[libav-api] Cannot open stream

Manuel Torres manuel.torres.fernandez at gmail.com
Thu Jun 12 18:23:25 CEST 2014


Does that mean that I will not be able to open the stream unless I modify
the libav code?


On Thu, Jun 12, 2014 at 5:54 PM, Joshua Kordani <jkordani at lsa2.com> wrote:

> Additionally, the rtpmap line in the sdp file comes AFTER the fmtp line,
> this causes wireshark to be confused, and according to the comments in
> libavformat/rtsp.c, may not be handled by the library, as the dynamic
> handler may not have the knowledge that the fmtp string is associated with
> an h264 stream, so the sprops-param line may just be discarded.
>
> Joshua Kordani
> LSA Autonomy
>
>
> On 6/12/14 10:24 AM, Joshua Kordani wrote:
>
>> It also should be noted that in the sdp, the server is indicating that it
>> will only be providing single nal packets "packetization-mode=0" but
>> instead provides an rtp stream with fragmented nals.  In this case,
>> packetization-mode should be non-zero.  I don't know if this is confusing
>> the library at all (I doubt it) but I figured I'd say something.
>>
>> Joshua Kordani
>> LSA Autonomy
>>
>> On 6/12/14 2:07 AM, Manuel Torres wrote:
>>
>>> SPS and PPS are not present. I can see IDRs with a frequency of 60-100ms.
>>> Any thoughts?
>>>
>>>
>>> On Thu, Jun 12, 2014 at 7:50 AM, Manuel Torres <
>>> manuel.torres.fernandez at gmail.com> wrote:
>>>
>>>  This is what avplay displays when opening the stream:
>>>> http://pastebin.com/K6jmtGps
>>>>
>>>> My code can open the BigBuckBunny stream.
>>>>
>>>> I will now check the Wireshark capture and let you know.
>>>>
>>>>
>>>>
>>>> On Wed, Jun 11, 2014 at 7:34 PM, Joshua Kordani <jkordani at lsa2.com>
>>>> wrote:
>>>>
>>>>  and alternatively, what happens when you point your code at the
>>>>> following
>>>>> rtsp url?
>>>>> rtsp://184.72.239.149/vod/mp4:BigBuckBunny_115k.mov
>>>>>
>>>>> Joshua Kordani
>>>>> LSA Autonomy
>>>>>
>>>>> On 6/11/14 11:49 AM, Manuel Torres wrote:
>>>>>
>>>>>  Done. I captured just a few seconds to keep the file size low. Here is
>>>>>> the
>>>>>> download link:
>>>>>>
>>>>>> https://www.wetransfer.com/downloads/8d6c64606d347f395c6a0dfd870241
>>>>>> 9b20140611154702/5f67e064c7ebf8c694577589d69c1d5420140611154702/c7dee4
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Jun 11, 2014 at 5:32 PM, Joshua Kordani <jkordani at lsa2.com>
>>>>>> wrote:
>>>>>>
>>>>>>   Can you make a short wireshark capture that includes the rtsp as
>>>>>> well as
>>>>>>
>>>>>>> the rtp traffic going from this camera, for, say, 30 seconds?  Do
>>>>>>> this
>>>>>>> using your program to start the feed.
>>>>>>>
>>>>>>> Joshua Kordani
>>>>>>> LSA Autonomy
>>>>>>>
>>>>>>>
>>>>>>> On 6/11/14 11:21 AM, Manuel Torres wrote:
>>>>>>>
>>>>>>>   No. It is an external source of which I have no control and I
>>>>>>> cannot
>>>>>>>
>>>>>>>> figure
>>>>>>>> out what is diferent in it from the rest if the sources I can open
>>>>>>>> with
>>>>>>>> both avplay and my code. It puzzles me even more that VLC and
>>>>>>>> MPlayer
>>>>>>>> do
>>>>>>>> open the stream.
>>>>>>>>
>>>>>>>> Enviado desde dispositivo móvil.
>>>>>>>> Sent from mobile device.
>>>>>>>> On Jun 11, 2014 5:15 PM, "Joshua Kordani" <jkordani at lsa2.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>    Are you creating this stream yourself?
>>>>>>>>
>>>>>>>>  Joshua Kordani
>>>>>>>>> LSA Autonomy
>>>>>>>>>
>>>>>>>>> On 6/11/14 11:08 AM, Manuel Torres wrote:
>>>>>>>>>
>>>>>>>>>    If by "resource" you mean the URL, the answer is no, avplay
>>>>>>>>> does not
>>>>>>>>>
>>>>>>>>>  display the video. The traces in my first e-mail are also
>>>>>>>>>> displayed
>>>>>>>>>> by
>>>>>>>>>> avplay, that is, no size and no color space.
>>>>>>>>>>
>>>>>>>>>> Enviado desde dispositivo móvil.
>>>>>>>>>> Sent from mobile device.
>>>>>>>>>> On Jun 11, 2014 4:10 PM, "Luca Barbato" <lu_zero at gentoo.org>
>>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>>     On 11/06/14 09:41, Manuel Torres wrote:
>>>>>>>>>>
>>>>>>>>>>   First of all, thank you Luca and Joshua for taking the time to
>>>>>>>>>> help
>>>>>>>>>>
>>>>>>>>>>> me
>>>>>>>>>>>
>>>>>>>>>>>     and
>>>>>>>>>>>>
>>>>>>>>>>>>     thank you very much Joshua for that awesome explanation. I
>>>>>>>>>>> see
>>>>>>>>>>> that
>>>>>>>>>>>
>>>>>>>>>>>  there
>>>>>>>>>>>> is a lot to learn.
>>>>>>>>>>>>
>>>>>>>>>>>> Back on topic:
>>>>>>>>>>>> I checked the format context and the codec context and I only
>>>>>>>>>>>> found an
>>>>>>>>>>>> empty (NULL) "extradata" field in the codec context. I also
>>>>>>>>>>>> checked
>>>>>>>>>>>> some
>>>>>>>>>>>> other fields in both structures where I thought the data could
>>>>>>>>>>>> be
>>>>>>>>>>>> but
>>>>>>>>>>>>
>>>>>>>>>>>>    found
>>>>>>>>>>>>
>>>>>>>>>>>>     nothing. Am I looking in the right place?
>>>>>>>>>>>
>>>>>>>>>>>      Looks quite strange, if you just do avplay rtsp://resource
>>>>>>>>>>>>
>>>>>>>>>>>>   does it play?
>>>>>>>>>>>>
>>>>>>>>>>> lu
>>>>>>>>>>>
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