[FFmpeg-devel] [PATCH] applehttp: reload interval is duration of last segment

[Andrey Utkin]

Revised patch.

---
 libavformat/applehttp.c |   28 +++++++++++++++++++++++-----
 1 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/libavformat/applehttp.c b/libavformat/applehttp.c
index 99febc6..27c446e 100644
--- a/libavformat/applehttp.c
+++ b/libavformat/applehttp.c
@@ -373,14 +373,33 @@ static int read_data(void *opaque, uint8_t *buf,
int buf_size)
     struct variant *v = opaque;
     AppleHTTPContext *c = v->parent->priv_data;
     int ret, i;
+    int64_t reload_interval;

 restart:
     if (!v->input) {
 reload:
-        /* If this is a live stream and target_duration has elapsed since
-         * the last playlist reload, reload the variant playlists now. */
+        /*
+         * According to draft-pantos-http-live-streaming-07, 6.3.4.,
+         * === quote ===
+         * The initial minimum reload delay is the duration of the last media
+         * segment in the Playlist.  Media segment duration is specified by the
+         * EXTINF tag.
+         * If the client reloads a Playlist file and finds that it has not
+         * changed then it MUST wait for a period of one-half the target
+         * duration before retrying.
+         * === quote end ===
+         * This code does not follow it strictly.
+         * It uses last segment's EXTINF as reload interval.
+         * If, at some reason, we have empty segments list after last reload,
+         * TARGETDURATION is used as reload interval.
+         */
+        reload_interval = v->n_segments > 0 ?
+            v->segments[v->n_segments - 1]->duration :
+            v->target_duration; // not by spec, just fallback to what we have
+        reload_interval *= 1000000; // microseconds, to be like last_load_time
+
         if (!v->finished &&
-            av_gettime() - v->last_load_time >= v->target_duration*1000000 &&
+            av_gettime() - v->last_load_time >= reload_interval &&
             (ret = parse_playlist(c, v->url, v, NULL)) < 0)
                 return ret;
         if (v->cur_seq_no < v->start_seq_no) {
@@ -392,8 +411,7 @@ reload:
         if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
             if (v->finished)
                 return AVERROR_EOF;
-            while (av_gettime() - v->last_load_time <
-                   v->target_duration*1000000) {
+            while (av_gettime() - v->last_load_time < reload_interval) {
                 if (ff_check_interrupt(c->interrupt_callback))
                     return AVERROR_EXIT;
                 usleep(100*1000);



-- 
Andrey Utkin
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