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• How to set command output as variable in batch

  6 décembre 2016, par Crankrune

  First, I’ve googled and googled how to fix this problem, with no luck. I’m working on making a batch file to re-encode audio in a file to aac if it’s ac-3 or ogg using ffmpeg. I know how to do the conversion with ffmpeg, just not how to automate it only if the audio matches a certain codec. To get the audio codec for the file, I have two different methods, one with ffprobe, and the other with MediaInfo.

  MediaInfo --Inform="Audio;%%Format%%" "input.mkv"

  or

  ffprobe -v error -select_streams a:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1 "input.mkv"

  However, my issue is with setting a variable from the command output. This is the code I’ve been trying, to no avail.

  SETLOCAL
  
  
  
  for %%a in (*.mp4) do (
  
  
  
  MediaInfo --Inform="Audio;%%Format%%" "%%a">codec.txt
  
  
  
  SET /p codec=code>

  Obviously, this is only a section of my goal, but this is the part I can’t seem to get past. I have checked, by removing the "DEL codec.txt" part, that is in fact storing the correct output in the text file, but it’s not importing it into the variable. Anyway I can set the output to a variable is fine, this is just the way I often found in my search.

  Any help is much appreciated.

• Getting ffprobe or avprobe not found while using youtube_dl module

  26 décembre 2016, par Avinash

  import youtube_dl
  
  
  
  
  
  options = {
  
      'format':'bestaudio/best',
  
      'extractaudio':True,
  
      'audioformat': 'mp3',
  
      'outtmpl':'%(id)s.%(ext)s',
  
      'noplaylist':True,
  
      'nocheckcertificate':True,
  
      'postprocessors': [{
  
          'key': 'FFmpegExtractAudio',
  
          'preferredcodec': 'mp3',
  
          'preferredquality': '192',
  
      }],
  
  
  
  }
  
  
  
  with youtube_dl.YoutubeDL(options) as ydl:
  
      ydl.download(['http://www.youtube.com/watch?v=BaW_jenozKc'])

  I am Getting

  "youtube_dl.utils.DownloadError : ERROR : ffprobe or avprobe not found.
  Please install one."

  I downloaded ffmpeg and tried giving its bin folder location in path variable . I also tried copying that bin folder to my youtube_dl package folder. None of them worked.

  Thanks in advance.

• 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 :)