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• Piping ffmpeg output into ffplay stdin with boost

  21 décembre 2020, par botiapa

  I'm trying to pipe the output of an ffmpeg process into an ffplay process (Sort of like a playback). My problem is the following : If I copy the output character by character (by character I mean char) it works correctly, other than it consuming a whole lot of cpu power. However when I try to pipe chunks into it (by using a buffer), ffplay for some reason doesn't even recognize the input.

  


  bp::ipstream iso;
bp::ipstream ise;
bp::opstream in;
    
bp::child ffmpeg(bp::search_path("ffmpeg"), bp::args({"-loglevel", "quiet", "-f", "pulse", "-i", "default", "-f", "wav", "-bitexact", "-nostdin", "-"}), bp::std_out > iso, bp::std_err > ise);
bp::child ffplay(bp::search_path("ffplay"), bp::args({"-loglevel", "verbose", "-nodisp", "-f", "wav", "-i", "-"}), bp::std_in < in, bp::std_out > bp::null);


  


  Here are the 2 code snippets for comparison :

  


  Here it is copying char by char

  


  while(ffmpeg.running()) {
    char c;
    c = iso.get();
    in << c;
}


  


  And here it is copying with the help of a buffer

  


  char buffer[1024];
while(ffmpeg.running()) {
    iso.get(buffer, 1024);
    in << buffer;
}


  


  I can provide ffplay output if necessary, however I didn't see any errors or things like that.

  


• avfilter/af_asubboost : add boost option

  13 mai 2022, par Paul B Mahol

  avfilter/af_asubboost : add boost option
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/af_asubboost.c

• C++ Boost launching FFMPEG doesnt work, working ok via terminal

  21 juin 2023, par Pit Digger

  I am launching an FFMPEG process from C++ , the command is workign fine from terminal command line, but gives error when laucnhed from code. What could cause this ?

  


  Error

  


  [AVFilterGraph @ 0x3cfadc0] Error parsing filterchain "[0:v]split=3[v1][v2][v3];[v1]copy[v1out];[v2]scale=w=1280:h=720[v2out];[v3]scale=w=640:h=360[v3out]"
    
[AVFilterGraph @ 0x2f9fb00] Error parsing filterchain 
    
[AVFilterGraph @ 0x3cfadc0] Trailing garbage after a filter: split=3[v1][v2][v3];[v1]copy[v1out];[v2]scale=w=1280:h=720[v2out];[v3]scale=w=640:h=360[v3out]


  


  Code

  


  std::vector args;
args.push_back("-i"); args.push_back("input.mp4");
args.push_back("-filter_complex");
args.push_back("\"[0:v]split=3[v1][v2][v3];[v1]copy[v1out];[v2]scale=w=1280:h=720[v2out];[v3]scale=w=640:h=360[v3out]\"");

args.push_back("-map");  args.push_back("[v1out]");
args.push_back("-c:v:0");  args.push_back("libx264");
args.push_back("-x264-params");  args.push_back("\"nal-hrd=cbr:force-cfr=1\"");
args.push_back("-b:v:0");  args.push_back("1M");
args.push_back("-maxrate:v:0");  args.push_back("2M");
args.push_back("-minrate:v:0");  args.push_back("2M");
args.push_back("-bufsize:v:0");  args.push_back("2M");
args.push_back("-preset");  args.push_back("fast");
args.push_back("-g");  args.push_back("48");
args.push_back("-sc_threshold");  args.push_back("0");
args.push_back("-keyint_min");  args.push_back("48");

args.push_back("-map");  args.push_back("[v2out]");
args.push_back("-c:v:1");  args.push_back("libx264");
args.push_back("-x264-params");  args.push_back("\"nal-hrd=cbr:force-cfr=1\"");
args.push_back("-b:v:1");  args.push_back("1M");
args.push_back("-maxrate:v:1");  args.push_back("1M");
args.push_back("-minrate:v:1");  args.push_back("1M");
args.push_back("-bufsize:v:1");  args.push_back("1M");
args.push_back("-preset");  args.push_back("fast");
args.push_back("-g");  args.push_back("48");
args.push_back("-sc_threshold");  args.push_back("0");
args.push_back("-keyint_min");  args.push_back("48");

args.push_back("-map");  args.push_back("[v3out]");
args.push_back("-c:v:2");  args.push_back("libx264");
args.push_back("-x264-params");  args.push_back("\"nal-hrd=cbr:force-cfr=1\"");
args.push_back("-b:v:2");  args.push_back("500K");
args.push_back("-maxrate:v:2");  args.push_back("500K");
args.push_back("-minrate:v:2");  args.push_back("500K");
args.push_back("-bufsize:v:2");  args.push_back("500K");
args.push_back("-preset");  args.push_back("fast");
args.push_back("-g");  args.push_back("48");
args.push_back("-sc_threshold");  args.push_back("0");
args.push_back("-keyint_min");  args.push_back("48");

args.push_back("-map");  args.push_back("a:0");
args.push_back("-c:a:0");  args.push_back("aac");
args.push_back("-b:a:0");  args.push_back("96k");
args.push_back("-ac");  args.push_back("2");
args.push_back("-map");  args.push_back("a:0");
args.push_back("-c:a:1");  args.push_back("aac");
args.push_back("-b:a:1");  args.push_back("96k");
args.push_back("-ac");  args.push_back("2");
args.push_back("-map");  args.push_back("a:0");
args.push_back("-c:a:2");  args.push_back("aac");
args.push_back("-b:a:2");  args.push_back("48k");
args.push_back("-ac");  args.push_back("2");

args.push_back("-avoid_negative_ts");  args.push_back("1");
args.push_back("-f");  args.push_back("hls");
args.push_back("-hls_time");  args.push_back("6");
args.push_back("-hls_list_size");  args.push_back("15");
args.push_back("-hls_flags");  args.push_back("independent_segments");
args.push_back("-hls_segment_type");  args.push_back("mpegts");
args.push_back("-hls_segment_filename");  args.push_back("/output/stream_%v_data%02d.ts");
args.push_back("-master_pl_name");  args.push_back("index.m3u8");
args.push_back("-var_stream_map");  args.push_back("\"v:0,a:0 v:1,a:1 v:2,a:2\"");
args.push_back("/output/stream_%v.m3u8");


m_childProcess = std::make_unique(
            bp::exe = ffmpegPath,
            bp::args = args);


  


  Command that above code builds (indented for visibility) :

  


   ffmpeg -i input.mp4 -c copy -filter_complex "[0:v]split=3[v1][v2][v3];[v1]copy[v1out];[v2]scale=w=1280:h=720[v2out];[v3]scale=w=640:h=360[v3out]" 
-map [v1out] -c:v:0 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 1M -maxrate:v:0 2M -minrate:v:0 2M -bufsize:v:0 2M -preset fast -g 48 -sc_threshold 0 -keyint_min 48 
-map [v2out] -c:v:1 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:1 1M -maxrate:v:1 1M -minrate:v:1 1M -bufsize:v:1 1M -preset fast -g 48 -sc_threshold 0 -keyint_min 48  
-map [v3out] -c:v:2 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:2 500K -maxrate:v:2 500K -minrate:v:2 500K -bufsize:v:2 500K -preset fast -g 48 -sc_threshold 0 -keyint_min 48 -map a:0 -c:a:0 aac -b:a:0 96k -ac 2 
-map a:0 -c:a:1 aac -b:a:1 96k -ac 2 -map a:0 -c:a:2 aac -b:a:2 48k -ac 2 
-avoid_negative_ts 1 -f hls -hls_time 6 -hls_list_size 15 -hls_flags independent_segments -hls_segment_type mpegts -hls_segment_filename /output/stream_%v_data%02d.ts -master_pl_name index.m3u8 -var_stream_map "v:0,a:0 v:1,a:1 v:2,a:2" /output/stream_%v.m3u8