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• Saving highest quality video from video-capture card

  23 décembre 2013, par DusteD

  I have a machine with 2x3 3ghz dual-core xeon and 4x10krpm scsi 320 disks in raid0.
  The capture card is an osprey 560 64 bit pci card.
  Operating system is currently Windows Server 2003.

  The video-stream that I can open with VLC using direct show is rather nice quality.
  However, trying to save this video-stream without loss of quality has proven quite difficult,
  using the h264 codec I am able to achieve a satisfying quality, however, all 4 cores jump to 100% load after a few second and then it start dropping frames, the machine is not powerful enough for realtime encoding. I've not been able to achieve satisfying mpeg1 or 4 quality, no matter which bitrate I set..

  Thing is, the disks in this machine are pretty fast even by todays standard, and they are bored.. I don't care about disk-usage, I want quality.
  I have searched in vain for a way to pump that beautiful videostream that I see in VLC onto the disk for later encoding, I reckon the disks would be fast enough, or maybe something which would apply a light compression, enough that the disks can keep up, but not so much as to loose visible quality.

  I have tried FFMPEG as it seems capable of streaming a yuv4 stream down to the disk, but ofcause FFMPEG is unable to open the dshow device ( same error as this guy Ffmpeg streaming from capturing device Osprey 450e fails )

  Please recommend a capable and (preferably) software which can do this.

• ffmpeg converting mp4 to gif with color palette results in truncated video

  6 décembre 2019, par Tik0

  I want to generate a gif from my mp4 movie with ffmpeg (ffmpeg version 2.8.15-0ubuntu0.16.04.1) using a color palette. Everything works fine if I do not use a palette :

  $ ffmpeg -i in.mp4 -filter_complex "scale=160:-1" out.gif
  
  ...
  
  frame= 2003 fps=251 q=-0.0 Lsize=   21172kB time=00:01:20.12 bitrate=2164.7kbits/s    
  
  video:21155kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.077667%

  But using a palette like so results in Buffer queue overflow, dropping messages and a truncated video

  $ ffmpeg -i in.mp4 -filter_complex "[0:v] scale=160:-1, split [a][b];[a] palettegen [p];[b][p] paletteuse" out.gif
  
  ....
  
  [Parsed_paletteuse_3 @ 0xc56de0] [framesync @ 0xd1af08] Buffer queue overflow, dropping.
  
  Last message repeated 36 times
  
  [Parsed_paletteuse_3 @ 0xc56de0] [framesync @ 0xd1af08] Buffer queue overflow, dropping.
  
  Last message repeated 106 times
  
  ...
  
  [Parsed_palettegen_2 @ 0xc56d40] 255(+1) colors generated out of 1347441 colors; ratio=0.000189
  
  frame=   65 fps=5.4 q=-0.0 Lsize=    1036kB time=00:01:20.12 bitrate= 105.9kbits/s    
  
  video:1035kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.124664%

• aarch64 : hevc : Produce epel_uni_w_hv functions for both neon and i8mm

  20 mars 2024, par Martin Storsjö

  aarch64 : hevc : Produce epel_uni_w_hv functions for both neon and i8mm
  AWS Graviton 3 :
  
  put_hevc_epel_uni_w_hv4_8_c : 191.2
  
  put_hevc_epel_uni_w_hv4_8_neon : 87.7
  
  put_hevc_epel_uni_w_hv4_8_i8mm : 83.2
  
  put_hevc_epel_uni_w_hv6_8_c : 349.5
  
  put_hevc_epel_uni_w_hv6_8_neon : 153.0
  
  put_hevc_epel_uni_w_hv6_8_i8mm : 148.5
  
  put_hevc_epel_uni_w_hv8_8_c : 581.2
  
  put_hevc_epel_uni_w_hv8_8_neon : 166.7
  
  put_hevc_epel_uni_w_hv8_8_i8mm : 163.5
  
  put_hevc_epel_uni_w_hv12_8_c : 1230.0
  
  put_hevc_epel_uni_w_hv12_8_neon : 387.7
  
  put_hevc_epel_uni_w_hv12_8_i8mm : 370.2
  
  put_hevc_epel_uni_w_hv16_8_c : 2003.2
  
  put_hevc_epel_uni_w_hv16_8_neon : 501.5
  
  put_hevc_epel_uni_w_hv16_8_i8mm : 490.2
  
  put_hevc_epel_uni_w_hv24_8_c : 4448.7
  
  put_hevc_epel_uni_w_hv24_8_neon : 1092.2
  
  put_hevc_epel_uni_w_hv24_8_i8mm : 1069.7
  
  put_hevc_epel_uni_w_hv32_8_c : 7817.2
  
  put_hevc_epel_uni_w_hv32_8_neon : 1916.2
  
  put_hevc_epel_uni_w_hv32_8_i8mm : 1829.5
  
  put_hevc_epel_uni_w_hv48_8_c : 16728.2
  
  put_hevc_epel_uni_w_hv48_8_neon : 4263.7
  
  put_hevc_epel_uni_w_hv48_8_i8mm : 4342.7
  
  put_hevc_epel_uni_w_hv64_8_c : 29563.2
  
  put_hevc_epel_uni_w_hv64_8_neon : 7474.2
  
  put_hevc_epel_uni_w_hv64_8_i8mm : 7128.5
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/aarch64/hevcdsp_epel_neon.S
  • [DH] libavcodec/aarch64/hevcdsp_init_aarch64.c