[FFmpeg-trac] #1642(avformat:closed): -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:  closed
             Priority:  normal       |                Component:  avformat
              Version:  git-master   |               Resolution:  fixed
             Keywords:  segment,     |               Blocked By:
  HLS, m3u8                          |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  1            |
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Comment (by kelexel):

 I am sorry, but I think your patch broke -f segment !

 First of, you did not add #EXT-X-TARGETDURATION:X in segment_list_open,
 you added in in segment_list_close, no clue why. From my tests and
 compared m3u8 playlists, this tag needs to sit on top, otherwise you
 cannot use HLS for live RTMP transcoding !

 Second, I do not understand your per-file generated #EXTINF tags.

 Here is the result of what i produces for me:

 >>>
 #EXTM3U
 #EXT-X-VERSION:4
 #EXTINF:11.217433,
 alpha_720p00000.ts
 #EXTINF:9.605956,
 alpha_720p00001.ts
 #EXTINF:9.617756,
 alpha_720p00002.ts
 #EXTINF:6.033333,
 alpha_720p00003.ts
 #EXT-X-TARGETDURATION:11
 #EXT-X-ENDLIST
 <<<

 First, my segment_time is 10, here we have 11 (no clue why).
 Second, I thought #EXTINF should give the duration of each segment, where
 here, we get wacky, decrementing durations (why?!)

 Conclusion, this patch does bring some m3u8 goodness, and is certainly
 more elegant that my (unexperienced) patch.

 But it does not work with live transcoded HLS streams.

 If you want to fix it, move #EXT-X-TARGETDURATION on top, ensure it has a
 valid segment_time and fix (or explain) the wacky #EXTINF tags

 Thank you.

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1642#comment:3>
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