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<p class=MsoNormal><span lang=EN-US>Dear all,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We are very interested to retrieve raw data
from IP cameras (MJPEG, MPEG4, H.264) via RTSP and using your Live 555. <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>In order to do it we implemented the Demux
class which inherit from the class FramedSource.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Inside de Demux class we have the
AfterReadingFrame which is call each time a frame is available.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Definition of AfterReadingFrame.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>static void AfterReadingFrame(void* clientData,
unsigned frameSize,unsigned /*numTruncatedBytes*/,struct timeval
presentationTime,unsigned /*durationInMicroseconds*/);<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>The function AfterReadingFrame is passed to
the getNextFrame as seen below.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>subsession->readSource()->getNextFrame(m_FrameBuffer,MAX_RTP_FRAME_SIZE,RTSP.AfterReadingFrame,subsession,onSourceClosure,subsession);<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Inside of the AfterReadingFrame function we
are accessing to the frame buffer, variable fTo and looking for the frame size
from the variable fFrameSize<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>MediaSubsession* bufferQueue =
(MediaSubsession*)clientData;<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Demux *sFrame =
(Demux*)bufferQueue->readSource();<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>unsigned char* pBuffer = sFrame->fTo;<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>unsigned int FrameSize = sFrame->
fFrameSize;<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We think that the buffer obtained and size
is correct.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>However, when trying to write
directly the frame to a file (MJPEG video stream) or create a header jpg and<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>to add the pBuffer we cannot see the saved
frame.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>What contains the pBuffer? Raw data or the
frame with its header.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Is that the best way to retrieve raw data
from a IP camera?<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Thank you in advance!<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Best Regards,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Josep Aguilera.<o:p></o:p></span></p>
<p class=MsoNormal><o:p> </o:p></p>
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