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• lavc/flacdsp : R-V V LPC16 function

  15 novembre 2023, par Rémi Denis-Courmont

  lavc/flacdsp : R-V V LPC16 function
  In this case, the inner loop computing the scalar product can be reduced
  
  to just one multiplication and one sum even with 128-bit vectors. The
  
  result is a lot simpler, but also brings more modest performance gains :
  flac_lpc_16_13_c :       15241.0
  
  flac_lpc_16_13_rvv_i32 : 11230.0
  
  flac_lpc_16_16_c :       17884.0
  
  flac_lpc_16_16_rvv_i32 : 12125.7
  
  flac_lpc_16_29_c :       27847.7
  
  flac_lpc_16_29_rvv_i32 : 10494.0
  
  flac_lpc_16_32_c :       30051.5
  
  flac_lpc_16_32_rvv_i32 : 10355.0
  

  • [DH] libavcodec/riscv/flacdsp_init.c
  • [DH] libavcodec/riscv/flacdsp_rvv.S

• how can I assign unique AVFoundation camera device names ?

  28 avril 2023, par mcgregor94086

  Short summary :
I have a USB multi-camera array device. According to system_profiler, each of these webcams share the same name : "USB Camera". I have no unique name I can use with FFMPEG AVFoundation and get images from that specific camera. How can I tell FFMPEG the specific camera that I want (each has a unique USB path that I normally use to identify a specific camera.

  


  I can solve this problem on Linux, but I can't figure out how to do it on macOS.

  


  How I might do this on Linux
I know the unique USB Path to each camera, and I would like to use this to assign a unique Name that I can address using FFMPEG when taking images. On Linux I can use the udev system to make those assignments,

  


  In Linux, I can reassign a new unique camera name using /etc/udev/rules.d/60-v4l.rules. with something like this :

  


  SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_1, ENVID_V4L_PRODUCT="Cam_00"
SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_3, ENVID_V4L_PRODUCT="Cam_01"
...

  


  More details :
Of course macOS doesn't work this way, as it uses AVFoundation to address video devices.

  


  When I attach the device I see that 16 new cameras now appear when I type query system_profiler SPCameraDataType, it prints the output shown further below

  


  You may notice that there are 16 cameras all named "USB Camera :" but system_profiler is reporting that each has a "Unique ID :" that is different for each camera. This Unique ID is composed of a unique USB Path (e.g. '0x1441311') concatenated with the "Vendor ID" ('00bda') and product ID ('5829') all expressed in hexadecimal.

  


  Unfortunately, this means every camera has the same generic name in iPhoto, and when specifying the input camera in FFMPEG with AVFoundation syntax, I can't seem to indicate which specific camera I want.

  


  I want to take 1 photo from each camera in a specific order. I have a table that maps each camera's USB Path to a desired name that would make it easy for me to trigger the camera captures in the sequence I desire.

  


  In Linux, I can reassign a new unique camera name using /etc/udev/rules.d/60-v4l.rules.

  


  SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_1, ENVID_V4L_PRODUCT="Cam_00"
SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_3, ENVID_V4L_PRODUCT="Cam_01"
...

  


  % system_profiler SPCameraDataType

  


  Camera :

  


  USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144131100bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144200000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141400bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144131300bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141300bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144121200bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144121400bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144133000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144131200bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141100bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144143000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144121300bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144110000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141200bda5829

FaceTime HD Camera (Built-in):

  Model ID: UVC Camera VendorID_1452 ProductID_34068
  Unique ID: 0x8020000005ac8514

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144300000bda5829


  


  MacBook Pro, OS X 10.11
Posted on Apr 27, 2023 10:49 PM
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• avfilter/vf_yadif_cuda : remove unnecessary private struct fields

  15 juin 2023, par Philip Langdale

  avfilter/vf_yadif_cuda : remove unnecessary private struct fields
  I'm not sure why I originally did this, but there's no good reason to
  
  put pointers to the cuda context and stream in the priv struct. They
  
  are directly available in the device context that is already being
  
  stored there.
  

  • [DH] libavfilter/vf_yadif_cuda.c