[gst-devel] A/V Synchronization in Pipe

[Stefan de Konink]

Hi Andy,

Andy Wingo wrote:
> I can't believe Thomas didn't reply. He must have been jealous, having
> had this desire for a while but holding off for the Right Solution :-)
If he wants, we operate near The Hague, so he can join us typing all
commands in commandline ;) (Yes, I tryed flumotion, but performance wise
we were better off with some bash scripts.)

> 1) DV capture for those of us working on Flumotion gives us near-perfect
> sync. To encode into ogg, you'd do like this:
> 
> gst-launch-0.8 \
>   dv1394src ! dvdec drop-factor=2 name=d \
>    d.video ! { queue ! videorate ! ffmpegcolorspace ! theoraenc \
>                ! queue } ! { oggmux name=mux ! filesink } \
>    d.audio ! { queue ! audiorate ! audioconvert ! rawvorbisenc \
>                ! queue } ! mux.
> 
> Unfortunately something strange is happenning on my side that's making
> this not work. I'll be looking at this. Obviously it works in flumotion.
I'm going to test it again on friday. I didn't use the drop-factor and I
use osssrc/alsasrc, because it is more easy to connect an XLR ->
mini-jack into the line in of the Laptop than mic-in of the DV Cam.

> 2) Position of the window -- what does this mean? You want to do an
> overlay? videomixer does this, and quite well -- see
> flumotion/components/converters/overlay/overlay.py for the pipeline. To
> set the position you set object properties on the videomixer sink pads.
> The source is the best documentation unfortunately.
I have tryed videomixer, but on my production P4, putting in 320x200
theora, videoscale to 640x480, videomixer seems a bit to much.
Textoverlay is already something critical... and yes I should try to
invest in some real processors...

Though I want someother thing, maybe I can do that with videomixer too.
In the beginning we started with Helixplayer, and SMIL files. Thanks to
Akos we have SMIL for audio now, but video is stil premature.
I want a static-background with a position of the video. That could all
be realised with videomixer, but is it also possible with xvimagesink?
To position the window on a specified location? Like:
[width]x[height]+[x offset]+[y offset]

> Neat. Let us know how it goes.
I'll if the overhead doesn't gets to high.

> It seems that's where development is these days. Well I'll be working on
> dv1394src today and maybe tomorrow, in 0.9, so I suppose it's time to
> start thinking about this stuff.
Could you plz, plz, plz, also implement dv1394sink :)


Stefan