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• ffmpeg QSV hardware encoder with x11grab screen capture

  11 janvier 2020, par Toby Eggitt

  I believe I have built ffmpeg with support for my motherboard’s Intel graphics processor chip, but I have not succeeded in showing this working in any way. My goal is to use it for screen capture (the ffmpeg I built does capture screen successfully using the software encoding, but this is far too slow to be useful—it manages about 12fps at a very modest quality).

  My main problem—I think—is that I don’t know how to use these encoders, the examples I found all fail, which makes me suspect that what I’ve built is broken in some way. However, I also have no idea how I can verify that I built this correctly, but the following are true :

  • The five components that I built to get to this all compiled without
    errors (they were libva, gmmlib, intel-media-driver, libmfx, and
    ffmpeg
  • The output of ffmpeg -encoders includes four encoders with _qsv in
    their names including h264_qsv
  • Most of the commands I have tried result in output of this form :

      [h264_qsv @ 0x55ef1dc72040] Low power mode is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current frame rate is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current picture structure is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current resolution is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current pixel format is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] some encoding parameters are not supported by the QSV runtime. Please double check the input parameters.
  
      Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  I have the impression this thing might be fussy about many parameters of this sort but have no idea where to find out what it would like. Any suggestions at all, how to verify it, or better yet, how to issue a command that captures screen and encodes with the hardware, would be most welcome.

• lavc/h264dsp : optimise R-V V weight for shorter heights

  1er septembre 2024, par Rémi Denis-Courmont

  lavc/h264dsp : optimise R-V V weight for shorter heights
  The height is a power of two of up to 16 rows. The current code was
  
  optimised for large sample counts.
  T-Head C908 :
  
  h264_weight2_8_c :                                      211.7 ( 1.00x)
  
  h264_weight2_8_rvv_i32 :                   before       184.0 ( 1.15x)
  
  h264_weight2_8_rvv_i32 :                   after         54.2 ( 3.90x)
  
  h264_weight4_8_c :                                      285.7 ( 1.00x)
  
  h264_weight4_8_rvv_i32 :                   before       341.2 ( 0.86x)
  
  h264_weight4_8_rvv_i32 :                   after         82.2 ( 3.47x)
  
  h264_weight8_8_c :                                      498.7 ( 1.00x)
  
  h264_weight8_8_rvv_i32 :                   before       683.7 ( 0.73x)
  
  h264_weight8_8_rvv_i64 :                   after        128.5 ( 3.95x)
  
  h264_weight16_8_c :                                     878.2 ( 1.00x)
  
  h264_weight16_8_rvv_i32 :                  unchanged    239.5 ( 3.67x)
  SpacemiT X60 :
  
  h264_weight2_8_c :                                      207.2 ( 1.00x)
  
  h264_weight2_8_rvv_i32 :                   before       259.6 ( 0.80x)
  
  h264_weight2_8_rvv_i32 :                   after         82.2 ( 2.52x)
  
  h264_weight4_8_c :                                      290.8 ( 1.00x)
  
  h264_weight4_8_rvv_i32 :                   before       509.6 ( 0.57x)
  
  h264_weight4_8_rvv_i32 :                   after         61.5 ( 4.73x)
  
  h264_weight8_8_c :                                      498.8 ( 1.00x)
  
  h264_weight8_8_rvv_i32 :                   before      1019.8 ( 0.49x)
  
  h264_weight8_8_rvv_i64 :                   after         71.8 ( 6.95x)
  
  h264_weight16_8_c :                                     874.0 ( 1.00x)
  
  h264_weight16_8_rvv_i32 :                  unchanged    249.0 ( 3.51x)
  

  • [DH] libavcodec/riscv/h264dsp_init.c
  • [DH] libavcodec/riscv/h264dsp_rvv.S

• How to take snapshot with multiple web cameras at the same time using PHP in Centos ?

  13 novembre 2014, par galengodis

  I’m trying to take still photos / snapshots with multiple web cameras at the same time through php / shell_execute.

  This is what I use so I can the cameras in the background.

  shell_exec('ffmpeg -f video4linux2 -s 1280x960 -i /dev/video0 -q:v 0 -b:v 10000k -vcodec mjpeg -vframes 1 /var/www/html/cam1.jpg -y > /dev/null 2>/dev/null &');
  
  
  
  shell_exec('ffmpeg -f video4linux2 -s 1280x960 -i /dev/video1 -q:v 0 -b:v 10000k -vcodec mjpeg -vframes 1 /var/www/html/cam2.jpg -y > /dev/null 2>/dev/null &');

  It outputs only one image from the cameras. If i run them one at a time with the same code everything works. Fyi the "&" at the end makes the php run in background. Read more here about shell_exec background process : Is there a way to use shell_exec without waiting for the command to complete ?

  > [root@localhost ~]# lsusb 
  
  > Bus 001 Device 002: ID 8087:8000 Intel Corp.
  
  > Bus 002 Device 004: ID 1a40:0201 Terminus Technology Inc. FE 2.1
  
  > 7-port Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root
  
  > hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus
  
  > 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002
  
  > Device 006: ID 046d:0825 Logitech, Inc. Webcam C270 Bus 002 Device
  
  > 005: ID 0c45:6340 Microdia
  
  > 
  
  > [root@localhost ~]# find /dev/bus/ /dev/bus/ /dev/bus/usb
  
  > /dev/bus/usb/003 /dev/bus/usb/003/001 /dev/bus/usb/002
  
  > /dev/bus/usb/002/006 /dev/bus/usb/002/005 /dev/bus/usb/002/004
  
  > /dev/bus/usb/002/001 /dev/bus/usb/001 /dev/bus/usb/001/002
  
  > /dev/bus/usb/001/001

  I’ve tried with altering applications between ffmpeg and streamer. So the problem seems to be USB-related. The both cameras are plugged into a USB-hub (with an external power supply). The cameras are of different brands.

  I’m on Centos 7, 64bit.