Recherche avancée

Sur d’autres sites (12498)

• hwcontext_vulkan : initialize semaphores of DMABUF imports

  12 mars 2020, par Lynne

  hwcontext_vulkan : initialize semaphores of DMABUF imports
  There was a recent change in Intel's driver that triggered a driver-internal
  
  error if the semaphore given to the command buffer wasn't initialized.
  
  Given that the specifications require the semaphore to be initialized,
  
  this is within spec. Unlike what's causing it in the first place, which is
  
  that there are no ways to extract/import dma sync objects from DMABUFs,
  
  so we must leave our semaphores bare.
  

  • [DH] libavutil/hwcontext_vulkan.c

• Failed to hard-ware accelerate video decoding via Tesla P40

  20 mai 2018, par Potemkin

  While I am writing a surveillance video recognition demo, I find it is much slower to simply play a video in the server(Xeon E5-2680 2.4GHz, Tesla P40) than in my laptop(i7-8550 1.8GHz, Intel UHD Graphics 620).

  I use DXVA-Checker to see the video decoder device, and notice that my laptop use the GPU for decoding, but the server use no GPU for the job. Then I check ’nvidia-smi’, and it shows all of GPUs are running in TCC driver model, not WDDM driver model. And I cannot turn it to WDDM because nvidia-smi says it is not supported.

  The video play demo is written via OPENCV, in which the video decoding part is from ffmpeg. The server runs in Windows-server-2012, and my laptop is on Windows 10.

  The question is how can I get the server decoding videos with GPUs, and is this the reason for the slowness or there is something else ?

• Vc1 video playback jerking

  12 novembre 2015, par kopalvich

  I’m trying to play vc1 coded video in matroska container.

  For that I’m using ffmpeg’s av_read_frame function and a sertain video driver, which requires AVPacket’s data to be prefixed by PES header.
  In AVPacket only dts field is valid, pts is AV_NOPTS_VALUE. I write dts value into PES header instead of pts.

  Video driver logs constant framerate change from 23976 to 24000 and vice versa. The video jerks. Although I put framerate into PES header (value 23976 is what ffmpeg’s probing gives), but apparently, it’s changing according to current packet’s pts.

  I tried to look at AVCodecParserContext’s pts_dts_delta and dts_ref_dts_delta but they are of AV_NOPTS_VALUE, its pts and dts are the same as of AVPacket

  Please advise how to get proper pts values, or what to do to solve it.

  Thanks.

  EDIT :
  I saw in ffplay.c they use av_frame_get_best_effort_timestamp but that’s after decoding by ffmpeg’s means, which I cannot afford.