How to burn in subtitles to a video file [VC UG]
Before you can follow this guide, you should already have imported your subtitles to your Item. You can read more about how to add subtitles to an Item here.
A sequence consists of a number of audio and/or video tracks, each with a number of segments. Each segment has a position in the timeline (in and out) and references a specific interval and track of an item. If you have a sequence attached to an item in Vidispine the subtitle metadata can be included in the output file. To do this, you need to use a shape tag where <burnSubtitles>true</burnSubtitles> is set in the <video> element. Note that overlapping subtitle timespans are not allowed and will cause the render job to fail.
Let’s say we have an item VX-811 which has a sequence attached to it, and the following metadata;
<MetadataDocument xmlns="http://xml.vidispine.com/schema/vidispine">
...
<timespan start="72140@PAL" end="72260@PAL">
<group>
<name>stl_subtitle</name>
<field><name>stl_justification</name><value>center</value></field>
<field><name>stl_text</name><value>No, I am your father.</value></field>
</group>
</timespan>
<timespan start="72320@PAL" end="72490@PAL">
<group>
<name>stl_subtitle</name>
<field><name>stl_justification</name><value>center</value></field>
<field><name>stl_text</name><value>No... that's not true! That's impossible!</value></field>
</group>
</timespan>
...
</MetadataDocument>
And we have the following shape-tag called MP4_512_SUB;
<TranscodePresetDocument xmlns="http://xml.vidispine.com/schema/vidispine">
<format>mp4</format>
<audio>
<codec>aac</codec>
<bitrate>96000</bitrate>
</audio>
<video>
<scaling>
<width>512</width>
<height>288</height>
</scaling>
<codec>h264</codec>
<bitrate>2000000</bitrate>
<framerate>
<numerator>1</numerator>
<denominator>25</denominator>
</framerate>
<burnSubtitles>true</burnSubtitles>
</video>
</TranscodePresetDocument>
Then a render job is started using:
POST /item/VX-811/sequence/render?tag=MP4_512_SUB
<JobDocument xmlns="http://xml.vidispine.com/schema/vidispine"><jobId>VX-1436</jobId><user>admin</user><started>2013-03-08T13:02:15.654Z</started><status>READY</status><type>CONFORM</type><priority>MEDIUM</priority></JobDocument>
This will render the sequence and include any subtitle metadata as subtitles in the output video.