Recherche avancée

Sur d’autres sites (2781)

• Turn png sequence into avi with alpha and could import to premiere

  13 février 2023, par xjlin

  I have pngs with alpha, I want to turn them to avi and use in premiere, so I could use the alpha transparency to make my premiere project convenient.

  


  I use ffmpeg to do this, but unfortunately, I failed.

  


  First, I use ffmpeg -f image2 -framerate 12 -start_number 24 -i %04d.png cut1.avi.
This video could import premiere, but it has low quality, and the alpha transparency doesn't work, it has black background.

  


  Then I use ffmpeg with -vcodec and -c:v parms to improve quality, but this avi couldn't import to premiere, it tells me format doesn't support.

  


  So, how can I turn pngs to high quality avi and I can import it to pr with alpha transparency ?

  


  Thanks.

  


• avformat/electronicarts : add option to return alpha channel in the main video stream...

  13 novembre 2022, par Marton Balint

  avformat/electronicarts : add option to return alpha channel in the main video stream in VP6A codec
  VP6 alpha in EA format is a second VP6 encoded video stream where only the Y
  
  component is used and is interpreted as the alpha channel of the first VP6
  
  stream. The alpha VP6 stream is muxed separately from the main VP6 stream, has
  
  its own stream headers and packet headers. In theory the two streams might not
  
  even have the same resolution (although most likely that is not something that
  
  is seen or supported in the wild), but the format is capable of doing it.
  Merged VP6 alpha (also known as the VP6A codec) means that a packet of the
  
  video stream contains the corresponding packet of both VP6 substreams like
  
  this :
  OffsetOfAlpha, DataPacket, AlphaDataPacket
  So data and alpha data of a frame is merged to a single packet, this is how VP6
  
  video with alpha is muxed in FLV and SWF.
  The first approach is more like how the demuxer sees data in the EA format,
  
  unfortunately it is different to what the FLV or SWF format expects, so -
  
  having no better place for it in the framework - I decided to do an optional
  
  format conversion in the EA demuxer.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] doc/demuxers.texi
  • [DH] libavformat/electronicarts.c
  • [DH] libavformat/version.h

• ffmpeg I have 4 .png images on an alpha video the images do not appear ?

  29 novembre 2022, par mod N

  png images on an alpha video the images do not appear ? on the alpha zone if I remove "colorchannelmixer=aa=0.01" it appears on the video
if you want i can send you the video
if a nice person could help me i'm a taker

  


  ffmpeg/ffmpeg
  
-i agence_montage_video/6382315603f21_test_neutreb_VF.mp4
  
-i agence_quatre_img/"1669476945.png"
  
-i agence_quatre_img/"1669476908.png"
  
-i agence_quatre_img/"1669476891.png"
  
-i agence_quatre_img/"1669476831.png"
  
-filter_complex
  
"[1:v]format=rgba,scale=1080:1080,colorchannelmixer=aa=0.01 [logo] ;
  
[2:v]format=rgba,scale=1080:1080,colorchannelmixer=aa=0.01 [logo2] ;
  
[3:v]format=rgba,scale=1080:1080 ,colorchannelmixer=aa=0.01[logo3] ;
  
[4:v]format=rgba,scale=1080:1080 ,colorchannelmixer=aa=0.01[logo4] ;
  
[0:v][logo]overlay=(W-w)/2 :(H-h)/2:enable='between(t,0,6)':format=auto,format=yuv420p [f0] ;
  
[f0][logo2]overlay=(W-w)/2 :(H-h)/2:enable='between(t,6,8)':format=auto,format=yuv420p [f1] ;
  
[f1][logo3]overlay=(W-w)/2 :(H-h)/2:enable='between(t,8,10)':format=auto,format=yuv420p [f2] ;
  
[f2][logo4]overlay=(W-w)/2 :(H-h)/2:enable='between(t,10,"13")' [out]"
  
-map "[out]" agence_quatre_img/"19"_.mov