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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>Hi All.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>I’m using ffmpeg for transcoding live ip multicasting video on server linux Centos 5.9 OS. This is my ffmpeg command<o:p></o:p></span></p><p class=MsoNormal><b><span style='font-size:12.0pt;background:yellow;mso-highlight:yellow'>ffmpeg -i "udp:// x.x.x.x:6000?fifo_size=1000000&overrun_nonfatal=1&timeout=1000000" -filter:v yadif=0:-1:1 -vcodec libx264 -vprofile main -level 30 -tune zerolatency -pass 1 -b:v 900k -minrate 900k -maxrate 900k -bufsize 900k -x264opts nal_hrd=cbr:rc_lookahead=40:interlaced=1:scenecut=0:cabac=1:keyint=120:deblock=0,0:aud=1:qpmin=16:qpmax=51:qpstep=10:ref=2:mixed-refs=1:subme=9:me=esa:chroma_me=0:merange=64:8x8dct=0:fast_pskip=0:chroma_qp_offset=0:trellis=2:psy=0:bframes=0:weightp=2:sliced_threads -s:v 720x576 -r:v 25 -force_key_frames 'expr:gte(t,n_forced*3)' -threads 0 -acodec aac -strict -2 -ac 1 -ar 32000 -b:a 32k -filter:a volume=1 -f mpegts -muxrate 1400k udp://x.x.x.x:6000?pkt_size=1316</span></b><b><span style='font-size:12.0pt'><o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:12.0pt'><o:p> </o:p></span></b></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>My output video is for broadcasting so I have to configure CBR video output by feature –muxrate. But when I watch this stream on VLC the bitrate change very much not constant. The null packet is very high to force cbr mpeg2ts output.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'><img width=493 height=367 id="Picture_x0020_2" src="cid:image005.jpg@01CFBB26.63925700" alt="Description: cid:image005.jpg@01CFBB26.63925700"></span><span style='font-size:12.0pt;color:#1F06B6'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>I also measure IP output video by HST3000 JDSU equipment and I see the measurement result is very bad as images.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>The PCR Jitter, IGMP Latency, Jitter Max which is not good as measurement standard by JDSU<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'><img width=353 height=208 id="Picture_x0020_5" src="cid:image006.jpg@01CFBB26.63925700" alt="Description: cid:image006.jpg@01CFBB26.63925700"></span><span style='font-size:12.0pt;color:#1F06B6'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'><img width=503 height=361 id="Picture_x0020_1" src="cid:image008.jpg@01CFBB26.63925700" alt="Description: cid:image008.jpg@01CFBB26.63925700"><img width=472 height=360 id="Picture_x0020_3" src="cid:image010.jpg@01CFBB26.63925700" alt="Description: cid:image010.jpg@01CFBB26.63925700"><img width=498 height=365 id="Picture_x0020_4" src="cid:image015.jpg@01CFBB26.63925700" alt="Description: cid:image015.jpg@01CFBB26.63925700"></span><span style='font-size:12.0pt;color:#1F06B6'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>I try many way to change the ffmpeg command but not successful. The bitrate changes sometime > 1400kbps a lot. I think the problem may be the bitrate not constant. I have heard to change the muxrate output is CBR, it had to be change the code C mpegtsenc.c in <a href="http://ffmpeg.org/libavformat.html"><span style='color:#1F06B6;text-decoration:none'>libavformat</span></a> library to new patch.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>So could you help me fix this problem and make the measurment result is better.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>Thank you so much.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#1F06B6'>Best Regards<o:p></o:p></span></p><p class=MsoNormal><b><i><span style='font-size:12.0pt;color:#1F06B6'>Đặng Đức Hưng</span></i></b><i><span style='font-size:12.0pt;color:blue'><o:p></o:p></span></i></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>