From: Li Kai <wolflee...@gmail.com>
Refer to https://datatracker.ietf.org/doc/html/rfc8216#section-4.3.5.2
Signed-off-by: Li Kai <wolflee...@gmail.com>
---
libavformat/hls.c | 68 ++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 62 insertions(+), 6 deletions(-)
diff --git a/libavformat/hls.c b/libavformat/hls.c
index 8204f55df3..96923c3eac 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -120,6 +120,8 @@ struct playlist {
enum PlaylistType type;
int64_t target_duration;
int64_t start_seq_no;
+ int time_offset_flag;
+ int64_t start_time_offset;
int n_segments;
struct segment **segments;
int needed;
@@ -741,6 +743,7 @@ static int parse_playlist(HLSContext *c, const char *url,
struct segment **prev_segments = NULL;
int prev_n_segments = 0;
int64_t prev_start_seq_no = -1;
+ const char *p;
if (is_http && !in && c->http_persistent && c->playlist_pb) {
in = c->playlist_pb;
@@ -889,6 +892,18 @@ static int parse_playlist(HLSContext *c, const char *url,
cur_init_section->key = NULL;
}
+ } else if (av_strstart(line, "#EXT-X-START:", &ptr)) {
+ ret = ensure_playlist(c, &pls, url);
+ if (ret < 0) {
+ goto fail;
+ }
+ if (av_strstart(ptr, "TIME-OFFSET=", &p)) {
+ float offset = strtof(p, NULL);
+ pls->start_time_offset = offset * AV_TIME_BASE;
+ pls->time_offset_flag = 1;
+ } else {
+ goto fail;
+ }
} else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
if (pls)
pls->finished = 1;
@@ -1719,12 +1734,53 @@ static int64_t select_cur_seq_no(HLSContext *c, struct
playlist *pls)
* require us to download a segment to inspect its timestamps. */
return c->cur_seq_no;
- /* If this is a live stream, start live_start_index segments from the
- * start or end */
- if (c->live_start_index < 0)
- return pls->start_seq_no + FFMAX(pls->n_segments +
c->live_start_index, 0);
- else
- return pls->start_seq_no + FFMIN(c->live_start_index,
pls->n_segments - 1);
+ if (!pls->time_offset_flag) {
+ /* If this is a live stream, start live_start_index segments from
the
+ * start or end */
+ if (c->live_start_index < 0)
+ return pls->start_seq_no + FFMAX(pls->n_segments +
+ c->live_start_index, 0);
+ else
+ return pls->start_seq_no + FFMIN(c->live_start_index,
+ pls->n_segments - 1);
+ } else {
+ /* If playlist indicate a TIME-OFFSET, need to recalculate seq_no
*/
+ int i;
+ int64_t start_timestamp;
+ int64_t playlist_duration = 0;
+ int64_t cur_timestamp = c->cur_timestamp == AV_NOPTS_VALUE ? 0 :
+ c->cur_timestamp;
+
+ for (i = 0; i < pls->n_segments; i++) {
+ playlist_duration += pls->segments[i]->duration;
+ }
+ /* If the absolute value of TIME-OFFSET exceeds
+ * the duration of the Playlist, it indicates either the end of the
+ * Playlist (if positive) or the beginning of the Playlist (if
+ * negative). */
+ if (pls->start_time_offset >=0 &&
+ pls->start_time_offset > playlist_duration)
+ start_timestamp = cur_timestamp + playlist_duration;
+ else if (pls->start_time_offset >= 0 &&
+ pls->start_time_offset <= playlist_duration)
+ start_timestamp = cur_timestamp + pls->start_time_offset;
+ else if (pls->start_time_offset < 0 &&
+ pls->start_time_offset < -playlist_duration)
+ start_timestamp = cur_timestamp;
+ else if (pls->start_time_offset < 0 &&
+ pls->start_time_offset > -playlist_duration)
+ start_timestamp = cur_timestamp + playlist_duration +
+ pls->start_time_offset;
+ else
+ start_timestamp = cur_timestamp;
+
+ find_timestamp_in_playlist(c, pls, start_timestamp, &seq_no, NULL);
+ av_log(c, AV_LOG_DEBUG, "start_timestamp: %" PRId64
+ "cur_timestamp:%" PRId64
+ "cur_seq_no:%" PRId64 "\n",
+ start_timestamp, cur_timestamp, seq_no);
+ return seq_no;
+ }
}
/* Otherwise just start on the first segment. */
--
2.25.1
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
