How to dump a stream faster than real time...

andrea sarkiaponius at alice.it
Mon Apr 4 10:16:50 PDT 2011


On Mon, 2011-03-21 at 06:32 +0200, Marco Ballesio wrote:
> Hi,
> 
> sorry for the late reply, but I'm always one week in the future..
> 

Dear Marco,

have you made any progress about this issue?

Best regards.

> Being interested in RAI stuff as well, I found your question quite
> interesting. Maybe you've already understood what's the point (or
> maybe not) btw I'm writing here my outcomes not to completely waste
> the time spent so far ;) .
> 
> First of all, I checked with wireshark what are the changes in RTSP
> packets and especially into the SDP contents when setting/not setting
> the -bandwidth parameter with mplayer.
> 
> following the above steps it has been easy to note that the
> SET_PARAMETER method (as for RFC2326, par. 10.9) is used to control
> the server bandwidth.
> 
> Now, a simple grep SET_PARAMETER in the GStreamer sources shows many results in:
> 
> - gstrtspdefs.c (plugins-base)
> - rtspreal.c (plugins-ugly)
> - OT: many results in pulseaudio sources (!!)
> 
> In the first case, SET_PARAMETERS appears to be used only for logging
> purposes, while in the second it's used only for a single purpose
> (setting the url).. bad luck.
> 
> It should anyway be quite simple to modify gstrtspsrc to behave as
> expected when using the connection_speed property, which FWIW appears
> not to be used anywhere. Is this a bug or a work-in-progress feature?
> In the first case I have an half-cooked patch that should do the
> trick, but would the mplayer way (using SET_PARAMETERS instead of an
> header in the SETUP message) be the right one?
> 
> Regards
> 
> On Mon, Mar 14, 2011 at 5:54 PM, andrea <sarkiaponius at alice.it> wrote:
> > On Mon, 2011-03-14 at 16:26 +0200, Stefan Kost wrote:
> >> On 12.03.2011 17:59, andrea wrote:
> >> > Hi,
> >> >
> >> > I try again since my previous message was ignored. If I'm asking the
> >> > wrong mailing list just let me know.
> >> Nobody is ignoring your message. It could just mean that no one has an
> >> answer.
> >
> > Sorry, I wouldn't mean to be unpolite.
> >
> >> > I'm using a command line like the following to download old episodes of
> >> > some audio programmes of italian broadcasting company (Rai).
> >> >
> >> > gst-launch-0.10 gstrtpsession bandwidth=40000000 rtspsrc
> >> > location=rtsp://mm6.rai.it/radiofonia/radio3/napoli/uomini_profeti/2010/uomini_profeti2010_09_19.ra connection-speed=2100000 ! decodebin2 ! wavenc !filesink location=prova.wav
> >> Why do you create an extra rtspsession? It won't be used. Both plugins
> >> have several examples in the manual.
> >
> > I tried this way because of the bandwidth property of gstrtspsession.
> > Indeed it makes no difference, as you said.
> >
> > It seems really hard to find a solution. That's a pity, because
> > gstreamer seems the only way to access RTSP streams through
> > TelecomItalia routers. Actually, I found that ffmper does it too, but it
> > has no option to control the speed nor the bandwidth.
> >
> > Best regards and many thanks.
> >
> >>
> >> Stefan
> >> > Actually, the episodes are not real streams, but just RealAudio files
> >> > that you can only access via RTSP.
> >> >
> >> > The above command line works perfectly but, despite the "bandwidth" and
> >> > "connection-speed" options, to download the file it simply takes exactly
> >> > the duration of the episode (they usually last 45 minutes each).
> >> > I've using mplayer too, to do the same, and it has a wonderful option
> >> > "-bandwidth" which, with a value, say, of 4000000, just lets you
> >> > download the same file above in less than one minute!
> >> >
> >> > I'm wondering if there is some way to do the same with some gstreamer
> >> > pipeline. I mean, some way to accelerate the download just as mplayer
> >> > does. It would be very very nice because mplayer has problems with some
> >> > ADSL router and some networks here in Italy, while gstreamer does not.
> >> > Best regards.
> >> >
> >>
> >> _______________________________________________
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> >> gstreamer-devel at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> >
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> >
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