Using ffmpeg to record m3u8 link results in out-of-sync audio/video

[thestormarchive]

Hello!

I am trying to record a m3u8 link (via any method), and everything that I try fails to produce audio/video that are synced.

At first, I tried to use the "Open Network Stream" > "Stream" feature in VLC. This records the file just fine, but it stops the recording whenever the segment changes (i.e., the TV channel goes to commercial break or vice-versa). I also tried using the record feature, but with the same result.

Then, I moved on to OBS (I know this is not the most efficient solution, but I just need something that works). I tried to record using a "Media Source" and a "VLC Video Source." Both of these resulted in similar problems.

Finally, I have tried ffmpeg. This seemed to work, as the stream would continue to record over the change in segment (commercial break). But, now there is a new problem. The audio and video become out of sync. They are not consistently out of sync (such as the audio being one second behind the video), but it gets worse and worse as the video goes on.

What I believe to be happening is that the last commercial/segment before they return from commercial break is being skipped in the video recording. The recording always begins in-sync, but grows progressively worse after each commercial break. For now, this has been (tediously) fixed by re-syncing the audio and video in a video editor, but takes a lot of time.

Here is the command I am using with ffmpeg:

ffmpeg -i [link] -c copy recordingfilename.mkv

(I have changed the actual link to "[link]" to avoid copyright issues)
(Note: when I just watch (not stream) the link in VLC, there is no issue. I guess VLC has a different way of syncing the segments than other methods.)

What can I change to be able to record this without issue?
Thank you so much for any help! Much appreciated!

[Sviests]

Use streamlink or one of youtube-dl / yt-dlp.