[FFmpeg-user] FFMPEG HLS Streaming: Older segment program date time also changing in playlist.m3u8 when re-streaming after discontinuity

[Suriya Velusamy]

Hi,

Following is the ffmpeg command used to stream the data.

ffmpeg -re -f avfoundation
-framerate 30 -i 0
-codec:v h264_videotoolbox -x264-params keyint=120:scenecut=0
-codec:a copy -f hls
-hls_list_size 60
-hls_time 10
-hls_flags delete_segments
-hls_flags +append_list
-hls_flags +discont_start
-hls_flags +program_date_time
-strftime 1
-strftime_mkdir 1
-hls_segment_filename
'%Y%m%dT%H%M%S%z.ts' playlist.m3u8

Following is the playlist.m3u8 content which generated for few seconds.


#EXTM3U

#EXT-X-VERSION:3

#EXT-X-TARGETDURATION:10

#EXT-X-MEDIA-SEQUENCE:0

#EXT-X-DISCONTINUITY

#EXT-X-DISCONTINUITY

#EXTINF:10.000000,

#EXT-X-PROGRAM-DATE-TIME:2020-11-09T22:07:53.000+0530

20201109T220753+0530.ts

#EXTINF:10.000000,

#EXT-X-PROGRAM-DATE-TIME:2020-11-09T22:08:03.000+0530

20201109T220803+0530.ts

#EXT-X-ENDLIST

When the re-stream happens(in case of restarting the streaming service), the program date time of older segments(before #EXT-X-DISCONTINUITY) also get changed like below which is unexpected.


#EXTM3U

#EXT-X-VERSION:3

#EXT-X-TARGETDURATION:10

#EXT-X-MEDIA-SEQUENCE:0

#EXT-X-DISCONTINUITY

#EXT-X-DISCONTINUITY

#EXTINF:10.000000,

#EXT-X-PROGRAM-DATE-TIME:2020-11-09T22:12:50.633+0530

20201109T220753+0530.ts

#EXTINF:10.000000,

#EXT-X-PROGRAM-DATE-TIME:2020-11-09T22:13:00.633+0530

20201109T220803+0530.ts

#EXT-X-DISCONTINUITY

#EXTINF:10.000000,

#EXT-X-PROGRAM-DATE-TIME:2020-11-09T22:13:12.000+0530

20201109T221312+0530.ts

#EXTINF:5.400000,

#EXT-X-PROGRAM-DATE-TIME:2020-11-09T22:13:22.000+0530

20201109T221322+0530.ts

#EXT-X-ENDLIST

Why the program date time of older segment should change? Should we add any arguments explicitly in ffmpeg command to handle this?

Regards,
Suriya V.










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Suriya Velusamy | Software Engineer | Product Engineering | Redflex Group
E Suriya.Velusamy at redflex.com<mailto:Suriya.Velusamy at redflex.com>
4/293, Old Mahabalipuram Road, Perungudi, Chennai Tamil Nadu 600096, India

www.redflex.com<http://www.redflex.com>


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