Recherche avancée

Sur d’autres sites (7623)

• Create and combine a blank video stream with a subtitle steam

  10 décembre 2014, par CPO

  I have a live .ts stream that contains a video stream, audio stream and subtitle stream. What I want to do is to display the video in full, eg video and audio and subtitles, but in parallel take the same stream and ’blank’ the video to black, but allow the subtitle stream to be rendered into that video stream for display separately from the fully displayed streams. The reason for this is to allow the subtitles to be displayed separately and cropped,from a second projector, but to have a black backgroung to avoid distractions when there is no subtitle present. I believe this can be achieved using FFMPEG but my limited experience with this utility rather limits my progress. I believe that the blanked video stream needs to be the same frame rate and resolution as the original in order that the rendered subtitles stay in synch with the original video stream. Any help or suggestions warmly welcomed. Thank you

• lavc/h264dsp : fix R-V V weight_pixels pointer arithmetic

  17 novembre 2024, par Rémi Denis-Courmont

  lavc/h264dsp : fix R-V V weight_pixels pointer arithmetic
  As of 459a1512f13ae1fdd404ff9281b02d225ac70a09,
  
  the code is unrolled to process two rows per iteration.
  
  The output cursor thus needs to be incremented by twice the
  
  stride, which is taken care of with SH1ADD. However the original
  
  ADD from the original implemetation was incorrectly left over.
  

  • [DH] libavcodec/riscv/h264dsp_rvv.S

• audio is not exact copy in ffmpeg proxies

  9 mars 2023, par 5Diraptor

  I always work with proxy footage in Premiere Pro, so I have a batch file set up to run any new raw footage through ffmpeg and produce a proxy version. I avoid creating proxies through Premiere Pro as it's slow, I have little control over the output, and often the proxies aren't compressed as much as they could be.

  


  This is the command I run to create proxies. It also overlays a watermark so that it is obvious when proxies are used.

  


  ffmpeg -i "original.MOV" -i "proxy_overlay.png" -filter_complex "overlay=0:0" -crf 20 -c:v libx264 -c:a copy "Proxy/proxy_for_original.mov"


  


  This has always been fine, but I've received some footage to work on from a different camera, and when I create proxies and try to attach them in Premiere Pro, I get the error : "Proxy Media and Full Resolution Media must have matching audio channels."

  


  

  


  When I compare the file properties in Premiere Pro, I see this :

  


  Original :

  


  

  


  Proxy :

  


  

  


  As you can see, the original contains 8x audio tracks and a timecode track, but the proxy version doesn't state this.

  


  I've been working on the ffmpeg command to try and retain the original audio details, but nothing I do seems to work. I thought that the command -c:a copy would copy the audio tracks across without any changes at all. However I can't seem to find a command that creates an exact copy of all audio tracks. Also does the timecode track matter, should I map this to the proxy as well ?