[linux-audio-user] gstreamer, rhythmbox, and mp3

[Florian Schmidt]

On Tuesday 06 February 2007, david wrote:
> Paul Davis wrote:
> > On Mon, 2007-02-05 at 22:34 -0500, carmen wrote:
> >>>> it solves a number of problems that nobody
> >>>> else has bothered to solve.
> >>>
> >>> Like what? I play media stuff of all kinds without GStreamer even
> >>> installed.
> >>
> >> what happens when your card doesn't have dmix, and gstreamer is
> >> already playing a stream at 48khz to hw:0,1, and another app wants to
> >> play a 44.1 khz beep to the same output. does it via some mutex/IPC
> >> magic switch over to software mixing the two streams, without
> >> requiring a resident sound daemon? if so, i'd consider that a solved
> >> problem that nobody else wanted to tackle..
> >
> > gstreamer doesn't solve that problem. far from it. other than the fact
> > that it can talk to some audio sinks that do solve it.
> >
> > the kinds of problem i am referring to have to do mostly with complex
> > sync cases when an app is playing two streams (e.g. video + audio) and
> > needs to maintain careful sync no matter what the downstream data
> > pathway looks like. also, it has some abilities to split and recombine
> > data streams in ways that are not useful for everyday use but can be
> > very handy in a toolbox.finally, the existence of *legal* MP3 codecs for
> > gst from fluendo (with other codecs to come) should not be overlooked.
> >
> > i am by no means a gstreamer fanboy, but i do think that the gst
> > architecture has evolved over quite a significant period to be able to
> > do things that, AFAIK, no other media framework on linux does.
>
> ok, sort of sounds like a solution in search of a problem to me. I guess
> I've not encountered anything needing it's abilities.

Oh well, there are many uses. I.e. writing a video editor and other multimedia 
apps should become pretty easy. I.e. there's a gstreamer based hd recording 
software (jokosher) and while i haven't tried it in a while it looked quite 
promising.

Then there's the whole field of video editing where the sync issues paul 
mentioned are extremely important. I think there's evolving video editor 
software based on gstreamer. I.e. pitivi.

Thirdly it's a multimedia framework that is very easy usable for custom 
application developers. I have written a media player for a client (to be 
used in neuroscientific experiments) based on gstreamers playbin element and 
XV overlay into a gtk+ window with very little problems (actually most of the 
code is logic for the experiments and the gstreamer handling code is very 
very small compared to the other stuff)..

If you look at the history of multimedia on linux you will see that every app 
basically has reinvented the wheel and since there's a myriad of apps, this 
has been done a myriad of times. gstreamer tries to overcome this by 
providing a powerful and usable framework. And it's really working pretty 
well these days..

Flo

P.S.: try i.e.:

gst-launch-0.10 playbin uri=file:///path/to/some/media/file

on the commandline. Be it video or audio, here on my box this even plays avi's 
and wmv's.. And setting up a video for playback from within an application 
isn't much harder than that (if you don't need the advanced possibilities 
gstreamer offers on top of that)..

It even automagically uses jack if it's running :) (this is on ubuntu feisty 
though)

P.P.S.: I'm not a gstreamer fanboy either but looking at it objectively, it's 
a big step forward for linux multimedia..

-- 
Palimm Palimm!
http://tapas.affenbande.org