On Mon, Jun 8, 2009 at 16:06, Tim Starling<tstarling(a)wikimedia.org> wrote:
As a technical
sidenote, it should be mentioned that recoding a lossy
format to another lossy format results _always_ a worse quality output
than the source lossy format. The amount of quality loss depends on
countless factors and usually do not render the result useless, but
the quality difference may be still audible/visible.
But if we can do resizing and quality conversion post-upload, then we
can encourage users to upload their videos with the best possible
quality, they won't be forced to upload at a quality suitable for web
download. We can store the source video unconverted for archival
purposes. When we reduce the quality of a video for a web user, the
Good in theory, but how many people are prepared to upload videos in
original format? It is most of the time even uncompressed, like DV,
and may add up to even a few gigabytes. (I don't remember, but I
believe it was around a gigabyte per minute or so.)
And it requires an enermous amount of storage space too.
Still I may be completely wrong since I have never checked how long
videos do we possess on average. And naturally this method (that we
convert lossy from original excellnt quality masters) is the best,
since then we control the output format and not the uploader.
--
byte-byte,
grin