From 1836a88926907664f15271e69ced8baebad360d0 Mon Sep 17 00:00:00 2001
From: Hendrik Leppkes <[email protected]>
Date: Tue, 28 Dec 2021 14:38:10 +0100
Subject: [PATCH] hevcdec: skip slices with missing PPS instead of skipping the
 entire packet

Aborting decoding of the entire packet on a missing PPS can result in
missing the actual PPS on streams with badly ordered NALs, where the
SPS/PPS/VPS are stitched to the back of the previous frame, instead of
the beginning of the next frame.

Instead, skip the undecodable slice, and let the decoder process further
NALs in the same packet.
---
 libavcodec/hevcdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 3aa70e2245..c2451d682e 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -575,7 +575,7 @@ static int hls_slice_header(HEVCContext *s)
     sh->pps_id = get_ue_golomb_long(gb);
     if (sh->pps_id >= HEVC_MAX_PPS_COUNT || !s->ps.pps_list[sh->pps_id]) {
         av_log(s->avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", sh->pps_id);
-        return AVERROR_INVALIDDATA;
+        return 1; // skip slice with missing PPS
     }
     if (!sh->first_slice_in_pic_flag &&
         s->ps.pps != (HEVCPPS*)s->ps.pps_list[sh->pps_id]->data) {
--
2.33.0.windows.2