Recherche avancée

Sur d’autres sites (4514)

• Compiling FFMPEG on CentOS DigitalOcean

  29 juillet 2015, par coder_uk

  I set up a DigitalOcean instance running CentOS 6.5 and successfully followed the guide to compile FFMPEG (https://trac.ffmpeg.org/wiki/CompilationGuide/Centos). Hurrah !

  But of course I realised that by default, DigitalOcean creates a root user and so ffmpeg now lives in /root/bin/ffmpeg. Which isn’t ideal because when I want to exec the ffmpeg bin from nginx, I would have to run nginx as root for it to have permission.

  Questions ...

  1) Long-shot, but presumably if I change the owner of the ffmpeg binary to nginx, it still won’t work, because nginx won’t be able to access the /root folder it is in. Correct ?

  2) I could run nginx as root (’user root’). But this seems like a very bad idea. Correct ?

  3) Which leaves me with the option of creating a new user, and then compiling ffmpeg into its home folder. But : which user ? EC2 creates ’ec2-user’, so should I make my own equivalent for DO ? But then won’t I have to run nginx as that user, else I’ll run into the same problem ?

  Or should I compile ffmpeg into the ’nginx’ home folder, if indeed it has one ? Is that how it is supposed to be done ?

  Since compiling ffmpeg takes ages, I don’t want to keep doing it, and the static files all seem very out of date. Thanks

• Round number of bits read to next byte

  4 décembre 2014, par watwat2014

  I have a header that can be any number of bits, and there is a variable called ByteAlign that’s calculated by subtracting the current file position from the file position at the beginning of the file, the point of this variable is to pad the header to the next complete byte. so if the header is taking up 57 bits, the ByteAlign variable needs to be 7 bits in length to pad the header to 64 bits total, or 8 bytes.

  Solutions that don’t work :

  Variable % 8 - 8, the result is the answer, but negative.

  8 % Variable ; this is completely inaccurate, and gives answers like 29, which is blatantly wrong, the largest number it should be is 7.

  how exactly do I do this ?

• Is it possible to count from a given number when extracting images from a video with FFmpeg ?

  10 septembre 2014, par Konstantin

  I am using ffmpeg to extract still images from a video. First from the beginning of the video, to a given time and then from the end of the video from a given time. So I am using two ffmpeg command line to achieve my goal. My problem is when I save the images both sequence start from 1 or 00000001, and I want to start the second sequence at some different (but greater) number than the first sequence ends. My command are :

  wine avs2yuv.exe input1.avs - | ffmpeg -y -f yuv4mpegpipe -i - -f image2 -vf fps=fps=0.1 -q:v 2 ./thumb001/%09d.jpg"
  
  
  
  wine avs2yuv.exe input2.avs - | ffmpeg -y -f yuv4mpegpipe -i - -f image2 -vf fps=fps=15 -q:v 2 ./thumb002/%09d.jpg"

  I made my avisynth files to yield the appropriate parts of the video I need.
  For example when the first command extarct 1500 images, name of the last file is 000001500.jpg
  I want the second command to start the counting from 1501 or maybe more, to get file names from 000001501.jpg, 000001502.jpg, etc.