• Broadcasting

  Livestream – dropped frames in recorded video

  Posted by Marina Cotrim on March 30, 2017 at 8:38 pm

  Hi everyone,

  Where I work, we use Livestream Studio to capture videos from a broadcast camera.
  We’ve been using the same set up in a few months, but recently we are having problems with dropped frames.
  At some point in the video (wich normally has 20-30 minutes), the audio “crackles”, the sync is lost, and we notice that there was a jump in the video.
  Then the video continues ok, the audio is delayed by some frames.

  I looked at the file info with Media Info and here’s what I got:

  General
  Complete name : 03-03.mp4
  Format : MPEG-4
  Format profile : Base Media
  Codec ID : isom
  File size : 1.46 GiB
  Duration : 25mn 12s
  Overall bit rate mode : Variable
  Overall bit rate : 8 307 Kbps
  Encoded date : UTC 2017-03-06 11:44:41
  Tagged date : UTC 2017-03-18 18:39:15

  Video
  ID : 1
  Format : AVC
  Format/Info : Advanced Video Codec
  Format profile : High@L4.0
  Format settings, CABAC : Yes
  Format settings, ReFrames : 1 frame
  Format settings, GOP : M=1, N=60
  Codec ID : avc1
  Codec ID/Info : Advanced Video Coding
  Duration : 25mn 12s
  Bit rate mode : Variable
  Bit rate : 7 983 Kbps
  Maximum bit rate : 12.1 Mbps
  Width : 1 920 pixels
  Height : 1 080 pixels
  Display aspect ratio : 16:9
  Frame rate mode : Variable
  Frame rate : 29.970 fps
  Minimum frame rate : 9.990 fps
  Maximum frame rate : 29.970 fps
  Color space : YUV
  Chroma subsampling : 4:2:0
  Bit depth : 8 bits
  Scan type : Progressive
  Bits/(Pixel*Frame) : 0.128
  Stream size : 1.41 GiB (96%)
  Language : English
  Encoded date : UTC 2017-03-06 11:44:41
  Tagged date : UTC 2017-03-06 11:44:41

  Audio
  ID : 2
  Format : AAC
  Format/Info : Advanced Audio Codec
  Format profile : LC
  Codec ID : 40
  Duration : 25mn 12s
  Bit rate mode : Variable
  Bit rate : 320 Kbps
  Channel(s) : 2 channels
  Channel positions : Front: L R
  Sampling rate : 44.1 KHz
  Compression mode : Lossy
  Stream size : 57.7 MiB (4%)
  Language : English
  Encoded date : UTC 2017-03-06 11:44:41
  Tagged date : UTC 2017-03-06 11:44:41

  I noticed the framerate is variable, but i’m sure that the reason for that is the dropped frames. When the problem doesn’t happen, the framerate is constant.
  Also, it’s not an internet issue, because i’m not livestreaming (and even offline sometimes).

  Does anyone has any ideas on how to fix it?
  Thank you!

  Marina Cotrim replied 9 years, 1 month ago 1 Member · 0 Replies
• 0 Replies

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