decode byte-stream video without gmainloop

[Matthew Waters]

1. You should download debug symbols for GStreamer to get better backtraces.
2. Are you calling gst_init() at the beginning of your program ?

Cheers
-Matt

On 3/2/20 9:59 pm, Karl Lattimer wrote:
> I seem to be getting *somewhere* but I’m having an issue with creating
> a new GstBuffer 
>
> This seems strange, I’ve tried both 
>
>     buffer = gst_buffer_new_and_alloc(data_len);
>
> and
>
>     buffer = gst_buffer_new ();
>     memory = gst_allocator_alloc (NULL, data_len, NULL);
>     gst_buffer_insert_memory (buffer, -1, memory);
>
> both methods cause a segfault… Not sure why, I mean, I’m only
> requesting a memory allocation so this should be OK right? 
>
> backtrace isn’t entirely revealing 
>
> #0  0x00007ffff7e6c07din gst_allocator_alloc() at
> /usr/lib/x86_64-linux-gnu/libgstreamer-1.0.so.0
>
> Regards,
>  K
>
>
>> On 3 Feb 2020, at 08:00, Matthew Waters <ystreet00 at gmail.com
>> <mailto:ystreet00 at gmail.com>> wrote:
>>
>> On 3/2/20 6:24 pm, Karl Lattimer wrote:
>>>
>>>>> and push that data into a gstreamer pipeline. As far as I understand
>>>>> the raop_ntp_t struct contains information regarding time
>>>>> synchronisation and pts provides an accurate timestamp. In my tests
>>>>> with gstreamer so far I’ve taken the buffer, dumped it to disk as an
>>>>> MP4 file, then used a simple playbin pipeline to open the file and
>>>>> play it. 
>>>>
>>>> Have you looked at the appsrc element ? Note that GStreamer processing
>>>> is asynchronous, so you may have to copy the pointer, or make sure that
>>>> your wrapped buffer is consumed before returning.
>>>>
>>>> https://gstreamer.freedesktop.org/documentation/tutorials/basic/short-cutting-the-pipeline.html?gi-language=c
>>>
>>> It’s my understanding that for that to work I’d need a gmainloop in
>>> order to callback the appropriate functions for need data and have
>>> enough data, as well as being able to emit the signal push-data
>>> which seems to be where the data is inserted into the pipeline. 
>>>
>>> Is this correct? I don’t think I can shove a gmainloop into RPiPlay
>>> it’s pretty much dependent on the data stream and has it’s own
>>> mainloop for that purpose.
>>
>> You don't need a mainloop running to emit or retrieve those signals
>> on appsrc.  Nothing in GStreamer requires there to be any kind of
>> mainloop running except for platform or plugin specifics which are
>> few and far between (e.g. MacOS video output).
>>
>> Cheers
>> -Matt
>>
>>>>
>>>>>
>>>>> I’d also like to know if it’s possible to get a playbin to dump the
>>>>> pipeline that it’s using out somehow, there’s quite a lot of
>>>>> information in the verbose output, but I can’t seem to spot a
>>>>> pipeline which I could use on the command line in place of playbin, I
>>>>> think that would help me in the final goal. 
>>>>
>>>> When you are using gst-launch-1.0 you can dump the pipeline into DOT
>>>> files using the env GST_DEBUG_DUMP_DOT_DIR=
>>>>
>>>> To get the same thing in your application, you have to call:
>>>>
>>>>  GST_DEBUG_BIN_TO_DOT_FILE(bin, GST_DEBUG_GRAPH_SHOW_ALL, file_name);
>>>
>>> perfect thanks! 
>>>
>>> K,
>>>
>>> _______________________________________________
>>> gstreamer-devel mailing list
>>> gstreamer-devel at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>
>>
>> _______________________________________________
>> gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> <mailto:gstreamer-devel at lists.freedesktop.org>
>> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20200203/abb8ae9c/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: OpenPGP digital signature
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20200203/abb8ae9c/attachment-0001.sig>