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qtdemux: do not align reverse playback reference stream twice

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Timestamp rounding issues could lead to going backwards 2 keyframe periods
(rather than only 1).  While this is not necessarily a problem, it might
potentially place additional (buffering) load on downstream and could be
avoided (because We Can).

Fixes #623629.
This commit is contained in:
Mark Nauwelaerts 2010-07-08 18:57:21 +02:00
parent 2a22e9d487
commit bbded080e0
1 changed files with 31 additions and 16 deletions
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47
gst/qtdemux/qtdemux.c
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@ -1919,6 +1919,7 @@ gst_qtdemux_seek_to_previous_keyframe (GstQTDemux * qtdemux)
{ {
guint8 n = 0; guint8 n = 0;
guint32 seg_idx = 0, k_index = 0; guint32 seg_idx = 0, k_index = 0;
guint32 ref_seg_idx, ref_k_index;
guint64 k_pos = 0, last_stop = 0; guint64 k_pos = 0, last_stop = 0;
QtDemuxSegment *seg = NULL; QtDemuxSegment *seg = NULL;
QtDemuxStream *ref_str = NULL; QtDemuxStream *ref_str = NULL;
@ -2016,33 +2017,47 @@ gst_qtdemux_seek_to_previous_keyframe (GstQTDemux * qtdemux)
goto eos; goto eos;
} }
ref_seg_idx = ref_str->segment_index;
ref_k_index = k_index;
/* Align them all on this */ /* Align them all on this */
for (n = 0; n < qtdemux->n_streams; n++) { for (n = 0; n < qtdemux->n_streams; n++) {
guint32 index = 0; guint32 index = 0;
guint64 media_start = 0, seg_time = 0; guint64 media_start = 0, seg_time = 0;
QtDemuxStream *str = qtdemux->streams[n]; QtDemuxStream *str = qtdemux->streams[n];
seg_idx = gst_qtdemux_find_segment (qtdemux, str, k_pos); /* aligning reference stream again might lead to backing up to yet another
GST_DEBUG_OBJECT (qtdemux, "align segment %d", seg_idx); * keyframe (due to timestamp rounding issues),
* potentially putting more load on downstream; so let's try to avoid */
if (str == ref_str) {
seg_idx = ref_seg_idx;
seg = &str->segments[seg_idx];
k_index = ref_k_index;
GST_DEBUG_OBJECT (qtdemux, "reference stream segment %d, "
"sample at index %d", ref_str->segment_index, k_index);
} else {
seg_idx = gst_qtdemux_find_segment (qtdemux, str, k_pos);
GST_DEBUG_OBJECT (qtdemux, "align segment %d", seg_idx);
/* segment not found, continue with normal flow */ /* segment not found, continue with normal flow */
if (seg_idx == -1) if (seg_idx == -1)
continue; continue;
/* get segment and time in the segment */ /* get segment and time in the segment */
seg = &str->segments[seg_idx]; seg = &str->segments[seg_idx];
seg_time = k_pos - seg->time; seg_time = k_pos - seg->time;
/* get the media time in the segment */ /* get the media time in the segment */
media_start = seg->media_start + seg_time; media_start = seg->media_start + seg_time;
/* get the index of the sample with media time */ /* get the index of the sample with media time */
index = gst_qtdemux_find_index (qtdemux, str, media_start); index = gst_qtdemux_find_index (qtdemux, str, media_start);
GST_DEBUG_OBJECT (qtdemux, "sample for %" GST_TIME_FORMAT " at %u", GST_DEBUG_OBJECT (qtdemux, "sample for %" GST_TIME_FORMAT " at %u",
GST_TIME_ARGS (media_start), index); GST_TIME_ARGS (media_start), index);
/* find previous keyframe */ /* find previous keyframe */
k_index = gst_qtdemux_find_keyframe (qtdemux, str, index); k_index = gst_qtdemux_find_keyframe (qtdemux, str, index);
}
/* Remember until where we want to go */ /* Remember until where we want to go */
str->to_sample = str->from_sample - 1; str->to_sample = str->from_sample - 1;