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• FFmpeg Not Transcoding In Real Time

  2 décembre 2018, par Nimble

  Been setting up a recording build for a friend to resemble mine, but I can’t seem to get things to work in real-time despite sufficient (as far as I can tell) hardware.

  System specs : 8600K, GTX 1050ti, 16Gb RAM, 1tb 860 EVO

  Test command :

  ffmpeg -y -hide_banner -thread_queue_size 9999 -indexmem 9999 -guess_layout_max 0 -f dshow -rtbufsize 2147.48M `
  
  -video_size 1920x1080 -framerate 60 `
  
  -i video="@device_pnp_\\?\usb#vid_07ca&pid_0570&mi_00#7&3886ab1a&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global":audio="@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{0A494693-5F33-4304-88D7-394757E09648}" `
  
  -thread_queue_size 9999 -indexmem 9999 -guess_layout_max 0 -f dshow -rtbufsize 2147.48M `
  
  -video_size 1920x1080 -framerate 60 `
  
  -i video="@device_pnp_\\?\usb#vid_07ca&pid_0570&mi_00#7&24df76f&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global":audio="@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{0E6F0DEF-2B29-4117-8D30-13F01160AC5B}" `
  
  -map 0:0,0:1 -map 0:1 -c:v h264_nvenc -r 60 -rc-lookahead 120 -forced-idr 1 -strict_gop 1 -sc_threshold 0 -flags +cgop `
  
  -force_key_frames "expr:gte(t,n_forced*2)" -preset: llhp -pix_fmt nv12 -b:v 250M -minrate 250M -maxrate 250M `
  
  -bufsize 250M -c:a aac -ar 44100 -b:a 384k -ac 2 -af "aresample=async=250" -vsync 1 -ss 00:00:00.000 `
  
  -max_muxing_queue_size 9999 -f segment -segment_time 600 -segment_wrap 9 -reset_timestamps 1 `
  
  -segment_format_options max_delay=0 C:\Users\Jordan\Videos\FFmpeg\Left\Left%02d.ts `
  
  -map 1:0,1:1 -map 1:1 -c:v h264_nvenc -r 60 -rc-lookahead 120 -forced-idr 1 -strict_gop 1 -sc_threshold 0 -flags +cgop `
  
  -force_key_frames "expr:gte(t,n_forced*2)" -preset: llhp -pix_fmt nv12 -b:v 250M -minrate 250M -maxrate 250M `
  
  -bufsize 250M -c:a aac -ar 44100 -b:a 384k -ac 2 -af "aresample=async=250" -vsync 1 -ss 00:00:00.000 `
  
  -max_muxing_queue_size 9999 -f segment -segment_time 600 -segment_wrap 9 -reset_timestamps 1 `
  
  -segment_format_options max_delay=0 C:\Users\Jordan\Videos\FFmpeg\Right\Right%02d.ts

  For one reason or another this command is not transcoding video in real-time, which is a big issue when you’re trying to record not simply convert a file. When I omit one of the two outputs or if I halve the resolution of each input / output everything works in real-time. This would make me believe there is a bottleneck in the system somewhere but when monitoring everything in task manager nothing is even close to capping out (GPU encoder, cpu, ram, and SSD below 30% usage).

  Furthermore when I try recording both streams in one 4K60 video via OBS things work perfectly fine, as in real-time. So I don’t understand how transcoding two 1080p60 streams in FFmpeg would be anymore intensive than one 4K60 stream in OBS... When looking at the GPUs encoding chip usage it shows about 30% for the two 1080p60 streams on FFmpeg and 80% usage for single 4K60 stream in OBS, yet the OBS recording is real-time while the FFmpeg recording is at .6x speed.

  Lastly I run a very similar command at home but instead of two 1080p60 streams I’m doing 2 4K60 streams, a 1080p60 stream, and another 2 audio streams without issue. I do have a GTX 1080 though... however when monitoring usage for the 1050 TI being used in this situation nothing points to a GPU bottlecap.

  Any insight would be greatly appreciated, been going at this for hours now with no clue as to what could be causing this.

• FFMPEG is really slow at extracting subtitles

  3 mars 2021, par Gustav P Svensson

  I'm trying to extract the subtitles from a 1080P video, around 40min long. I'm currently using this command (using fluent-ffmpeg in node, but the translated command is this) :

  


  ffmpeg -threads 3  -map 0: -c copy 


  


  This command takes about 20-30 min to complete. I've searched quite a lot on how to speed up this process, if I look at my task manager I can see that ffmpeg is using 0.1% of the CPU which makes me think that it's possible to speed up this process.

  


  I'm not sure if the -threads option is actually doing anything when extracting subtitles but I don't think it should make it slower atleast ?

  


  So my question is, is it possible to speed up this process ? I appriciate any help.

  


  Full FFMPEG log:
fmpeg version 3.4.8-0ubuntu0.2 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version=0ubuntu0.2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, matroska,webm, from '/home/test.mkv:
  Metadata:
    encoder         : libebml v1.3.6 + libmatroska v1.4.9
    creation_time   : 2019-03-14T16:46:55.000000Z
  Duration: 00:41:20.29, start: 0.000000, bitrate: 6430 kb/s
    Stream #0:0: Video: h264 (Main), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
    Metadata:
      BPS-eng         : 5788926
      DURATION-eng    : 00:41:20.020000000
      NUMBER_OF_FRAMES-eng: 59461
      NUMBER_OF_BYTES-eng: 1794581562
      _STATISTICS_WRITING_APP-eng: mkvmerge v31.0.0 ('Dolores In A Shoestand') 64-bit
      _STATISTICS_WRITING_DATE_UTC-eng: 2019-03-14 16:46:55
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
    Stream #0:1(eng): Audio: eac3, 48000 Hz, 5.1(side), fltp, 640 kb/s (default)
    Metadata:
      title           : English
      BPS-eng         : 640000
      DURATION-eng    : 00:41:20.288000000
      NUMBER_OF_FRAMES-eng: 77509
      NUMBER_OF_BYTES-eng: 198423040
      _STATISTICS_WRITING_APP-eng: mkvmerge v31.0.0 ('Dolores In A Shoestand') 64-bit
      _STATISTICS_WRITING_DATE_UTC-eng: 2019-03-14 16:46:55
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
    Stream #0:2(eng): Subtitle: subrip
    Metadata:
      BPS-eng         : 80
      DURATION-eng    : 00:40:22.295000000
      NUMBER_OF_FRAMES-eng: 645
      NUMBER_OF_BYTES-eng: 24473
      _STATISTICS_WRITING_APP-eng: mkvmerge v31.0.0 ('Dolores In A Shoestand') 64-bit
      _STATISTICS_WRITING_DATE_UTC-eng: 2019-03-14 16:46:55
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
    Stream #0:3(eng): Subtitle: subrip
    Metadata:
      title           : SDH
      BPS-eng         : 86
      DURATION-eng    : 00:40:31.012000000
      NUMBER_OF_FRAMES-eng: 709
      NUMBER_OF_BYTES-eng: 26142
      _STATISTICS_WRITING_APP-eng: mkvmerge v31.0.0 ('Dolores In A Shoestand') 64-bit
      _STATISTICS_WRITING_DATE_UTC-eng: 2019-03-14 16:46:55
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Output #0, srt, to 'test6.srt':
  Metadata:
    encoder         : Lavf57.83.100
    Stream #0:0(eng): Subtitle: subrip
    Metadata:
      BPS-eng         : 80
      DURATION-eng    : 00:40:22.295000000
      NUMBER_OF_FRAMES-eng: 645
      NUMBER_OF_BYTES-eng: 24473
      _STATISTICS_WRITING_APP-eng: mkvmerge v31.0.0 ('Dolores In A Shoestand') 64-bit
      _STATISTICS_WRITING_DATE_UTC-eng: 2019-03-14 16:46:55
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Stream mapping:
  Stream #0:2 -> #0:0 (copy)
Press [q] to stop, [?] for help
size=      46kB time=00:40:36.68 bitrate=   0.2kbits/s speed=11.6x    
video:0kB audio:0kB subtitle:24kB other streams:0kB global headers:0kB muxing overhead: 94.438766%


  


• ffmpeg does not decode some h264 streams

  12 janvier 2016, par Andrey

  I have some ip of cameras on the local network.I receive video stream with live555 library (I took testRtspClient as a basis) and decode frames with ffmpeg (avcodec_decode_video2). Everything perfectly works.
  Problems begin when I try to decode a stream from an internet.

  The first problem - some packets lost, so defects appears. But it’s not a problem. Problem - after stop and start video stream it is necessary to wait for about 5 minutes of streaming before ffmpeg is able to decode something from the same ip camera. If packets doesn’t lost then everithing ok.

  The second problem - there is camera which sends video with resolution 2048х1538. The frame of such resolution is sent by several packets. live555 normally brings together them but when the frame is transferred to the decoder, the decoder returns the packet length, but got frame always 0.

  Here some my code :

  #define RECEIVE_BUFFER_SIZE 1000000
  
  AVCodecContext* avCodecContext; //definition
  
  AVFrame *frame;  //definition
  
  ...
  
  //init code
  
  _fReceiveBuffer = new uint8_t[RECEIVE_BUFFER_SIZE+512]; //buffer to receive frame
  
  ZeroMemory(_fReceiveBuffer, RECEIVE_BUFFER_SIZE + 512); //zeros
  
  _bufferSize = RECEIVE_BUFFER_SIZE * sizeof(uint8_t); //buffer size
  
  
  
  static const  uint8_t startCode[4] = { 0x00, 0x00, 0x00, 0x01 }; //this is for 0 0 0 1
  
  //before frame will transfer to decoder
  
  memcpy(_fReceiveBuffer, (void*)startCode, sizeof(uint8_t)* 4);
  
  _fReceiveBuffer += sizeof(sizeof(uint8_t)* 4);
  
  _bufferSize -= sizeof(sizeof(uint8_t)* 4);
  
  
  
  AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_H264); //find codec
  
  
  
  avCodecContext = avcodec_alloc_context3(codec); 
  
  avCodecContext->flags |= AV_PKT_FLAG_KEY;
  
  avcodec_open2(avCodecContext, codec, NULL);
  
  
  
  frame = av_frame_alloc();
  
  
  
  //frame
  
  void DummySink::afterGettingFrame(unsigned frameSize, unsigned numTruncatedBytes,
  
  struct timeval presentationTime, unsigned durationInMicroseconds) {
  
  
  
  if (strcmp(fSubsession.codecName(), "H264") == 0)
  
  {
  
      //code from onvif device manager
  
      static const uint8_t startCode3[] = { 0x00, 0x00, 0x01 };
  
      static const uint8_t startCode4[] = { 0x00, 0x00, 0x00, 0x01 };
  
      auto correctedFrameSize = frameSize;
  
      auto correctedBufferPtr = fPlObj->_fReceiveBuffer;
  
      if (frameSize < sizeof(startCode4) || memcmp(startCode4, correctedBufferPtr, sizeof(startCode4)) != 0){
  
          if (frameSize < sizeof(startCode3) || memcmp(startCode3, correctedBufferPtr, sizeof(startCode3)) != 0){
  
              correctedFrameSize += sizeof(uint8_t)* 4;
  
              correctedBufferPtr -= sizeof(uint8_t)* 4;
  
          }
  
      }
  
  
  
      ProcessFrame(correctedBufferPtr, correctedFrameSize, presentationTime, durationInMicroseconds);
  
  }
  
  continuePlaying();
  
  }
  
  
  
  void DummySink::ProcessFrame(unsigned char* framePtr, int frameSize, struct timeval presentationTime, unsigned duration)    {
  
  
  
  AVPacket avpkt;
  
  av_init_packet(&avpkt);
  
  avpkt.data = framePtr;
  
  avpkt.size = frameSize;
  
  while (avpkt.size > 0) {
  
      int got_frame = 0;
  
  
  
      int len = avcodec_decode_video2(avCodecContext, frame, &got_frame, &avpkt);
  
      if (len < 0) {
  
          //TODO: log error
  
          return;
  
      }
  
      else if (got_frame == 0)
  
      {
  
  //I tried this code, bacause "codecs which have the AV_CODEC_CAP_DELAY capability set have a delay between input and output"
  
  //but it didn't help
  
          /*AVPacket emptyPacket;
  
          av_init_packet(&emptyPacket);
  
          emptyPacket.data = NULL;
  
          emptyPacket.size = 0;
  
          emptyPacket.stream_index = avpkt.stream_index;
  
          len = avcodec_decode_video2(avCodecContext, frame, &got_frame, &emptyPacket);
  
          if ( got_frame == 1) goto next;*/
  
          return;
  
      }
  
  next:
  
      //... here code for view with DirectDraw - everithing ok with it
  
      avpkt.size -= len;
  
      avpkt.data += len;
  
  }
  
  }

  I alsa tried to send frame to decoder with sps and pps information :

  0 0 0 1 sps 0 0 0 1 pps 0 0 0 1 frame

  but it is not help.

  Interesting that avcodec_decode_video2 does not return frame with second problem (return all size of frame), but width and height in avCodecContext are set correctly. I can’t understart why it doesn’t return frame.

  Can anyone help with these problems ?