery *query)
+{
+    GST_LOG("transform %p, query %p", transform, query);
+    gst_query_set_latency(query, transform->attrs.low_latency, 0, 0);
+    return true;
+}
+
+static gboolean transform_src_query_cb(GstPad *pad, GstObject *parent, GstQuery *query)
+{
+    struct wg_transform *transform = gst_pad_get_element_private(pad);
+
+    switch (query->type)
+    {
+    case GST_QUERY_LATENCY:
+        return transform_src_query_latency(transform, query);
+    default:
+        return gst_pad_query_default(pad, parent, query);
+    }
+}
+
 static gboolean transform_sink_query_cb(GstPad *pad, GstObject *parent, GstQuery *query)
 {
     struct wg_transform *transform = gst_pad_get_element_private(pad);
@@ -312,6 +332,9 @@ NTSTATUS wg_transform_create(void *args)
     if (!transform->my_src)
         goto out;

+    gst_pad_set_element_private(transform->my_src, transform);
+    gst_pad_set_query_function(transform->my_src, transform_src_query_cb);
+
     if (!(transform->output_caps = wg_format_to_caps(&output_format)))
         goto out;
     if (!(template = gst_pad_template_new("sink", GST_PAD_SINK, GST_PAD_ALWAYS, transform->output_caps)))