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• batch FOR loop with FFMPEG

  27 décembre 2014, par user3604398

  I want to divide a .mp4 file into smaller .mp4 clips using ffmpeg.

  This is the code without a loop :

  ffmpeg -i source-file.mp4 -ss 0 -t 600 first-10-min.mp4
  
  ffmpeg -i source-file.mp4 -ss 600 -t 600 second-10-min.mp4
  
  ffmpeg -i source-file.mp4 -ss 1200 -t 600 third-10-min.mp4
  
  ...

  How do I make it into a loop in Microsoft DOS ? So far I have this :

  for /r $i in (*.mp4) do "C:\Program Files\FFMPEG\bin\ffmpeg.exe" -i "C:\Users\Name\Videos\2014-12-27-0926-45.mp4" -ss 0 -t 600

  Also someone said to put -codec copy in somewhere but I don’t know where.

• FFmpeg library : modified muxing sample for FLTP input and FLTP audio, loses audio

  21 janvier 2014, par taansari

  Based on muxing sample that comes with FFmpeg docs, I have modified it, from input format as S16 to FLTP (planar stereo), and outputting to webm format (stereo).

  Since input is now FLTP, I am filling two arrays, then encoding again to FLTP. There are no obvious errors given on screen, but the resulting webm video does not play any audio (just the video content). This is just proof of concept in understanding things ; here is an added (crude) function to fill up input FLTP stereo buffer :

  static void get_audio_frame_for_planar_stereo(int16_t **samples, int frame_size, int nb_channels)
  
  {
  
      int j, i, v[2];
  
      int16_t *q1 = (int16_t *) samples[0];
  
      int16_t *q2 = (int16_t *) samples[1];
  
  
  
      for (j = 0; j < frame_size; j++)
  
      {
  
          v[0] = (int)(sin(t) * 10000);
  
          v[1] = (int)(tan(t) * 10000);
  
          *q1++ = v[0];
  
          *q2++ = v[1];
  
          t     += tincr;
  
          tincr += tincr2;
  
      }
  
  }

  Which I am calling from inside write_audio_frame() function.

  Note also, wherever code reffered AV_SAMPLE_FMT_S16 as input, I have changed to AV_SAMPLE_FMT_FLTP.

  Whole workable source is here :

  https://gist.github.com/anonymous/05d1d7662e9feafc45a6

  When run with ffprobe.exe, with these instructions :

  ffprobe -show_packets output.webm >output.txt

  I see nothing out of ordinary, all pts/dts values appear to be in place :

  https://gist.github.com/anonymous/3ed0d6308700ab991704

  Could someone highlight cause of this mis-interpretation ?

  Thanks for your time...

  p.s. I am using Zeranoe FFmpeg Windows builds (32 bit), built on Jan 9 2014 22:04:35 with gcc 4.8.2.(GCC)

  Edit : Based on your guidance elsewhere, I tried the following :

      /* set options */
  
      //av_opt_set_int       (swr_ctx, "in_channel_count",   c->channels,       0);
  
      //av_opt_set_int       (swr_ctx, "in_sample_rate",     c->sample_rate,    0);
  
      //av_opt_set_sample_fmt(swr_ctx, "in_sample_fmt",      AV_SAMPLE_FMT_FLTP, 0);
  
      //av_opt_set_int       (swr_ctx, "out_channel_count",  c->channels,       0);
  
      //av_opt_set_int       (swr_ctx, "out_sample_rate",    c->sample_rate,    0);
  
      //av_opt_set_sample_fmt(swr_ctx, "out_sample_fmt",     c->sample_fmt,     0);
  
  
  
      av_opt_set_int(swr_ctx, "in_channel_layout",    AV_CH_LAYOUT_STEREO, 0);
  
      av_opt_set_int(swr_ctx, "in_sample_rate",       c->sample_rate, 0);
  
      av_opt_set_sample_fmt(swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_FLTP, 0);
  
  
  
      av_opt_set_int(swr_ctx, "out_channel_layout",    AV_CH_LAYOUT_STEREO, 0);
  
      av_opt_set_int(swr_ctx, "out_sample_rate",       c->sample_rate, 0);
  
      av_opt_set_sample_fmt(swr_ctx, "out_sample_fmt", AV_SAMPLE_FMT_FLTP, 0);

  And the revised function :

  static void get_audio_frame_for_planar_stereo(uint8_t **samples, int frame_size, int nb_channels)
  
  {
  
      int j, i;
  
      float v[2];
  
      float *q1 = (float *) samples[0];
  
      float *q2 = (float *) samples[1];
  
  
  
      for (j = 0; j < frame_size; j++) 
  
      {
  
          v[0] = (tan(t) * 1);
  
          v[1] = (sin(t) * 1);
  
          *q1++ = v[0];
  
          *q2++ = v[1];
  
          t     += tincr;
  
          tincr += tincr2;
  
      }
  
  }

  Now it appears to be working properly. I tried changing function parameters from uint8_t** to float**, as well as src_samples_data from uint8_t** to float**, but did not make any difference, in a view.

  Updated code : https://gist.github.com/anonymous/35371b2c106961029c3d

  Thanks for highlighting the place(s) that result in this behavior !

• Centos : TERM enivornment Variable Not Set

  21 janvier 2014, par Architact

  I am working on a mobile application which allows users to upload videos, upon upload the videos are converted to mp4 format, I am using a shell script for that purpose, the script was working fine on our last server but we switched our server and now it has stopped working, the log files of apache are printing.

  [Tue Jan 21 00:57:37.003944 2014] [:error] TERM environment variable not set.
  
  [Tue Jan 21 00:57:37.148531 2014] [:error] ./script.sh: line 3: ffmpeg: command not found
  
  [Tue Jan 21 00:57:37.148794 2014] [:error] script.sh: line 4: ffmpeg: command not found

  The content of script.sh are

  #!/bin/bash -p
  
  clear
  
  ffmpeg -i $filename -strict experimental -ar 22050 converted.mp4<br />
  
  ffmpeg -itsoffset -1 -i  converted.mp4 -vframes 25 -filter:v scale="min(500\, iw):-1"  thumbnail.png

  I am calling the script form php using

  shell_exec("script.sh 52567afa374c61381399290.mp4");

  Any help would be greatly appreciated.

  Thanks