From 13ca5d34ba5c473211daaae0a101123bcaada3e6 Mon Sep 17 00:00:00 2001
From: Mark Thompson <sw@jkqxz.net>
Date: Mon, 11 Dec 2017 00:22:42 +0000
Subject: [PATCH] cbs_h264: Add hack for pic_timing with no active SPS

If there is exactly one possible SPS but it is not yet active then just
assume that it should be the active one.
---
 libavcodec/cbs_h264_syntax_template.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/libavcodec/cbs_h264_syntax_template.c b/libavcodec/cbs_h264_syntax_template.c
index 0fe18441c0..c2fd546822 100644
--- a/libavcodec/cbs_h264_syntax_template.c
+++ b/libavcodec/cbs_h264_syntax_template.c
@@ -560,6 +560,22 @@ static int FUNC(sei_pic_timing)(CodedBitstreamContext *ctx, RWContext *rw,
     int err;
 
     sps = h264->active_sps;
+    if (!sps) {
+        // If there is exactly one possible SPS but it is not yet active
+        // then just assume that it should be the active one.
+        int i, k = -1;
+        for (i = 0; i < H264_MAX_SPS_COUNT; i++) {
+            if (h264->sps[i]) {
+                if (k >= 0) {
+                    k = -1;
+                    break;
+                }
+                k = i;
+            }
+        }
+        if (k >= 0)
+            sps = h264->sps[k];
+    }
     if (!sps) {
         av_log(ctx->log_ctx, AV_LOG_ERROR,
                "No active SPS for pic_timing.\n");