v4l2 element stay in READY state

Thu Feb 12 12:47:44 PST 2015

Also, when you see something that says 'WARNING' or 'ERROR', copy several
lines around those lines and post them here.

On Thu, Feb 12, 2015 at 3:36 PM, Sérgio Agostinho <
sergio.r.agostinho at gmail.com> wrote:

> Indeed, follow Chuck's advice and in the meantime make some more
> experiments.
>
> What happens if you try to set all elements to PAUSE and then to PLAY
> again (once they're linked)? Try to set the rtspsrc and the decodebin to
> PAUSE before linking the v4l2sink and then set everything to PLAY.
>
> Cheers
>
> 2015-02-12 20:34 GMT+01:00 Chuck Crisler <ccrisler at mutualink.net>:
>
>> It sounds like it is time to crank up logging on the decodebin and
>> v4l2sink elements to see what is(n't) happening.
>>
>> Something like:
>> export GST_DEBUG=decodebin:5,v4l2sink:5
>>
>> This should generate enough messages to understand what is failing.
>>
>> On Thu, Feb 12, 2015 at 5:05 AM, Russell <danrenjian at gmail.com> wrote:
>>
>>> By the way, target v4l2 device is created by v4l2loopback
>>> <https://github.com/umlaeute/v4l2loopback>
>>> Besides, I have output the caps of all pads (static or dynamic) of these
>>> elements whenever one of them change states. They seem to be fixed at the
>>> end. That is, (dynamic) src pad of rtspsrc and sink pad of decodebin have
>>> same fixed caps, and (dynamic) src pad of decodebin and sink pad of
>>> v4l2sink have same fixed caps. Does that mean the caps negotiation is
>>> completed?
>>>
>>> Thanks,
>>> Russell
>>>
>>> On Thu, Feb 12, 2015 at 5:58 PM, Russell <danrenjian at gmail.com> wrote:
>>>
>>>> fakesink works, too.
>>>> rtspsrc, decodebin and fakesink (as well as the pipeline itself) are
>>>> all in PLAYING state at the end.
>>>>
>>>> Thanks,
>>>> Russell
>>>>
>>>> On Thu, Feb 12, 2015 at 5:46 PM, Russell <danrenjian at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> autovideosink in code works ok, will give fakesink a try.
>>>>>
>>>>> Thanks,
>>>>> Russell
>>>>>
>>>>> On Thu, Feb 12, 2015 at 5:03 PM, Sérgio Agostinho <
>>>>> sergio.r.agostinho at gmail.com> wrote:
>>>>>
>>>>>> Just for completion, do you have the same issue if you replace
>>>>>> v4l2sink for fakesink and then for an autovideosink *in your code*.
>>>>>> Trying to understand if this is something specific about the way you're
>>>>>> connecting v4l2sink or just live sinks in general.
>>>>>>
>>>>>> Cheers
>>>>>> Sérgio
>>>>>>
>>>>>> 2015-02-12 7:44 GMT+01:00 Russell <danrenjian at gmail.com>:
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> Here is how I add and link decodebin and v4l2sink into pipeline:
>>>>>>>
>>>>>>>    1. When a new src pad is created for rtspsrc
>>>>>>>       1. add decodebin to pipeline
>>>>>>>       2. set decodebin to PLAYING async
>>>>>>>       3. link src pad of rtspsrc to sink pad of decodebin
>>>>>>>    2. When a new src pad is created for decodebin
>>>>>>>       1. add v4l2sink to pipeline
>>>>>>>       2. set v4l2sink to PLAYING async
>>>>>>>       3. link src pad of decodebin to sink pad of v4l2sink
>>>>>>>
>>>>>>> Eventually, rtspsrc will be PLAYING, decodebin be PAUSED, and
>>>>>>> v4l2sink be READY.
>>>>>>>
>>>>>>> But if I detect state change for decodebin, so what when it move to
>>>>>>> PAUSED, I set its state to PLAYING asyc again, then eventually decodebin
>>>>>>> would be in PLAYING state.
>>>>>>> v4l2sink would always be READY state even if I set its state several
>>>>>>> times like decodebin.
>>>>>>>
>>>>>>> And, If I only did 1 and no 2 as decribed above (that is, without
>>>>>>> adding and linking for v4l2sink), then both rtspsrc and decodebin would be
>>>>>>> in PLAYING state.
>>>>>>>
>>>>>>>
>>>>>>> Is there anything else I can try??
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Russell
>>>>>>>
>>>>>>>
>>>>>>> On Thu, Feb 12, 2015 at 9:06 AM, Russell <danrenjian at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hi, Wonchul
>>>>>>>>
>>>>>>>> How can I confirm whether v4l2sink receives any buffer, are there
>>>>>>>> any logs that I can inspect?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Russell
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Wed, Feb 11, 2015 at 10:06 PM, Wonchul Lee <chul0812 at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> I guess that v4l2sink didn't receive any buffer.
>>>>>>>>> Sink element what inherited from basesink will change to PAUSED
>>>>>>>>> states
>>>>>>>>> after receiving a buffer for preroll.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> http://cgit.freedesktop.org/gstreamer/gstreamer/tree/docs/design/part-states.txt#n41
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 2015-02-11 18:23 GMT+09:00 Sérgio Agostinho <
>>>>>>>>> sergio.r.agostinho at gmail.com>:
>>>>>>>>> > Hi Russel,
>>>>>>>>> >
>>>>>>>>> > If you do
>>>>>>>>> >
>>>>>>>>> > gst-launch-1.0 videotestsrc ! v4l2sink
>>>>>>>>> >
>>>>>>>>> > do you see video on your v4l2device? Also, if you do
>>>>>>>>> >
>>>>>>>>> > gst-launch-1.0 rtspsrc location=rtspaddress ! decodebin !
>>>>>>>>> autovideosink
>>>>>>>>> >
>>>>>>>>> > Do you see your rtsp video stream playing on a window?
>>>>>>>>> >
>>>>>>>>> > Cheers
>>>>>>>>> >
>>>>>>>>> >
>>>>>>>>> > 2015-02-11 7:50 GMT+01:00 Russell <danrenjian at gmail.com>:
>>>>>>>>> >>
>>>>>>>>> >> Hi,
>>>>>>>>> >>
>>>>>>>>> >> I was trying this pipeline to feed rtsp stream into a v4l2
>>>>>>>>> virtual
>>>>>>>>> >> loopback device:
>>>>>>>>> >> gst-launch-1.0 rtspsrc location=rtspaddress ! decodebin !
>>>>>>>>> v4l2sink
>>>>>>>>> >>
>>>>>>>>> >> Terminal gave this output and stops, and there are no video in
>>>>>>>>> the v4l2
>>>>>>>>> >> device:
>>>>>>>>> >> Progress: (request) Sending PLAY request
>>>>>>>>> >> Progress: (request) Sending PLAY request
>>>>>>>>> >> Progress: (request) Sent PLAY request
>>>>>>>>> >>
>>>>>>>>> >>
>>>>>>>>> >> So I am implementing the pipeline in c to see what happened.
>>>>>>>>> decodebin and
>>>>>>>>> >> v4l2sink are added and linked on on pad-added event. Eventually
>>>>>>>>> I found the
>>>>>>>>> >> v4l2sink element stay in READY state while the other two are
>>>>>>>>> PLAYING. I have
>>>>>>>>> >> set v4l2sink to PLAYING asynchronously but the state does not
>>>>>>>>> change.
>>>>>>>>> >>
>>>>>>>>> >> What is the matter here? and where I can find any detailed
>>>>>>>>> reason why
>>>>>>>>> >> v4l2sink cannot go to PLAYING state?
>>>>>>>>> >>
>>>>>>>>> >> Thanks in advance.
>>>>>>>>> >>
>>>>>>>>> >> Sincerely,
>>>>>>>>> >> Russell
>>>>>>>>> >>
>>>>>>>>> >> _______________________________________________
>>>>>>>>> >> gstreamer-devel mailing list
>>>>>>>>> >> gstreamer-devel at lists.freedesktop.org
>>>>>>>>> >> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>>>>>>>> >>
>>>>>>>>> >
>>>>>>>>> >
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