/* searches for a cluster start from @pos,
* return GST_FLOW_OK and cluster position in @pos if found */
static GstFlowReturn
-gst_matroska_demux_search_cluster (GstMatroskaDemux * demux, gint64 * pos)
+gst_matroska_demux_search_cluster (GstMatroskaDemux * demux, gint64 * pos,
+ gboolean forward)
{
gint64 newpos = *pos;
gint64 orig_offset;
orig_offset = demux->common.offset;
- GST_LOG_OBJECT (demux, "searching cluster following offset %" G_GINT64_FORMAT,
- *pos);
+ GST_LOG_OBJECT (demux, "searching cluster %s offset %" G_GINT64_FORMAT,
+ forward ? "following" : "preceding", *pos);
if (demux->clusters) {
gint64 *cpos;
cpos = gst_util_array_binary_search (demux->clusters->data,
demux->clusters->len, sizeof (gint64),
(GCompareDataFunc) gst_matroska_cluster_compare,
- GST_SEARCH_MODE_AFTER, pos, NULL);
+ forward ? GST_SEARCH_MODE_AFTER : GST_SEARCH_MODE_BEFORE, pos, NULL);
/* sanity check */
if (cpos) {
GST_DEBUG_OBJECT (demux,
GstByteReader reader;
gint cluster_pos;
+ if (!forward)
+ newpos = MAX (0, newpos - chunk);
if (buf != NULL) {
gst_buffer_unmap (buf, &map);
gst_buffer_unref (buf);
}
gst_byte_reader_init (&reader, data, size);
- resume:
- cluster_pos = gst_byte_reader_masked_scan_uint32 (&reader, 0xffffffff,
- GST_MATROSKA_ID_CLUSTER, 0, gst_byte_reader_get_remaining (&reader));
+ cluster_pos = -1;
+ while (1) {
+ gint found = gst_byte_reader_masked_scan_uint32 (&reader, 0xffffffff,
+ GST_MATROSKA_ID_CLUSTER, 0, gst_byte_reader_get_remaining (&reader));
+ if (forward) {
+ cluster_pos = found;
+ break;
+ }
+ /* need last occurrence when searching backwards */
+ if (found >= 0) {
+ cluster_pos = gst_byte_reader_get_pos (&reader) + found;
+ gst_byte_reader_skip (&reader, found + 4);
+ } else {
+ break;
+ }
+ }
+
if (cluster_pos >= 0) {
newpos += cluster_pos;
- /* prepare resuming at next byte */
- if (!gst_byte_reader_skip (&reader, cluster_pos + 1)) {
- GST_DEBUG_OBJECT (demux, "Need more data -> continue");
- continue;
- }
GST_DEBUG_OBJECT (demux,
"found cluster ebml id at offset %" G_GINT64_FORMAT, newpos);
/* extra checks whether we really sync'ed to a cluster:
GST_ELEMENT_CAST (demux), &id, &length, &needed);
if (ret != GST_FLOW_OK) {
GST_DEBUG_OBJECT (demux, "need more data -> continue");
- continue;
+ goto next;
}
g_assert (id == GST_MATROSKA_ID_CLUSTER);
GST_DEBUG_OBJECT (demux, "cluster size %" G_GUINT64_FORMAT ", prefix %d",
demux->common.offset += length + needed;
ret = gst_matroska_read_common_peek_id_length_pull (&demux->common,
GST_ELEMENT_CAST (demux), &id, &length, &needed);
- if (ret != GST_FLOW_OK) {
- /* we skipped one byte in the reader above, need to accomodate for
- * that when resuming skipping from the reader instead of reading a
- * new chunk */
- newpos += 1;
- goto resume;
- }
+ if (ret != GST_FLOW_OK)
+ goto next;
GST_DEBUG_OBJECT (demux, "next element is %scluster",
id == GST_MATROSKA_ID_CLUSTER ? "" : "not ");
if (id == GST_MATROSKA_ID_CLUSTER)
break;
- /* not ok, resume
- * we skipped one byte in the reader above, need to accomodate for
- * that when resuming skipping from the reader instead of reading a
- * new chunk */
- newpos += 1;
- goto resume;
+ next:
+ if (forward)
+ newpos += 1;
} else {
/* partial cluster id may have been in tail of buffer */
- newpos += MAX (gst_byte_reader_get_remaining (&reader), 4) - 3;
+ newpos +=
+ forward ? MAX (gst_byte_reader_get_remaining (&reader), 4) - 3 : 3;
}
}
GstMatroskaIndex *entry = NULL;
GstMatroskaReadState current_state;
GstClockTime otime, prev_cluster_time, current_cluster_time, cluster_time;
- gint64 opos, newpos, startpos = 0, current_offset;
+ GstClockTime atime;
+ gint64 opos, newpos, current_offset;
gint64 prev_cluster_offset = -1, current_cluster_offset, cluster_offset;
+ gint64 apos, maxpos;
guint64 cluster_size = 0;
- const guint chunk = 64 * 1024;
GstFlowReturn ret;
guint64 length;
guint32 id;
guint needed;
- /* (under)estimate new position, resync using cluster ebml id,
- * and scan forward to appropriate cluster
- * (and re-estimate if need to go backward) */
-
- prev_cluster_time = GST_CLOCK_TIME_NONE;
+ /* estimate new position, resync using cluster ebml id,
+ * and bisect further or scan forward to appropriate cluster */
/* store some current state */
current_state = demux->common.state;
/* estimate using start and current position */
GST_OBJECT_LOCK (demux);
- opos = demux->common.offset - demux->common.ebml_segment_start;
+ apos = demux->first_cluster_offset;
+ atime = demux->stream_start_time;
+ opos = demux->common.offset;
otime = demux->common.segment.position;
GST_OBJECT_UNLOCK (demux);
/* sanitize */
- time = MAX (time, demux->stream_start_time);
+ time = MAX (time, atime);
+ otime = MAX (otime, atime);
+ opos = MAX (opos, apos);
+
+ maxpos = gst_matroska_read_common_get_length (&demux->common);
- /* avoid division by zero in first estimation below */
- if (otime <= demux->stream_start_time)
- otime = time;
+ /* invariants;
+ * apos <= opos
+ * atime <= otime
+ * apos always refer to a cluster before target time;
+ * opos may or may not be after target time, but if it is once so,
+ * then also in next iteration
+ * */
retry:
GST_LOG_OBJECT (demux,
+ "apos: %" G_GUINT64_FORMAT ", atime: %" GST_TIME_FORMAT ", %"
+ GST_TIME_FORMAT " in stream time, "
"opos: %" G_GUINT64_FORMAT ", otime: %" GST_TIME_FORMAT ", %"
GST_TIME_FORMAT " in stream time (start %" GST_TIME_FORMAT "), time %"
- GST_TIME_FORMAT, opos, GST_TIME_ARGS (otime),
- GST_TIME_ARGS (otime - demux->stream_start_time),
+ GST_TIME_FORMAT, apos, GST_TIME_ARGS (atime),
+ GST_TIME_ARGS (atime - demux->stream_start_time), opos,
+ GST_TIME_ARGS (otime), GST_TIME_ARGS (otime - demux->stream_start_time),
GST_TIME_ARGS (demux->stream_start_time), GST_TIME_ARGS (time));
- if (otime <= demux->stream_start_time) {
- newpos = 0;
+ g_assert (atime <= otime);
+ g_assert (apos <= opos);
+ if (time == GST_CLOCK_TIME_NONE) {
+ GST_DEBUG_OBJECT (demux, "searching last cluster");
+ newpos = maxpos;
+ if (newpos == -1) {
+ GST_DEBUG_OBJECT (demux, "unknown file size; bailing out");
+ goto exit;
+ }
+ } else if (otime <= atime) {
+ newpos = apos;
} else {
- newpos =
- gst_util_uint64_scale (opos - demux->common.ebml_segment_start,
- time - demux->stream_start_time,
- otime - demux->stream_start_time) - chunk;
- if (newpos < 0)
- newpos = 0;
+ newpos = apos +
+ gst_util_uint64_scale (opos - apos, time - atime, otime - atime);
+ if (maxpos != -1 && newpos > maxpos)
+ newpos = maxpos;
}
- /* favour undershoot */
- newpos = newpos * 90 / 100;
- newpos += demux->common.ebml_segment_start;
GST_DEBUG_OBJECT (demux,
"estimated offset for %" GST_TIME_FORMAT ": %" G_GINT64_FORMAT,
GST_TIME_ARGS (time), newpos);
- /* and at least start scanning before previous scan start to avoid looping */
- startpos = startpos * 90 / 100;
- if (startpos && startpos < newpos)
- newpos = startpos;
-
- /* read in at newpos and scan for ebml cluster id */
- startpos = newpos;
- while (1) {
-
- ret = gst_matroska_demux_search_cluster (demux, &newpos);
- if (ret == GST_FLOW_EOS) {
- /* heuristic HACK */
- newpos = startpos * 80 / 100;
- GST_DEBUG_OBJECT (demux, "EOS; "
- "new estimated offset for %" GST_TIME_FORMAT ": %" G_GINT64_FORMAT,
- GST_TIME_ARGS (time), newpos);
- startpos = newpos;
- continue;
- } else if (ret != GST_FLOW_OK) {
+ /* search backwards */
+ if (newpos > apos) {
+ ret = gst_matroska_demux_search_cluster (demux, &newpos, FALSE);
+ if (ret != GST_FLOW_OK)
goto exit;
- } else {
- break;
- }
}
/* then start scanning and parsing for cluster time,
- * re-estimate if overshoot, otherwise next cluster and so on */
+ * re-estimate if possible, otherwise next cluster and so on */
+ /* note that each re-estimate is entered with a change in apos or opos,
+ * avoiding infinite loop */
demux->common.offset = newpos;
demux->cluster_time = cluster_time = GST_CLOCK_TIME_NONE;
cluster_size = 0;
+ prev_cluster_time = GST_CLOCK_TIME_NONE;
while (1) {
/* peek and parse some elements */
ret = gst_matroska_read_common_peek_id_length_pull (&demux->common,
GST_DEBUG_OBJECT (demux, "found cluster at offset %" G_GINT64_FORMAT
" with time %" GST_TIME_FORMAT, cluster_offset,
GST_TIME_ARGS (cluster_time));
+ if (time == GST_CLOCK_TIME_NONE) {
+ GST_DEBUG_OBJECT (demux, "found last cluster");
+ prev_cluster_time = cluster_time;
+ prev_cluster_offset = cluster_offset;
+ break;
+ }
if (cluster_time > time) {
GST_DEBUG_OBJECT (demux, "overshot target");
/* cluster overshoots */
goto retry;
}
} else {
+ /* cluster undershoots */
+ GST_DEBUG_OBJECT (demux, "undershot target");
+ /* ok if close enough */
+ if (GST_CLOCK_DIFF (cluster_time, time) < 5 * GST_SECOND) {
+ GST_DEBUG_OBJECT (demux, "target close enough");
+ prev_cluster_time = cluster_time;
+ prev_cluster_offset = cluster_offset;
+ break;
+ }
+ if (otime > time) {
+ /* we are in between atime and otime => can bisect if worthwhile */
+ if (prev_cluster_time != GST_CLOCK_TIME_NONE &&
+ cluster_time > prev_cluster_time &&
+ (GST_CLOCK_DIFF (prev_cluster_time, cluster_time) * 10 <
+ GST_CLOCK_DIFF (cluster_time, time))) {
+ /* we moved at least one cluster forward,
+ * and it looks like target is still far away,
+ * let's estimate again */
+ GST_DEBUG_OBJECT (demux, "bisecting with new apos");
+ apos = cluster_offset;
+ atime = cluster_time;
+ goto retry;
+ }
+ }
/* cluster undershoots, goto next one */
prev_cluster_time = cluster_time;
prev_cluster_offset = cluster_offset;
* search for cluster mark following current pos */
pos = demux->common.offset;
GST_WARNING_OBJECT (demux, "parse error, looking for next cluster");
- if ((ret = gst_matroska_demux_search_cluster (demux, &pos)) != GST_FLOW_OK) {
+ if ((ret = gst_matroska_demux_search_cluster (demux, &pos, TRUE)) !=
+ GST_FLOW_OK) {
/* did not work, give up */
return ret;
} else {
projects / platform / upstream / gstreamer.git / commitdiff