vulkan/hevc: handle missing active PPS

I don't pretend to understand how we get into this situation, but there
are files out there where we can end up with the active PPS not being
identified when we call vk_hevc_end_frame. In these situations today,
we will segfault. So, before we give up, see if we can get the active
PPS id from the slice header, and use that if possible.

If that still doesn't work, return an error instead of segfaulting.

1 files changed, 14 insertions, 1 deletions

diff --git a/libavcodec/vulkan_hevc.c b/libavcodec/vulkan_hevc.c
index af5da3984b..ab0f6b96d0 100644
--- a/libavcodec/vulkan_hevc.c
+++ b/libavcodec/vulkan_hevc.c
@@ -900,6 +900,7 @@ static int vk_hevc_end_frame(AVCodecContext *avctx)
     FFVulkanDecodePicture *vp = &hp->vp;
     FFVulkanDecodePicture *rvp[HEVC_MAX_REFS] = { 0 };
     AVFrame *rav[HEVC_MAX_REFS] = { 0 };
+    int err;
 
     if (!hp->h265_pic_info.sliceSegmentCount)
         return 0;
@@ -908,7 +909,19 @@ static int vk_hevc_end_frame(AVCodecContext *avctx)
         const HEVCSPS *sps = h->ps.sps;
         const HEVCPPS *pps = h->ps.pps;
 
-        int err = vk_hevc_create_params(avctx, &dec->session_params);
+        if (!pps) {
+            unsigned int pps_id = h->sh.pps_id;
+            if (pps_id < HEVC_MAX_PPS_COUNT && h->ps.pps_list[pps_id] != NULL)
+                pps = (const HEVCPPS *)h->ps.pps_list[pps_id]->data;
+        }
+
+        if (!pps) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Encountered frame without a valid active PPS reference.\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        err = vk_hevc_create_params(avctx, &dec->session_params);
         if (err < 0)
             return err;