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• ffmpeg yield different results when used in the application

  5 mai 2020, par xoail

  This is perplexing me. I am using ffmpeg to convert m4a to wav audio. When I use it with fluent-ffmpeg the output mime is audio/wave while when I do it using terminal I get audio/wav. For extactly same commands. The application I am trying to play these files is rejecting my audio/wave file.

  



  Using node (results in audio/wave) :

  



  const ffmpegPath = require('@ffmpeg-installer/ffmpeg')
const ffmpeg = require('fluent-ffmpeg');
ffmpeg()
.setFfmpegPath(ffmpegPath)
.input('source.m4a')
.outputOptions(['-ac 1','-ar 16000'])
.save('out.wav')


  



  Using terminal (results in audio/wav) :

  



  /same/path/to/static-ffmpeg-as-in-node-program/ffmpeg -i source.m4a -ac 1 -ar 16000 out.wav


  



  I've both of their encoding as, PCM S16 LE (s16l), 16 bits/sample, mono and 16khz samplerate audio files. I've tried adding other flags and got same results on both scenarios : -vn -acodec pcm_s16le -ar 16000 -ac 1 -f wav. Just that one doesnt work. And I have no idea why.

  



  I've also tried not using fluent-ffmpeg but using spawn and got same audio/wave file.

  



  Any insight ?

  


• Strange results when converting rgb yuv using ffmpeg in python

  20 avril 2020, par user3569998

  I have JPG images and I am trying to do the following :

  



  

  1. resize the input and save the result into PNG

  


  2. convert PNG images to YUV (for instance yuv444p10le) in AVI container

  


  3. convert AVI back to PNG image.

  


  



  I am using python 3 and ffmpeg Linux version installed on Colab

  



  I printed the difference between resized_png and restored_png. I have values of 255 which doesn't make sense at all.

  



   [[[  0 255   1]
  [  0   0   1]
  [  0 255   1]
  ...
  [  1   0   0]
  [  1   0   0]
  [  2   0   1]]

 [[  0 255   1]
  [  0 255   1]
  [  1   0   0]
  ...
  [  1   0   0]
  [  1   0   0]
  [  1   0   0]]

 [[  0   0   1]
  [  0   0   1]
  [  0   0   1]
  ...
  [  1 255   0]
  [  1 255   1]
  [  1   0   0]]

 ...

 [[255   0   0]
  [255   0   1]
  [255   0   1]
  ...
  [  0   0   0]
  [  0   0   1]
  [255   0   1]]

 [[255   0   1]
  [255   0   1]
  [255   0   1]
  ...
  [  0   0   1]
  [  0   0   1]
  [  0   0   0]]

 [[255   0   1]
  [255   0   1]
  [255   0   1]
  ...
  [255   1   0]
  [255   0   0]
  [255   0   1]]]


  



  input_image = '/content/drive/My Drive/Colab Notebooks/adv_dnn/datasets/im2.jpg'
output_resized = '/content/drive/My Drive/Colab Notebooks/adv_dnn/datasets/im2.png'
folder_path = '/content/drive/My Drive/Colab Notebooks/adv_dnn/datasets/'

#do resize
# code = subprocess.call('cd /usr/bin/ffmpeg',  shell=True)
# print(code)
cmd_resize = ['ffmpeg', '-y', '-i',  input_image,'-vf', 'scale=224:224', output_resized]
process = subprocess.Popen(cmd_resize, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
out, err = process.communicate()
print(out)
print(err)

fmt = ['yuv420p', 'yuv420p10le', 'yuv444p', 'yuv444p10le']
for f in fmt:
  cmd2YUV = ['ffmpeg', '-y', '-i', output_resized, '-c:v', 'libx264', '-preset', 'placebo',\
             '-qp', '0', '-x264-params', "keyint=15:no-deblock=1", '-pix_fmt', f, \
             '-sws_flags', 'spline+accurate_rnd+full_chroma_int', \
             '-vf', "colorspace=bt709:iall=bt601-6-625:fast=1", '-color_range', '1', '-colorspace', '1', 
             '-color_primaries', '1', '-color_trc', '1', folder_path+'im2_'+f+'.avi']
  process = subprocess.Popen(cmd2YUV, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  out, err = process.communicate()
  print(out)
  print(err)

  cmd2PNG = ['ffmpeg', '-y', '-i',  folder_path+'im2_'+f+'.avi', '-compression_level', '10', '-pred', 'mixed', \
             '-pix_fmt', 'rgb24', '-sws_flags', '+accurate_rnd+full_chroma_int', \
             folder_path+'im2_'+f+'.png']
  process = subprocess.Popen(cmd2PNG, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  out, err = process.communicate()
  print(out)
  print(err)

im1=pilim.open('/content/drive/My Drive/Colab Notebooks/adv_dnn/datasets/im2.png')
im2=pilim.open('/content/drive/My Drive/Colab Notebooks/adv_dnn/datasets/im2_yuv444p10le.png')
im1_2d = np.asarray(im1)
im2_2d = np.asarray(im2)
print(im2_2d-im1_2d)


  


• Removing one audio track from a movie results in audio desync when copying, but not when reencoding --- why ?

  18 avril 2020, par chsk

  I'm trying to remove a superfluous audio track from a movie file. Specifically, this movie on archive.org has the original audio as track 2, and what appears to be a slavic (Russian ?) voiceover in track 1. I'd like to get rid of the latter.

  



  I found this question that suggested I should do the following :

  



  ffmpeg -i Benjamín\ dúfa.avi -map 0 -map -0:a:0 -c copy Benjamín\ dúfa\ \(aðeins\ íslenskt\ tal\).avi

  



  But this doesn't work : after removing the first audio track, audio and video are not in sync in the resulting file anymore (when played in VLC). Now, I was able to overcome this problem by also reencoding the remaining audio track along the way, using

  



  ffmpeg -i Benjamín\ dúfa.avi -map 0 -map -0:a:0 -c:v copy Benjamín\ dúfa\ \(aðeins\ íslenskt\ tal\).avi

  



  But while this works, I'd like to understand why copying the audio track instead does not. I suppose it's a somewhat philosophical question --- consider it a matter of intellectual curiosity, combined with an aversion to needless lossy re-encoding.

  



  So if anyone can explain this to me, I'd very grateful. Thanks !

  



  EDIT : as per Gyan's request, here's ffmpeg's output for the first command :

  



  ffmpeg version 4.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.1.1 (GCC) 20190807
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, avi, from 'Benjam├¡n d├║fa.avi':
  Metadata:
    encoder         : VirtualDubModRus 1.5.10.2 (build 2542/release)
    IAS1            : Islenska
  Duration: 01:27:37.00, start: 0.000000, bitrate: 1313 kb/s
    Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 979 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 192 kb/s
    Stream #0:2: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 128 kb/s
Output #0, avi, to 'b.avi':
  Metadata:
    IAS1            : Islenska
    ISFT            : Lavf58.29.100
    Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], q=2-31, 979 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 128 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:2 -> #0:1 (copy)
Press [q] to stop, [?] for help
[avi @ 0000000002bf00c0] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
frame=131425 fps=7616 q=-1.0 Lsize=  718952kB time=01:27:37.00 bitrate=1120.3kbits/s speed= 305x
video:628523kB audio:82141kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.166227%


  



  And also for the second, for comparison :

  



  ffmpeg version 4.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.1.1 (GCC) 20190807
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, avi, from 'Benjam├¡n d├║fa.avi':
  Metadata:
    encoder         : VirtualDubModRus 1.5.10.2 (build 2542/release)
    IAS1            : Islenska
  Duration: 01:27:37.00, start: 0.000000, bitrate: 1313 kb/s
    Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 979 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 192 kb/s
    Stream #0:2: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 128 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:2 -> #0:1 (mp3 (mp3float) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, avi, to 'b2.avi':
  Metadata:
    IAS1            : Islenska
    ISFT            : Lavf58.29.100
    Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], q=2-31, 979 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: mp3 (libmp3lame) (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp
    Metadata:
      encoder         : Lavc58.54.100 libmp3lame
[avi @ 00000000004b7440] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
frame=131425 fps=1090 q=-1.0 Lsize=  718952kB time=01:27:37.00 bitrate=1120.3kbits/s speed=43.6x
video:628523kB audio:82141kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.166233%