stagefright: use small timeout for input buffer in SimpleDecodingSource

An input is not immediately available after MediaCodec.flush, resulting
in needlessly waiting for an output buffer.

Bug: 27169137
Change-Id: I3aa5872ee4f570d9da63a4cc87f3beeff61c43b0
diff --git a/media/libstagefright/SimpleDecodingSource.cpp b/media/libstagefright/SimpleDecodingSource.cpp
index e722ca6..407ac77 100644
--- a/media/libstagefright/SimpleDecodingSource.cpp
+++ b/media/libstagefright/SimpleDecodingSource.cpp
@@ -31,6 +31,7 @@
 using namespace android;
 
 const int64_t kTimeoutWaitForOutputUs = 500000; // 0.5 seconds
+const int64_t kTimeoutWaitForInputUs = 5000; // 5 milliseconds
 
 //static
 sp<SimpleDecodingSource> SimpleDecodingSource::Create(
@@ -205,13 +206,14 @@
         return ERROR_END_OF_STREAM;
     }
 
-    for (int retries = 1; ++retries; ) {
+    for (int retries = 0; ++retries; ) {
         // If we fill all available input buffers, we should expect that
         // the codec produces at least one output buffer. Also, the codec
         // should produce an output buffer in at most 1 seconds. Retry a
         // few times nonetheless.
         while (!me->mQueuedInputEOS) {
-            res = mCodec->dequeueInputBuffer(&in_ix, 0);
+            // allow some time to get input buffer after flush
+            res = mCodec->dequeueInputBuffer(&in_ix, kTimeoutWaitForInputUs);
             if (res == -EAGAIN) {
                 // no available input buffers
                 break;