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

andrea sarkiaponius at alice.it
Mon Mar 21 10:29:47 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..
> 
> 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

Dear Marco, 

many thanks for your answer. I will try to understand it more deeply,
because it seems very promising.

I tried to examine wireshark packets, too, but it seemed to difficult
for me. As you maybe read in my message, I'm tring with gstreamer
because my new ADSL router blocks mplayer some way. I posted a message
on mplayer-user, but no one has a solution.

It's really strange that connection-speed is not used. I'm not sure I'm
able to use your patch, but if you don't mind you can send it. Please
note that I'm not a developer, though I wrote many small C programs, but
nothing so complex as gstreamer source! I'm just a user, and my goal is
to take all audio contents that can be downloaded from RAI before they
close their sites or delete those contents.

But know mplayer doesn't work here at home...

Best 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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