Re: [xine-devel] Using the xine libraries to generate movie thumbnails

[Mike M. <mel...@pc...>]

On Fri, 13 Sep 2002, Vikash K. Mansinghka wrote:

> I'm interested in using the xine libraries to create a program which
> can generate a series of thumbnails for movies (snapshots evenly
> spaced in time) from a variety of movie formats. I was wondering if
> any of you knew of an existing solution, or, if not, where a good
> starting point in the xine libraries would be (or if you think this is
> a horrible idea, and if so, why).
>
> I sent a message to this effect some weeks ago, but received no reply,
> and am now subscribed to the list, fwiw.

	Hmm, you don't give up, posting on both lists. Admirable...:) I
have been meaning to address this, so here goes:

	First, can you outline your idea a little more? Do you want to
derive a new CLI or GUI tool based on xine-lib, or extend the existing
programs that currently sit on top of xine-lib? What exactly will this
program do? It sounds like it will open up a media file and yank out
frames. What will it do when it gets those frames? Scale them down and
display them to the user? Dump them to a file?

	Then there's the evenly-spaced part: To truly achieve this, you
would have to play through the file from start to finish. At first, I
thought about somehow just asking for keyframes, but that would be
unworkable.

	Though I have contributed a bunch of components to xine, I have
mainly restricted myself to A/V decoders and file demuxers. I admit that I
do not know much about the primary xine-lib engine. However, per my
understanding, a frontend program that uses xine-lib asks it to open a
file and start playing the file. Then the frontend can ask it to seek, ask
for snapshots, etc. The snapshot functionality should be the piece you are
interested in. I envision that you can poll the engine to ask where it
currently is in the playback time continuum and ask for snapshots
periodically.

	And of course, please remember that the team is busily
transitioning the API right now (another reason that good documentation
does not exist right now).

	So if I understand your goals, the answer is yes, xine-lib can
pull this off.

	Thanks...
--
	-Mike Melanson