Fix already processed fragments being recognised as new due to change of base fragments url #51
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The same fragment might have different urls on two consequent updates of hls playlist, in which case last_fragment exact value will not be found in the urls list, which will lead to new_idx being set to zero and already processed fragments being downloaded for a second time. To deal with this instead of full fragments urls only filename parts are used for comparison, since they only contain fragment number, which is unique for a given fragment and doesn't change.
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Thanks! I've been wondering why some of my recordings have repeated segments, but looks like this is the issue. |
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Same fragments might get different urls on a different worker server on two consecutive updates of hls playlist.
HLSDownloader._fill_queuerelies on comparison of full fragment urls to pick new ones, so when this happens it will treat all urls from the current playlist chunk as new, which will cause about ten fragments to get downloaded for a second time, leading to about a ten seconds segment of the video being repeated twice in the recording.Here is an example of two different urls pointing to fragment with the same number and seemingly the same content:
This PR makes it that only filename part of the fragment url (
73436.tsfor the links above) is used for comparison, which fixes the issue.Currently there is no warning issued when it happens, but it can still be detected by
[hls] Found 12 new fragmentsline in output. Perhaps some dedicated debug message should be added?