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• Read a Bytes image from Amazon Kinesis output in python

  14 février 2020, par Varun_Rathinam

  I used imageio.get_reader(BytesIO(a),  'ffmpeg') to load a bytes image and save it as normal image.

  But the below error throws when I read the image using imageio.get_reader(BytesIO(a),  'ffmpeg')

  Traceback (most recent call last):
  
    File "<stdin>", line 1, in <module>
  
    File "/home/tango/anaconda3/lib/python3.6/site-packages/imageio/core/functions.py", line 186, in get_reader
  
      return format.get_reader(request)
  
    File "/home/tango/anaconda3/lib/python3.6/site-packages/imageio/core/format.py", line 164, in get_reader
  
      return self.Reader(self, request)
  
    File "/home/tango/anaconda3/lib/python3.6/site-packages/imageio/core/format.py", line 214, in __init__
  
      self._open(**self.request.kwargs.copy())
  
    File "/home/tango/anaconda3/lib/python3.6/site-packages/imageio/plugins/ffmpeg.py", line 323, in _open
  
      self._initialize()
  
    File "/home/tango/anaconda3/lib/python3.6/site-packages/imageio/plugins/ffmpeg.py", line 466, in _initialize
  
      self._meta.update(self._read_gen.__next__())
  
    File "/home/tango/anaconda3/lib/python3.6/site-packages/imageio_ffmpeg/_io.py", line 150, in read_frames
  
      raise IOError(fmt.format(err2))
  
  OSError: Could not load meta information
  
  === stderr ===
  
  
  
  ffmpeg version 4.2 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 7.3.0 (crosstool-NG 1.23.0.449-a04d0)
  
    configuration: --prefix=/home/tango/anaconda3 --cc=/home/conda/feedstock_root/build_artifacts/ffmpeg_1566210161358/_build_env/bin/x86_64-conda_cos6-linux-gnu-cc --disable-doc --disable-openssl --enable-avresample --enable-gnutls --enable-gpl --enable-hardcoded-tables --enable-libfreetype --enable-libopenh264 --enable-libx264 --enable-pic --enable-pthreads --enable-shared --enable-static --enable-version3 --enable-zlib --enable-libmp3lame
  
    libavutil      56. 31.100 / 56. 31.100
  
    libavcodec     58. 54.100 / 58. 54.100
  
    libavformat    58. 29.100 / 58. 29.100
  
    libavdevice    58.  8.100 / 58.  8.100
  
    libavfilter     7. 57.100 /  7. 57.100
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  5.100 /  5.  5.100
  
    libswresample   3.  5.100 /  3.  5.100
  
    libpostproc    55.  5.100 / 55.  5.100
  
  [matroska,webm @ 0x5619b9da3cc0] File ended prematurely
  
  [matroska,webm @ 0x5619b9da3cc0] Could not find codec parameters for stream 0 (Video: h264, none, 1280x720): unspecified pixel format
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  Input #0, matroska,webm, from '/tmp/imageio_zm6hhpgr':
  
    Metadata:
  
      title           : Kinesis Video SDK
  
      encoder         : Kinesis Video SDK 1.0.0
  
      AWS_KINESISVIDEO_FRAGMENT_NUMBER: 91343852333183888465720004820715065721442989478
  
      AWS_KINESISVIDEO_SERVER_TIMESTAMP: 1580791384.096
  
      AWS_KINESISVIDEO_PRODUCER_TIMESTAMP: 1580791377.843
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0(eng): Video: h264, none, 1280x720, SAR 1:1 DAR 16:9, 1k tbr, 1k tbn, 2k tbc (default)
  
      Metadata:
  
        title           : kinesis_video
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native))
  
  Press [q] to stop, [?] for help
  
  Cannot determine format of input stream 0:0 after EOF
  
  Error marking filters as finished
  
  Conversion failed!
  
  </module></stdin>

  The above approach to read a MKV bytes file was done based on this thread

  Or is there is any approach to parse and read the MKV bytes file.

• Direct3d Color space conversion in GPU

  12 juin 2019, par eruslu

  Creating direct3d surface inYV12 format and rendering video frames in yuv420 format causes a blur video. Seems like there is a smog on video. I think this is because yuv 420 color space format’s data range is in 16-235 for Y planes and 16-240 for U and V planes. They are not in range of 0-255.

  I changed color format to BGRA in CPU by using ffmpeg’s sws_scale() function and I created direct3d surface in BGRA format and then displayed video is OK. But cpu consumption is very high due to color space conversion. Is there any way to make color conversion in GPU or is there another way to have sharp video display ?

  This is how I create YV12 surface

  m_pDirect3DDevice->CreateOffscreenPlainSurface(_srcWidth, _srcHeight, (D3DFORMAT)MAKEFOURCC('Y', 'V', '1', '2'), D3DPOOL_DEFAULT, &m_pDirect3DSurfaceRender, NULL);

  Here I copy yuv planes of camera’s video frames data to direct3d surface

          BYTE* pict = (BYTE*)d3d_rect.pBits;
  
          BYTE* Y = pY;
  
          BYTE* V = pV;
  
          BYTE* U = pU;
  
  
  
          for (int y = 0; y < _srcHeight; y++)
  
          {
  
              memcpy(pict, Y, p1);
  
              pict += d3d_rect.Pitch;
  
              Y += p1;
  
          }
  
          for (int y = 0; y < _srcHeight >> 1; y++)
  
          {
  
              memcpy(pict, V, p3);
  
              pict += d3d_rect.Pitch >> 1;
  
              V += p3;
  
          }
  
          for (int y = 0; y < _srcHeight >> 1; y++)
  
          {
  
              memcpy(pict, U, p2);
  
              pict += d3d_rect.Pitch >> 1;
  
              U += p2;
  
          }

  I appreciate your help, thank you.

• How to merge Video and Subtitle on Google Colab with only specifying file path using mkvmerge ?

  25 août 2022, par SomeName

  On Google Colab I found a code to merge Video and Subtitle using mkvmerge with only specifying the folder path also there is a option to include attachments fonts if preferred but The code doesn't work ?

  


  I tried this but it didn't seem to work? When I execute the code it does nothing? İt won't start muxing video and Subtitle? https://pastebin.com/raw/q85DTkta

  


  Could someone help me with this code ? What am I missing ?