[FFmpeg-trac] #1642(avformat:reopened): -f segment: automagically generate #EXTM3U tags to -segment_list generated playlists

[FFmpeg]

#1642: -f segment: automagically generate #EXTM3U tags to -segment_list generated
playlists
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             Reporter:  kelexel      |                    Owner:
                 Type:  enhancement  |                   Status:  reopened
             Priority:  normal       |                Component:  avformat
              Version:  git-master   |               Resolution:
             Keywords:  segment,     |               Blocked By:
  HLS, m3u8                          |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  1            |
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Comment (by kelexel):

 I might have spotted an issue.

 Take the following example:

 ffmpeg -i rtmp://foo.ext/app/stream ... -f ... -segment_list_live

 Here we're transcoding a live rtmp feed, ok.

 Problem:

 If broadcaster disconnects from RTMP server (connection issue, whatever)
 ffmpeg assumes the stream is ending, thus adds EXT-X-ENDLIST tag to the
 playlist.

 HLS clients when seeing this tag will go from live > record mode, so the
 stream playback will end on the HLS clients.

 Now, broadcaster comes back online, streams again to the rtmpd, and we re-
 start ffmpeg.
 A new playlist is normally generated ... all *seems* fine BUT(!!!):

 If HLS clients "refresh" the url, they will most likely pick the cached
 playlist rather than the one.. And since the cached playlist has
 EXT-X-ENDLIST in it, it will just "replay" the last containing segments
 and totally ignore the new server-side playlist.

 So, in theory, if using -segment_list_live it is a bad idea to write
 EXT-X-ENDLIST..

 BUT (hehe), there *seems* to be another -useful- tag, namely "#EXT-X
 -ALLOW-CACHE:1/0"
 I think it's mostly meant for caching mpegts files, but might also work
 with the playlists.

 Will test and report my findings..

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1642#comment:21>
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