vaapidecode: improve "no free surface" conditions.

Previously, vaapidecode would wait up to one second until a free surface
is available, or it aborts decoding. Now, vaapidecode waits until the
last decoded surface was to be presented, plus one second. Besides, end
times are now expressed relative to the monotonic clock.

2 files changed, 24 insertions, 13 deletions

diff --git a/gst/vaapi/gstvaapidecode.c b/gst/vaapi/gstvaapidecode.c
index 0b9643fa..4a4f4e74 100644
--- a/gst/vaapi/gstvaapidecode.c
+++ b/gst/vaapi/gstvaapidecode.c
@@ -189,28 +189,30 @@ gst_vaapidecode_step(GstVaapiDecode *decode)
     GstVaapiDecoderStatus status;
     GstBuffer *buffer;
     GstFlowReturn ret;
-    guint tries;
+    GstClockTime timestamp;
+    gint64 end_time;
 
     for (;;) {
-        tries = 0;
-    again:
+        end_time = decode->render_time_base;
+        if (!end_time)
+            end_time = g_get_monotonic_time();
+        end_time += GST_TIME_AS_USECONDS(decode->last_buffer_time);
+        end_time += G_TIME_SPAN_SECOND;
+
         proxy = gst_vaapi_decoder_get_surface(decode->decoder, &status);
         if (!proxy) {
             if (status == GST_VAAPI_DECODER_STATUS_ERROR_NO_SURFACE) {
-                /* Wait for a VA surface to be displayed and free'd */
-                if (++tries > 100)
-                    goto error_decode_timeout;
-                GTimeVal timeout;
-                g_get_current_time(&timeout);
-                g_time_val_add(&timeout, 10000); /* 10 ms each step */
+                gboolean was_signalled;
                 g_mutex_lock(decode->decoder_mutex);
-                g_cond_timed_wait(
+                was_signalled = g_cond_wait_until(
                     decode->decoder_ready,
                     decode->decoder_mutex,
-                    &timeout
+                    end_time
                 );
                 g_mutex_unlock(decode->decoder_mutex);
-                goto again;
+                if (was_signalled)
+                    continue;
+                goto error_decode_timeout;
             }
             if (status != GST_VAAPI_DECODER_STATUS_ERROR_NO_DATA)
                 goto error_decode;
@@ -228,7 +230,12 @@ gst_vaapidecode_step(GstVaapiDecode *decode)
         if (!buffer)
             goto error_create_buffer;
 
-        GST_BUFFER_TIMESTAMP(buffer) = GST_VAAPI_SURFACE_PROXY_TIMESTAMP(proxy);
+        timestamp = GST_VAAPI_SURFACE_PROXY_TIMESTAMP(proxy);
+        if (!decode->render_time_base)
+            decode->render_time_base = g_get_monotonic_time();
+        decode->last_buffer_time = timestamp;
+
+        GST_BUFFER_TIMESTAMP(buffer) = timestamp;
         GST_BUFFER_DURATION(buffer) = GST_VAAPI_SURFACE_PROXY_DURATION(proxy);
         gst_buffer_set_caps(buffer, GST_PAD_CAPS(decode->srcpad));
 
@@ -710,6 +717,8 @@ gst_vaapidecode_init(GstVaapiDecode *decode)
     decode->decoder_caps        = NULL;
     decode->allowed_caps        = NULL;
     decode->delayed_new_seg     = NULL;
+    decode->render_time_base    = 0;
+    decode->last_buffer_time    = 0;
     decode->is_ready            = FALSE;
 
     /* Pad through which data comes in to the element */
diff --git a/gst/vaapi/gstvaapidecode.h b/gst/vaapi/gstvaapidecode.h
index 408ee08c..68799df5 100644
--- a/gst/vaapi/gstvaapidecode.h
+++ b/gst/vaapi/gstvaapidecode.h
@@ -72,6 +72,8 @@ struct _GstVaapiDecode {
     GstCaps            *decoder_caps;
     GstCaps            *allowed_caps;
     GstEvent           *delayed_new_seg;
+    gint64              render_time_base;
+    GstClockTime        last_buffer_time;
     unsigned int        is_ready        : 1;
 };