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• Generate individual HLS-compatible .ts segments on-demand by downloading as little bytes as possible from a remote input file

  27 janvier 2017, par Romain Cointepas

  I’m trying to generate individual HLS-compatible .ts segments on-demand by downloading/reading as little bytes as possible from a remote input file (hosted on a server supporting byte-ranges requests).

  One of the application for this would be to be able to transcode and play on Apple TV (via Airplay) a remote file that is not Airplay compatible, without having to download the entire file first.

  I am generating the playlist myself, and I have access to the ffprobe results for the remote file (that gives video duration, etc.).

  I have something working that plays via Airplay but with small video and audio glitches between each segments when I use the following command to generate each segment :

  ffmpeg -ss 60 -t 6 -i http://s3.amazonaws.com/misc-12345/avicii.vob -f mpegts -map 0:v:0 -map 0:a:0 -c:v libx264 -bsf:v h264_mp4toannexb -force_key_frames "expr:gte(t,n_forced*6)" -forced-idr 1 -pix_fmt yuv420p -colorspace bt709 -c:a aac -async 1 -preset ultrafast pipe:1

  Note : above command is for segment 11.ts, and in the m3u8 playlist I advertise each segment duration as 6 seconds.

  Here is a Youtube video showing the audio/video glitches between segments :
  https://www.youtube.com/watch?v=0vMwgbSfsu0

  The segment or hls modules of ffmpeg can’t be used because they both generate all the segments at once.

  I’ve been struggling on this for some days now and I would really appreciate some help !

• Web camera Logitech and Linux

  8 novembre 2019, par Nick Saw

  I have Logitech C310 camera with the declared characteristics of 720p 30fps.

  If you connect the camera to windows, the recording is fully consistent with the stated 720p 30fps - the picture is clear.

  The challenge is to connect the same camera to OrangePI (server Armbian) and to save video files on it.

  The camera appears as /dev/video0.

  sudo ffmpeg -f v4l2 -s 1280x720 -i /dev/video0 output.wmv

  As a result, I get a crumbly picture with a frequency of 5 fps.

  Maybe I’m using ffmpeg incorrectly ? Please help me who has experience with Web cameras on Linux ...
  Thanks in advance.

  USB-camera configuration :

  v4l2-ctl --all --device=/dev/video0
  
  
  
  
  
  Driver Info (not using libv4l2):
  
          Driver name   : uvcvideo
  
          Card type     : UVC Camera (046d:081b)
  
          Bus info      : usb-1c1c000.usb-1
  
          Driver version: 4.14.18
  
          Capabilities  : 0x84200001
  
                  Video Capture
  
                  Streaming
  
                  Extended Pix Format
  
                  Device Capabilities
  
          Device Caps   : 0x04200001
  
                  Video Capture
  
                  Streaming
  
                  Extended Pix Format
  
  Priority: 2
  
  Video input : 0 (Camera 1: ok)
  
  Format Video Capture:
  
          Width/Height      : 1280/720
  
          Pixel Format      : 'YUYV'
  
          Field             : None
  
          Bytes per Line    : 2560
  
          Size Image        : 1843200
  
          Colorspace        : sRGB
  
          Transfer Function : Default
  
          YCbCr/HSV Encoding: Default
  
          Quantization      : Default
  
          Flags             :
  
  Crop Capability Video Capture:
  
          Bounds      : Left 0, Top 0, Width 1280, Height 720
  
          Default     : Left 0, Top 0, Width 1280, Height 720
  
          Pixel Aspect: 1/1
  
  Selection: crop_default, Left 0, Top 0, Width 1280, Height 720
  
  Selection: crop_bounds, Left 0, Top 0, Width 1280, Height 720
  
  Streaming Parameters Video Capture:
  
          Capabilities     : timeperframe
  
          Frames per second: 5.000 (5/1)
  
          Read buffers     : 0
  
                       brightness (int)    : min=0 max=255 step=1 default=128 value=128
  
                         contrast (int)    : min=0 max=255 step=1 default=32 value=32
  
                       saturation (int)    : min=0 max=255 step=1 default=32 value=32
  
   white_balance_temperature_auto (bool)   : default=1 value=1
  
                             gain (int)    : min=0 max=255 step=1 default=64 value=192
  
             power_line_frequency (menu)   : min=0 max=2 default=2 value=2
  
        white_balance_temperature (int)    : min=0 max=10000 step=10 default=4000 value=4610 flags=inactive
  
                        sharpness (int)    : min=0 max=255 step=1 default=24 value=24
  
           backlight_compensation (int)    : min=0 max=1 step=1 default=0 value=0
  
                    exposure_auto (menu)   : min=0 max=3 default=3 value=3
  
                exposure_absolute (int)    : min=1 max=10000 step=1 default=166 value=249 flags=inactive
  
           exposure_auto_priority (bool)   : default=0 value=1
  
                        led1_mode (menu)   : min=0 max=3 default=3 value=3
  
                   led1_frequency (int)    : min=0 max=131 step=1 default=0 value=0

• Anomalie #3058 (Nouveau) : Incohérence sur le statut de webmestre nécessaire pour désinstaller un ...

  21 septembre 2013, par Maïeul Rouquette

  Sous SPIP 3.0.11
  - on teste le statut de webmestre pour le bouton de déinstall de plugin lié à chaque plugin
  - on ne le teste pas pour l’option de désactivation dans le menu déroulant