From 9afe700005ff47a6368734814fd58bbfaed62f04 Mon Sep 17 00:00:00 2001
From: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
Date: Tue, 11 Sep 2012 15:54:20 +0200
Subject: [PATCH] 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.
---
 gst/vaapi/gstvaapidecode.c | 35 ++++++++++++++++++++++-------------
 gst/vaapi/gstvaapidecode.h |  2 ++
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/gst/vaapi/gstvaapidecode.c b/gst/vaapi/gstvaapidecode.c
index 0b9643fa35..4a4f4e74e3 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 408ee08c1a..68799df52e 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;
 };