Recherche avancée

Sur d’autres sites (6207)

• AVFormatContext : interrupt callback proper usage ?

  17 juillet 2021, par Daniel

  AVFormatContext's interrupt_callback field is a

  


  


  Custom interrupt callbacks for the I/O layer.

  


  


  It's type is AVIOInterruptCB, and it explains in comment section :

  


  


  Callback for checking whether to abort blocking functions.

  


  AVERROR_EXIT is returned in this case by the interrupted function. During blocking operations, callback is called with opaque as parameter. If the callback returns 1, the blocking operation will be aborted.

  


  No members can be added to this struct without a major bump, if new elements have been added after this struct in AVFormatContext or AVIOContext.

  


  


  I have 2 questions :

  


  

  1. what does the last section means ? Especially "without a major bump" ?

  


  2. If I use this along with an RTSP source, when I close the input by avformat_close_input, the "TEARDOWN" message is being sent out, however it won't reach the RTSP server.

  


  


  For 2 : here is a quick pseudo-code for demo :

  


  int pkts = 0;
bool early_exit = false;

int InterruptCallback(void* ctx) {
    return early_exit ? 1 : 0;
}

void main() {
  ctx = avformat_alloc_context
  ctx->interrupt_callback.callback = InterruptCallback;

  avformat_open_input
  avformat_find_stream_info
  pkts=0;
  while(!early_exit) {
    av_read_frame

    if (pkts++ > 100) early_exit=true;
  }

  avformat_close_input
}


  


  In case I don't use the interrupt callback at all, TEARDOWN is being sent out, and it also reaches the RTSP server so it can actually tear down the connection. Otherwise, it won't tear down it, and I have to wait until TCP socket times out.

  


  What is the proper way of using this interrupt callback ?

  


• ffmpeg slideshow not working

  4 février 2013, par Benjen

  I am trying to create a simple slideshow video based on two images ('ocean001.jpg' and 'ocean002.jpg'). I am using the command as listed in the ffmpeg documentation, but i always end up with a blank (e.g. black) video file 15 seconds in duration.

  I have checked to confirm that the two image files are the same size. Both are 1024x768px.There are also no errors reported.

  Can anyone tell me what I am doing wrong ?

  Here is the output of the command I am using :

  ffmpeg -f image2 -r 1/15 -i ocean%03d.jpg -vcodec libx264 out.mp4

  Below is the output of the above command :

  ffmpeg version 1.0 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Sep 29 2012 11:22:50 with gcc 4.7.1 (GCC) 20120721 (prerelease)
  
    configuration: --prefix=/usr --enable-libmp3lame --enable-libvorbis --enable-libxvid --enable-libx264 --enable-libvpx --enable-libtheora --enable-libgsm --enable-libspeex --enable-postproc --enable-shared --enable-x11grab --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libschroedinger --enable-libopenjpeg --enable-librtmp --enable-libpulse --enable-libv4l2 --enable-gpl --enable-version3 --enable-runtime-cpudetect --disable-debug --disable-static
  
    libavutil      51. 73.101 / 51. 73.101
  
    libavcodec     54. 59.100 / 54. 59.100
  
    libavformat    54. 29.104 / 54. 29.104
  
    libavdevice    54.  2.101 / 54.  2.101
  
    libavfilter     3. 17.100 /  3. 17.100
  
    libswscale      2.  1.101 /  2.  1.101
  
    libswresample   0. 15.100 /  0. 15.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  Input #0, image2, from 'ocean%03d.jpg':
  
    Duration: 00:00:30.00, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: mjpeg, yuvj444p, 1024x768 [SAR 72:72 DAR 4:3], 1 tbr, 0.07 tbn, 0.07 tbc
  
  [libx264 @ 0x22debc0] using SAR=1/1
  
  [libx264 @ 0x22debc0] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle Cache64
  
  [libx264 @ 0x22debc0] profile High, level 3.1
  
  [libx264 @ 0x22debc0] 264 - core 124 - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=1 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'out.mp4':
  
    Metadata:
  
      encoder         : Lavf54.29.104
  
      Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuvj420p, 1024x768 [SAR 1:1 DAR 4:3], q=-1--1, 1 tbn, 0.07 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mjpeg -> libx264)
  
  Press [q] to stop, [?] for help
  
  frame=    2 fps=0.0 q=17.0 Lsize=     215kB time=00:00:30.00 bitrate=  58.7kbits/s    
  
  video:214kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.363298%
  
  [libx264 @ 0x22debc0] frame I:1     Avg QP:16.68  size:132919
  
  [libx264 @ 0x22debc0] frame P:1     Avg QP:14.27  size: 85767
  
  [libx264 @ 0x22debc0] mb I  I16..4:  0.0% 100.0%  0.0%
  
  [libx264 @ 0x22debc0] mb P  I16..4:  8.1% 82.9%  9.0%  P16..4:  0.0%  0.0%  0.0%  0.0%  0.0%    skip: 0.0%
  
  [libx264 @ 0x22debc0] 8x8 transform intra:91.5% inter:100.0%
  
  [libx264 @ 0x22debc0] coded y,uvDC,uvAC intra: 97.6% 96.7% 80.8% inter: 100.0% 100.0% 100.0%
  
  [libx264 @ 0x22debc0] i16 v,h,dc,p:  1%  3%  1% 96%
  
  [libx264 @ 0x22debc0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 12% 18% 28%  7%  5%  5%  7%  7% 11%
  
  [libx264 @ 0x22debc0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 26% 16% 12%  8% 10%  8%  6%  8%  5%
  
  [libx264 @ 0x22debc0] i8c dc,h,v,p: 39% 25% 16% 20%
  
  [libx264 @ 0x22debc0] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x22debc0] kb/s:58.32

• Encountered problems when trying to run the code of article "Compressed Video Action Recognition", beginner, need some guidance, thanks a lot

  27 décembre 2018, par Wonderful

  Here is the problem I encountered.
  enter image description here