WebM data for a file, once we have it, is fine -- it's stable and the
codecs we support are well documented. Any future changes we make to
playback technology will always go back to that source file when
re-encoding, so it won't degrade even if we change things in the future.
However as you note, most video footage is originally shot or edited and
encoded using other lossy encoding formats, meaning a WebM copy uploaded to
us is often one generation of lossy encoding farther down than it would
have been had we accepted MP4 H.264/AAC files or other common formats
directly. And if someone wants to reuse the footage they find on Commons,
they might need to reencode again, depending on the support in their
editing tools.
When encoding at a suitably high data rate and quality this is not a huge
problem, but I've seen a lot of Ogg and WebM videos on Commons that were
encoded at *really* low bitrates by mistake and there's no way to restore
the quality without an earlier-generation file to work from.
I would recommend backing up your own files just for certainly, especially
if you want to pass the files on to be re-edited.
Ideally, we would accept your camera's output (likely MP4 H.264/AAC)
directly, and you would have no need to manually maintain separate archives
of your source files. The formats involved are well-documented
international standards, well-supported by open-source software, but made
difficult for some usage scenarios by the patents on encoding and decoding;
unlike the early-2000s-era undocumented video formats they are not
"proprietary", but they are still "patent-encumbered".
I cannot speak to the legal issues of redistributing MP4 H.264/AAC files
that were encoded elsewhere, or decoding on our servers to re-encode as a
free format for playback, but would be very interested in supporting such
uploads if we can. And it would be very easy to do technically; we need
only change a configuration option to allow MP4 uploads, which would then
be treated just like our existing Ogg and WebM source uploads.
However allowing upload and redistribution of MP4 sources was one of the
scenarios rejected by the Commons community in 2014 in favor of "no MP4
support":
https://commons.wikimedia.org/wiki/Commons:Requests_for_comment/MP4_Video
I think it would be wise to reconsider some of these past decisions; four
years later support for WebM *playback* is better than it was with native
MS Edge support and a JavaScript/WebAssembly shim for Safari, but the
difficulties for *contributors and reusers* of video files remain as big as
they were.
-- brion
On Tue, Oct 30, 2018, 5:26 PM Kunal Mehta via Commons-l <
commons-l(a)lists.wikimedia.org> wrote:
Hi,
I've been working on recording and uploading video to Commons lately,
and I'm wondering what to do with the original files that my camera
recorded (in a proprietary format unfortunately).
So, is WebM/VP8 suitable for long-term archival? Or does it make sense
to backup the original files for use later down the road?
-- Legoktm
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