[FFmpeg-devel] Forward frame wall clock time from avdevice to HLS muxer

[Andreas Rheinhardt]

Jesper Ek:
> Hi,
> 
> I have implemented a libavdevice to capture audio and video from an AJA
> Kona card (similar to decklink). I'm then using the HLS muxer to encode my
> stream. Now I need the HLS EXT-X-PROGRAM-DATE-TIME tag to specify exactly
> when the input source was recorded, so my plan is to forward the "wall
> clock time" (from the avdevice implementation) to the hls muxer, and use
> that instead of using system time (av_gettime()).
> 
> I cant use PTS, so what is the correct way to pass "wall clock time"
> metadata for every frame to the HLS encoder?
> 
> I noticed that the decklink implementation uses
> `av_packet_add_side_data(&pkt, AV_PKT_DATA_STRINGS_METADATA, ...)` to add
> timecode information, is this the correct approach?
> 

AV_PKT_DATA_PRFT side data might be the right tool for you.

> I hope this mailing list is appropriate for my question, otherwise please
> forgive me.

It is only appropriate for this mailing list if you want to improve
FFmpeg itself (i.e. by making the hls muxer use AV_PKT_DATA_PRFT; the
dash muxer already seems to use it). If not, the user mailing list is
the right place.

- Andreas