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• Revision 1e30547984 : Skip mode search based on reference frame consistency This commit enables the e

  12 août 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Skip mode search based on reference frame consistency

  This commit enables the encoder to skip NEARMV and ZEROMV if the
  above and left blocks have identical reference frame, and the
  current reference is different from that. It reduces the runtime
  of speed 3 for test sequences :
  bus cif at 1000 kbps 10064 ms -> 9823 ms
  pedestrian 1080p at 2000 kbps 193078 ms -> 189559 ms

  The compression performance is changed by
  derf -0.085%
  stdhd -0.103%

  Change-Id : If304f26d42e6412152a84c3dd7b02635c38444f4

• 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.

• Revision 8350e7fe38 : Make intra prediction pointers RTCD-based. This probably has a mildly negative

  9 juillet 2013, par Ronald S. Bultje

  Changed Paths :
   Modify /vp9/common/vp9_reconintra.c

  
   Modify /vp9/common/vp9_rtcd_defs.sh

  
   Modify /vp9/common/x86/vp9_recon_sse2.asm

  
   Delete /vp9/common/x86/vp9_recon_wrapper_sse2.c

  
   Modify /vp9/encoder/vp9_mbgraph.c

  
   Modify /vp9/vp9_common.mk

  
  
  Make intra prediction pointers RTCD-based.

  This probably has a mildly negative impact on performance, but will
  (in future commits - or possibly merged with this one) allow SIMD
  implementations of individual intra prediction functions. We may
  perhaps want to consider having separate functions per txfm-size
  also (i.e. 4x4, 8x8, 16x16 and 32x32 intra prediction functions for
  each intra prediction mode), but I haven't played much with that
  yet.

  Change-Id : Ie739985eee0a3fcbb7aed29ee6910fdb653ea269