diff --git a/doc/muxers.texi b/doc/muxers.texi
index f6071484ff..87c19a5cb9 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -1086,6 +1086,9 @@ seeking. This flag should be used with the @code{hls_time} option.
 @item program_date_time
 Generate @code{EXT-X-PROGRAM-DATE-TIME} tags.
 
+@item init_program_date_time
+Time to start program date time at.
+
 @item second_level_segment_index
 Makes it possible to use segment indexes as %%d in hls_segment_filename expression
 besides date/time values when strftime is on.
diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index 4ef84c05c1..5dfff6b2b6 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -212,6 +212,8 @@ typedef struct HLSContext {
     int64_t recording_time;
     int64_t max_seg_size; // every segment file max size
 
+    char *init_program_date_time;
+
     char *baseurl;
     char *vtt_format_options_str;
     char *subtitle_filename;
@@ -1192,6 +1194,25 @@ static int hls_append_segment(struct AVFormatContext *s, HLSContext *hls,
     return 0;
 }
 
+static double parse_iso8601(const char *ptr) {
+    struct tm program_date_time;
+    int y,M,d,h,m,s;
+    double ms;
+    if (sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, &s, &ms) != 7) {
+        return -1;
+    }
+
+    program_date_time.tm_year = y - 1900;
+    program_date_time.tm_mon = M - 1;
+    program_date_time.tm_mday = d;
+    program_date_time.tm_hour = h;
+    program_date_time.tm_min = m;
+    program_date_time.tm_sec = s;
+    program_date_time.tm_isdst = -1;
+
+    return mktime(&program_date_time) + (double)(ms / 1000);
+}
+
 static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs)
 {
     HLSContext *hls = s->priv_data;
@@ -1257,24 +1278,11 @@ static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs
                 }
             }
         } else if (av_strstart(line, "#EXT-X-PROGRAM-DATE-TIME:", &ptr)) {
-            struct tm program_date_time;
-            int y,M,d,h,m,s;
-            double ms;
-            if (sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, &s, &ms) != 7) {
+            discont_program_date_time = parse_iso8601(ptr);
+            if (discont_program_date_time < 0) {
                 ret = AVERROR_INVALIDDATA;
                 goto fail;
             }
-
-            program_date_time.tm_year = y - 1900;
-            program_date_time.tm_mon = M - 1;
-            program_date_time.tm_mday = d;
-            program_date_time.tm_hour = h;
-            program_date_time.tm_min = m;
-            program_date_time.tm_sec = s;
-            program_date_time.tm_isdst = -1;
-
-            discont_program_date_time = mktime(&program_date_time);
-            discont_program_date_time += (double)(ms / 1000);
         } else if (av_strstart(line, "#", NULL)) {
             continue;
         } else if (line[0]) {
@@ -2867,7 +2875,7 @@ static int hls_init(AVFormatContext *s)
     char *p = NULL;
     int http_base_proto = ff_is_http_proto(s->url);
     int fmp4_init_filename_len = strlen(hls->fmp4_init_filename) + 1;
-    double initial_program_date_time = av_gettime() / 1000000.0;
+    double initial_program_date_time = hls->init_program_date_time ? parse_iso8601(hls->init_program_date_time) : av_gettime() / 1000000.0;
 
     if (hls->use_localtime) {
         pattern = get_default_pattern_localtime_fmt(s);
@@ -3141,6 +3149,7 @@ static const AVOption options[] = {
     {"split_by_time", "split the hls segment by time which user set by hls_time", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SPLIT_BY_TIME }, 0, UINT_MAX,   E, "flags"},
     {"append_list", "append the new segments into old hls segment list", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_APPEND_LIST }, 0, UINT_MAX,   E, "flags"},
     {"program_date_time", "add EXT-X-PROGRAM-DATE-TIME", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_PROGRAM_DATE_TIME }, 0, UINT_MAX,   E, "flags"},
+    {"init_program_date_time", "Time to start program date time at", OFFSET(init_program_date_time), AV_OPT_TYPE_STRING, .flags = E},
     {"second_level_segment_index", "include segment index in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_INDEX }, 0, UINT_MAX,   E, "flags"},
     {"second_level_segment_duration", "include segment duration in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_DURATION }, 0, UINT_MAX,   E, "flags"},
     {"second_level_segment_size", "include segment size in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_SIZE }, 0, UINT_MAX,   E, "flags"},
