[FFmpeg-devel] [PATCH 17/18] avformat/hls: do not care about stream start timestamps

[Anssi Hannula]

While selecting a packet to return to caller in read_packet(), the code
corrects the timestamps for starting timestamps.

However, this is wrong, since for live streams the initial timestamps
might differ just because of the time delay between the retrieval of the
various Media Playlists.

Fortunately, spec 6.2.4 mandates that all variant streams must have
matching timestamps, so we do not need to correct for initial
timestamps.

Drop the correction code.

Note that ID3 and WebVTT MPEGTS timestamps were previously ignored, so
this code was previously actually needed.

Signed-off-by: Anssi Hannula <anssi.hannula at iki.fi>
---
 libavformat/hls.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/libavformat/hls.c b/libavformat/hls.c
index c4e6dac..07c3c80 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -1361,19 +1361,12 @@ start:
             } else if (pls->cur_seq_no == minpls->cur_seq_no) {
                 int64_t dts     =    pls->pkt.dts;
                 int64_t mindts  = minpls->pkt.dts;
-                AVStream *st    =    pls->ctx->streams[pls->pkt.stream_index];
-                AVStream *minst = minpls->ctx->streams[minpls->pkt.stream_index];
                 AVRational tb    = get_timebase(   pls,    pls->pkt.stream_index);
                 AVRational mintb = get_timebase(minpls, minpls->pkt.stream_index);
 
                 if (dts == AV_NOPTS_VALUE) {
                     minplaylist = i;
                 } else if (mindts != AV_NOPTS_VALUE) {
-                    if (st->start_time    != AV_NOPTS_VALUE)
-                        dts    -= st->start_time;
-                    if (minst->start_time != AV_NOPTS_VALUE)
-                        mindts -= minst->start_time;
-
                     if (av_compare_ts(dts, tb,
                                       mindts, mintb) < 0)
                         minplaylist = i;
-- 
1.8.1.5