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• ffmpeg - Timecode & Fractional Frame Rate (Duplicating Frames)

  29 mars 2018, par Nimble

  I record two different frame rates using ffmpeg, 60 and 100. Or at least I thought I was recording 60 and 100, now it seems it’s actually 59.94 and 99.98.

  Here is the command I was using :

  ffmpeg -y -thread_queue_size 9999 -guess_layout_max 0 -f dshow -video_size 1920x1080 -rtbufsize 2147.48M -framerate 60 ^
  
  -pixel_format yuyv422 -i video="Game Capture HD60 S (Video) (#01)":audio="ADAT (5+6) (RME Fireface UC)" -map 0:0,0:1 ^
  
  -map 0:1 -c:v h264_nvenc -preset: llhp -pix_fmt yuv420p -b:v 40M -minrate 40M -maxrate 40M -bufsize 40M -b:a 384k -ac 2 ^
  
  -r 60 -af "pan=mono|c0=c0, adelay=84" -vsync 1 -max_muxing_queue_size 9999 -f segment -segment_time 600 ^
  
  -segment_wrap 9 -reset_timestamps 1 C:\Users\djcim\Videos\PC\Camera\CPC%02d.ts ^
  
  -thread_queue_size 9999 -f dshow -video_size 3440x1440 -rtbufsize 2147.48M -framerate 100 -pixel_format nv12 ^
  
  -itsoffset 00:00:00.215 -i video="Video (00 Pro Capture HDMI 4K+)" -thread_queue_size 9999 -guess_layout_max 0 -f dshow ^
  
  -rtbufsize 2147.48M -i audio="SPDIF/ADAT (1+2) (RME Fireface UC)" -map 1:0,2:0 -map 6:0 -c:v h264_nvenc -preset: llhp ^
  
  -pix_fmt nv12 -b:v 250M -minrate 250M -maxrate 250M -bufsize 250M -b:a 384k -ac 2 -r 100 -af "adelay=141|141" -vsync 1 ^
  
  -max_muxing_queue_size 9999 -f segment -segment_time 600 -segment_wrap 9 -reset_timestamps 1 ^
  
  C:\Users\djcim\Videos\PC\PC\PC%02d.ts

  I thought all was well with my frame rates, sure ffmpeg was duplicating frames every once in a while, but I thought it was just a random occurrence caused by ffmpeg dropping a frame during processing and therefore needed to duplicate one to make it up. I didn’t think duplicating a few frames would be noticeable in the footage... until I was reviewing some from the first output, which is actually a camera, and noticed very slight stutters consistently 3 times a minute. This began to bug me, it was very noticeable and I wanted smooth footage. A bit confused I decided to try the first output by itself and watch ffmpeg to see when frames were being duplicated and found that it was duplicating frames every 17 second (16.66 to be more precise).

  After doing the math (1/16.66=.06) I realized that the frame rate of that first capture card was actually 59.94. Doing the same thing for the other output I found that my "100fps" footage is actually 99.98. But what does that really entail ?

  Should I change the fps to 59.94 and 99.98 ? Wont that cause synchronization issues as 99.98 (100*.0002=99.98) isn’t the same standard as 59.94 (60*.001=59.94) ? Or does that mean I just need to set the second output to 99.9 (100*.001=99.9) to match the standard of the first output and drop frames ? If that is the case does this mean in my editing program, Adobe Premiere, I would need to export the final video as 59.94fps not 60fps to avoid duplication of frames ? Or is there some method within timecode that remedies this issue ?

  I guess I just really don’t understand drop frame and non-drop frame timecode / timecode in general. Up until yesterday when something said 60fps I thought it meant literally 60fps but I guess 99% of the time it actually means 59.94. I’d really like to just avoid the duplication of frames as it ruins what would be a smooth experience but don’t know if I can while trying to keep everything synchronized.

  Any help or insight would be appreciated, sorry if my question is a bit confusing I am undoubtedly confused.

• FFMpegm. Unable to get video stream from a onvif camera

  15 avril 2018, par Denis Gottardello

  I have implemented ffmpeg in my own application to watch live video from video cameras.
  I have tested my application with 2 models of onvif camera and the application works perfectly.
  The customer has got another model of video cameram still onvif h264 but I can’t watch the live stream.
  I can wath it using vlc but when I try to watch it with my application I obtain the following error :

  Input #0, rtsp, from 'rtsp://admin:admin@172.30.153.33:554/1':
  
    Metadata:
  
      title           : h264.mp4
  
    Duration: N/A, bitrate: 64 kb/s
  
      Stream #0:0: Video: h264, none, 90k tbr, 90k tbn, 180k tbc
  
      Stream #0:1: Audio: pcm_mulaw, 8000 Hz, 1 channels, s16, 64 kb/s
  
  [rtsp @ 0x7f86b8004e00] UDP timeout, retrying with TCP
  
  [rtsp @ 0x7f86b8004e00] method PAUSE failed: 455 Method Not Valid In This State
  
  [rtsp @ 0x7f86b8005000] Could not find codec parameters for stream 0 (Video: h264, none): unspecified size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options

  I have already tried to modify analyzeduration and probesize without any good result.

  How to resolve this error ?
  Could it be caused by a not up-to-date h264 library ?

• Raspberry PI3 records video without quality from IP Camera

  22 avril 2018, par Marcos da Cruz Sibilio Jr.

  I try to record video using : raspberry pi 3, IP Camera and ffmpeg command.
  I installed ffmpeg by surce code for enable libx264 it works but not very well.
  I use the syntax (in raspberry command line) :

  ffmpeg -i "rtsp://192.168.100.108:554/user=admin&password=admin&channel=1&stream=0.sdp?" -t 00:01:00 -an -y -framerate 25 -vcodec:a copy -vcodec:a h264  video_teste.h264

  after that I copy the file for my notebook and run :

  MP4Box -fps 30 -add video_teste.h264 v.mp4

  after tha I can watch the video (v.mp4) but the image is like that :
  image by video recorded

  command ffmpeg retuns this lines :
  ffmpeg results

  I tried some configurations for ffmpeg, tried the resolution camera (D1 and 720p), tried to record with opencv (it is installed too).
  I need to record h264 video in raspberry Pi (I will use extern HD for record the videos) and transfer to my server by ftp, but it is necessary that the video quality is good.