[FFmpeg-devel] [PATCH 11/19] avformat/hls: track seeking on a per-playlist basis
Anssi Hannula
anssi.hannula at iki.fi
Fri Jan 3 15:21:35 CET 2014
Seeking needs to be tracked on a per-playlist basis, since the resyncing
code in hls_read_packet() has to sync each playlist to the seek
timestamp instead of stopping after the first playlist has reached it.
Also, change the segment selection to go straight to the next segment
if the seek position is in the last 100ms of a segment.
Signed-off-by: Anssi Hannula <anssi.hannula at iki.fi>
---
TODO: replace hardcoded 100000 with AV_TIME_BASE/10, maybe split the
100ms stuff to a separate patch
libavformat/hls.c | 108 +++++++++++++++++++++++++++++++++++-------------------
1 file changed, 71 insertions(+), 37 deletions(-)
diff --git a/libavformat/hls.c b/libavformat/hls.c
index 1290fd0..7a69eaa 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -110,6 +110,9 @@ struct playlist {
int is_subtitle;
enum Reopen reopen_subtitle;
+ int64_t seek_timestamp;
+ int seek_flags;
+
/* Renditions associated with this playlist, if any.
* Alternative rendition playlists have a single rendition associated
* with them, and variant main Media Playlists may have
@@ -157,8 +160,6 @@ typedef struct HLSContext {
int end_of_segment;
int first_packet;
int64_t first_timestamp;
- int64_t seek_timestamp;
- int seek_flags;
AVIOInterruptCB *interrupt_callback;
AVDictionary *demuxer_options;
char *user_agent; ///< holds HTTP user agent set as an AVOption to the HTTP protocol context
@@ -245,6 +246,7 @@ static struct playlist *new_playlist(HLSContext *c, const char *url,
return NULL;
reset_packet(&pls->pkt);
ff_make_absolute_url(pls->url, sizeof(pls->url), base, url);
+ pls->seek_timestamp = AV_NOPTS_VALUE;
dynarray_add(&c->playlists, &c->n_playlists, pls);
return pls;
@@ -897,6 +899,35 @@ static void add_metadata_from_renditions(AVFormatContext *s, struct playlist *pl
}
}
+/* if timestamp was in valid range: returns 1 and sets seq_no
+ * if not: returns 0 and sets seq_no to closest segment */
+static int find_timestamp_in_playlist(HLSContext *c, struct playlist *pls,
+ int64_t timestamp, int *seq_no)
+{
+ int i;
+ int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ?
+ 0 : c->first_timestamp;
+
+ if (timestamp < pos) {
+ *seq_no = pls->start_seq_no;
+ return 0;
+ }
+
+ for (i = 0; i < pls->n_segments; i++) {
+ int64_t diff = pos + pls->segments[i]->duration - timestamp;
+ /* if we are within 100ms of segment end, just select the next segment */
+ if (diff > 0 && (diff >= 100000 || i == pls->n_segments - 1)) {
+ *seq_no = pls->start_seq_no + i;
+ return 1;
+ }
+ pos += pls->segments[i]->duration;
+ }
+
+ *seq_no = pls->start_seq_no + pls->n_segments - 1;
+
+ return 0;
+}
+
static int hls_read_header(AVFormatContext *s)
{
URLContext *u = (s->flags & AVFMT_FLAG_CUSTOM_IO) ? NULL : s->pb->opaque;
@@ -1084,7 +1115,6 @@ static int hls_read_header(AVFormatContext *s)
c->first_packet = 1;
c->first_timestamp = AV_NOPTS_VALUE;
- c->seek_timestamp = AV_NOPTS_VALUE;
return 0;
fail:
@@ -1201,21 +1231,21 @@ start:
AV_TIME_BASE_Q);
}
- if (c->seek_timestamp == AV_NOPTS_VALUE)
+ if (pls->seek_timestamp == AV_NOPTS_VALUE)
break;
if (pls->pkt.dts == AV_NOPTS_VALUE) {
- c->seek_timestamp = AV_NOPTS_VALUE;
+ pls->seek_timestamp = AV_NOPTS_VALUE;
break;
}
tb = pls->ctx->streams[pls->pkt.stream_index]->time_base;
ts_diff = av_rescale_rnd(pls->pkt.dts, AV_TIME_BASE,
tb.den, AV_ROUND_DOWN) -
- c->seek_timestamp;
- if (ts_diff >= 0 && (c->seek_flags & AVSEEK_FLAG_ANY ||
+ pls->seek_timestamp;
+ if (ts_diff >= 0 && (pls->seek_flags & AVSEEK_FLAG_ANY ||
pls->pkt.flags & AV_PKT_FLAG_KEY)) {
- c->seek_timestamp = AV_NOPTS_VALUE;
+ pls->seek_timestamp = AV_NOPTS_VALUE;
break;
}
av_free_packet(&pls->pkt);
@@ -1281,32 +1311,40 @@ static int hls_read_seek(AVFormatContext *s, int stream_index,
int64_t timestamp, int flags)
{
HLSContext *c = s->priv_data;
- int i, j, ret;
+ int i;
+ int64_t seek_timestamp;
+ int valid_for = -1;
if ((flags & AVSEEK_FLAG_BYTE) || !c->variants[0]->playlists[0]->finished)
return AVERROR(ENOSYS);
- c->seek_flags = flags;
- c->seek_timestamp = stream_index < 0 ? timestamp :
- av_rescale_rnd(timestamp, AV_TIME_BASE,
- s->streams[stream_index]->time_base.den,
- flags & AVSEEK_FLAG_BACKWARD ?
- AV_ROUND_DOWN : AV_ROUND_UP);
- timestamp = av_rescale_rnd(timestamp, AV_TIME_BASE, stream_index >= 0 ?
- s->streams[stream_index]->time_base.den :
- AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
- AV_ROUND_DOWN : AV_ROUND_UP);
- if (s->duration < c->seek_timestamp) {
- c->seek_timestamp = AV_NOPTS_VALUE;
+ seek_timestamp = stream_index < 0 ? timestamp :
+ av_rescale_rnd(timestamp, AV_TIME_BASE,
+ s->streams[stream_index]->time_base.den,
+ flags & AVSEEK_FLAG_BACKWARD ?
+ AV_ROUND_DOWN : AV_ROUND_UP);
+
+ if (s->duration < seek_timestamp)
return AVERROR(EIO);
+
+ for (i = 0; i < c->n_playlists; i++) {
+ /* check first that the timestamp is valid for some playlist */
+ struct playlist *pls = c->playlists[i];
+ int seq_no;
+ if (find_timestamp_in_playlist(c, pls, seek_timestamp, &seq_no)) {
+ /* set segment now so we do not need to search again below */
+ pls->cur_seq_no = seq_no;
+ valid_for = i;
+ break;
+ }
}
- ret = AVERROR(EIO);
+ if (valid_for < 0)
+ return AVERROR(EIO);
+
for (i = 0; i < c->n_playlists; i++) {
/* Reset reading */
struct playlist *pls = c->playlists[i];
- int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ?
- 0 : c->first_timestamp;
if (pls->input) {
ffurl_close(pls->input);
pls->input = NULL;
@@ -1327,20 +1365,16 @@ static int hls_read_seek(AVFormatContext *s, int stream_index,
if (pls->reopen_subtitle == REOPEN_AFTER_CONSUMED)
pls->reopen_subtitle = REOPEN_BEFORE_READ;
- /* Locate the segment that contains the target timestamp */
- for (j = 0; j < pls->n_segments; j++) {
- if (timestamp >= pos &&
- timestamp < pos + pls->segments[j]->duration) {
- pls->cur_seq_no = pls->start_seq_no + j;
- ret = 0;
- break;
- }
- pos += pls->segments[j]->duration;
- }
- if (ret)
- c->seek_timestamp = AV_NOPTS_VALUE;
+ pls->seek_timestamp = seek_timestamp;
+ pls->seek_flags = flags;
+
+ /* set closest segment seq_no for playlists not handled above */
+ if (valid_for != i)
+ find_timestamp_in_playlist(c, pls, seek_timestamp, &pls->cur_seq_no);
+ after_segment_switch(pls);
}
- return ret;
+
+ return 0;
}
static int hls_probe(AVProbeData *p)
--
1.8.1.5
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