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• Chrome times out on streaming FFMPEG output from ASP.NET Web Api

  3 août 2014, par Hayden McAfee

  I’ve got a unique problem here !

  UPDATE 2 So it turns out the development below is FALSE, the inconsistency of the bug made it seem like not closing the stream made it work... but in fact the same issue persists !

  UPDATE Interesting development ; if I comment out ffmpegBufferedIn.Close(); below, the entire stream always goes through fine... the request just never ends. What could be going on here ?

  I’m writing a web service that stores audio files in Azure Blob Storage, and converts them to MP3 live when requested through my ASP.NET Web API endpoint. I accomplish this by using ’DownloadToStream’ via the Azure Storage API, feeding that stream through the STDIN of an FFMPEG process, and sending the STDOUT stream as the request response.

  The block of code that does this looks like this :

  public HttpResponseMessage Get(Guid songid)
  
  {
  
      // This could take awhile.
  
      HttpContext.Current.Server.ScriptTimeout = 600;
  
  
  
      Process ffmpeg = new Process();
  
      ProcessStartInfo startinfo = new ProcessStartInfo(HostingEnvironment.MapPath("~/App_Data/executables/ffmpeg.exe"), "-i - -vn -ar 44100 -ac 2 -ab 192k -f mp3 - ");
  
      startinfo.RedirectStandardError = true;
  
      startinfo.RedirectStandardOutput = true;
  
      startinfo.RedirectStandardInput = true;
  
      startinfo.UseShellExecute = false;
  
      startinfo.CreateNoWindow = true;
  
      ffmpeg.StartInfo = startinfo;
  
      ffmpeg.ErrorDataReceived += ffmpeg_ErrorDataReceived;
  
  
  
      // Our response is a stream
  
      var response = Request.CreateResponse();
  
      response.StatusCode = HttpStatusCode.OK;
  
  
  
      // Retrieve storage account from connection string.
  
      CloudStorageAccount storageAccount = CloudStorageAccount.Parse(
  
          CloudConfigurationManager.GetSetting("StorageConnectionString"));
  
  
  
      // Create the blob client.
  
      CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
  
  
  
      // Retrieve reference to a previously created container.
  
      CloudBlobContainer container = blobClient.GetContainerReference("songs");
  
  
  
      // Retrieve reference to a blob
  
      CloudBlockBlob blockBlob = container.GetBlockBlobReference(songid.ToString());
  
  
  
      ffmpeg.Start();
  
      ffmpeg.BeginErrorReadLine();
  
  
  
      // Buffer the streams
  
      var ffmpegBufferedIn = new BufferedStream(ffmpeg.StandardInput.BaseStream);
  
      var ffmpegBufferedOut = new BufferedStream(ffmpeg.StandardOutput.BaseStream);
  
  
  
      blockBlob.DownloadToStreamAsync(ffmpegBufferedIn).ContinueWith((t) => {
  
          ffmpegBufferedIn.Flush();
  
          ffmpegBufferedIn.Close();
  
      });
  
  
  
      response.Content = new StreamContent(ffmpegBufferedOut);
  
      response.Content.Headers.ContentType = new MediaTypeHeaderValue("audio/mpeg");
  
  
  
      System.Diagnostics.Debug.WriteLine("Returned response.");
  
      return response;
  
  }

  This works quite well in all browsers - all except for Chrome, which has an interesting way of buffering audio streams. Chrome will buffer the first 2 megabytes of a stream, then keep the connection open and wait until the user gets closer to playing the next segment of a file before consuming the rest of the stream. This should be fine - and for some songs it is. For others, I get this :

  

  At first I thought this was due to some kind of timeout - But it happens at a different time and size for each file. It is consistent within about 15 seconds on the same songs, however. The output on the server side is normal - no exceptions thrown, and FFMpeg finishes encoding the song successfully.

  Here’s the server-side output of the above request :

  ffmpeg version N-64919-ga613257 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Jul 23 2014 00:27:32 with gcc 4.8.3 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-decklink --enable-zlib
  
    libavutil      52. 92.101 / 52. 92.101
  
    libavcodec     55. 69.100 / 55. 69.100
  
    libavformat    55. 48.101 / 55. 48.101
  
    libavdevice    55. 13.102 / 55. 13.102
  
    libavfilter     4. 11.102 /  4. 11.102
  
    libswscale      2.  6.100 /  2.  6.100
  
    libswresample   0. 19.100 /  0. 19.100
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Input #0, mp3, from 'pipe:':
  
    Metadata:
  
      TSRC            : AUUM71001516
  
      title           : Sunlight
  
      track           : 2
  
      artist          : Bag Raiders
  
      copyright       : 2010 Modular Recordings
  
      genre           : Electronic
  
      album           : Bag Raiders
  
      album_artist    : Bag Raiders
  
      disc            : 1/1
  
      publisher       : Modular Recordings
  
      composer        : Chris Stracey/Jack Glass/Dan Black
  
      date            : 2010
  
    Duration: N/A, start: 0.000000, bitrate: 320 kb/s
  
      Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 320 kb/s
  
      Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg), 600x600 [SAR 300:300 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
  
      Metadata:
  
        title           : 
  
        comment         : Other
  
  Output #0, mp3, to 'pipe:':
  
    Metadata:
  
      TSRC            : AUUM71001516
  
      TIT2            : Sunlight
  
      TRCK            : 2
  
      TPE1            : Bag Raiders
  
      TCOP            : 2010 Modular Recordings
  
      TCON            : Electronic
  
      TALB            : Bag Raiders
  
      TPE2            : Bag Raiders
  
      TPOS            : 1/1
  
      TPUB            : Modular Recordings
  
      TCOM            : Chris Stracey/Jack Glass/Dan Black
  
      TDRL            : 2010
  
      TSSE            : Lavf55.48.101
  
      Stream #0:0: Audio: mp3 (libmp3lame), 44100 Hz, stereo, s16p, 192 kb/s
  
      Metadata:
  
        encoder         : Lavc55.69.100 libmp3lame
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mp3 (native) -> mp3 (libmp3lame))
  
  size=       6kB time=00:00:00.21 bitrate= 227.6kbits/s    
  
  size=     102kB time=00:00:04.31 bitrate= 193.7kbits/s    
  
  size=     202kB time=00:00:08.56 bitrate= 192.9kbits/s    
  
  size=     341kB time=00:00:14.49 bitrate= 192.5kbits/s    
  
  size=     489kB time=00:00:20.82 bitrate= 192.4kbits/s    
  
  size=     642kB time=00:00:27.35 bitrate= 192.3kbits/s    
  
  size=     792kB time=00:00:33.75 bitrate= 192.2kbits/s    
  
  size=     950kB time=00:00:40.49 bitrate= 192.2kbits/s    
  
  size=    1106kB time=00:00:47.15 bitrate= 192.2kbits/s    
  
  size=    1258kB time=00:00:53.63 bitrate= 192.1kbits/s    
  
  size=    1415kB time=00:01:00.31 bitrate= 192.1kbits/s    
  
  size=    1563kB time=00:01:06.66 bitrate= 192.1kbits/s    
  
  size=    1710kB time=00:01:12.90 bitrate= 192.1kbits/s    
  
  size=    1857kB time=00:01:19.17 bitrate= 192.1kbits/s    
  
  size=    2008kB time=00:01:25.63 bitrate= 192.1kbits/s    
  
  size=    2162kB time=00:01:32.21 bitrate= 192.1kbits/s    
  
  size=    2299kB time=00:01:38.03 bitrate= 192.1kbits/s    
  
  size=    2457kB time=00:01:44.80 bitrate= 192.1kbits/s    
  
  size=    2600kB time=00:01:50.89 bitrate= 192.1kbits/s    
  
  size=    2755kB time=00:01:57.52 bitrate= 192.1kbits/s    
  
  size=    2864kB time=00:02:02.17 bitrate= 192.1kbits/s    
  
  size=    3022kB time=00:02:08.88 bitrate= 192.1kbits/s    
  
  size=    3172kB time=00:02:15.31 bitrate= 192.1kbits/s    
  
  size=    3284kB time=00:02:20.06 bitrate= 192.1kbits/s    
  
  size=    3385kB time=00:02:24.40 bitrate= 192.1kbits/s    
  
  size=    3529kB time=00:02:30.51 bitrate= 192.0kbits/s    
  
  size=    3687kB time=00:02:37.25 bitrate= 192.0kbits/s    
  
  size=    3838kB time=00:02:43.71 bitrate= 192.0kbits/s    
  
  size=    3988kB time=00:02:50.11 bitrate= 192.0kbits/s    
  
  size=    4138kB time=00:02:56.53 bitrate= 192.0kbits/s    
  
  size=    4279kB time=00:03:02.54 bitrate= 192.0kbits/s    
  
  size=    4408kB time=00:03:08.03 bitrate= 192.0kbits/s    
  
  size=    4544kB time=00:03:13.85 bitrate= 192.0kbits/s    
  
  size=    4683kB time=00:03:19.78 bitrate= 192.0kbits/s    
  
  size=    4805kB time=00:03:24.95 bitrate= 192.0kbits/s    
  
  size=    4939kB time=00:03:30.67 bitrate= 192.0kbits/s    
  
  size=    5049kB time=00:03:35.38 bitrate= 192.0kbits/s    
  
  size=    5141kB time=00:03:39.32 bitrate= 192.0kbits/s    
  
  size=    5263kB time=00:03:44.49 bitrate= 192.0kbits/s    
  
  size=    5372kB time=00:03:49.17 bitrate= 192.0kbits/s    
  
  The thread 0xb24 has exited with code 259 (0x103).
  
  size=    5436kB time=00:03:51.91 bitrate= 192.0kbits/s    
  
  size=    5509kB time=00:03:55.02 bitrate= 192.0kbits/s    
  
  size=    5657kB time=00:04:01.32 bitrate= 192.0kbits/s    
  
  size=    5702kB time=00:04:03.22 bitrate= 192.0kbits/s
  
  
  
  video:0kB audio:5701kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.005738%

  Any ideas ? I’m grateful for suggestions - I’ve been chasing this for a week now !

• FFMPEG H264 with custom overlay per frame

  4 octobre 2020, par La bla bla

  We have a stream that is stored in the cloud (Amazon S3) as individual H264 frames. The frames are stored as framexxxxxx.264, the numbering doesn't start from 0 but rather from some larger number, say 1000 (so, frame001000.264)

  


  The goal is to create a mp4 clip which is either timelapse or just faster for inspection and other checking (much faster, compressing around 3 hours of video down to < 20 minutes), this also requires we overlay the frame number (the filename) on the frame itself

  &#xA;

  At first I was creating a timelapse by pulling from S3 only the keyframes (i-frames ? still rather new to codecs & stuff) and overlaying the filename on them and saving as png (which probably isn't needed, but that's what I did) using (this command is used inside a python script)

  &#xA;

  ffmpeg -y -i {h264_name} -vf \"scale=1920:-1, 
drawtext=fontfile=/usr/share/fonts/truetype/ubuntu-font-family/Ubuntu-B.ttf:fontsize=34:text={txt}:fontcolor=white:x=50:y=50:bordercolor=black:borderw=2\" 
-c:a copy -pix_fmt yuv420p {basename}.png


  &#xA;

  after this I combined all the frames by using python to convert the lowest numbered frame to 0.png and incrementing (so it would be continuous, because I only used keyframes the numbers originally weren't sequential) and running

  &#xA;

  ffmpeg -y -f image2 -i %d.png -r {self.params.fps} -vcodec libx264 -crf {self.params.crf} -pix_fmt yuv420p {out_file}


  &#xA;

  and this worked great, but the difference between keyframes was too long to allow for proper inspection

  &#xA;

  so now for the question(s)

  &#xA;

  since I know frames that are not keyframes (p-frames ?) can't be used alone by ffmpeg, the method of overlaying the file name and converting it to png (or keep as h264, same thing) won't work, or at least, I couldn't find a way for it to work, maybe there's a way to specify a frame's keyframe ?, how can one overlay the filename (and not the frame number as shown here for example)

  &#xA;

  Also, is it possible to skip some p-frames between the keyframes ? (so if a keyframe is every 30 frames, we would take a keyframe, a frame 15 frames later, and next another keyframe)

  &#xA;

  I thought about using ffmpeg's pipe option to feed it with the files as they're being downloaded, but I'm not sure if I can specify drawtext this way

  &#xA;

  Also, if there's another alternative that can achieve that (at first I was converting to png, using python and OpenCV to add the filename and then merging the pngs to mp4, but then I found drawtext can do that in a single command so I used it)

  &#xA;

• AWS : Best way to generate a thumbnail for every frame of a s3 uploaded video

  4 janvier 2018, par danielfranca

  I need to process a video file, transcode it and generate a thumbnail for every frame.

  It should happen every time there’s a new video on a specific AWS bucket.

  I found out that AWS Lambda should be the best service for that

  However, it is not working as expected and I’ll explain why

  I’ve created a simple Python2.7 file using FFVideo
  It seems that this library doesn’t support Python3.

  It is a nice abstraction on top of ffmpeg

  To deploy the package I had run lld on the FFVideo shared object, and then copied everything to my project directory, as described in their documentation.
  Zipped it and upload to AWS Lambda

  Yet it doesn’t work, I keep getting errors as if the /usr/lib64/libstdc++ is missing, even after copied it to the projecct dir, also tried /usr/lib64 and /lib64

  Then as a second thought I wonder if just running ffmpeg wouldn’t be easier...
  So I just copied ffmpeg to the project dir and did a simple Python script to call it.

  Missing shared objects, ok, lld again and copied everything to the directory.

  Then AWS Lambda seems to be completely broken, I can’t save it anymore and it just says "Fix errors before saving"
  But no error message, nothing

  I even have attempted to write inline a simple code, but now AWS Lambda don’t even open the online editor.
  I also tried to remove all the shared objects I have added, returning to the original state, but still same generic error.
  Same thing if I just create a new lambda function with same old code.

  Doesn’t matter what I do it never even enable the Save button anymore.
  I thought it might be just some AWS unstability, but it been a while.

  I’ve looked to a similar project using Node
  and it doesn’t seem to include anything except ffmpeg

  My other idea is to use SQS to trigger a python script somewhere else to create the thumbnails

  Any idea how is the best approach for that ?