do not merge last segment of a dash rep by default and added -merge-last-seg to enable it

applications/mp4box/main.c

@@ -461,6 +461,7 @@ void PrintDASHUsage()
 	        "                        !! Do not use with multiple periods, nor when DASH duration is not a multiple of GOP size !!\n"
 	        " -cues                ignores dash duration and segment according to cue times in given XML file. See tests/media/dash_cues for examples.\n"
 	        " -strict-cues         throw error if something is wrong while parsing cues or applying cue-based segmentation.\n"
+	        " -merge-last-seg      merges last segment if shorter than half the target duration.\n"
 	        "\n");
 }
 
@@ -2288,6 +2289,7 @@ Bool do_bin_nhml = GF_FALSE;
 #endif
 GF_ISOFile *file;
 Bool frag_real_time = GF_FALSE;
+Bool merge_last_seg = GF_FALSE;
 u64 dash_start_date=0;
 GF_DASH_ContentLocationMode cp_location_mode = GF_DASH_CPMODE_ADAPTATION_SET;
 Double mpd_update_time = GF_FALSE;
@@ -3856,6 +3858,9 @@ Bool mp4box_parse_args(int argc, char **argv)
 		else if (!stricmp(arg, "-frag-rt")) {
 			frag_real_time = GF_TRUE;
 		}
+		else if (!stricmp(arg, "-merge-last-seg")) {
+			merge_last_seg = GF_TRUE;
+		}
 		else if (!stricmp(arg, "-start-date")) {
 			dash_start_date = gf_net_parse_date(argv[i+1]);
 			i++;
@@ -4696,6 +4701,7 @@ int mp4boxMain(int argc, char **argv)
 		if (!e) e = gf_dasher_set_test_mode(dasher,force_test_mode);
 		if (!e) e = gf_dasher_enable_loop_inputs(dasher, ! no_loop);
 		if (!e) e = gf_dasher_set_split_on_bound(dasher, split_on_bound);
+		if (!e) e = gf_dasher_set_last_segment_merge(dasher, merge_last_seg);
 		if (!e) e = gf_dasher_set_split_on_closest(dasher, split_on_closest);
 		if (!e && dash_cues) e = gf_dasher_set_cues(dasher, dash_cues, strict_cues);
 		if (!e) e = gf_dasher_set_isobmff_options(dasher, mvex_after_traks, sdtp_in_traf);

include/gpac/media_tools.h

@@ -938,6 +938,14 @@ GF_Err gf_dasher_enable_loop_inputs(GF_DASHSegmenter *dasher, Bool do_loop);
 */
 GF_Err gf_dasher_set_split_on_bound(GF_DASHSegmenter *dasher, Bool split_on_bound);
 
+/*!
+ Enable/Disable last segment merging (disabled by default).
+ *	\param dasher the DASH segmenter object
+ *	\param merge_last_seg if true, last segment is merged into previous if duration less than half target dur
+ *	\return error code if any
+*/
+GF_Err gf_dasher_set_last_segment_merge(GF_DASHSegmenter *dasher, Bool merge_last_seg);
+
 /*!
  Enable/Disable split on closest mode.
  *	\param dasher the DASH segmenter object

src/export.cpp

@@ -2203,7 +2203,7 @@
 #pragma comment (linker, EXPORT_SYMBOL(gf_dasher_set_cues) )
 #pragma comment (linker, EXPORT_SYMBOL(gf_dasher_set_isobmff_options) )
 #pragma comment (linker, EXPORT_SYMBOL(gf_dasher_set_test_mode) )
-
+#pragma comment (linker, EXPORT_SYMBOL(gf_dasher_set_last_segment_merge) )
 
 #pragma comment (linker, EXPORT_SYMBOL(gf_dasher_next_update_time) )
 

src/media_tools/dash_segmenter.c

@@ -148,9 +148,11 @@ struct __gf_dash_segmenter
 
 	/* indicates if a segment must contain its theorical boundary */
 	Bool split_on_bound;
-
 	/* used to segment video as close to the boundary as possible */
 	Bool split_on_closest;
+
+	Bool merge_last_seg;
+
 	const char *cues_file;
 	Bool strict_cues;
 
@@ -2274,8 +2276,12 @@ restart_fragmentation_pass:
 							next_sap_time = isom_get_next_sap_time(input, tf, tf->OriginalTrack, tf->SampleCount, tf->SampleNum + 2, &next_sap_is_eos);
 
 							//align behaviour of -bound and -closest in legacy with master: if eos, do not create last segment
-							if ((dasher->split_on_bound || dasher->split_on_closest) && next_sap_is_eos)
-								next_sap_time = 0;
+							if ((dasher->split_on_bound || dasher->split_on_closest) && next_sap_is_eos && dasher->merge_last_seg) {
+								u64 next_seg_dur = (next_sap_time - tf->last_sample_cts);
+								if (2 * next_seg_dur * dasher->dash_scale < MaxSegmentDuration * tf->TimeScale) {
+									next_sap_time = 0;
+								}
+							}
 
 							/*if no more SAP after this one, do not switch segment*/
 							if (next_sap_time) {
@@ -6584,6 +6590,14 @@ GF_Err gf_dasher_set_split_on_bound(GF_DASHSegmenter *dasher, Bool split_on_boun
 	return GF_OK;
 }
 
+GF_EXPORT
+GF_Err gf_dasher_set_last_segment_merge(GF_DASHSegmenter *dasher, Bool merge_last_seg)
+{
+	if (!dasher) return GF_BAD_PARAM;
+	dasher->merge_last_seg = merge_last_seg;
+	return GF_OK;
+}
+
 GF_EXPORT
 GF_Err gf_dasher_set_split_on_closest(GF_DASHSegmenter *dasher, Bool split_on_closest)
 {