コード例 #1
0
ファイル: DashManifestParser.cs プロジェクト: ice0/test
        public bool Parse()
        {
            try
            {
#if DEBUG
                Logger.Log("Begin parsing DASH manifest");
#endif
                ParseMPDElement();
                UpdateBaseUrl();

                var periods = document.DocumentElement.ChildNodes.Where(node => node.NodeName.Equals("Period"));
#if DEBUG
                Logger.Log(periods.Count().ToString() + " Periods found");
#endif
                foreach (var period in periods)
                {
                    Period dashPeriod = new Period();
                    periodStart = TimeSpan.FromSeconds(0);
                    ParsePeriodElement(period, ref dashPeriod);

                    var adaptationSets = period.ChildNodes.Where(node => node.NodeName.Equals("AdaptationSet"));
#if DEBUG
                    Logger.Log(adaptationSets.Count().ToString() + " Adaptation Sets found");
#endif
                    foreach (var adaptationSet in adaptationSets)
                    {
                        MediaStream stream = new MediaStream();

                        if (adaptationSet.Attributes.GetNamedItem("mimeType") != null)
                        {
                            stream.MimeType = adaptationSet.Attributes.GetNamedItem("mimeType").InnerText;
                        }
                        if (adaptationSet.Attributes.GetNamedItem("lang") != null)
                        {
                            stream.Language = adaptationSet.Attributes.GetNamedItem("lang").InnerText.Replace(" ", string.Empty);
                        }

                        var representations = adaptationSet.ChildNodes.Where(node => node.NodeName.Equals("Representation"));
                        //We are only grabbing one Representation in an Adaptation Set (the lowest one, just to be safe)
                        //(No support for adaptive streaming)
                        IXmlNode representation = GetLowestBitrateRepresentation(representations);
#if DEBUG
                        Logger.Log(representations.Count().ToString() + " Representations in " + stream.MimeType + " Adaptation Set with bitrate " + uint.Parse(representation.Attributes.GetNamedItem("bandwidth").InnerText));
#endif

                        //Parse Representation Element
                        uint   bitrate;
                        string repID = string.Empty;
                        ParseRepresentationElement(representation,
                                                   out bitrate,
                                                   out repID);

                        var segmentTemplateQuery = adaptationSet.ChildNodes.Where(node => node.NodeName.Equals("SegmentTemplate"));
                        var segmentListQuery     = adaptationSet.ChildNodes.Where(node => node.NodeName.Equals("SegmentList"));
                        var segmentBaseQuery     = adaptationSet.ChildNodes.Where(node => node.NodeName.Equals("SegmentBase"));
                        if (segmentTemplateQuery.Count() != 0)
                        {
                            stream.SegmentInfoType = MediaStream.SegmentInformationType.Template;
                            //Parse Segment Template Element
                            UInt64 timescale              = 1;
                            string initializationFormat   = string.Empty;
                            string mediaFormat            = string.Empty;
                            UInt64 segmentDuration        = 0;
                            uint   startNumber            = 1;
                            UInt64 presentationTimeOffset = 0;
                            var    segmentTemplate        = segmentTemplateQuery.First();

                            ParseSegmentTemplateElement(segmentTemplate,
                                                        ref timescale, ref initializationFormat,
                                                        ref mediaFormat, ref segmentDuration,
                                                        ref startNumber, ref presentationTimeOffset);

                            DeterminePeriodStart(presentationTimeOffset, period, ref dashPeriod);

                            string initializationUrl;
                            //$Number$ and $Time$ will never be present in the initialization URL
                            ExpandDASHUrlSegmentTemplate(initializationFormat, manifest.BaseUrl,
                                                         bitrate, repID, 0, 0, out initializationUrl);
                            stream.InitSegmentUrl = initializationUrl;

                            var segmentTimelineQuery = segmentTemplate.ChildNodes.Where(node => node.NodeName.Equals("SegmentTimeline"));

                            MediaSegmentInformation segmentInfo = new MediaSegmentInformation();
                            segmentInfo.Timescale        = timescale;
                            segmentInfo.RepresentationID = repID;
                            segmentInfo.Bitrate          = bitrate;

                            //No timeline present.
                            //Instead of populating the segments in the stream, we will give just enough information to produce
                            //the information to construct media segment urls on the fly in the SourceBufferManager
                            if (segmentTimelineQuery.Count() == 0)
                            {
#if DEBUG
                                Logger.Log("Making number base segment info from SegmentTemplate");
#endif
                                stream.SegmentTemplateBase = MediaStream.SegmentTemplateIdentifier.Number;

                                segmentInfo.Duration    = segmentDuration;
                                segmentInfo.UrlTemplate = mediaFormat;

                                UInt64 segmentNumber = startNumber;
                                if (manifest.IsLive)
                                {
                                    var hnsFragmentDuration = ((segmentDuration * 10000000) / timescale);
                                    CalculateNumberIdentifierForLive(hnsFragmentDuration, ref segmentNumber);
                                }
                                segmentInfo.StartNumber = segmentNumber;

                                segmentInfo.StartTimestamp = segmentDuration * (segmentNumber - 1);

                                stream.CanGenerateSegmentsDynamically = true;
                            }
                            else
                            {
                                stream.SegmentTemplateBase = MediaStream.SegmentTemplateIdentifier.Time;

                                MakeTimelineInfo(segmentTimelineQuery.First(), bitrate, timescale,
                                                 repID, startNumber, presentationTimeOffset,
                                                 mediaFormat, ref stream);
                            }

                            stream.SegmentInformation = segmentInfo;
                        }
                        else if (segmentListQuery.Count() != 0)
                        {
#if DEBUG
                            Logger.Log("Manifest parsing error: " + "Does not support a SegmentList implementation");
#endif
                            stream.SegmentInfoType = MediaStream.SegmentInformationType.List;
                        }
                        else
                        {
#if DEBUG
                            Logger.Log("Manifest parsing error: " + "Does not support a SegmentBase or BaseUrl implementation");
#endif
                            stream.SegmentInfoType = MediaStream.SegmentInformationType.Base;
                        }


                        dashPeriod.AddStream(stream);
                    } // each adaptation set

                    manifest.AddPeriod(dashPeriod);
                }// each period
                manifest.SetFirstSelectedPeriod();
            }
            catch (Exception e)
            {
#if DEBUG
                Logger.Log("Manifest parsing error " + Logger.Display(e));
#endif
                return(false);
            }
            return(true);
        }