Sur d’autres sites (11243)

• Desktop grabbing with FFmpeg at 60 fps using NVENC codec

  5 juillet 2016, par Akatosh

  I’m having trouble recording my desktop at 60FPS using the latest Windows compiled FFmpeg with NVENC codec. Metadata says the file is 60 fps but when I play it, I can see clearly see it is not 60FPS.

  The command-line I use is the following :

  ffmpeg -y -rtbufsize 2000M -f gdigrab -framerate 60 -offset_x 0 -offset_y 0 -video_size 1920x1080 -i desktop -c:v h264_nvenc -preset:v fast -pix_fmt nv12 out.mp4

  I tried using a real time buffer, using another DirectShow device, changing the profile or forcing a bitrate, but the video always seems to be at 30fps.

  Recording the screen using NVIDIA’s ShadowPlay works well, so I know it’s feasible on my machine.

  Using FFprobe to check the ShadowPlay’s output file I can see :

  Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p(tv,
  smpte170m/smpte170m/bt470m), 1920x1080 [SAR 1:1 DAR 16:9], 4573 kb/s,
  59.38 fps, 240 tbr, 60k tbn, 120 tbc (default)

  But If I force my output to have the same bitrate and profile I get :

  Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p,
  1920x1080 [SAR 1:1 DAR 16:9], 5519 kb/s, 60 fps, 60 tbr, 15360 tbn,
  120 tbc (default)

  I can see tbr and tbn are different, so I know my output is duplicating frames.

  For testing, all of my recordings had this 60 frame rate test page on the background, and I could clearly see the differences.

  I know ShadowPlay probably does a lot more under the hood than FFmpeg using the same codec. I know OBS can do it quite easily but I want to understand what I am doing wrong. Maybe it’s some FFmpeg limitation ?

  Full console output

  Using -v trace command :

  [gdigrab @ 0000000002572cc0] Capturing whole desktop as 1920x1080x32 at (0,0)
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1850,750) -> (1842,741)
  
  [gdigrab @ 0000000002572cc0] Probe buffer size limit of 5000000 bytes reached
  
  [gdigrab @ 0000000002572cc0] Stream #0: not enough frames to estimate rate; consider increasing probesize
  
  [gdigrab @ 0000000002572cc0] stream 0: start_time: 1467123648.275 duration: -9223372036854.775
  
  [gdigrab @ 0000000002572cc0] format: start_time: 1467123648.275 duration: -9223372036854.775 bitrate=3981337 kb/s
  
  Input #0, gdigrab, from 'desktop':
  
    Duration: N/A, start: 1467123648.275484, bitrate: 3981337 kb/s
  
      Stream #0:0, 1, 1/1000000: Video: bmp, 1 reference frame, bgra, 1920x1080 (0x0), 0/1, 3981337 kb/s, 60 fps, 1000k tbr, 1000k tbn, 1000k tbc
  
  Successfully opened the file.
  
  Parsing a group of options: output file out.mp4.
  
  Applying option c:v (codec name) with argument h264_nvenc.
  
  Applying option pix_fmt (set pixel format) with argument nv12.
  
  Successfully parsed a group of options.
  
  Opening an output file: out.mp4.
  
  [file @ 0000000000e3a7c0] Setting default whitelist 'file,crypto'
  
  Successfully opened the file.
  
  detected 8 logical cores
  
  [graph 0 input from stream 0:0 @ 000000000257ec00] Setting 'video_size' to value '1920x1080'
  
  [graph 0 input from stream 0:0 @ 000000000257ec00] Setting 'pix_fmt' to value '30'
  
  [graph 0 input from stream 0:0 @ 000000000257ec00] Setting 'time_base' to value '1/1000000'
  
  [graph 0 input from stream 0:0 @ 000000000257ec00] Setting 'pixel_aspect' to value '0/1'
  
  [graph 0 input from stream 0:0 @ 000000000257ec00] Setting 'sws_param' to value 'flags=2'
  
  [graph 0 input from stream 0:0 @ 000000000257ec00] Setting 'frame_rate' to value '60/1'
  
  [graph 0 input from stream 0:0 @ 000000000257ec00] w:1920 h:1080 pixfmt:bgra tb:1/1000000 fr:60/1 sar:0/1 sws_param:flags=2
  
  [format @ 000000000257ffc0] compat: called with args=[nv12]
  
  [format @ 000000000257ffc0] Setting 'pix_fmts' to value 'nv12'
  
  [auto-inserted scaler 0 @ 00000000025802c0] Setting 'flags' to value 'bicubic'
  
  [auto-inserted scaler 0 @ 00000000025802c0] w:iw h:ih flags:'bicubic' interl:0
  
  [format @ 000000000257ffc0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'Parsed_null_0' and the filter 'format'
  
  [AVFilterGraph @ 0000000000e373c0] query_formats: 4 queried, 2 merged, 1 already done, 0 delayed
  
  [auto-inserted scaler 0 @ 00000000025802c0] w:1920 h:1080 fmt:bgra sar:0/1 -> w:1920 h:1080 fmt:nv12 sar:0/1 flags:0x4
  
  [h264_nvenc @ 0000000000e3ca20] Nvenc initialized successfully
  
  [h264_nvenc @ 0000000000e3ca20] 1 CUDA capable devices found
  
  [h264_nvenc @ 0000000000e3ca20] [ GPU #0 - < GeForce GTX 670 > has Compute SM 3.0 ]
  
  [h264_nvenc @ 0000000000e3ca20] supports NVENC
  
  [mp4 @ 0000000000e3b580] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
  
  Output #0, mp4, to 'out.mp4':
  
    Metadata:
  
      encoder         : Lavf57.40.101
  
      Stream #0:0, 0, 1/15360: Video: h264 (h264_nvenc) (Main), 1 reference frame ([33][0][0][0] / 0x0021), nv12, 1920x1080, 0/1, q=-1--1, 2000 kb/s, 60 fps, 15360 tbn, 60 tbc
  
      Metadata:
  
        encoder         : Lavc57.47.100 h264_nvenc
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/2000000 buffer size: 4000000 vbv_delay: -1
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (bmp (native) -> h264 (h264_nvenc))
  
  Press [q] to stop, [?] for help
  
  cur_dts is invalid (this is harmless if it occurs once at the start per stream)
  
  Clipping frame in rate conversion by 0.000008
  
  cur_dts is invalid (this is harmless if it occurs once at the start per stream)
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1850,750) -> (1842,741)
  
  *** 35 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1850,750) -> (1842,741)
  
  *** 7 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1850,649) -> (1850,649)
  
  *** 1 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1858,535) -> (1858,535)
  
  *** 3 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1859,454) -> (1859,454)
  
  *** 2 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1865,384) -> (1865,384)
  
  *** 2 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1846,348) -> (1846,348)
  
  *** 3 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1770,347) -> (1770,347)
  
  *** 2 dup!
  
  [gdigrab @ 0000000002572cc0] Cursor pos (1545,388) -> (1545,388)
  
  *** 4 dup!
  
  frame=   69 fps=0.0 q=35.0 size=     184kB time=00:00:00.63 bitrate=2384.0kbits/[gdigrab @ 0000000002572cc0] Cursor pos (1523,389) -> (1519,378)

• Evolution #4156 (En cours) : filtre mult() : warning non numeric value

  4 septembre 2018, par b b

  Le problème semble réglé et il y a une alternative proposée par marcimat, on peut fermer le ticket ?

• Evolution #3603 : Ergonomie des onglets de sélection des plugins

  21 avril 2020, par b b

  Oui j’ai vu, très bien, je ne fais que proposer une formule alternative à "mises à jour seulment (3)" ^^