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• PowerShell and = inside a & call parameter

  18 mars 2018, par Tupsi

  I am trying to run the following inside a powershell script :

  ffmpeg.exe -hide_banner -i .\input.mkv -passlogfile input -c:v libvpx-vp9 -b:v 0 -crf 31 -tile-columns 6 -tile-rows 2 -threads 8 -pass 2 -speed 1 -frame-parallel 1 -row-mt 1 -c:a libopus -b:a 256000 -c:s copy -af aformat=channel_layouts=5.1 -auto-alt-ref 1 -lag-in-frames 25 -y output.mkv

  This works fine on either cmd or powershell line directly, but not if I try to run it inside a .ps1 with &. I get the following error :

  Unrecognized option '-hide_banner -i .\input.mkv -passlogfile input -c:v libvpx-vp9 -b:v 0 -crf 31 -tile-columns 6 -tile-rows 2 -threads 8 -pass 2 -speed 1 -frame-parallel 1 -row-mt 1 -c:a libopus -b:a 256000 -c:s copy -auto-alt-ref 1 -lag-in-frames 25 -y -af aformat=channel_layouts=5.1 output.mkv'. Error splitting the argument list: Option not found

  Digging around a bit it seems that the double = with the -af afilter=channel_layouts=5.1 is pissing powershell off and I have no clue how to get around it. Already tried escaping it in some ways with no luck.

  Is there any way I can pass these kind of arguments to my exe without powershell complaining to be unable to split up the arguments ? Don’t understand the shell tries it in the first place anyway as it should all go to my ffmpeg.exe in the first place.

• issue in ffmpeg Timestamp calculation after amix audio filter

  25 avril 2016, par Stackoverfloooow

  I am developing an audio player application using ffmpeg which will handle dynamic audio trac switching and mixing.
  I am able to successfully achieve track switching dynamically. But I am facing challenges in audio mixing.

  I am using "amix" audio filters to mix multiple audio tracks. I am able to mix audio tracks successfully. But when I try to extract the timestamp (using av_frame_get_best_effort_timestamp) after audio mixing I am getting discontinuous audio timestamps. Please have a look at the below given log snapshots at different time intervals. Any help to pin-point the issue will be greatly appreciated. Thank you. Please let me know if you need further information.

  Frame position calculation :

      double realTime = av_frame_get_best_effort_timestamp(RawFrame)
  
      auto formatContext = m_FFMpegData->formatContext() ;
  
      auto timeBase = formatContext->streams[streamId]->time_base ;
  
      double framePosition = realTime * av_q2d(timeBase) ;
  

  Graph :

  

      Logs :
  
      -----------------------------
  
      DEC  -> Pos :  "00:00:00:20"
  
      DEC  -> Pos :  "00:00:00:22"
  
      DEC  -> Pos :  "00:00:00:24"
  
      Issue in Audio Timestamp continuity
  
      DEC  -> Pos :  "00:00:00:22"
  
      DEC  -> Pos :  "00:00:00:23"
  
      DEC  -> Pos :  "00:00:00:24"
      -----------------------------
  
      DEC  -> Pos :  "00:00:03:16"
  
      DEC  -> Pos :  "00:00:03:17"
  
      DEC  -> Pos :  "00:00:03:27"
  
      Issue in Audio Timestamp continuity
  
      DEC  -> Pos :  "00:00:03:18"
  
      DEC  -> Pos :  "00:00:03:19"
  
      DEC  -> Pos :  "00:00:03:20"
      -----------------------------
  
      DEC  -> Pos :  "00:00:04:08"
  
      DEC  -> Pos :  "00:00:04:09"
  
      DEC  -> Pos :  "00:00:04:21"
  
      Issue in Audio Timestamp continuity
  
      DEC  -> Pos :  "00:00:04:10"
  
      DEC  -> Pos :  "00:00:04:10"
  
      DEC  -> Pos :  "00:00:04:11"
      -----------------------------
  
      DEC  -> Pos :  "00:00:06:12"
  
      DEC  -> Pos :  "00:00:06:13"
  
      DEC  -> Pos :  "00:00:07:00"
  
      Issue in Audio Timestamp continuity
  
      DEC  -> Pos :  "00:00:06:14"
  
      DEC  -> Pos :  "00:00:06:15"
  
      DEC  -> Pos :  "00:00:06:15"
      -----------------------------
  
      DEC  -> Pos :  "00:00:07:03"
  
      DEC  -> Pos :  "00:00:07:05"
  
      DEC  -> Pos :  "00:00:07:24"
  
      Issue in Audio Timestamp continuity
  
      DEC  -> Pos :  "00:00:07:05"
  
      DEC  -> Pos :  "00:00:07:06"
  
      DEC  -> Pos :  "00:00:07:07"
      -----------------------------
  
      DEC  -> Pos :  "00:00:09:07"
  
      DEC  -> Pos :  "00:00:09:09"
  
      DEC  -> Pos :  "00:00:10:04"
  
      Issue in Audio Timestamp continuity
  
      DEC  -> Pos :  "00:00:09:10"
  
      DEC  -> Pos :  "00:00:09:10"
  
      DEC  -> Pos :  "00:00:09:11"
  

• Encode video with H.264 using FFmpeg in Windows

  4 novembre 2019, par cbuchart

  I’m trying to encode a video with H.264 using FFmpeg (AV_CODEC_ID_H264), but I’m unable to init the codec correctly. No issues at all when using other codec like AV_CODEC_ID_MPEG1VIDEO.

  avcodec_register_all();
  
  
  
  auto codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  if (!codec) { return false; }
  
  
  
  auto codec_context = avcodec_alloc_context3(codec);
  
  if (!codec_context) { return false; }
  
  
  
  codec_context->codec_id = codec->id;
  
  codec_context->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  codec_context->width = w; // w = 1280 on tests
  
  codec_context->height = h; // h = 1024 on tests
  
  codec_context->bit_rate = w * h * 4;
  
  
  
  codec_context->time_base = { 1, fps }; // fps = 50 on tests
  
  codec_context->framerate = { fps, 1 };
  
  
  
  codec_context->gop_size = 10;
  
  
  
  codec_context->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
  if (codec->id == AV_CODEC_ID_H264) {
  
      av_opt_set(codec_context->priv_data, "preset", "veryfast", 0);
  
  }
  
  
  
  if (avcodec_open2(codec_context, codec, nullptr) < 0) { return false; } // < Fails here

  The first error message I received is :

  [h264_amf @ 08e75900] DLL amfrt32.dll failed to open

  As far as I was able to find, that DLL belongs to the Advanced Media Framework, a SDK to access HW acceleration from AMD hardware. I don’t own an AMD card, so I don’t have such drivers nor SDK installed in my computer. Anyway, I downloaded the SDK and copied driver’s DLLs to my binaries directory. The missing DLL error was removed, but, as expected, the module was not correctly initialized :

  [h264_amf @ 0375b600] CreateComponent(AMFVideoEncoderVCE_AVC) failed with error 13

  Question : Am I missing anything (parameters, dependencies) ? Is there any way to disable the AMF acceleration or to mark it as optional / auto-detect / whatever ?

  PS : I’m expecting to run the encoding executable in a very heterogeneous client-base, assuming Windows 10 and barely anything else, so I can’t mark as mandatory vendor-specific accelerations.

  PS : I’m using the pre-compiled LGPL build of FFmpeg 4.2.1 from https://ffmpeg.zeranoe.com/builds/ for Windows 32 bits. My code is being compiled using Visual Studio 2017.

  If the problem is in the pre-compiled version, I’m happy with re-building it. If so, which configuration parameters should I use when building x264 or ffmpeg then ?