Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Report on the implementation of WebVTT in MP4 in GPAC

14,122 views

Published on

This presentation was made during the MPEG 105th meeting reporting on the implementation of the WebVTT in MP4 support in the GPAC project

  • Login to see the comments

  • Be the first to like this

Report on the implementation of WebVTT in MP4 in GPAC

  1. 1. Institut Mines-Télécom Report of WebVTT implementation Cyril Concolato m30301
  2. 2. Institut Mines-Télécom Status  Implementation within GPAC • http://gpac.sourceforge.net • 14496-12 • 14496-30  Support for WebVTT packaging with MP4Box  Support for WebVTT playback with MP4Client (& others)  Plan to support next • PlainText (SVG, HTML, …) • TTML (with meta box) – test suite available ? 31/07/2013 GPAC & WebVTT - m303012
  3. 3. Institut Mines-Télécom Packaging into WebVTTCueBoxes  Basic usages MP4Box -add file1.vtt:lang=en subtitle1.mp4 MP4Box -add file2.srt:FMT=VTT:lang=en subtitle2.mp4 • More options (layout, edit list, frame rate change…) • More usages: split, concatenate, export (SRT -> WebVTT) • Problem: 3GPP Text Box for WebVTT ? 31/07/2013 GPAC & WebVTT - m303013
  4. 4. Institut Mines-Télécom DASH and WebVTT and others  Basic usage MP4Box -dash 10000 subtitle.mp4:role=subtitle video.mp4 • Other options (fragment duration …) • Use of redundant samples if necessary • Example ─ Possibility to mix 3GPP Timed Text and WebVTT  Problems • Exposing track layout in MPD for WebVTT is not always useful • Missing ability to store the role in the MP4 file format 31/07/2013 GPAC & WebVTT - m303014
  5. 5. Institut Mines-Télécom Example <Period duration="PT0H10M0.00S"> <AdaptationSet segmentAlignment="true" group="1"> <Role schemeIdUri="urn:mpeg:dash:role:2011" value="subtitle"/> <Representation id="1" mimeType="video/mp4" codecs="tx3g" width="1920" height="1080" startWithSAP="1" bandwidth="391"> <SegmentTemplate timescale="1000" duration="10000" media="counter-tx3g_dash$Number$.m4s" startNumber="1" initialization="counter-tx3g_dashinit.mp4"/> </Representation> </AdaptationSet> <AdaptationSet segmentAlignment="true" group="1"> <Role schemeIdUri="urn:mpeg:dash:role:2011" value="subtitle"/> <Representation id="2" mimeType="video/mp4" codecs="wvtt" width="1920" height="1080" startWithSAP="1" bandwidth="606"> <SegmentTemplate timescale="1000" duration="10000" media="counter-vtt_dash$Number$.m4s" startNumber="1" initialization="counter-vtt_dashinit.mp4"/> </Representation> </AdaptationSet> </Period>31/07/2013 GPAC & WebVTT - m303015
  6. 6. Institut Mines-Télécom Playback of WebVTT in MP4 31/07/2013 GPAC & WebVTT - m303016 MP4 Parser MP4 File (WebVTT) WebVTT Cues JavaScript Conversion (configurable) SVG Tiny 1.2 elements Rendering GPAC Player
  7. 7. Institut Mines-Télécom Playback of WebVTT in MP4  Status • Tested in the following configurations ─ Local file, progressive http download, DASH ─ With or without video • Rendering Feature support ─ Top-based line positioning, bottom-based line positioning, explicit positioning ─ Line wrapping ─ Multiline cues ─ Multiple cues simultaneously ─ Basic text styling: italic, bold, underlined  Problems? • Metadata (name,value) pair ─ Regions? ─ Need for a new box • WebVTTCueSourceIdBox 31/07/2013 GPAC & WebVTT - m303017
  8. 8. Institut Mines-Télécom Demonstration 31/07/2013 GPAC & WebVTT - m303018

×