From f6ae7fc2b4d2c0c5d2a8cb8ebc55f4157156c9f1 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Thu, 30 Nov 2017 23:38:49 -0800
Subject: [PATCH] Improve decoder compatibility by using num_ref_frames=1 when
 RFI is disabled. Fixes decoder hangs on Amlogic SoCs.

---
 src/SdpGenerator.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/SdpGenerator.c b/src/SdpGenerator.c
index 4cbc4f8..98f7a8f 100644
--- a/src/SdpGenerator.c
+++ b/src/SdpGenerator.c
@@ -323,6 +323,18 @@ static PSDP_OPTION getAttributesList(char*urlSafeAddr) {
             sprintf(payloadStr, "%d", slicesPerFrame);
             err |= addAttributeString(&optionHead, "x-nv-video[0].videoEncoderSlicesPerFrame", payloadStr);
         }
+
+        if (AppVersionQuad[0] >= 7) {
+            if (isReferenceFrameInvalidationEnabled()) {
+                err |= addAttributeString(&optionHead, "x-nv-video[0].maxNumReferenceFrames", "0");
+            }
+            else {
+                // Restrict the video stream to 1 reference frame if we're not using
+                // reference frame invalidation. This helps to improve compatibility with
+                // some decoders that don't like the default of having 16 reference frames.
+                err |= addAttributeString(&optionHead, "x-nv-video[0].maxNumReferenceFrames", "1");
+            }
+        }
         
         if (StreamConfig.audioConfiguration == AUDIO_CONFIGURATION_51_SURROUND) {
             audioChannelCount = CHANNEL_COUNT_51_SURROUND;