[FFmpeg-user] HLS Streaming - FFMPEG: Program date time of older segment 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 a 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 does the program date time of older segments change? Should we add any
arguments explicitly in ffmpeg command to handle this?



Regards,

Suriya V.