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• What is a correct way of ffmpeg dshow webcamera properties save and load ?

  12 juin 2020, par C0oo1D

  Command (PS == Windows PowerShell) :

  



  PS D:\> ffmpeg -f dshow -show_video_device_dialog True -video_device_save some_profile.txt -i 'video=MicrosoftR LifeCam Studio(TM)'


  



  FFmpeg Header :

  



  ffmpeg version git-2020-06-04-7f81785 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9.3.1 (GCC) 20200523
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 49.100 / 56. 49.100
  libavcodec     58. 90.100 / 58. 90.100
  libavformat    58. 44.100 / 58. 44.100
  libavdevice    58.  9.103 / 58.  9.103
  libavfilter     7. 84.100 /  7. 84.100
  libswscale      5.  6.101 /  5.  6.101
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100


  



  Error after OK/Cancel/Close in camera settings dialog (empty file was created). Also tried without dialog - the same problem :

  



  [dshow @ 0715de40] Query for IPersistStream failed.
video=Microsoft® LifeCam Studio(TM): I/O error


  



  I assume that problem at the camera side, but I don't exclude my blindness (didn’t find any examples of saving settings or required command options in the documentation).

  



  Perhaps there is another way to save / load webcamera properties ?

  


• Unexpected result from Python re.search for command line output

  23 mai 2020, par Fernando Ortega

  I'm using subprocess.Popen to run an ffmpeg command (in Windows) and then extract the part of the output that has the frame count with a regex expression using re.search. Sometimes, not always, I get the wrong result from search even if the printed command output string clearly shows what I expect.

  



  When I use re.findall I get 2 results, the "wrong" one and the expected one, but in the output string of the command I still only see one option. I'd like to understand why this is happening.

  



  Here's the code I'm running :

  



  import re
import subprocess

# path to video with 300 frames
cmd = r'ffmpeg -i C:\...\300frames_HUD.avi -map 0:v:0 -c copy -f null -'
p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
output_info = p.communicate()[0]

regex = r'(frame=\s*)([0-9]+)'
search_result = re.search(regex, output_info)
findall_result = re.findall(regex, output_info)
print "SEARCH"
print '0', search_result.group(0)
print '1', search_result.group(1)
print '2', search_result.group(2)

print "FIND ALL"
print findall_result


  



  Here are the results I get :

  



  SEARCH
0 frame=  293
1 frame=  
2 293
FIND ALL
[('frame=  ', '293'), ('frame=  ', '300')]


  



  And here is the printed output_info, the ffmpeg command output I'm searching on :

  



  ffmpeg version git-2020-03-15-c467328 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9.2.1 (GCC) 20200122
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 42.100 / 56. 42.100
  libavcodec     58. 75.100 / 58. 75.100
  libavformat    58. 41.100 / 58. 41.100
  libavdevice    58.  9.103 / 58.  9.103
  libavfilter     7. 77.100 /  7. 77.100
  libswscale      5.  6.101 /  5.  6.101
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100
Input #0, avi, from 'C:\...\300frames_HUD.avi':
  Duration: 00:00:10.00, start: 0.000000, bitrate: 373255 kb/s
    Stream #0:0: Video: rawvideo, bgr24, 960x540, 374496 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
    Metadata:
      title           : V
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf58.41.100
    Stream #0:0: Video: rawvideo, bgr24, 960x540, q=2-31, 374496 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
    Metadata:
      title           : V
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame=  300 fps=0.0 q=-1.0 Lsize=N/A time=00:00:10.00 bitrate=N/A speed=19.4x    
video:455625kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown


  



  I'm essentially looking for the 300 number in frame=  300.
I can reproduce this easily when I execute it inside my IDE (pycharm) twice in a row quickly.

  


• ffmpeg, lower fps with gpu - too many packets buffered

  29 mai 2020, par Alter

  I'm trying to lower the fps for a large set of videos. Unfortunately, I don't have much experience with ffmpeg

  



  This is my current command, which is a hybrid of multiple posts. At this point it's more guess work than anything else

  



  ffmpeg \
  -y -hwaccel_output_format cuda -hwaccel_device 0 -hwaccel cuvid -c:v mpeg2_cuvid \
  -i myinput.mp4 -r 25 -c:v hevc_nvenc-b:v 128K -strict -2 -movflags faststart \ 
  /workspace/videos/24fps_trial2/rat1-control2.mp4 -c:v hevc_nvenc


  



  The gist of it is just that I'm trying to lower fps and use hardware acceleration since my dataset is large

  



  The message I get is

  



  Trailing option(s) found in the command: may be ignored.
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x453a100] decoding for stream 0 failed
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x453a100] Could not find codec parameters for stream 0 (Video: mpeg2video (hvc1 / 0x31637668), none(tv), 2704x1520, 59946 kb/s): unspecified pixel format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/workspace/gs/Rat Controls Jan 2020 /Rat 1 Control 2 .MP4':
  Metadata:
    major_brand     : mp41
    minor_version   : 538120216
    compatible_brands: mp41
    creation_time   : 2020-01-07T09:45:34.000000Z
    firmware        : HD7.01.01.70.00
  Duration: 00:01:49.63, start: 0.000000, bitrate: 60202 kb/s
    Stream #0:0(eng): Video: mpeg2video (hvc1 / 0x31637668), none(tv), 2704x1520, 59946 kb/s, 119.88 fps, 119.88 tbr, 120k tbn, 120k tbc (default)
    Metadata:
      creation_time   : 2020-01-07T09:45:34.000000Z
      handler_name    : GoPro H.265
      encoder         : GoPro H.265 encoder
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s (default)
    Metadata:
      creation_time   : 2020-01-07T09:45:34.000000Z
      handler_name    : GoPro AAC
    Stream #0:2(eng): Data: bin_data (gpmd / 0x646D7067), 29 kb/s (default)
    Metadata:
      creation_time   : 2020-01-07T09:45:34.000000Z
      handler_name    : GoPro MET
    Stream #0:3(eng): Data: none (fdsc / 0x63736466), 21 kb/s (default)
    Metadata:
      creation_time   : 2020-01-07T09:45:34.000000Z
      handler_name    : GoPro SOS
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video (mpeg2_cuvid) -> hevc (hevc_nvenc))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
Too many packets buffered for output stream 0:1.
[aac @ 0x45bf880] Qavg: 746.362
[aac @ 0x45bf880] 2 frames left in the queue on closing
Conversion failed!