Fix blinking cues when segmented over multiple segments or chunks #4103
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…onsecutive segments or chunks
…onsecutive segments or chunks
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Thanks @bbert . Can you please check against https://dash.akamaized.net/akamai/test/caption_test/ElephantsDream/elephants_dream_480p_heaac5_1_https.mpd . This seems to break with these changes as cues are extended that are not supposed to be extended.
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From the dash.js call: @bbert to hide this behind a settings flag to overcome potential problems on LG devices |
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This PR fixes an issue in case a same cue is segmented over consecutive segments or chunks.
In this case, we have multiple consecutive cues but with same content, potentially leading to blinking effect.
This blinking effect is more observable with image subtitles. Here is a link to a sample stream which is a copy of the reference stream "[DASH-IF] IMSC1 (CMAF) Image Subtitles", but with cue "eng: 00:00:03" that is segmented over 2 segments:
https://broadpeak-tv.github.io/test-content/dash/imsc-image/imsc1_img.mpd
To fix this issue, the proposed solution is to update previous cue endTime, instead of a creating a new cue, when consecutive cues (
endTime(N) === startTime(N+1)) contents are equal.