[Live-devel] about parsing SDP description file

[hong liu]

Dear Ross,
 
 I used openRTSP to get a H264 file in mp4 format from Darwin Streaming Server. I encoded into the H264 with image size 352x288 by x264 and encapsulated into the mp4 file using MP4Box.  I tried the command of "openRTP -v -4 rtsp://192.168.0.1/a01.mp4" and however the received mp4 file is in wrong image size, which is default size in the program. So I looked to the SDP file, as shown in the below:
 v=0
 o=- 2209842806 1145641443000 IN IP4 142.92.36.55
 s=\a01_hinted.mp4
 u=http://epox3.dgbt.crc.ca
 e=admin at epox3.dgbt.crc.ca
 c=IN IP4 0.0.0.0
 b=AS:113
 t=0 0
 a=maxprate:26.000000
 a=range:npt=0-  12.00000
 a=control:*
 m=video 0 RTP/AVP 96
 b=AS:113
 b=TIAS:107
 a=maxprate:26
 a=rtpmap:96 H264/90000
 a=control:trackID=3
 a=cliprect:0,0,288,352
 a=framesize:96 352-288
 a=fmtp:96 packetization-mode=1;profile-level-id=4D0028;sprop-parameter-sets=Z00AKJZkCwS0IAAAfQAADqYQgA==,aO48gA==
 a=range:npt=0-  12.00000
 
 I found there was no the line of "a=x-dimensions:<width>,<height>" to update the default width and height by the real dimension. I just found the lines of "a=cliprect:0,0,288,352" and "a=framesize:96 352-288". 
 
 First, I didn't find any explanation about the sematics for these two attributes on Internet. Could you explain it in detail? So I am not so sure if I am doing right in write one more member  function in the   MediaSubsession class to parse either one of them to update the default image dimension by real one.
 
 Thank you for your help!
 

Hong Liu
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