[FFmpeg-user] function trace

Marc Elliott elliott2w1 at gmail.com
Sun Oct 14 01:50:45 CEST 2012


Hello.  I am streaming a raw video and I am trying to trace the function
calls that take place between the motion estimation functions (in
libavcodec/motion_est.c) and the write function (in libavformat/http.c).
 The size of my video frames are 320x240 which, given the yuv420 format,
results in a total buffer size of 115,200.  I have been able to trace the
function calls all the way up until the motion estimation but I am having
trouble tracking down what takes place after that.

During motion estimation, I have verified that the original data is what is
being worked with.  However, I have also found that 11 or so frames go
through motion detection before the write function is being called.  When
the write function is called, the buffer size is only 4096.  So, what I'm
trying to determine is how the data goes from 11 or so frames of size
115,200 to one buffer size of 4096.  I'm assuming that, during motion
estimation, the error frames are being calculated and then further
compressed somehow but I have not been able to determine where or how this
is happening.   If anyone could give me a hint as to where to start looking
in order to determine how the data is getting manipulated, I would really
appreciate it.  Thanks.

Marc Elliott


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