Sur d’autres sites (9265)

• lavf/mux : rewrite guessing the packet duration

  29 novembre 2020, par Anton Khirnov

  lavf/mux : rewrite guessing the packet duration
  Factor out the code into a separate muxing-specific function.
  
  Stop accessing the deprecated AVStream-embedded codec context, use the
  
  average framerate (if specified) instead.
  

  • [DH] libavformat/mux.c
  • [DH] tests/ref/fate/asf-repldata
  • [DH] tests/ref/fate/ffmpeg-attached_pics
  • [DH] tests/ref/fate/ffmpeg-streamloop
  • [DH] tests/ref/fate/g2m2
  • [DH] tests/ref/fate/iff-byterun1
  • [DH] tests/ref/fate/iff-ilbm
  • [DH] tests/ref/fate/iv8-demux
  • [DH] tests/ref/fate/mimic
  • [DH] tests/ref/fate/mss2-pal
  • [DH] tests/ref/fate/mss2-pals
  • [DH] tests/ref/fate/mss2-rgb555
  • [DH] tests/ref/fate/mss2-rgb555s
  • [DH] tests/ref/fate/nuv-rtjpeg
  • [DH] tests/ref/fate/segment-mp4-to-ts
  • [DH] tests/ref/fate/smjpeg-demux
  • [DH] tests/ref/fate/vp9-tiling-pedestrian
  • [DH] tests/ref/lavf-fate/vp8.ogg

• Sampling video every N frames starting at n0 initial frame

  4 avril 2017, par Atcold

  Question

  I am trying to figure out how to sample a video stream x[n] every N frames, starting at frame n_i, i < N, so that I end up with N new videos of length len(x) / N.

  In formula this is simply : y_i[n] = x[n_i + n * N].

  Here there is a diagram of what I am trying to achieve :
  

  The greedy solution would be simply dumping the frames to a folder and then create new videos out of appropriately indexed frames.
  I was hoping there were some more elegant solution with ffmpeg since I have to process hundreds of video.

  Implementation

  Finally, I managed to write the final implementation, which I am reporting here for completeness.
  It does scale the minimum dimension to 256, does not process more than max_frames ; performs the sampling every k frames, send the first k - 1 samples to one folder and the k-th one to another one. It also set the output frame rate to the input average frame rate, since otherwise some videos will go at 120 Hz...

  k=5
  
  kk=$(awk "BEGIN{print 1/$k}")
  
  ffmpeg \
  
      -i $src_video_path \
  
      -an \
  
      -loglevel error \
  
      -filter_complex \
  
          "setpts=$kk*PTS, \
  
          scale=w=2*trunc(128*max(1\, iw/ih)):h=2*trunc(128*max(1\, ih/iw))[m]; \
  
          [m]select=n=$k:e=(mod(n\,$k)+1)*lt(n\,$max_frames) \
  
          $(for ((i=1; i<=$k; i++)); do
  
              echo -n "[a$i]"
  
          done)" \
  
      $(for ((i=1; i<$k; i++)); do
  
          echo -n "-r $fps -map [a$i] $dst_video_path/$i.mp4 "
  
      done
  
      echo -n "-r $fps -map [a$k] $val_video_path/$k.mp4"
  
      )

• ffmpeg /dev/video1 : No space left on device

  4 avril 2017, par chaitanya kiran

  While converting and redirecting USB camera stream to a multicast ip I’m facing below error.

  ffmpeg -f v4l2 -i /dev/video1 -s 720x480 -pix_fmt yuv420p -c:v mpeg2video -aspect 4:3 -r 30 -g 15 -ar 0 -streamid 0:48 -bf 2 -b:v 100k -bufsize 400k -maxrate 3825k -f rtp_mpegts rtp ://239.0.2.2:5001

  ffmpeg version 3.2.4-static http://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.1 (Debian 5.4.1-5) 20170205
  configuration : —enable-gpl —enable-version3 —enable-static —disable-debug —disable-ffplay —disable-indev=sndio —disable-outdev=sndio —cc=gcc-5 —enable-fontconfig —enable-frei0r —enable-gnutls —enable-gray —enable-libass —enable-libfreetype —enable-libfribidi —enable-libmp3lame —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libopenjpeg —enable-libopus —enable-librtmp —enable-libsoxr —enable-libspeex —enable-libtheora —enable-libvidstab —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libwebp —enable-libx264 —enable-libx265 —enable-libxvid —enable-libzimg
  libavutil 55. 34.101 / 55. 34.101
  libavcodec 57. 64.101 / 57. 64.101
  libavformat 57. 56.101 / 57. 56.101
  libavdevice 57. 1.100 / 57. 1.100
  libavfilter 6. 65.100 / 6. 65.100
  libswscale 4. 2.100 / 4. 2.100
  libswresample 2. 3.100 / 2. 3.100
  libpostproc 54. 1.100 / 54. 1.100

  [video4linux2,v4l2 @ 0xb982f80] ioctl(VIDIOC_STREAMON) : No space left on device
  /dev/video1 : No space left on device

  Below are top and free -m command outputs

  top

  top - 20:10:13 up 16 min, 4 users, load average : 0.49, 0.37, 0.28
  Tasks : 257 total, 1 running, 256 sleeping, 0 stopped, 0 zombie
  %Cpu(s) : 3.4 us, 0.2 sy, 0.0 ni, 95.9 id, 0.5 wa, 0.0 hi, 0.0 si, 0.0 st
  KiB Mem : 13457292 total, 12299768 free, 650672 used, 506852 buff/cache
  KiB Swap : 3670012 total, 3670012 free, 0 used. 12710776 avail Mem

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
  4095 root 20 0 333376 153296 138660 S 25.9 1.1 1:09.41 ffmpeg
  1551 root 20 0 84804 40076 17756 S 0.7 0.3 0:24.00 Xorg.bin
  2574 user 20 0 66900 27436 21268 S 0.7 0.2 0:11.30 gnome-terminal-
  4373 root 20 0 7800 3852 3196 R 0.7 0.0 0:00.03 top
  610 root 20 0 0 0 0 S 0.3 0.0 0:00.03 kworker/4:2
  3762 user 20 0 816928 217120 75100 S 0.3 1.6 0:56.34 firefox
  4240 root 20 0 0 0 0 S 0.3 0.0 0:02.24 kworker/0:2
  1 root 20 0 27464 7508 5044 S 0.0 0.1 0:01.95 systemd
  2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
  3 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
  5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
  7 root 20 0 0 0 0 S 0.0 0.0 0:01.29 rcu_sched

  free -m

            total        used        free      shared  buff/cache   available

  Mem : 13141 621 12025 2 495 12426
  Swap : 3583 0 3583

  cat /proc/meminfo |grep -i vmalloc

  VmallocTotal : 524288 kB
  VmallocUsed : 204736 kB
  VmallocChunk : 316560 kB

  P.S: : There is already an instance of ffmpeg running on the machine on /dev/video0.

  Any help in resolving issue would be greatly appreciated