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• ffmpeg randomly hangs and takes huge cpu usage when recording audio streams

  7 décembre 2017, par Maximax40

  I am trying to record 54 radio station using ffmpeg for Windows. I get those audio from different URL and separate instances of ffmpeg record and encode them to .wav format. It works great, it does it’s job with a very low cpu and memory usage and I get the results I want. However, sometimes a random ffmpeg process seems to hang and start using 25% cpu usage on it’s own and stop recording.

  It happens several times a day, and everytime I need to restart the process. If I’m not paying attention to the processes when one is stall, others will start to hang as well. If 4 of them hangs, I get 100% cpu usage and more than half of the recordings stops working, probably because of overload or something.

  When a process stall, I don’t get any error in the cmd window, it just freezes. It really seems to be random, because 2 computers are doing the same thing and record the exact same streams, but when a process stall on a computer, the same process works fine on the other, so I don’t think it’s related to the stream input.

  Here is an example of the command I use to launch a ffmpeg process :

  ffmpeg -y -i "http://icecast-cftx.rncm.ca/cftx.mp3" -ab 3200 -ar 16000 -ac 1 -f segment -segment_time 600 -strftime 1 "audios/CBFFMTR %%Y-%%m-%%d %%H-%%M-%%S.wav"

  Can anyone help me on this issue ? It’s really sad that I can’t rely on this software because of this.

  Thank you

  EDIT : After another check, I realise that when a recording crash on one of the computers, the same one crash on the other.

• scale issues when adding images to a video

  27 septembre 2019, par Geo

  When I add two images to a video, the second image added is scaled down for some reason.

  I have two images arrow.png and icon1.png and one background.mp4 video, when I added the two images onto the video, the result is that the first image is added with the right size, but the second image is added with reduced size, probably in half of the specified size.

  this is my command :

  ffmpeg -i background.mp4 -i arrow.png -i icon1.png -filter_complex "[1:v]scale=311:175,setsar=1,format=bgra[img1];
  
  [img1]rotate=30*PI/180:c=none:ow=rotw(30*PI/180):oh=roth(30*PI/180)[rotate1];[2:v]scale=319:179,setsar=1,format=bgra[img2];
  
  [img2]rotate=59*PI/180:c=none:ow=rotw(59*PI/180):oh=roth(59*PI/180)[rotate2];[0][rotate1]overlay=242:-22:enable='between(t,0,6)',scale=hd720[overlay1];
  
  [overlay1][rotate2]overlay=34:13:enable='between(t,0,6)',scale=hd720" -c:a copy -c:v libx264 -preset ultrafast -y test01.mp4

  I am expecting the same size as the specified

• arm : vp9 : Add NEON optimizations of VP9 MC functions

  3 novembre 2016, par Martin Storsjö

  arm : vp9 : Add NEON optimizations of VP9 MC functions
  This work is sponsored by, and copyright, Google.
  The filter coefficients are signed values, where the product of the
  
  multiplication with one individual filter coefficient doesn’t
  
  overflow a 16 bit signed value (the largest filter coefficient is
  
  127). But when the products are accumulated, the resulting sum can
  
  overflow the 16 bit signed range. Instead of accumulating in 32 bit,
  
  we accumulate the largest product (either index 3 or 4) last with a
  
  saturated addition.
  (The VP8 MC asm does something similar, but slightly simpler, by
  
  accumulating each half of the filter separately. In the VP9 MC
  
  filters, each half of the filter can also overflow though, so the
  
  largest component has to be handled individually.)
  Examples of relative speedup compared to the C version, from checkasm :
  
                         Cortex      A7     A8     A9    A53
  
  vp9_avg4_neon :                   1.71   1.15   1.42   1.49
  
  vp9_avg8_neon :                   2.51   3.63   3.14   2.58
  
  vp9_avg16_neon :                  2.95   6.76   3.01   2.84
  
  vp9_avg32_neon :                  3.29   6.64   2.85   3.00
  
  vp9_avg64_neon :                  3.47   6.67   3.14   2.80
  
  vp9_avg_8tap_smooth_4h_neon :     3.22   4.73   2.76   4.67
  
  vp9_avg_8tap_smooth_4hv_neon :    3.67   4.76   3.28   4.71
  
  vp9_avg_8tap_smooth_4v_neon :     5.52   7.60   4.60   6.31
  
  vp9_avg_8tap_smooth_8h_neon :     6.22   9.04   5.12   9.32
  
  vp9_avg_8tap_smooth_8hv_neon :    6.38   8.21   5.72   8.17
  
  vp9_avg_8tap_smooth_8v_neon :     9.22  12.66   8.15  11.10
  
  vp9_avg_8tap_smooth_64h_neon :    7.02  10.23   5.54  11.58
  
  vp9_avg_8tap_smooth_64hv_neon :   6.76   9.46   5.93   9.40
  
  vp9_avg_8tap_smooth_64v_neon :   10.76  14.13   9.46  13.37
  
  vp9_put4_neon :                   1.11   1.47   1.00   1.21
  
  vp9_put8_neon :                   1.23   2.17   1.94   1.48
  
  vp9_put16_neon :                  1.63   4.02   1.73   1.97
  
  vp9_put32_neon :                  1.56   4.92   2.00   1.96
  
  vp9_put64_neon :                  2.10   5.28   2.03   2.35
  
  vp9_put_8tap_smooth_4h_neon :     3.11   4.35   2.63   4.35
  
  vp9_put_8tap_smooth_4hv_neon :    3.67   4.69   3.25   4.71
  
  vp9_put_8tap_smooth_4v_neon :     5.45   7.27   4.49   6.52
  
  vp9_put_8tap_smooth_8h_neon :     5.97   8.18   4.81   8.56
  
  vp9_put_8tap_smooth_8hv_neon :    6.39   7.90   5.64   8.15
  
  vp9_put_8tap_smooth_8v_neon :     9.03  11.84   8.07  11.51
  
  vp9_put_8tap_smooth_64h_neon :    6.78   9.48   4.88  10.89
  
  vp9_put_8tap_smooth_64hv_neon :   6.99   8.87   5.94   9.56
  
  vp9_put_8tap_smooth_64v_neon :   10.69  13.30   9.43  14.34
  For the larger 8tap filters, the speedup vs C code is around 5-14x.
  This is significantly faster than libvpx’s implementation of the same
  
  functions, at least when comparing the put_8tap_smooth_64 functions
  
  (compared to vpx_convolve8_horiz_neon and vpx_convolve8_vert_neon from
  
  libvpx).
  Absolute runtimes from checkasm :
  
                            Cortex      A7        A8        A9       A53
  
  vp9_put_8tap_smooth_64h_neon :    20150.3   14489.4   19733.6   10863.7
  
  libvpx vpx_convolve8_horiz_neon : 52623.3   19736.4   21907.7   25027.7
  vp9_put_8tap_smooth_64v_neon :    14455.0   12303.9   13746.4    9628.9
  
  libvpx vpx_convolve8_vert_neon :  42090.0   17706.2   17659.9   16941.2
  Thus, on the A9, the horizontal filter is only marginally faster than
  
  libvpx, while our version is significantly faster on the other cores,
  
  and the vertical filter is significantly faster on all cores. The
  
  difference is especially large on the A7.
  The libvpx implementation does the accumulation in 32 bit, which
  
  probably explains most of the differences.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavcodec/arm/Makefile
  • [DBH] libavcodec/arm/vp9dsp_init_arm.c
  • [DBH] libavcodec/arm/vp9mc_neon.S
  • [DBH] libavcodec/vp9.h
  • [DBH] libavcodec/vp9block.c
  • [DBH] libavcodec/vp9dsp.c