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• Integrating CUDA-based video decoder into libavcodec/ffmpeg

  1er février 2019, par tmlen

  I have a CUDA-based decoder of a video format running on the GPU. I am trying to add a "codec" into libavcodec that uses it as external decoder

  Currenty, I have it working such that I can play a sequence of pictures using ffplay, which
  get decoded on the GPU with the external decoder.

  But with the current implementation, the codec module copies its output (in a RGB24 pixel format) from GPU memory to host memory after each frame, and gives this to libavcodec in its AVFrame. So with this when using ffplay, it will copy the output images back and forth between GPU and host two times (as ffplay has to copy the data to GPU for display).

  My goal is to leave the uncompressed data on GPU using on a CUDA device buffer, and have ffmpeg use it.

  ffmpeg seems to have support for this using AVHWAccel.

  • Is there any example implementation that uses this with a CUDA based decoder (not using the dedicated hardware decoders through NVDEC, CUVID, etc.) ?

  • Does ffmpeg need the output in a pixel format in a CUDA buffer, or can it also be in texture memory, in a CUDA array ?

  • Is it possible to have the hardware decoder as primary decoder of the AVCodec. It seems that hardware-acceleration is foreseen as an add-on, with the software decoder implemented by AVCodec available as fallback ?

  • It seems that ffmpeg will allocate a pool of CUDA buffers to receive its output. Is it also possible to allocate the output buffers oneself in the module’s implementation, and control how many buffers there will be.

  • Is it possible to control with how many CPU threads the decoder will be called ? With the external decoder’s interface, ideal would be one writer thread that pushes compressed codestreams, and one reader thread that pulls the uncompressed output to a CUDA buffer.

• Python imageio cant read/write | First-Order-Model

  19 août 2020, par user10847428

  I want to make a first order model with https://github.com/AliaksandrSiarohin/first-order-model , but when I run the crop-video.py with python 3.8 I get this windows popup :

  


  This program cannot run on your pc
....

  


  When I close it the CMD was show this :

  


      H:\first-order-model\first-order-model>py crop-video.py --inp driving_video/zsebibaba.mp4&#xA;Traceback (most recent call last):&#xA;  File "crop-video.py", line 154, in <module>&#xA;    commands = process_video(args)&#xA;  File "crop-video.py", line 87, in process_video&#xA;    video = imageio.get_reader(args.inp)&#xA;  File "C:\Python38\lib\site-packages\imageio\core\functions.py", line 129, in get_reader&#xA;    return format.get_reader(request)&#xA;  File "C:\Python38\lib\site-packages\imageio\core\format.py", line 168, in get_reader&#xA;    return self.Reader(self, request)&#xA;  File "C:\Python38\lib\site-packages\imageio\core\format.py", line 217, in __init__&#xA;    self._open(**self.request.kwargs.copy())&#xA;  File "C:\Python38\lib\site-packages\imageio\plugins\ffmpeg.py", line 358, in _open&#xA;    self._load_infos()&#xA;  File "C:\Python38\lib\site-packages\imageio\plugins\ffmpeg.py", line 523, in _load_infos&#xA;    raise IOError(fmt % err2)&#xA;OSError: Could not load meta information&#xA;=== stderr ===&#xA;&#xA;A hozzfrs megtagadva. ( Acces denied)&#xA;</module>

  


  The python38 folder in the C : is read-only and I tried change it but didnt work.

  


  How can I solve this problem ?

  


• rtmp : Support reading interleaved chunks.

  17 septembre 2013, par Josh Allmann

  rtmp : Support reading interleaved chunks.
  A given packet won’t always come in contiguously ; sometimes
  
  they may be broken up on chunk boundaries by packets of another
  
  channel.
  This support primarily involves tracking information about the
  
  data that’s been read, so the reader can pick up where it left
  
  off for a given channel.
  As a side effect, we no longer over-report the bytes read if
  
  (toread = MIN(size, chunk_size)) == size
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/rtmppkt.c
  • [DBH] libavformat/rtmppkt.h
  • [DBH] libavformat/rtmpproto.c