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• FPS drop in FFMPEG streaming processes to FB from production server

  30 janvier 2017, par Aakash Gupta

  I have made a rails app that can stream live videos to facebook rtmp server and deployed it on AWS. I have used nginx as web server. The major problem that I am encountering after viewing log files of FFMpeg processes is that sometimes the FPS of FFmpeg process starts to drop. In some cases, it remains stable at 25 FPS but in some cases, it remains at 25 only for sometime, and after that it starts to drop and sometimes it falls to even 3-4 FPS which is unacceptable during live streaming. As FFMpeg process is quite heavy, I would also like to share my CPU info as well.

  CPU information is :

  cat /proc/cpuinfo
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 63
model name  : Intel(R) Xeon(R) CPU E5-2676 v3 @ 2.40GHz
stepping    : 2
microcode   : 0x25
cpu MHz     : 2400.070
cache size  : 30720 KB
physical id : 0
siblings    : 1
core id     : 0
cpu cores   : 1
apicid      : 0
initial apicid  : 0
fpu     : yes
fpu_exception   : yes
cpuid level : 13
wp      : yes
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm xsaveopt fsgsbase bmi1 avx2 smep bmi2 erms invpcid
bogomips    : 4800.14
clflush size    : 64
cache_alignment : 64
address sizes   : 46 bits physical, 48 bits virtual
power management:

  FFMPEG log file with unstable fps : https://drive.google.com/open?id=0B1gtp1iXJppkUndFamk4M0lRYzA

  FFMPEG log file with stable fps : https://drive.google.com/open?id=0B1gtp1iXJppkMkVCZEJjYWJrVTA

  When FPS was stable, I also tried to run another parallel FFMpeg process from the same server which resulted in FPS dropping of both the processes to 13-14 FPS.

  I am currently using this FFMPEG command :

  ffmpeg -loop 1 -re -y -f image2 -i "image_path" -i "audio_path.aac" -acodec copy -bsf:a aac_adtstoasc -pix_fmt yuv420p -profile:v high -s 1280x720 -vb 400k -maxrate 400k -minrate 400k -bufsize 600k -deinterlace -vcodec libx264 -preset veryfast -g 30 -r 30 -t 14400 -strict -2 -f flv "rtmp_server_link"

  I never face this problem when I try to stream to FB using app on my localhost.

  So, my questions are :

  1. What can be the reason for this FPS drop ?
  2. Can upscaling production server help me fix this issue ?
  3. Can I run multiple FFMpeg processes for streaming from same server without performance drop ?

  Thanks in advance :)

• How To Specify FFMPEG Input Volume For Multple Input Files

  30 septembre 2014, par gbd

  I have 6 similar/separate audio input files feeding into ffmpeg - no video. I’m mixing the 6 input channels down to a stereo output using amix and that works fine. But now I need to change the volume of each individual input channel before the mix down - or maybe as part of the mix down. I’ve looked at and tried aeval (which seems very slow) in the form

   'aeval=val(0)*volChg1:c=same|val(1)*volChg2:c=same|val(2)*volChg3:c=same|val(3)*volChg4:c=same|val(4)*volChg5:c=same|val(5)*volChg6:c=same'

  but that only seems to change the volume of the first channel.

  So the whole input part of my ffmpeg expression looks something like this right now :

  -i inFilePath1 -i inFilePath2 -i inFilePath3 -i inFilePath4 -i inFilePath5 -i inFilePath6 
  
  -filter_complex 'aeval=val(0)*$volChg1:c=same|val(1)*$volChg2:c=same|val(2)*$volChg3:c=same|val(3)*$volChg4:c=same|val(4)*$volChg5:c=same|val(5)*$volChg6:c=same','amix=inputs=6:duration=longest'

  $volChg1-6 are php variables containing the individual volume multipliers - 0.5 for example should halve the volume of that individual channel while 1.0 would leave it unaffected. How do I do this ?

• How to show segment lengths of hls file with ffmpeg

  30 mai 2017, par endorphins

  I’m trying to use ffmpeg to retrieve the segment duration of every segment for every stream of an HLS file. It looks like I can do this if I know all of the names of the individual files in advance and call ffprobe on each one. This seems really tedious and I won’t always know the names of all of the individual files, only the main .m3u8. Is there any way I can get all of this information with just one ffmpeg command ?

  Additionally, is the duration retrieved by ffprobe on a .aac file accurate ? I get the message that it’s "Estimating duration from bitrate, this may be inaccurate".