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• Extremely slow rendering time using Moviepy

  15 janvier 2024, par pacorisas

  I'm trying to create the following : two stacked videos (one on top of each other) with subtitles (like those videos you see in tiktok) from an srt file. For this, I'm first taking the top and bottom video and creating a CompositeVideoClip :

  


  clips_array([[video_clip], [random_bottom_clip]])


  


  Then, I'm taking this CompositeVideoClip and using a generator, creating the SubtitlesClip which then I will add to another CompositeVideoClip :

  


  sub = SubtitlesClip(os.path.join(temp_directory, f"subtitles.srt"), generator)
final = CompositeVideoClip([myvideo, sub.set_position(('center', 'center'))]).set_duration("00:02:40")


  


  Lastly, I'm adding some more text-clips (just an small title for the video) and rendering :

  


  video_with_text = CompositeVideoClip([final] + text_clips)
video_with_text.write_videofile(part_path, fps=30,threads=12,codec="h264_nvenc")


  


  Here is the problem. I tried to render a video of 180 seconds (3 minutes) and the video takes up to hour and a half (80 minutes) which is wild. I tried some render settings as you can see like changing 'codec' and using all the 'threads' of my CPU.
I tried to not use so many CompositeVideoClips, I read that when you concatenate those the final render will suffer a lot, but I didn't manage to find a way "not to use" that many CompositeVideoClips, any idea ?

  


  My PC is not that bad. 16GB, AMD Ryzen 5 5600 6-Core , NVIDIA 1650 SUPER.

  


  My goal is to at least bring the render to less than an hour. Right now is like 1.23s/it

  


• vp9 : initial attempt at a idct_idct_4x4 12bpp x86 simd (sse2) impl.

  12 octobre 2015, par Ronald S. Bultje

  vp9 : initial attempt at a idct_idct_4x4 12bpp x86 simd (sse2) impl.
  The trouble with this function is that intermediates overflow 31+sign
  
  bits, so I’ve added some helpers (that will also be used in 10/12bpp
  
  8x8, 16x16 and 32x32) to make that easier, basically emulating a half-
  
  assed pmaddqd using 2xpmaddwd. It’s currently sse2-only, if anyone sees
  
  potential in adding ssse3, I’d love to hear it.
  

  • [DH] libavcodec/x86/vp9dsp_init_16bpp_template.c
  • [DH] libavcodec/x86/vp9itxfm_16bpp.asm

• How to properly scale the frame using ffmpeg in c++ ?

  7 septembre 2021, par Tolga

  I am trying to scale the frame extracted from video to half of the original width and height. However when I call the sws_scale(). I am getting error bad dst image pointers.

  


  Here is my code below related about swscale.

  


  sws_ctx = sws_getContext(avcc->width, avcc->height, avcc->pix_fmt, avcc->width / 2, avcc- 
height / 2, avcc->pix_fmt, SWS_BILINEAR, NULL, NULL, NULL);
sws_init_context(sws_ctx, NULL, NULL);

int num_bytes = av_image_get_buffer_size(avcc->pix_fmt, avcc->width / 2, avcc->width / 2, 0);
uint8_t* frameScaledBuf = (uint8_t*)av_malloc(num_bytes * sizeof(uint8_t));
av_image_fill_arrays(frameScaled->data, frameScaled->linesize, frameScaledBuf, avcc->pix_fmt, 
avcc->width / 2, avcc->height / 2, 0);
sws_scale(sws_ctx, frame->data, frame->linesize, 0, frame->height, frameScaled->data, frameScaled->linesize);