From 1fd094d96ba9b77921b087600912475edb31b985 Mon Sep 17 00:00:00 2001 From: Thiago Santos Date: Tue, 3 Dec 2013 15:08:25 -0300 Subject: [PATCH] qtdemux: improve fragment-start tracking Some buffers can have multiple moov atoms inside and the strategy of using the gst_adapter_prev_pts timestamp to get the base timestamp for the media of the fragment would fail as it would reuse the same base timestamp for all moofs in the buffer instead of accumulating the durations for all of them. Heres a better explanation of the issue: qtdemux receives a buffer where PTS(buf) = X buf -> moofA | moofB | moofC The problem was that PTS(buf) was used as the base timestamp for all 3 moofs, causing all buffers to be X based. In this case we want only moofA to be X based as it is what the PTS on buf means, and the other moofB and moofC just use the accumulated timestamp from the previous moofs durations. To solve this, this patch uses gst_adapter_prev_pts distance result, this allows qtdemux to calculate if it should use the resulting pts or just accumulate the samples as it can identify if the moofs belong to the same upstream buffer or not. https://bugzilla.gnome.org/show_bug.cgi?id=719783 --- gst/isomp4/qtdemux.c | 42 +++++++++++++++++++++++++++++------------- gst/isomp4/qtdemux.h | 1 + 2 files changed, 30 insertions(+), 13 deletions(-) diff --git a/gst/isomp4/qtdemux.c b/gst/isomp4/qtdemux.c index d2ca3f4f65..72000a9507 100644 --- a/gst/isomp4/qtdemux.c +++ b/gst/isomp4/qtdemux.c @@ -537,6 +537,7 @@ gst_qtdemux_init (GstQTDemux * qtdemux) qtdemux->restoredata_buffer = NULL; qtdemux->restoredata_offset = GST_CLOCK_TIME_NONE; qtdemux->fragment_start = -1; + qtdemux->fragment_start_offset = -1; qtdemux->media_caps = NULL; qtdemux->exposed = FALSE; qtdemux->mss_mode = FALSE; @@ -1841,6 +1842,7 @@ gst_qtdemux_reset (GstQTDemux * qtdemux, gboolean hard) qtdemux->upstream_size = 0; qtdemux->fragment_start = -1; + qtdemux->fragment_start_offset = -1; qtdemux->duration = 0; qtdemux->mfra_offset = 0; qtdemux->moof_offset = 0; @@ -4592,18 +4594,8 @@ gst_qtdemux_chain (GstPad * sinkpad, GstObject * parent, GstBuffer * inbuf) { GstQTDemux *demux; GstFlowReturn ret = GST_FLOW_OK; - GstClockTime timestamp; - demux = GST_QTDEMUX (parent); - timestamp = GST_BUFFER_TIMESTAMP (inbuf); - - if (G_UNLIKELY (GST_CLOCK_TIME_IS_VALID (timestamp))) { - demux->fragment_start = timestamp; - GST_DEBUG_OBJECT (demux, "got fragment_start %" GST_TIME_FORMAT, - GST_TIME_ARGS (timestamp)); - } - gst_adapter_push (demux->adapter, inbuf); /* we never really mean to buffer that much */ @@ -4786,11 +4778,35 @@ gst_qtdemux_chain (GstPad * sinkpad, GstObject * parent, GstBuffer * inbuf) } } else if (fourcc == FOURCC_moof) { if ((demux->got_moov || demux->media_caps) && demux->fragmented) { + guint64 dist = 0; + GstClockTime prev_pts; + guint64 prev_offset; + GST_DEBUG_OBJECT (demux, "Parsing [moof]"); - /* the timestamp of the moof buffer is relevant as some scenarios - * won't have the initial timestamp in the atoms */ - demux->fragment_start = gst_adapter_prev_pts (demux->adapter, NULL); + /* + * The timestamp of the moof buffer is relevant as some scenarios + * won't have the initial timestamp in the atoms. Whenever a new + * buffer has started, we get that buffer's PTS and use it as a base + * timestamp for the trun entries. + * + * To keep track of the current buffer timestamp and starting point + * we use gst_adapter_prev_pts that gives us the PTS and the distance + * from the beggining of the buffer, with the distance and demux->offset + * we know if it is still the same buffer or not. + */ + prev_pts = gst_adapter_prev_pts (demux->adapter, &dist); + prev_offset = demux->offset - dist; + if (demux->fragment_start_offset == -1 + || prev_offset > demux->fragment_start_offset) { + demux->fragment_start_offset = prev_offset; + demux->fragment_start = prev_pts; + GST_DEBUG_OBJECT (demux, + "New fragment start found at: %" G_GUINT64_FORMAT " : %" + GST_TIME_FORMAT, demux->fragment_start_offset, + GST_TIME_ARGS (demux->fragment_start)); + } + if (!qtdemux_parse_moof (demux, data, demux->neededbytes, demux->offset, NULL)) { gst_adapter_unmap (demux->adapter); diff --git a/gst/isomp4/qtdemux.h b/gst/isomp4/qtdemux.h index a6b9768f58..e6cc769f3d 100644 --- a/gst/isomp4/qtdemux.h +++ b/gst/isomp4/qtdemux.h @@ -134,6 +134,7 @@ struct _GstQTDemux { gboolean exposed; gboolean mss_mode; /* flag to indicate that we're working with a smoothstreaming fragment */ guint64 fragment_start; + guint64 fragment_start_offset; gint64 chapters_track_id;