avformat/hls: Fixes overwriting existing #EXT-X-PROGRAM-DATE-TIME value in HLS playlist
fix ticket: 8989
This is is due to the following behavior in the current code:
1. The initial_prog_date_time gets set to the current local time
2. The existing playlist (.m3u8) file gets parsed and the segments
present are added to the variant stream
3. The new segment is created and added
4. The existing segments and the new segment are written to the
playlist file. The initial_prog_date_time from point 1 is used
for calculating "#EXT-X-PROGRAM-DATE-TIME" for the segments,
which results in incorrect "#EXT-X-PROGRAM-DATE-TIME" values
for existing segments
The following approach fixes this bug:
1. Add a new variable "discont_program_date_time" of type double
to HLSSegment struct
2. Store the "EXT-X-PROGRAM-DATE-TIME" value from the existing
segments in this variable
3. When writing to playlist file if "discont_program_date_time"
is set, then use that value for "EXT-X-PROGRAM-DATE-TIME" else
use the value present in vs->initial_prog_date_time
projects / ffmpeg / commit