nickon314
Posts: 116
Joined: Tue Jul 03, 2012 12:11 pm
Location: West Yorkshire

GStreamer dvbsrc pipeline example.

Fri May 24, 2013 4:00 pm

Hi,

I need a little help getting a gst-launch-1.0 command to work on the RPi.

I have a DVB-T USB adaptor, which I know works OK with the RPi because Kaffeine works - although it's too slow to be useful.

So, I now have GStreamer 1.0 installed, and I need a little help getting to watch live DVB-T tele.

Here is what I have got so far:

gst-launch-1.0 dvbsrc modulation="QAM 64" trans-mode=8k bandwidth=8 frequency=658000000 code-rate-lp=AUTO code-rate-hp=2/3 guard=4 hierarchy=0 ! tsdemux name=demux ! queue max-size-buffers=0 max-size-time=0 ! h264parse ! omxh264dec ! eglglessink

I know that the frequency is right, because the DVB-T locks on OK.
And, anyway, using w_scan found channels on that frequency.

But, my problem is that the gst-launch-10 doesn't actually do anything.
I just see this :

Setting pipeline to PAUSED...
Pipeline is live and does not need PREROLL ...
Got context from element 'eglglessink0': context, gst.egl.EGLDisplay=(GstEGLDisplay)NULL;
Setting pipeline to PLAYING ...
New clock: GstSystemClock

<-- Waits here for about 2 mins -->


Then, I get an error about internal data flow, then it quits.

So, what is wrong?!?!?
Help appreciated.


Regards

Nick

User avatar
fbutler
Posts: 302
Joined: Thu Mar 15, 2012 4:09 pm
Location: Surrey, England

Re: GStreamer dvbsrc pipeline example.

Fri May 24, 2013 4:18 pm

nickon314 wrote:Hi,

I need a little help getting a gst-launch-1.0 command to work on the RPi.

I have a DVB-T USB adaptor, which I know works OK with the RPi because Kaffeine works - although it's too slow to be useful.

So, I now have GStreamer 1.0 installed, and I need a little help getting to watch live DVB-T tele.

Here is what I have got so far:

gst-launch-1.0 dvbsrc modulation="QAM 64" trans-mode=8k bandwidth=8 frequency=658000000 code-rate-lp=AUTO code-rate-hp=2/3 guard=4 hierarchy=0 ! tsdemux name=demux ! queue max-size-buffers=0 max-size-time=0 ! h264parse ! omxh264dec ! eglglessink

I know that the frequency is right, because the DVB-T locks on OK.
And, anyway, using w_scan found channels on that frequency.

But, my problem is that the gst-launch-10 doesn't actually do anything.
I just see this :

Setting pipeline to PAUSED...
Pipeline is live and does not need PREROLL ...
Got context from element 'eglglessink0': context, gst.egl.EGLDisplay=(GstEGLDisplay)NULL;
Setting pipeline to PLAYING ...
New clock: GstSystemClock

<-- Waits here for about 2 mins -->


Then, I get an error about internal data flow, then it quits.

So, what is wrong?!?!?
Help appreciated.
Have a look at the gst-launch debug options to get more details on where it is failing by doing a man gst-launch-1.0

In particular look at the options:

--gst-debug-level=
--gst-debug-string=

I'd also add the -v and -e parameters to the gst-launch-1.0 command.

It would also be useful if you could provide the make and model of your DVB-T USB adaptor in case anyone here is using the same one.

nickon314
Posts: 116
Joined: Tue Jul 03, 2012 12:11 pm
Location: West Yorkshire

Re: GStreamer dvbsrc pipeline example.

Mon Jun 03, 2013 8:01 am

Hi,

The USB DVB-T device looks like this from 'lsusb' :

Bus 001 Device 005: ID 048d:9135 Integrated Technology Express, Inc. Zolid Mini DVB-T Stick .

I will look at those debug options now too.


Regards

Nick

nickon314
Posts: 116
Joined: Tue Jul 03, 2012 12:11 pm
Location: West Yorkshire

Re: GStreamer dvbsrc pipeline example.

Mon Jun 03, 2013 8:24 am

Using --gst-debug-level=4, I'm seeing a lot of these lines repeated:

0:00:07.102109788 2669 0xacdac0 WARN mpegtspacketizer mpegtspacketizer.c:3483:calculate_skew: delta - skew: 5124071:07:03.454236357 too big, reset skew

And, another similar one that says "backward timestamps at server but no timestamps"


Is that significant?

Regards

Nick

nickon314
Posts: 116
Joined: Tue Jul 03, 2012 12:11 pm
Location: West Yorkshire

Re: GStreamer dvbsrc pipeline example.

Mon Jun 03, 2013 10:20 am

I've also tested the videotestsrc too, to make sure that I see the colour bars OK. And that works OK using this:

gst-launch-1.0 videotestsrc ! textoverlay text="Hello" ! eglglessink

So, the problem I am having must be somewhere in the pipeline relating to tuning and demuxing and decoding.


Regards

Nick

User avatar
fbutler
Posts: 302
Joined: Thu Mar 15, 2012 4:09 pm
Location: Surrey, England

Re: GStreamer dvbsrc pipeline example.

Mon Jun 03, 2013 10:30 am

nickon314 wrote:I've also tested the videotestsrc too, to make sure that I see the colour bars OK. And that works OK using this:

gst-launch-1.0 videotestsrc ! textoverlay text="Hello" ! eglglessink

So, the problem I am having must be somewhere in the pipeline relating to tuning and demuxing and decoding.
Yeah, your best bet would be googling on the warning message or on the pipeline element names to find examples of other working similar pipelines.

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