From c64d56a2f53455f803456811873ff08fce98e122 Mon Sep 17 00:00:00 2001
From: Steven Liu <liuqi05@kuaishou.com>
Date: Tue, 20 Jul 2021 20:07:36 +0800
Subject: [PATCH] avformat/hlsenc: minus subtitle streams count when subtitle
 stream between video and audio streams

because subtitles streams will be written to webvtt m3u8 list
so the stream index should minus subtitles streams count when subtitle
between audio and video streams.
testcase:
before patch:
ffmpeg -i input -map 0:a:0 -map 0:s:0 -map 0:v:0 -f hls aaaa.m3u8
will EXC_BAD_ACCESS

after patch:
ffmpeg -i input -map 0:a:0 -map 0:s:0 -map 0:v:0 -f hls aaaa.m3u8
will ok

Signed-off-by: Steven Liu <liuqi05@kuaishou.com>
---
 libavformat/hlsenc.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index 8cd938eb97..7c37bc50b9 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -2293,6 +2293,7 @@ static int hls_write_header(AVFormatContext *s)
     VariantStream *vs = NULL;
 
     for (i = 0; i < hls->nb_varstreams; i++) {
+        int subtitle_streams = 0;
         vs = &hls->var_streams[i];
 
         ret = avformat_write_header(vs->avf, NULL);
@@ -2313,10 +2314,11 @@ static int hls_write_header(AVFormatContext *s)
             }
 
             if (outer_st->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE)
-                inner_st = vs->avf->streams[j];
-            else if (vs->vtt_avf)
+                inner_st = vs->avf->streams[j - subtitle_streams];
+            else if (vs->vtt_avf) {
                 inner_st = vs->vtt_avf->streams[0];
-            else {
+                subtitle_streams++;
+            } else {
                 /* We have a subtitle stream, when the user does not want one */
                 inner_st = NULL;
                 continue;
@@ -2403,6 +2405,7 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
     int is_ref_pkt = 1;
     int ret = 0, can_split = 1, i, j;
     int stream_index = 0;
+    int subtitle_streams = 0;
     int range_length = 0;
     const char *proto = NULL;
     int use_temp_file = 0;
@@ -2412,13 +2415,16 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
     for (i = 0; i < hls->nb_varstreams; i++) {
         vs = &hls->var_streams[i];
         for (j = 0; j < vs->nb_streams; j++) {
+            if (vs->streams[j]->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {
+                subtitle_streams++;
+            }
             if (vs->streams[j] == st) {
                 if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {
                     oc = vs->vtt_avf;
                     stream_index = 0;
                 } else {
                     oc = vs->avf;
-                    stream_index = j;
+                    stream_index = j - subtitle_streams;
                 }
                 break;
             }
@@ -2647,7 +2653,6 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
         if (ret < 0) {
             return ret;
         }
-
     }
 
     vs->packets_written++;