[FFmpeg-user] Very high latency of RTMP laptop webcam

Syed Hamid Rasool 14mseesrasool at seecs.edu.pk
Tue Dec 13 13:58:30 EET 2016

Command: ffmpeg -rtbufsize 100M -r 30 -f dshow -s 320x240 -i video="USB2.0
Camera" -vcodec h264 -pix_fmt yuyv422 -b:v 300k -preset ultrafast -f flv

Output #0, flv, to 'rtmp://':
    encoder         : Lavf57.59.100
    Stream #0:0: Video: h264 (libx264) ([7][0][0][0] / 0x0007), yuv422p,
320x240, q=-1--1, 300 kb/s, 30 fps, 1k tbn, 30 tbc
      encoder         : Lavc57.67.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/300000 buffer size: 0 vbv_delay: -1
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
Press [q] to stop, [?] for help
frame=    8 fps=0.0 q=28.0 size=       4kB time=00:00:00.00
bitrate=32504.0kbitsframe=   12 fps= 12 q=34.0 size=      22kB
time=00:00:00.13 bitrate=1343.9kbits/frame=   16 fps= 11 q=35.0 size=
33kB time=00:00:00.26 bitrate=1003.0kbits/frame=   21 fps= 10 q=32.0
size=      34kB time=00:00:00.43 bitrate= 642.1kbits/frame=   25 fps=9.9
q=30.0 size=      35kB time=00:00:00.56 bitrate= 505.5kbits/frame=   29
fps=9.6 q=29.0 size=      38kB time=00:00:00.70 bitrate=
444.9kbits/frame=   33 fps=9.3 q=29.0 size=      42kB time=00:00:00.83
bitrate= 412.7kbits/frame=   37 fps=9.1 q=29.0 size=      46kB
time=00:00:00.96 bitrate= 387.2kbits/frame=   42 fps=9.2 q=29.0 size=
50kB time=00:00:01.13 bitrate= 364.7kbits/frame=   46 fps=9.1 q=28.0
size=      54kB time=00:00:01.26 bitrate= 348.4kbits/frame=   50 fps=9.0
q=28.0 size=      59kB time=00:00:01.40 bitrate= 342.9kbits/frame=   54
fps=8.9 q=29.0 size=      64kB time=00:00:01.53 bitrate=
341.2kbits/frame=   59 fps=9.0 q=29.0 size=      70kB time=00:00:01.70
bitrate= 336.6kbits/frame=   63 fps=8.9 q=29.0 size=      74kB
time=00:00:01.83 bitrate= 332.5kbits/s speed=0.258x

On Tue, Dec 13, 2016 at 4:44 PM, Carl Eugen Hoyos <ceffmpeg at gmail.com>

> 2016-12-13 11:01 GMT+01:00 Syed Hamid Rasool <14mseesrasool at seecs.edu.pk>:
> > I have ran into another issue when running FFMpeg with a USB2.0 webcam.
> The
> > laptop's camera had compressed output (MJPEG) but this utility webcam
> only
> > has raw pixel format (yuyv422). Using the same command as above causes it
> > to work at speed 0.3x resulting in laggy and jittering output (10fps
> > compared to 30) when viewing it from server.
> Command line and complete, uncut console output missing.
> Please do not top-post here, Carl Eugen
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Syed Hamid Rasool

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