Yuck, a top post. Snip.

On Fri, 24 Oct 2025 12:55:59 -0700
Marc Shapiro <marcnshap@???> wrote:
> I have been using Video Download Helper in Firefox.  I just downloaded
> a video that worked perfectly.  Attempting to download the same video
> with yt-dlp resulted in a file just over half the size that appears to
> have video only, no audio.
>
> I will note that, while Video Download Helper usually works, there have
> been instances when it did not, and I had to use yt-dlp instead, so
> this is not a complete fix, but it does show that there are methods
> that do successfully download youtube videos currently.
>
> Marc
>

Youtube removed support for combined video and audio streams within the
last year. yt-dlp can download both and merge using ffmpeg, or you can
feed your video player both the video and audio in the format that the
player expects such that it plays both at the same time in sync together.

E.G. mpv --audio-files=foo.webm foo.mp4

If you want yt-dlp to merge the audio and video, they literally give
examples in the manpage, such as:

Format Selection examples

# Download and merge the best video-only format and the best audio-only
format,
# or download the best combined format if video-only format is not
available

yt-dlp -f "bv+ba/b"

I hope it helps,
David