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• Can't get the right formula to set frame pts for a stream using libav

  4 avril 2022, par user1365836

  I'm trying to save a stream of frames as mp4.
Source framerate is not fixed and it stay in the range [15,30]

  


  Encoder params :

  


  ...
eCodec.time_base = AVRational(1,3000);
eCodec.framerate = AVRational(30, 1);
...


  


  Stream params :

  


  eStream = avformat_new_stream(eFormat, null);                
eStream.codecpar = codecParams;
eStream.time_base = eCodec.time_base;


  


  Decoder time_base is 0/1 and it marks each frame with a pts like :

  


  480000
528000
576000
...


  


  PTS(f) is always == PTS(f-1)+48000

  


  Encoding (dFrame is the received frame, micro the elapsed time in microseconds) :

  


  av_frame_copy(eFrame, dFrame);
eFrame.pts = micro*3/1000;


  


  This make the video playing too fast.
I can't understand why, but changing micro*3/1000 to micro*3*4/1000 make the video play at the correct speed (checked against a clock after many minutes of varying fps)

  


  What am I missing ?

  


• Yes or no, will ffmpeg api do hardware decoding on iOS ?

  15 janvier 2019, par Fattie

  There seems to be conflicting information on this.

  https://trac.ffmpeg.org/wiki/HWAccelIntro

  notice the first diagram, it firmly marks iOS as “Y” on VideoToolbox

  

  however in the comments down the bottom it says

  VideoToolbox. ​VideoToolbox, only supported on macOS. H.264 decoding is available in FFmpeg/libavcodec.

  And in the confusing second diagram it says "Standalone" is not done for VideoToolbox.

  We have found that using ffmpeg compiled in to iOS .... it seems to not use hardware decoding, which is really a pain.

  1. With avcodec_get_hw_config() we get AV_PIX_FMT_VIDEOTOOLBOX, AV_HWDEVICE_TYPE_VIDEOTOOLBOX which is seemingly correct.

  2. But usage and framerates clearly shows everything is being done in CPU. The code is in ff_hevc_hls_residual_coding all the time. (That’s fffmpeg’s software decoder.)

  3. This very diff very long git.videolan.org URL here seems to suggest again it should all be working.

  4. Have tried every iPhone etc. of course

• FFMPEG & MistServer : RTMP Input/Output error

  17 octobre 2017, par brewcrazy

  I have an IP camera that outputs a RTSP stream that I’m trying to use to display a live feed on my website. This is a small site that only my wife and I will access so I’m trying to use a free streaming service. For that reason, I’ve decided to try MistServer’s open source option.

  I currently have downloaded MistServer and have it running without installation on my mac (sudo ./MistController). With MistServer running, I have a stream set up and default protocols configured. The stream is configured as follows :

  stream name: ipcam
  
  source: push://

  The configuration page gives me the following source to push to :

  RTMP full url: rtmp://127.0.0.1/live/ipcam
  
  RTMP url: rtmp://127.0.0.1/live/
  
  RTMP stream key: ipcam

  In the streams view, the stream’s status is unavailable, but I’m assuming this is because it isn’t receiving an input. I haven’t been able to confirm this via documentation.

  Here is the FFMPEG command that I am running and the error that I’m getting :

  ffmpeg -rtsp_transport tcp -i rtsp://<user>:@:554/live0.264 -acodec copy -vcodec copy -f flv rtmp://127.0.0.1/live/ipcam
  
  
  
  ffmpeg version 3.3.3 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with Apple LLVM version 8.1.0 (clang-802.0.42)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma --enable-vda
  
    libavutil      55. 58.100 / 55. 58.100
  
    libavcodec     57. 89.100 / 57. 89.100
  
    libavformat    57. 71.100 / 57. 71.100
  
    libavdevice    57.  6.100 / 57.  6.100
  
    libavfilter     6. 82.100 /  6. 82.100
  
    libavresample   3.  5.  0 /  3.  5.  0
  
    libswscale      4.  6.100 /  4.  6.100
  
    libswresample   2.  7.100 /  2.  7.100
  
    libpostproc    54.  5.100 / 54.  5.100
  
  Guessed Channel Layout for Input Stream #0.1 : mono
  
  Input #0, rtsp, from 'rtsp://<user>:@:554/live0.264':
  
    Metadata:
  
      title           : Session Streamed by LIBZRTSP
  
      comment         : live0.264
  
    Duration: N/A, start: 0.242000, bitrate: N/A
  
      Stream #0:0: Video: h264 (Main), yuv420p(progressive), 1280x720, 25 fps, 24.83 tbr, 90k tbn, 50 tbc
  
      Stream #0:1: Audio: pcm_mulaw, 8000 Hz, mono, s16, 64 kb/s
  
  rtmp://127.0.0.1/live/ipcam: Input/output error
  
  </user></user>

  I can’t determine from this error if the issue is the FFMPEG command or my MistServer configuration.