webmdashenc: Support for live stream manifests

This patch adds support for creating DASH manifests for WebM Live
Streams. It also updates the documentation and adds a fate test to
verify the behavior of the new muxer flag.
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/muxers.texi

@@ -1210,7 +1210,17 @@ is the @option{global_header} flag.
 
 WebM DASH Manifest muxer.
 
-This muxer implements the WebM DASH Manifest specification to generate the DASH manifest XML.
+This muxer implements the WebM DASH Manifest specification to generate the DASH
+manifest XML. It also supports manifest generation for DASH live streams.
+
+For more information see:
+
+@itemize @bullet
+@item
+WebM DASH Specification: @url{https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification}
+@item
+ISO DASH Specification: @url{http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip}
+@end itemize
 
 @subsection Options
 
@@ -1221,6 +1231,28 @@ This muxer supports the following options:
 This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x and y are the
 unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding
 audio and video streams. Any number of adaptation sets can be added using this option.
+
+@item live
+Set this to 1 to create a live stream DASH Manifest. Default: 0.
+
+@item chunk_start_index
+Start index of the first chunk. This will go in the @samp{startNumber} attribute
+of the @samp{SegmentTemplate} element in the manifest. Default: 0.
+
+@item chunk_duration_ms
+Duration of each chunk in milliseconds. This will go in the @samp{duration}
+attribute of the @samp{SegmentTemplate} element in the manifest. Default: 1000.
+
+@item utc_timing_url
+URL of the page that will return the UTC timestamp in ISO format. This will go
+in the @samp{value} attribute of the @samp{UTCTiming} element in the manifest.
+Default: None.
+
+@item time_shift_buffer_depth
+Smallest time (in seconds) shifting buffer for which any Representation is
+guaranteed to be available. This will go in the @samp{timeShiftBufferDepth}
+attribute of the @samp{MPD} element. Default: 60.
+
 @end table
 
 @subsection Example

tests/fate/vpx.mak

@@ -43,6 +43,9 @@ fate-webm-dash-manifest-unaligned-audio-streams: CMD = run ffmpeg -f webm_dash_m
 FATE_VP8-$(call DEMDEC, WEBM_DASH_MANIFEST, VP8) += fate-webm-dash-manifest-representations
 fate-webm-dash-manifest-representations: CMD = run ffmpeg -f webm_dash_manifest -i $(TARGET_SAMPLES)/vp8/dash_video1.webm -f webm_dash_manifest -i $(TARGET_SAMPLES)/vp8/dash_video4.webm -c copy -map 0 -map 1 -f webm_dash_manifest -adaptation_sets "id=0,streams=0,1" -
 
+FATE_VP8-$(call DEMDEC, WEBM_DASH_MANIFEST, VP8) += fate-webm-dash-manifest-live
+fate-webm-dash-manifest-live: CMD = run ffmpeg -f webm_dash_manifest -live 1 -i $(TARGET_SAMPLES)/vp8/dash_live_video_360.hdr -f webm_dash_manifest -live 1 -i $(TARGET_SAMPLES)/vp8/dash_live_audio_171.hdr -c copy -map 0 -map 1 -f webm_dash_manifest -live 1 -adaptation_sets "id=0,streams=0 id=1,streams=1" -chunk_start_index 1 -chunk_duration_ms 5000 -time_shift_buffer_depth 7200 -debug_mode 1 -
+
 FATE_SAMPLES_AVCONV += $(FATE_VP6-yes)
 fate-vp6: $(FATE_VP6-yes)
 

tests/ref/fate/webm-dash-manifest-live

+<?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="dynamic"
+  minBufferTime="PT1S"
+  profiles="urn:mpeg:dash:profile:isoff-live:2011"
+  availabilityStartTime=""
+  timeShiftBufferDepth="PT7200S">
+<UTCTiming
+  schemeIdUri="urn:mpeg:dash:utc:direct:2012"
+  value=""/>
+<Period id="0" start="PT0S" >
+<AdaptationSet id="0" mimeType="video/webm" codecs="vp9" bitstreamSwitching="true" subsegmentAlignment="true" subsegmentStartsWithSAP="1">
+<ContentComponent id="1" type="video"/>
+<SegmentTemplate timescale="1000" duration="5000" media="dash_live_video_$RepresentationID$_$Number$.chk" startNumber="1" initialization="dash_live_video_$RepresentationID$.hdr"/>
+<Representation id="360" bandwidth="1000000" width="640" height="360" codecs="vp9" mimeType="video/webm" startsWithSAP="1"></Representation>
+</AdaptationSet>
+<AdaptationSet id="1" mimeType="audio/webm" codecs="vorbis" bitstreamSwitching="true" subsegmentAlignment="true" subsegmentStartsWithSAP="1">
+<ContentComponent id="1" type="audio"/>
+<SegmentTemplate timescale="1000" duration="5000" media="dash_live_audio_$RepresentationID$_$Number$.chk" startNumber="1" initialization="dash_live_audio_$RepresentationID$.hdr"/>
+<Representation id="171" bandwidth="128000" audioSamplingRate="32000" codecs="vorbis" mimeType="audio/webm" startsWithSAP="1"></Representation>
+</AdaptationSet>
+</Period>
+</MPD>