unitproc/draft/bktemp-get_av_format

   1 #!/usr/bin/env bash
   2
   3 get_av_format() {
   4     # Desc: Gets audio/video format of file as string
   5     # Usage: get_av_format arg1
   6     # Depends: ffprobe
   7     # Version: 0.0.1
   8     # Input: arg1: input file path
   9     # Output: stdout (if valid audio or video format)
  10     #         exit code 0 if av file; 1 otherwise
  11     # Example: get_av_format myvideo.mp4
  12     #   Note: Would return "opus" if full ffprobe report had 'Audio: opus, 48000 Hz, stereo, fltp'
  13     # Note: Not tested with videos containing multiple video streams
  14     # Ref/Attrib: [1] https://stackoverflow.com/questions/5618363/is-there-a-way-to-use-ffmpeg-to-determine-the-encoding-of-a-file-before-transcod
  15     #             [2] https://stackoverflow.com/questions/44123532/how-to-find-out-the-file-extension-for-extracting-audio-tracks-with-ffmpeg-and-p#comment88464070_50723126
  16     # TODO 2022-08-19: output path of validated file to stdout for gnu parallel use
  17     local av_format file_in;
  18     local return_state;
  19     file_in="$1";
  20
  21     # Return error exit code if not audio file
  22     ## Return error if ffprobe itself exited on error
  23     if ! ffprobe -v error -show_entries stream=codec_name -of default=nokey=1:noprint_wrappers=1 "$file_in" 1>/dev/null 2>&1; then
  24         return_state="false";
  25     fi;
  26
  27     # Get av format
  28     av_format="$(ffprobe -v error -select_streams a -show_entries stream=codec_name -of default=nokey=1:noprint_wrappers=1 "$file_in")"; # see [1]
  29
  30     ## Return error if audio av is incorrectly formatted (e.g. reject if contains spaces)
  31     pattern="^[[:alnum:]]+$"; # alphanumeric string with no spaces
  32     if [[ $av_format =~ $pattern ]]; then
  33         return_state="true";
  34         # Report audio format
  35         echo "$av_format";
  36     else
  37         return_state="false";
  38     fi;
  39
  40     # Report exit code
  41     if [[ $return_state = "true" ]]; then
  42         return 0;
  43         # echo "$1" #TODO_______________
  44     else
  45         return 1;
  46     fi;
  47 } # Get audio format as stdout
  48
  49 # Author: Steven Baltakatei Sandoval
  50 # License: GPLv3+