[gst-devel] qtdemux questions

[Ronald Bultje]

Hi,

On Fri, 2004-01-09 at 19:38, W. Michael Petullo wrote:
> I am very interested in using gstreamer to manipulate and view QuickTime
> files.  I have several videos I created a few years ago using the
> quicktime4linux library.  Most of the files use MJPEG as their video
> codec and Ogg/Vorbis for audio.

Isn't audio just 'vorbis'?

> I have been twiddling around with gst-launch from a user's point of view
> for a while so I am not yet very good with the internals of the system
> (I volunteered to late to port GNOME's mixer applet to gstreamer).
> Right now, I am using gstreamer 0.7.3.  Though I can create gst-launch
> pipelines to play many kinds of audio and video, I can't get my QuickTime
> videos to play.

Well, what pipelines do you use? MJPEG should "sort of" play. Vorbis is
a bit of an issue (see below).

> 1.  Does qtdemux support arbitrary video and audio codecs within the
> QuickTime framework?  If so, could I see and example pipeline?

Yes. For example pipelines, see gst-plugins/tools/gst-launch-ext and
look for 'mov' in it.

> 2.  If not, what would have to be done to support this?

We support a limited amount of codecs. The issue is that for each fourcc
identifier in quicktime, you need to know the GStreamer caps structure
to map it to. That works for a fair amount of codecs, but I'm sure we've
forgotten some.

> 3.  It seems that qtdemux has replaced the OpenQuickTime gstreamer plugin.
> Is this true?  Or is the OpenQuickTime one the more promising plugin?

Openquicktime, from a Linux perspective, is dead. The qtdemux plugin
replaced it.

> 4.  Can I help with gstreamer/QuickTime?

Yes! :). You can help mapping unknown codecs. And you might be able to
help getting vorbis to work. We've got an issue here: vorbis and ogg are
quite related. We handle both together in one plugin. this needs to be
separated so we can handle vorbis in ogg, vorbis in quicktime and vorbis
in any other filetype. you could definately help here. Let us know if
you're interested.

Ronald

-- 
Ronald Bultje <rbultje at ronald.bitfreak.net>
Linux Video/Multimedia developer