HLS using fragmented mp4. Does VDH support this ?

Skip to first unread message


Aug 3, 2023, 7:12:14 AM8/3/23
to Video DownloadHelper Q&A
I noticed that Twitter is doing something unique with their videos. They're using m3u8 manifests but each segment of the video is streamed as .m4s

Normally this is how mpeg-dash streams their videos. HLS videos are streamed as .ts
segments most of the time but Twitter has gone with this approach of fragmented mp4
files. Could it be the reason VDH doesn't work yet for Twiiter.

Check out the attached master manifest & playlist manifest files.


Aug 3, 2023, 8:07:16 AM8/3/23
to Video DownloadHelper Q&A

Wild Willy

Aug 3, 2023, 2:13:34 PM8/3/23
to Video Download Helper Google Group
Interesting observation. I'm not sure I even noticed the chunks were .m4s in that other
thread. I don't usually look inside manifest files these days. I generally let ffprobe
do that for me. I do note that your master manifest shows captions. Up until now, VDH
has simply ignored captions. I'd be surprised if that is causing any sort of problem.
Your master manifest here is particularly simple. There are no descriptors for audio
streams. That means VDH should be less likely to get tripped up with the "separate video
& audio" issue. I imagine ffprobe would show simply 4 Programs with a video Stream & an
audio Stream in each Program, with no sharing of Streams. If you supply the input
parameter -strict experimental, I would expect each Program to also contain a third
Stream for the captions. Since the captions are supplied as a stream manifest as well,
there's no telling just from what you've posted whether the captions are vtt, srt, or
something else. An ffprobe would give us that (with -strict experimental). However, the
descriptor in the master manifest for the captions says they are machine generated. In
my mind, that brings their quality into question. They might be accurate; they might be
trash. You'd have to get them to see how close they are to whatever is being said in the

But it's still an interesting thought that .m4s chunks instead of .ts chunks might be
causing problems for VDH.


Sep 23, 2023, 4:08:30 AM9/23/23
to Video DownloadHelper Q&A
tubitv.com/watch is another site which uses the fragmented mp4 format, although instead of .m4s they're streaming the media as .mp4 files.
Surprisingly you can open these mp4 links in a new tab which are video & audio only.
Reply all
Reply to author
0 new messages