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• FFMPEG : Combine "Create video from images" + scale to x + add audio + overlay logo

  7 janvier 2020, par Thomas Wild

  I´m working on a webcam-project. It is for generating timelapse videos of sunset/sundown.

  I´m using a raspberrypi to generate them with gphoto2 + DSLR.

  At the end of the day the images should get to an video, with audio and an overlay logo.
  And it should be scaled to 1920 pixel.
  I got a nice solution an it worked.

  1. Producing the timelapse video an scale it :

     ffmpeg -y -framerate 25 -start_number 0000001 -i /var/www/html/webcam/2020-01-05_bilder/%7d.jpg -vf scale=1920:-1 -pix_fmt yuv420p /var/www/html/webcam/2020-01-05-tag-output-1920.mp4

  2. Taking the output of (1) and add an overlay-logo, add audio

     ffmpeg -y -i '/var/www/html/webcam/2020-01-05-tag-output-1920.mp4'
-i '/var/www/html/webcam-scripts/graphics/logo.png'
-i '/var/www/html/webcam-scripts/sounds/chill_time_5.mp3'
-shortest -filter_complex '[1][0]scale2ref=h=ow/mdar:w=iw/6[#A logo][liebfrauen]; [#A logo]format=argb,colorchannelmixer=aa=0.95[#B logo transparent]; [liebfrauen][#B logo transparent] overlay=(main_w-w)-(main_w*0.05):(main_h-h)-(main_h*0.01)'
-c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a aac -strict -2
'/var/www/html/webcam/2020-01-05-tag-1920.mp4

  I tried to combine both actions, but I get an error :

  ffmpeg -y -framerate 25 -start_number 0000001 -i '/var/www/html/webcam/2020-01-05_bilder/%7d.jpg' -vf scale=1920:-1 -pix_fmt yuv420p -i '/var/www/html/webcam-scripts/graphics/logo.png' -i '/var/www/html/webcam-scripts/sounds/chill_time_5.mp3' -shortest -filter_complex '[1][0]scale2ref=h=ow/mdar:w=iw/6[#A logo][liebfrauen]; [#A logo]format=argb,colorchannelmixer=aa=0.95[#B logo transparent]; [liebfrauen][#B logo transparent] overlay=(main_w-w)-(main_w*0.05):(main_h-h)-(main_h*0.01)' -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a aac -strict -2 '/var/www/html/webcam/2020-01-05-tag-1920.mp4'

  Error : Filtergraph ’scale=720 :-1’ was specified through the -vf/-af/-filter option for output stream 0:0, which is fed from a complex filtergraph.
   vf/-af/-filter and -filter_complex cannot be used together for the same stream.

  Isn`t it possible to combine these inputs and scale it ? Or ... Where is my misunderstanding ?

• download video by ffmpeg access denied [closed]

  14 septembre 2021, par Vĩnh Hội

  ffmpeg -i "https://stream2.hocmai.vn/media/FhxZzrGLdQz59MY4r2xKAA/1631218009/saturn/moon/2020-2021_s5/Toan/Luyen_thi_THPTQG/PEN-C_N3/Nguyen_Thanh_Tung/01.Ky_thuat_truy_nguoc_ham_28365/01_360.mp4/clipTo/60000/hocmai-14-v1-a1.ts" -c copy -bsf:a aac_adtstoasc "output.mp4"

  


  and fail
[https @ 000002133ca2e6c0] HTTP error 403 Forbidden
https://stream2.hocmai.vn/media/FhxZzrGLdQz59MY4r2xKAA/1631218009/saturn/moon/2020-2021_s5/Toan/Luyen_thi_THPTQG/PEN-C_N3/Nguyen_Thanh_Tung/01.Ky_thuat_truy_nguoc_ham_28365/01_360.mp4/clipTo/60000/hocmai-14-v1-a1.ts : Server returned 403 Forbidden (access denied)

  


• Extremely slow ffmpeg/sws_scale() - only on heavy duty

  28 septembre 2020, par user2328447

  I am writing a video player using ffmpeg (Windows only, Visual Studio 2015, 64 bit compile).
With common videos (up to 4K @ 30FPS), it works pretty good. But with my maximum target - 4K @ 60FPS, it fails. Decoding still is fast enough, but when it comes to YUV/BGRA conversion it is simply not fast enough, even though it's done in 16 threads (one thread per frame on a 16/32 core machine).

  



  So as a first countermeasure I skipped the conversion of some frames and got a stable frame rate of 40 that way. Comparing the two versions in Concurrency Visualizer, I found a strange issue I don't know the reason of.

  



  .

  



  Here's an image of the frameskip version :

You see that the conversion is pretty quick (average roughly 35ms)
Thus, as multiple threads are used, it also should be quick enough for 60FPS, but it isn't !

  



  .

  



  The image of the non-frameskip version shows why :

The conversion of a single frame has become ten times slower than before (average roughly 350ms). Now a heavy workload on many cores would of course cause a minor slowdown per core due to reduced turbo - let's say 10 or 20%. But never an extreme slowdown of 1000%.

  



  .

  



  Interesting detail is, that the stack trace of the non-frameskip version shows some system activity I don't really understand - beginning with ntoskrnl.exe!KiPageFault+0x373. There are no exceptions, other error messages or such - it just becomes extremely slow.

  



  Edit : A colleague just told me that this looks like a memory problem with paged-out memory at first glance - but my memory utilization is low (below 1GB, and more than 20GB free)

  



  Can anyone tell me what could be causing this ?