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• how to get 120fps encoded video to play at "normal" speed instead of slow mo

  1er mars 2023, par Patrick Vellia

  I used my GoPro Hero10 to record at 4k 120fps on a green screen. This original video plays slo-mo in QuickTime but "normal" speed in the browser. I want it playing normal speed, and if end user wants to slow it down they have the extra frames for that to maintain clarity, which is why I record at 120.

  


  I then used FFMPEG to create an image sequence of the video.

  


  Then I ran Image Magic to create the transparent frames.

  


  Then I put it back together with the following command for a HEVC mov file :

  


  ffmpeg -r 120 -f image2 -i transparent/image_transparent_%08d.png -vcodec hevc_videotoolbox -crf 28 -alpha_quality 1  -tag:v hvc1 output.mov


  


  I am still on an Intel MacBook Pro running FFMPEG 4.6 (as I've found 5+ was buggy with one of my commands a few months ago but can't remember which one, I think it was the videotoolbox).

  


  The GoPro video has the following stream data as input to the FFMPEG :

  


  Duration: 00:00:08.15, start: 0.000000, bitrate: 60160 kb/s
  Stream #0:0(eng): Video: hevc (Main) (hvc1 / 0x31637668), yuvj420p(pc, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 59891 kb/s, 119.88 fps, 119.88 tbr, 120k tbn, 119.88 tbc (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro H.265
      vendor_id       : [0][0][0][0]
      encoder         : GoPro H.265 encoder
      timecode        : 19:05:32:105
  Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro AAC  
      vendor_id       : [0][0][0][0]
      timecode        : 19:05:32:105
  Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro TCD  
      timecode        : 19:05:32:105
  Stream #0:3(eng): Data: bin_data (gpmd / 0x646D7067), 76 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro MET  


  


  Whereas the re-constructed video has the following data :

  


  Duration: 00:00:08.13, start: 0.000000, bitrate: 763650 kb/s
  Stream #0:0: Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, progressive), 3840x2160 [SAR 1:1 DAR 16:9], 763696 kb/s, 120 fps, 120 tbr, 15360 tbn, 15360 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : FFMP
      encoder         : Lavc58.134.100 hevc_videotoolbo


  


  When this re-constructed video plays in the browser, it is in slow-mo and I need to set the playbackRate to 4.0 for it to play "normally".

  


  Is there something I need to add to the video for the browser to play it at "normal" speed ?

  


  EDIT

  


  I just compared the two video streams :

  


  original:
Stream #0:0(eng): Video: hevc (Main) (hvc1 / 0x31637668), yuvj420p(pc, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 59891 kb/s, 119.88 fps, 119.88 tbr, 120k tbn, 119.88 tbc (default)

Reconstructed:
 Stream #0:0: Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, progressive), 3840x2160 [SAR 1:1 DAR 16:9], 763696 kb/s, 120 fps, 120 tbr, 15360 tbn, 15360 tbc (default)


  


  I don't quit understand all of this though. so here's what I notice :

  


  original.         reconstructed
--------------------------------
bt709             progressive
89871 kb/s.       763696 kb/s
119.88 fps.       120 fps
119.88 tbr.       120 tbr
120k tbr.         15360 tbr
11960 tbr.        15360 tbc


  


  Hmm. I suspect it has something to do with tbr and tbc whatever those are, or perhaps the progressive vs the bt709 ? the pirates are also vastly different.

  


• 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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how can I assign unique AVFoundation camera device names ?
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• Why ffmpeg concat results wrong fps ? How to avoid it ?

  29 avril 2024, par Jinglong

  I have several mp4 video files and want to concat there video streams into a new mp4 file. The command I used shows below :

  


  ffmpeg -f concat -safe 0 -i concat.txt -an -c:v copy -y out.mp4


  


  The fps of result does not meet expectations.

  


  For example, there are two input wrote in concat.txt :

  


  file temp_result_0.mp4
file temp_result_1.mp4


  


  




  


  


  


  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  file	duration	number of frames	fps	tbr
  temp_result_0.mp4	60.0	1200	20	20
  temp_result_0.mp4	0.1	2	20	20
  out.mp4	60.1	1202	19.97	20

  


  The out.mp4 has correct duration, nb_frames but wrong avg_frame_rate (expecting 20 but get 6010/301).

  


  ng01@MacBook-Pro-3 Downloads % ffprobe -select_streams v:0 -show_entries stream=r_frame_rate,avg_frame_rate,nb_frames,duration out.mp4
ffprobe version 7.0 Copyright (c) 2007-2024 the FFmpeg developers
  built with Apple clang version 15.0.0 (clang-1500.3.9.4)
  configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.0 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopenvino --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
  libavutil      59.  8.100 / 59.  8.100
  libavcodec     61.  3.100 / 61.  3.100
  libavformat    61.  1.100 / 61.  1.100
  libavdevice    61.  1.100 / 61.  1.100
  libavfilter    10.  1.100 / 10.  1.100
  libswscale      8.  1.100 /  8.  1.100
  libswresample   5.  1.100 /  5.  1.100
  libpostproc    58.  1.100 / 58.  1.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'out.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf60.14.100
  Duration: 00:01:00.10, start: 0.000000, bitrate: 1645 kb/s
  Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 1080x1920 [SAR 1:1 DAR 9:16], 1643 kb/s, 19.97 fps, 20 tbr, 10240 tbn (default)
      Metadata:
        handler_name    : VideoHandler
        vendor_id       : [0][0][0][0]
[STREAM]
r_frame_rate=20/1
avg_frame_rate=6010/301
duration=60.100000
nb_frames=1202
[/STREAM]


  


  I tried use lower version 4.1.3 of ffmpeg, the result has wrong fps and wrong duration. expectation duration is 60.10 but get 60.20