wrote:
On Tue, 20 Nov 2018 23:46:15 -0700, "Bill in Co"
surly_curmudgeon@earthlink wrote:

Anybody else lamenting the waning of the mp4 file format as an almost
defacto standard on the web (and elsewhere)? Why?

Well, for one, most of the tools we had for working on these files are now
useless, like tools to mux and demux the file, cut and edit the file, etc.
All those programs... I can't tell you how many times such mp4 tools have
come in handy for working with mp4 video files, like for cleaning up and
restoring the audio tracks from some Youtube clips, as just one example (and
boy do some of them need some work).

And two, and perhaps of more importance to most people, many TV sets won't
even play these new video formats - unlike the mp4 files. Sure, they can
still play mpg files, but that's pretty limiting, to say the least!

But I'll have to concede that mp4 was proprietary format, unlike webm and
its vp9 video codec, so here we are, whether we want it or not. I still
think it sucks. :-)


Rename any WEBM file to MP4 and is still plays. What is the difference,
or is there any difference at all aside from the extension?

Yes, there is a difference.

https://www.quirksmode.org/html5/tests/video.html

Notice how difficult it is to keep everybody happy ?

When you pick a single video mode/format, you're screwing
somebody out of the opportunity to view your video. It's much
better for the web page to "sniff" browser capability and
present a useful format.

*******

Anyone who designs cross-platform browsers, is not going to
depend on file extension for container information. You read
the header of the file to determine the container. Renaming
a .webm to .mp4 isn't going to fool anyone. In Windows, you
can use this package for such determinations.

http://gnuwin32.sourceforge.net/packages/file.htm

(If you use the Bash shell in Windows 10, "file" is already installed.)

While at one time, MIME declarations were used to identify
content, I don't know what the approach is today. For example,
I no longer see "octet-stream" failures on browsers any more,
which suggests MIME isn't being used or relied on absolutely.

A design that has to run on a Linux platform, isn't going
to rely on file extension. A design that only worked in
Windows, might. It would be interesting to test Internet
Explorer and see how it behaves to the "rename trick".

Paul