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qtdemux: delegate linear search for sample to binary search when possible

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Also arrange for parsing a sample prior to taking a reference to it,
which requires less memory layout assumptions for correctness.
This commit is contained in:
Mark Nauwelaerts 2010-11-04 10:05:15 +01:00
parent b7c27029e5
commit eb5c958143
1 changed files with 21 additions and 17 deletions
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38
gst/qtdemux/qtdemux.c
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@ -794,7 +794,7 @@ find_func (QtDemuxSample * s1, guint64 * media_time, gpointer user_data)
}
/* find the index of the sample that includes the data for @media_time using a
* binary search
* binary search. Only to be called in optimized cases of linear search below.
*
* Returns the index of the sample.
*/
@ -808,7 +808,7 @@ gst_qtdemux_find_index (GstQTDemux * qtdemux, QtDemuxStream * str,
/* convert media_time to mov format */
media_time = gst_util_uint64_scale (media_time, str->timescale, GST_SECOND);
result = gst_util_array_binary_search (str->samples, str->n_samples,
result = gst_util_array_binary_search (str->samples, str->stbl_index + 1,
sizeof (QtDemuxSample), (GCompareDataFunc) find_func,
GST_SEARCH_MODE_BEFORE, &media_time, NULL);
@ -821,7 +821,8 @@ gst_qtdemux_find_index (GstQTDemux * qtdemux, QtDemuxStream * str,
}
/* find the index of the sample that includes the data for @media_time using a
* linear search
* linear search, and keeping in mind that not all samples may have been parsed
* yet. If possible, it will delegate to binary search.
*
* Returns the index of the sample.
*/
@ -829,26 +830,29 @@ static guint32
gst_qtdemux_find_index_linear (GstQTDemux * qtdemux, QtDemuxStream * str,
guint64 media_time)
{
QtDemuxSample *result = str->samples;
guint32 index = 0;
guint64 mov_time;
/* convert media_time to mov format */
media_time =
mov_time =
gst_util_uint64_scale_ceil (media_time, str->timescale, GST_SECOND);
if (media_time == result->timestamp)
if (mov_time == str->samples[0].timestamp)
return index;
result++;
/* use faster search if requested time in already parsed range */
if (str->stbl_index >= 0 &&
mov_time <= str->samples[str->stbl_index].timestamp)
return gst_qtdemux_find_index (qtdemux, str, media_time);
while (index < str->n_samples - 1) {
if (!qtdemux_parse_samples (qtdemux, str, index + 1))
goto parse_failed;
if (media_time < result->timestamp)
if (mov_time < str->samples[index + 1].timestamp)
break;
index++;
result++;
}
return index;
@ -1003,7 +1007,7 @@ gst_qtdemux_adjust_seek (GstQTDemux * qtdemux, gint64 desired_time,
media_start = seg->media_start + seg_time;
/* get the index of the sample with media time */
index = gst_qtdemux_find_index (qtdemux, str, media_start);
index = gst_qtdemux_find_index_linear (qtdemux, str, media_start);
GST_DEBUG_OBJECT (qtdemux, "sample for %" GST_TIME_FORMAT " at %u",
GST_TIME_ARGS (media_start), index);
@ -2733,7 +2737,7 @@ gst_qtdemux_seek_to_previous_keyframe (GstQTDemux * qtdemux)
media_start = seg->media_start + seg_time;
/* get the index of the sample with media time */
index = gst_qtdemux_find_index (qtdemux, str, media_start);
index = gst_qtdemux_find_index_linear (qtdemux, str, media_start);
GST_DEBUG_OBJECT (qtdemux, "sample for %" GST_TIME_FORMAT " at %u",
GST_TIME_ARGS (media_start), index);
@ -2972,15 +2976,15 @@ gst_qtdemux_prepare_current_sample (GstQTDemux * qtdemux,
if (G_UNLIKELY (stream->sample_index >= stream->n_samples))
goto eos;
/* now get the info for the sample we're at */
sample = &stream->samples[stream->sample_index];
if (!qtdemux_parse_samples (qtdemux, stream, stream->sample_index)) {
GST_LOG_OBJECT (qtdemux, "Parsing of index %u failed!",
stream->sample_index);
return FALSE;
}
/* now get the info for the sample we're at */
sample = &stream->samples[stream->sample_index];
*timestamp = QTSAMPLE_PTS (stream, sample);
*offset = sample->offset;
*size = sample->size;
@ -3031,15 +3035,15 @@ gst_qtdemux_advance_sample (GstQTDemux * qtdemux, QtDemuxStream * stream)
if (G_UNLIKELY (stream->sample_index >= stream->n_samples))
goto next_segment;
/* get next sample */
sample = &stream->samples[stream->sample_index];
if (!qtdemux_parse_samples (qtdemux, stream, stream->sample_index)) {
GST_LOG_OBJECT (qtdemux, "Parsing of index %u failed!",
stream->sample_index);
return;
}
/* get next sample */
sample = &stream->samples[stream->sample_index];
/* see if we are past the segment */
if (G_UNLIKELY (gst_util_uint64_scale (sample->timestamp,
GST_SECOND, stream->timescale) >= segment->media_stop))