Recherche avancée

Sur d’autres sites (4066)

• Grep for a number between a certain range - Checking WAV Quality

  11 août 2014, par BT643

  I’m trying to write a regular expression (to be used in conjunction with ffmpeg, which can check that a WAV file is over a certain quality.

  The minimum should be :

  Audio Channels : 2 (Stereo)
  Audio Sample Rate : 44,100 Hz
  Audio Bitrate : 1411 Kbps
  Audio Bit Depth : 16 bit
  

  So I’ve tried the following commands so far :

  • /usr/local/bin/ffmpeg -i "/path/to/file.wav" 2>&1 | egrep 'stereo|2 channels'

  This works fine to get a stero (2 channel) WAV. I’m getting issues with the next part, searching between a range of numbers.

  • /usr/local/bin/ffmpeg -i "/path/to/file.wav" 2>&1 | egrep 'stereo|2 channels' | egrep '[41000-196000] Hz'

  Obviously this just searches each number individually, so it’s finding results if there’s a 4 OR 1 OR 0 OR 0 OR 0 etc...

  The bit rate and bit depth just needs to be OVER 1411 and 16 respectively.

  Thanks

  EDIT -
  Here’s the ffmpeg output for a low quality WAV which should be rejected :

  ffmpeg version git-2012-05-22-27127eb Copyright (c) 2000-2012 the FFmpeg developers
 built on May 22 2012 12:27:21 with gcc 4.6.1
 configuration: --enable-gpl --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree --enable-postproc --enable-version3 --enable-x11grab
 libavutil      51. 53.100 / 51. 53.100
 libavcodec     54. 21.101 / 54. 21.101
 libavformat    54.  6.100 / 54.  6.100
 libavdevice    53.  4.100 / 53.  4.100
 libavfilter     2. 75.100 /  2. 75.100
 libswscale      2.  1.100 /  2.  1.100
 libswresample   0. 15.100 /  0. 15.100
 libpostproc    52.  0.100 / 52.  0.100
[wav @ 0x355b140] max_analyze_duration 5000000 reached at 5056000
Guessed Channel Layout for  Input Stream #0.0 : stereo
Input #0, wav, from '/path/to/file.wav':
 Duration: 00:02:28.47, bitrate: 512 kb/s
   Stream #0:0: Audio: pcm_u8 ([1][0][0][0] / 0x0001), 32000 Hz, stereo, u8, 512 kb/s

• How to convert a video file into images in c language with libavcodec library ? [on hold]

  25 juillet 2018, par emb-pro

  I am very new to these ffmpeg and libavcodec, I want to produce the images from a video file. I have researched through the internet, I got the resources from dranger’s tutorials. When I was trying to compile that code, I was getting deprecated warnings. I got the updated code from github. Even though I am facing the same problem. Again I got the code from ffmpeg. But it is asking me to provide the correct codec when I am executing.

  I am compiling using the command

  gcc -o tutorial01 tutorial01.c -lavutil -lavformat -lavcodec -lz -lm

  I have installed new versions of ffmpeg, libavcodec, libavformats and libavutilities libraries. I am using ubuntu 16.

  I can update the question if you need any information. Thanks in advance.

• Concat 3 videos, setting the output frame-rate based on one of the three videos

  14 février 2023, par 3EK

  I have 3 videos that I would like to concat. An intro, a main video and an outro. All mp4s, all the same spec except the main video is a different frame rate to the other two video assets.

  


  I am trying to use ffprobe to find out the frame rate of the main video and then apply that frame rate to the output file.

  


  This is what I have so far, but it is not working.

  


  #!/bin/bash

mezzfile=mezzfile.mp4
tailtime=20
duration=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 $mezzfile)
framerate=$(ffprobe -v 0 -of compact=p=0 -select_streams 0 \
-show_entries stream=r_frame_rate '$mezzfile')

ffmpeg -hide_banner -y \
  -i sting.mp4 \
  -i $mezzfile \
  -i endboard.mp4 \
  -filter_complex \
    "[0:v]setpts=PTS-STARTPTS,fps=${framerate}[v_intro]; \
     [0:a]asetpts=PTS-STARTPTS,fps=${framerate}[a_intro]; \
     [1:v]setpts=PTS-STARTPTS,split[v_main1][v_main2]; \
     [1:a]asetpts=PTS-STARTPTS[a_main]; \
     [2:v]setpts=PTS-STARTPTS,fps=${framerate}[v_endboard]; \
     [v_main1]select='gt(t,$duration-$tailtime)',scale=w=iw/2:h=ih/2,setpts=PTS-STARTPTS[v_tail]; \
     [v_endboard][v_tail]overlay[v_pip]; \
     [v_main2]select='lte(t,$duration-$tailtime)',setpts=PTS-STARTPTS[v_mid]; \
     [v_intro][v_mid][v_pip]concat=n=3:v=1:a=0[v_out]; \
     [a_intro][a_main]concat=n=2:v=0:a=1[a_out]" \
  -map "[v_out]" \
  -map "[a_out]" \
  output.mp4


  


  Any help would be greatly appreciated !
Cheers !

  


  I have tried the code above. Hoping someone can help me figure out what I'm doing wrong ?