How to create a MPD file of MPEG-DASH to play a webm video?
indexRange contains Segment Index Box (sidx). It is basically metadata fragment that contains information about the fragments the player should request when downloading the file. This is a quote from the spec:
"indexRange specifies the byte range that contains the Segment Index in all Media Segments of the Representation. The byte range shall be expressed and formatted as a byte-range-spec as defined in RFC 2616, Clause 14.35.1. It is restricted to a single expression identifying a contiguous range of bytes."
sidx box is described in HERE and a parser can be found HERE and HERE(from dash.js project)
Initialization - According to spec:
"specifies the URL including a possible byte range for the Initialization Segment."
Hope it helped!
Comments
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Silvia almost 2 years
I'm following this demo which uses mediaSource API and MPEG DASH standard to play a .webm video. This is the MPD file used:
<?xml version="1.0" encoding="UTF-8"?> <MPD xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:mpeg:DASH:schema:MPD:2011" xsi:schemaLocation="urn:mpeg:DASH:schema:MPD:2011" type="static" mediaPresentationDuration="PT888.05S" minBufferTime="PT1S" profiles="urn:webm:dash:profile:webm-on-demand:2012"> <Period id="0" start="PT0S" duration="PT888.05S" > <AdaptationSet id="0" mimeType="video/webm" codecs="vp8" lang="eng" width="720" height="306" subsegmentAlignment="true" subsegmentStartsWithSAP="1" bitstreamSwitching="true"> <Representation id="1" bandwidth="534144"> <BaseURL>mevq_logo_720x306_0250k_int-150-150.webm</BaseURL> <SegmentBase indexRange="29052226-29054708"> <Initialization range="0-229" /> </SegmentBase> </Representation> <Representation id="2" bandwidth="1078766"> <BaseURL>mevq_logo_720x306_0500k_int-150-150.webm</BaseURL> <SegmentBase indexRange="56003676-56006200"> <Initialization range="0-229" /> </SegmentBase> </Representation> <Representation id="3" bandwidth="1745140"> <BaseURL>mevq_logo_720x306_0750k_int-150-150.webm</BaseURL> <SegmentBase indexRange="83686040-83688577"> <Initialization range="0-229" /> </SegmentBase> </Representation> <Representation id="4" bandwidth="2295403"> <BaseURL>mevq_logo_720x306_1000k_int-150-150.webm</BaseURL> <SegmentBase indexRange="111588024-111590567"> <Initialization range="0-229" /> </SegmentBase> </Representation> <Representation id="5" bandwidth="3797938"> <BaseURL>mevq_logo_720x306_1500k_int-150-150.webm</BaseURL> <SegmentBase indexRange="166960740-166963291"> <Initialization range="0-229" /> </SegmentBase> </Representation> <Representation id="6" bandwidth="6418657"> <BaseURL>mevq_logo_720x306_2000k_int-150-150.webm</BaseURL> <SegmentBase indexRange="222165200-222167753"> <Initialization range="0-229" /> </SegmentBase> </Representation> </AdaptationSet> <AdaptationSet id="1" mimeType="audio/webm" codecs="vorbis" lang="eng" audioSamplingRate="41000" subsegmentStartsWithSAP="1"> <Representation id="7" bandwidth="115479"> <BaseURL>evq_vorbis_128kbps_cues-5sec_tracks-2.webm</BaseURL> <SegmentBase indexRange="11944509-11947524"> <Initialization range="0-4501" /> </SegmentBase> </Representation> </AdaptationSet>
Does anybody know how to obtain/calculate the numbers 'SegmentBase indexRange' and 'Initialization range' for any video?
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Stefan Vasiljevic about 7 yearsAfter following those links I still could not find how Initialization.range and SegmentBase.rangeIndex are calculated. Can you explain or give a link to an example? THX!
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inbaly about 7 yearsStart with downloading the SegmentBase.rangeIndex, and view its binary data: curl -o <fileName> -r <1500-8000(SegmentBase.rangeIndex)> <url_of_mp4.mp4> You can use You can download/clone the dash.js project, there is an example in the code itself.
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Stefan Vasiljevic about 7 yearsSo you are saying that I should download the first chuck and read it and see where it ends and then populate the MPD with those values?
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inbaly over 4 years@StefanVasiljevic Yes.you will need to analize the sidx metadata.