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• Google Cloud Platform Storage JSON API upload breaks audio files..?! How to fix ?

  13 octobre 2017, par Zolai

  I did manage to upload files to Google storage with GCP resumable upload (json api) :
  https://cloud.google.com/storage/docs/json_api/v1/how-tos/resumable-upload

  Using jQuery and Plupload http://www.plupload.com

  But now it seems that audio files loses their codecs in upload and those won’t play or ffmpeg can’t probe those. More testing showed that actually .flac files are ok to ffmpeg, but for example .m4a files are not.

  I need to get most of the audio files uploaded to google storage and be able to probe those with ffmpeg. And must be able upload big files over 100Mb. That’s why I believe JSON API is best or only possible way.

  I think I have metadata also added correctly, but now I’m confused how to continue..
  Any ideas what could be the problem here ?

  EDIT (more info) :

  I had working software :

  • Using regular POST > /temp > Google Cloud Storage Client (php).
  • GCP Storage Client uploaded files with perfection.
  • Even that I named uploaded files with random unique name like "woeiwehf.tmp", those did work and ffmpeg could probe them fine.

  THEN something happened, I guess uploading like this was limited (or something) :

  • What meant that my solution couldn’t upload anymore big files, over 32Mb.

  • Well that wasn’t best solution anyway, so that’s okey, that this changed.

  NOW :

  • I have changed software so it uses GCP JSON API upload resumable, and this mainly works
  • But I had to change files to look like "woeiwehf.flac" or what ever type is. ".tmp" didn’t work anymore.
  • For example .flac files work nicely, but .m4a will not.
  • I’ve tested uploading many different ways, and it seems that JSON API upload loses at least codecs and bit rate.

  —

  I would be very grateful if I could get help how to resolve this.
  I guess one solution may could be to fork ffmpeg client and manually set audio codec, but I’m saving that for the last solution.

• Transparent PNG created in Imagemagick drawn as opaque in FFMPEG

  23 février 2015, par user2711915

  I am trying to script the creation of videos using ImageMagick to create some overlays which are then placed on top of a video.

  If I try to use the image created by ImageMagick directly the transparency is drawn as opaque.

  I have created a transparent PNG using ImageMagick draw commands. When loaded into GIMP and examined, the PNG has an alpha channel and each transparent pixel appears to have transparency : RGBA = 0,0,0,0

  This image when then used as an overlay in ffmpeg just has an opaque black background in the video.

  If I export the image again from GIMP then the file looks identical, but in the video just appears as a solid blue (the colour of the drawings in the overlay image).

  I can fix this by taking the overlay image, loading it in GIMP and then selecting all and creating a new image from the clipboard and exporting that (using exactly the same settings as when I re-exported before without creating a new file) and it will then work exactly as desired, showing the non-transparent portions of the overlay and not showing transparent parts.

  KEY QUESTION :

  How can I either script the conversion that somehow occurs when creating a new file in GIMP, or (much better) not have it go wrong in the first place ?

  Here are the two files :

  BROKEN :
  
  WORKS :
  
  What is the difference ?

• Glitchiness when I add transparency to a gif and convert it to webm

  5 avril 2017, par maxple

  Starting off I have this gif from google images :

  

  Then I convert the blue to transparency :

  convert octopus.gif -transparent "#00AEFF" octopus-transparent.gif

  Now I have this (note glitchiness has already started to appear)

  

  Now for the grand finale, I convert it to webm :

  convert octopus-transparent.gif tmp%03d.png
  
  
  
  ffmpeg -framerate 25 -f image2 -i ./tmp%03d.png -c:v libvpx -pix_fmt yuva420p octopus.webm

  See the following screenshot. It is still transparent, but the sizing is no longer steady, and frankly it’s starting to look a little creepy :

  

  I don’t really know much about video codecs and I’ve just got this far with others’ help. I’d appreciate advice as to how I can change these commands to avoid the glitches.