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• avcodec/dstdec : Replace AC overread check by sample rate check

  1er juillet 2020, par Michael Niedermayer

  avcodec/dstdec : Replace AC overread check by sample rate check
  Real files do skip coding 0 bits at the end, thus this kind of check
  
  does not work reliable.
  Fixes : Ticket 8770
  
  Fixes : dst-256fs44-6ch-refdstencoder.dff
  The samplerate is specified in ISO/IEC 14496-3:2005(E) as one of 3 fixed
  
  values, this also can be used to limit the duration and avoid the timeout
  This reverts commit f6df99dba1ae64b05d08fba8160d13eb9795042f.
  

  • [DH] libavcodec/dstdec.c

• FFMPEG and Matplotlib for animations - strange outputs ?

  27 juin 2020, par user13132640

  I'm trying to create animations using FFMPEG and matplotlib. Using the below code, I am creating the FFMpeg writer, and then using a loop, writing a series of graphs to the animation. However, the outputs I'm getting are very strange ; sometimes, when I watch the .mp4 file, the first 5 seconds are blank, then the video "ends" (the playback time on my media player says that it's complete), and at that point, my animation shows up. Other times, some frames are missing or skipped. I've tried searching around, but frankly I haven't found anyone with similar issues.

  


  I just installed the latest version of FFMpeg today.

  


  FFMpegWriter = manimation.writers['ffmpeg']
metadata = dict(title='Animation test', artist='name')
writer = FFMpegWriter(fps=1, metadata=metadata) # 1 frames per second, each year is 1 second


  


  Then, the plotting part...(I've excluded the code where I setup the fig, ax etc.)

  


  with writer.saving(fig, "animation.mp4", dpi=200):
    year = "2005"
    for i in range(4):

        d1_plot = d1[d1['Year'].str.contains(year, na=False)]
        ax.scatter(d1_plot["Lat"], d1_plot["Long"], c='g', s=d1_plot["Size"], transform=ccrs.PlateCarree())
        ax.set_title(year)
        writer.grab_frame()
        year = str(int(year)+1)


  


• FFMPEG - Width/ Height Not Divisible by 2 (Scaling to Generate MBR Output)

  15 avril 2020, par Sanjeev Pandey

  I am trying to generate multilple variants of videos in my library (Mp4 formats) and have renditions planned ranging from 1080p to 240p and popular sizes in between. For that I am taking a video with a AxB resolution and then running through a code (on bash) which scales them to desired following sizes - 
426x240
640x360
842x480
1280x720
1920x1080, with different bitrates of course, and then saves as Mp4 again.

  



  Now, this works just fine if source video has height and width divisible by 2, but code breaks on the following line for the videos with odd width and height :
-vf scale=w=${width}:h=${height}:force_original_aspect_ratio=decrease"

  



  Where 'width' and 'height' are the desired (and hardcoded) for every iteration : E.g. "426x240", and "640x360"

  



  The Error :
[libx264 @ 00000187da2a1580] width not divisible by 2 (639x360)
Error initializing output stream 1:0 -- Error while opening encoder for output stream #1:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  



  Now approaches those are explained in this one doesn't work for me since I am scaling - FFMPEG (libx264) "height not divisible by 2"

  



  And, I tried this one too but it seems all qualities are getting the same size -ffmpeg : width not divisible by 2 (when keep proportions)

  



  


  

  • This is how I tried to use this one : scale='bitand(oh*dar,65534)':'min(${height},ih)'

  


  


  



  Kindly suggest how to solve this, keeping in view that :
1. I have a very large library and I can't do manual change for every video
2. I need to scale the video and keep the aspect ratio

  



  Thanks !

  



  PS : [Edit] One way that I can see is padding all of the odd height/ weight videos using a second script in advance. This however doubles my work time and load. I would prefer to keep it in single script. This is the script I see that I can use for padding :
```ffmpeg -r 24 -i -vcodec libx264 -y -an -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2"`` (from : FFMPEG (libx264) "height not divisible by 2")