From dd5c7378bb92f174e7b3b36df3d7685ed60f29c6 Mon Sep 17 00:00:00 2001 From: Bela Bodecs Date: Sat, 18 Jan 2020 17:41:55 +0100 Subject: [PATCH] avformat/hlsenc: program_date_time and append_list flags conflict When program_date_time flag is present, in m3u8 playlist file each segment has a corresponding EXT-X-PROGRAM-DATE-TIME value. The intial program-date-time value is the actual current time at init and each new segment increments this value by its duration. When append_list flags is also present, existing playlist parsing by hls_append_segment treats existing segments as new segments regarding the program-date-time calculation. But it should not do that, because this way all real the new segments' EXT-X-PROGRAM-DATE-TIME values will be shifted erroneously by the sum duration of existing segments. Instead it should have decremented the initial program-date-time value by its duration. This would ensure that the first new segment's program-date-time value had the current time as it is expected. This patch corrects this behaviour and prevent existing segments to increment the value of initial_prog_date_time variable but decrements it. Reviewed-by: Steven Liu Signed-off-by: Bela Bodecs --- libavformat/hlsenc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c index e87f08b0e6..13f34197ed 100644 --- a/libavformat/hlsenc.c +++ b/libavformat/hlsenc.c @@ -1187,6 +1187,7 @@ static int parse_playlist(AVFormatContext *s, const char *url, VariantStream *vs is_segment = 0; new_start_pos = avio_tell(vs->avf->pb); vs->size = new_start_pos - vs->start_pos; + vs->initial_prog_date_time -= vs->duration; // this is a previously existing segment ret = hls_append_segment(s, hls, vs, vs->duration, vs->start_pos, vs->size); if (ret < 0) goto fail;