[FFmpeg-devel] [PATCH] avformat/hls:use EXT-X-START instead of live_start_index if it's in playlist
Li Kai
wolfleekay at gmail.com
Mon Jun 27 05:58:15 EEST 2022
OK, I got it.
Thanks a lot.
在 2022/6/27 上午10:23, Steven Liu 写道:
> Li Kai <wolfleekay at gmail.com> 于2022年6月25日周六 22:15写道：
>> OK, I add the option description in doc/demuxers.texi.
>>
>> About invalid EXT-X-START value, it's not played on Safari.
>> So I make it error to handle.
>>
>> You opinion, it's better way. The latest patch fix it.
>>
>>
>>
> @@ -741,6 +744,7 @@ 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 +893,20 @@ static int parse_playlist(HLSContext *c, const char *url,
> cur_init_section->key = NULL;
> }
>
> + } else if (av_strstart(line, "#EXT-X-START:", &ptr)) {
> Can the "const char *p;" move to here? And maybe make a clarify name
> will better i think, e.g. const char *time_offset_value?
>
> + 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 {
> + av_log(c->ctx, AV_LOG_WARNING, "#EXT-X-START value is"
> + "invalid, it will be ignored");
> + continue;
> + }
> } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
> if (pls)
> pls->finished = 1;
>
>
>
> Thanks
> Steven
-------------- next part --------------
From 9c812414bc21030182fda00e702ea6433c920c9d Mon Sep 17 00:00:00 2001
From: Li Kai <wolfleekay at gmail.com>
Date: Thu, 23 Jun 2022 00:55:38 +0800
Subject: [PATCH v4] avformat/hls: add #EXT-X-START tag support by
prefer_x_start opt
Signed-off-by: Li Kai <wolfleekay at gmail.com>
---
doc/demuxers.texi | 3 +++
libavformat/hls.c | 60 +++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 61 insertions(+), 2 deletions(-)
diff --git a/doc/demuxers.texi b/doc/demuxers.texi
index c95a9ae594..2b6dd86c2a 100644
--- a/doc/demuxers.texi
+++ b/doc/demuxers.texi
@@ -373,6 +373,9 @@ It accepts the following options:
@item live_start_index
segment index to start live streams at (negative values are from the end).
+ at item prefer_x_start
+prefer to use #EXT-X-START if it's in playlist instead of live_start_index.
+
@item allowed_extensions
',' separated list of file extensions that hls is allowed to access.
diff --git a/libavformat/hls.c b/libavformat/hls.c
index b736f093a9..8ea4ff4671 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;
@@ -211,6 +213,7 @@ typedef struct HLSContext {
int64_t cur_seq_no;
int m3u8_hold_counters;
int live_start_index;
+ int prefer_x_start;
int first_packet;
int64_t first_timestamp;
int64_t cur_timestamp;
@@ -889,6 +892,21 @@ 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;
+ }
+ const char *time_offset_value;
+ if (av_strstart(ptr, "TIME-OFFSET=", &time_offset_value)) {
+ float offset = strtof(time_offset_value, NULL);
+ pls->start_time_offset = offset * AV_TIME_BASE;
+ pls->time_offset_flag = 1;
+ } else {
+ av_log(c->ctx, AV_LOG_WARNING, "#EXT-X-START value is"
+ "invalid, it will be ignored");
+ continue;
+ }
} else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
if (pls)
pls->finished = 1;
@@ -1722,9 +1740,45 @@ static int64_t select_cur_seq_no(HLSContext *c, struct playlist *pls)
/* 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);
+ seq_no = 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);
+ seq_no = pls->start_seq_no + FFMIN(c->live_start_index,
+ pls->n_segments - 1);
+
+ /* If #EXT-X-START in playlist, need to recalculate */
+ if (pls->time_offset_flag && c->prefer_x_start) {
+ int64_t start_timestamp;
+ int64_t playlist_duration = 0;
+ int64_t cur_timestamp = c->cur_timestamp == AV_NOPTS_VALUE ? 0 :
+ c->cur_timestamp;
+
+ for (int 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);
+ }
+ return seq_no;
}
/* Otherwise just start on the first segment. */
@@ -2476,6 +2530,8 @@ static int hls_probe(const AVProbeData *p)
static const AVOption hls_options[] = {
{"live_start_index", "segment index to start live streams at (negative values are from the end)",
OFFSET(live_start_index), AV_OPT_TYPE_INT, {.i64 = -3}, INT_MIN, INT_MAX, FLAGS},
+ {"prefer_x_start", "prefer to use #EXT-X-START if it's in playlist instead of live_start_index",
+ OFFSET(prefer_x_start), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS},
{"allowed_extensions", "List of file extensions that hls is allowed to access",
OFFSET(allowed_extensions), AV_OPT_TYPE_STRING,
{.str = "3gp,aac,avi,ac3,eac3,flac,mkv,m3u8,m4a,m4s,m4v,mpg,mov,mp2,mp3,mp4,mpeg,mpegts,ogg,ogv,oga,ts,vob,wav"},
--
2.24.1 (Apple Git-126)
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