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• how to preserve transparency when scaling PNG with ffmpeg

  24 décembre 2020, par Richard

  I am using ffmpeg to scale my PNG images, and I find the transparency turns to white after scaling.
How can I preserve the transparency ? Thanks

  


  ffmpeg -i background_image.png -vf scale=1080:1920 output.png
ffmpeg version 4.3.1-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, png_pipe, from 'background_image.png':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: png, pal8(pc), 1440x2560, 25 tbr, 25 tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (png (native) -> png (native))
Press [q] to stop, [?] for help
Output #0, image2, to 'output.png':
  Metadata:
    encoder         : Lavf58.45.100
    Stream #0:0: Video: png, pal8, 1080x1920, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
    Metadata:
      encoder         : Lavc58.91.100 png
frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A speed=0.113x    
video:669kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown



  


  My Sample PNG file

  


  I don't know why my PNG file with transparency is converted to a jpg format with white after uploading to stackoverflow.

  


• FFmpeg : Unable to find a suitable output format for 'mpegts'

  27 avril 2021, par Chris

  I am using the following command on several video streams to pipe them into my TVHeadend server.

  


  pipe:///usr/bin/ffmpeg -i *URL* -c copy -metadata service_provider="My Provider" -metadata service_name="My Service"-f mpegts pipe:1


  


  This command works fine for most of the streams, but a few are throwing this error...

  


  ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 9.3.0 (Alpine 9.3.0)
configuration: --prefix=/usr --enable-avresample --enable-avfilter --enable-gnutls --enable-gpl --enable-libass --enable-libmp3lame --enable-libvorbis --enable-libvpx --enable-libxvid --enable-libx264 --enable-libx265 --enable-libtheora --enable-libv4l2 --enable-libdav1d --enable-postproc --enable-pic --enable-pthreads --enable-shared --enable-libxcb --enable-libssh --disable-stripping --disable-static --disable-librtmp --enable-vaapi --enable-vdpau --enable-libopus --enable-libaom --disable-debug
libavutil      56. 51.100 / 56. 51.100
libavcodec     58. 91.100 / 58. 91.100
libavformat    58. 45.100 / 58. 45.100
libavdevice    58. 10.100 / 58. 10.100
libavfilter     7. 85.100 /  7. 85.100
libavresample   4.  0.  0 /  4.  0.  0
libswscale      5.  7.100 /  5.  7.100
libswresample   3.  7.100 /  3.  7.100
libpostproc    55.  7.100 / 55.  7.100
[hls @ 0x7f7c03b0c5c0] Skip ('#EXT-X-VERSION:3')
[hls @ 0x7f7c03b0c5c0] Opening '****' for reading
[hls @ 0x7f7c03b0c5c0] Opening '****' for reading
Input #0, hls, from '****:
Duration: N/A, start: 3116.333433, bitrate: N/A
Program 0 
Metadata:
variant_bitrate : 0
Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
Metadata:
variant_bitrate : 0
Stream #0:1: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp
Metadata:
variant_bitrate : 0
[NULL @ 0x55f1a0fcec80] Unable to find a suitable output format for 'mpegts'
mpegts: Invalid argument


  


  The problem streams do work.
I searched before asking this question and everything I found was related to conversion.
Can anyone see what I am doing wrong ?
The reason behind the using FFmpeg and piping is to eliminate issues with stream freezes. FFmpeg just handles hitches etc better than simply adding the URL straight into my TVHeadend server.

  


• Python librosa NoBackendError even though ffmpeg is installed

  11 avril 2020, par Slavko Kovačević

  I recently installed librosa (package I've been using for a while on different PC) on my new PC with Windows 10 running. After that I've downloaded latest static version of ffmpeg and copied it to C: and added it to the Path. Tested ffmpeg and it works like a charm ! For python I am using Anaconda environment and after starting Jupyter Notebook and running librosa.load(path, sr = None) I've got

  



   in <module>&#xA;----> 1 audio = librosa.load(pathToJson)&#xA;&#xA;~\anaconda3\envs\tf_gpu\lib\site-packages\librosa\core\audio.py in load(path, sr, mono, offset, duration, dtype, res_type)&#xA;    117 &#xA;    118     y = []&#xA;--> 119     with audioread.audio_open(os.path.realpath(path)) as input_file:&#xA;    120         sr_native = input_file.samplerate&#xA;    121         n_channels = input_file.channels&#xA;&#xA;~\anaconda3\envs\tf_gpu\lib\site-packages\audioread\__init__.py in audio_open(path, backends)&#xA;    114 &#xA;    115     # All backends failed!&#xA;--> 116     raise NoBackendError()&#xA;&#xA;NoBackendError:&#xA;</module>

  



  strange isn't it ? Then I went all over the internet, doing whatnot trying to fix it and then I've got an idea to run my line of code inside anaconda command interface and it WORKS ?? How is this possible ? It is the same environment.

  



  python
Python 3.7.7 (default, Mar 23 2020, 23:19:08) [MSC v.1916 64 bit (AMD64)] :: Anaconda, Inc. on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import librosa
>>> librosa.load('test.wav')
(array([-0.00027   , -0.00039953, -0.0003659 , ..., -0.16393574,
       -0.17814247,  0.        ], dtype=float32), 22050)


  



  I did a lot of testing and I really prefer my Jupyter so any help would be appreciated. I tried the following : I've added C:\ffmpeg\bin and C:\ffmpeg to my Path for both User and System Variables. After that I've made specific variables for ffmpeg and ffmpeg_bin for both User and System Variables. No luck. After that I've tried installing ffmpeg using conda, without success. The last thing I've tested is this :

  



  import audioread
audioread.ffdec.FFmpegAudioFile('test.wav')


  



  and that works. Thanks