On Tuesday, March 20, 2012, David Gerard <dgerard(a)gmail.com> wrote:
On 20 March 2012 19:06, Ian Baker
<ian(a)wikimedia.org> wrote:
* WebM (aka VP8) is really not bad, but is
technically inferior to h.264
Main and High Profiles[1].
This comparison appears specious in the context of this thread, which
is the iPhone - the iPhone (which is the context of this thread)
doesn't support Main or High, only Baseline.
How does VP8 compare to H.264 Baseline profile?
(Up to 640x480, 'cos the iPhone doesn't go any higher of course. Is
the proposal to limit Wikimedia video to 640x480 as well, for the
mobile market?)
The iPhone 4s can play 1080p videos according to specs (scaled down to fit
960x640 of course). Several high-end phones now have 720p screens, and are
happy to play matching media. Tablets running related operating systems
have screen resolutions running from 1024x600 to 2048x1536. Other phones
with smaller screens, or on slow networks, might prefer to consume smaller
files.
TimedMediaHandler provides us the ability to generate transcodes at several
suitable sizes/bit rates. This is par for the course for video upload
sites, and simply brings us into line with standard industry practice. We
would already, per plan, be producing both smaller SD and larger HD files.
We can also produce Theora, WebM, *and* h.264 versions, or some subset
thereof, though additional formats mean more disk space and more transcode
time on upload.
But on a lot of devices, h.264 is the only realistic playback option.
Java's not available, JavaScript's not fast enough on little ARM CPUs. A
dedicated app might work (using more battery due to limited acceleration)
but would require additional installation with no benefit to the end-user,
who has already paid the patent license for the h.264 decoder in their
device as part of its price.
Our commitment to user freedom means we need to use patent-unencumbered
formats so *anyone* can use our stuff, including those on free platforms
who may not have a licensed h.264 decoder. The idea isn't actually to
*limit* our users to only free platforms. I think we do need to consider
reach and user experience here.
-- brion
- d.
_______________________________________________
Wikitech-l mailing list
Wikitech-l(a)lists.wikimedia.org
https://lists.wikimedia.org/mailman/listinfo/wikitech-l