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Peter Gusev
I'm dumping a video captured from a camera into two named pipes like this:

$ ffmpeg -f avfoundation -framerate 25 -pixel_format uyvy422 -i "0" -map
0:v -c copy -f rawvideo /tmp/preview -map 0:v -c copy -f rawvideo
/tmp/camera
ffmpeg version 3.4 Copyright © 2000-2017 the FFmpeg developers
  built with Apple LLVM version 9.0.0 (clang-900.0.38)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4 --enable-shared
--enable-pthreads --enable-version3 --enable-hardcoded-tables
--enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl
--enable-ffplay --enable-libmp3lame --enable-libx264 --enable-libxvid
--enable-opencl --enable-videotoolbox --disable-lzma
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, avfoundation, from '0':
  Duration: N/A, start: 3576.358767, bitrate: N/A
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 1280x720, 25
tbr, 1000k tbn, 1000k tbc
File '/tmp/preview' already exists. Overwrite ? [y/N] y
File '/tmp/camera' already exists. Overwrite ? [y/N] y
Output #0, rawvideo, to '/tmp/preview':
  Metadata:
    encoder         : Lavf57.83.100
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 1280x720,
q=2-31, 25 tbr, 1000k tbn, 1000k tbc
Output #1, rawvideo, to '/tmp/camera':
  Metadata:
    encoder         : Lavf57.83.100
    Stream #1:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 1280x720,
q=2-31, 25 tbr, 1000k tbn, 1000k tbc
Stream mapping:
  Stream #0:0 -> #0:0 ©
  Stream #0:0 -> #1:0 ©
Press [q] to stop, [?] for help
frame=11931 fps= 25 q=-1.0 q=-1.0 size=21505628kB time=00:07:59.96
bitrate=367060.0kbits/s speed=1.01x


then, I'm reading it using ffplay on two separate terminal windows like
this:

ffplay -f rawvideo -video_size 1280x720 -pixel_format uyvy422 -i
/tmp/preview
ffplay version 3.4 Copyright © 2003-2017 the FFmpeg developers
  built with Apple LLVM version 9.0.0 (clang-900.0.38)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4 --enable-shared
--enable-pthreads --enable-version3 --enable-hardcoded-tables
--enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl
--enable-ffplay --enable-libmp3lame --enable-libx264 --enable-libxvid
--enable-opencl --enable-videotoolbox --disable-lzma
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, rawvideo, from '/tmp/preview':q=    0KB sq=    0B f=0/0
  Duration: N/A, start: 0.000000, bitrate: 368640 kb/s
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 1280x720,
368640 kb/s, 25 tbr, 25 tbn, 25 tbc
 539.38 M-V: -0.010 fd=  14 aq=    0KB vq=16200KB sq=    0B f=0/0


Video plays back correctly color-wise and size-wise. However it "scrolls"
vertically all the time (not sure of the correct term here - vertical
sync?), see the screenshot attached. I believe it's due to some minor
error/mismatch in pixel formats and/or video size? But I can't pin point it
yet... Any help would be appreciated!

Thanks in advance!

--
Peter Gusev <https://www.linkedin.com/in/peter-gusev-8135441a/>
*[hidden email] <[hidden email]>*


*+1 213 587-27-48*


*Research Scholar @ REMAP UCLA <http://www.remap.ucla.edu/home/about>Video
streaming/ICN networks/Creative Coding/Interactive Media*
*dj peetonn <https://soundcloud.com/peter-gusev>*

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Re: (no subject)

Carl Eugen Hoyos-2
2018-09-13 18:32 GMT+02:00, Peter Gusev <[hidden email]>:

> Video plays back correctly color-wise and size-wise. However
> it "scrolls" vertically all the time

Does this also happen if you only use ffplay?
$ ffplay -f avfoundation -framerate 25 -pixel_format uyvy422 -i "0"

Please test current FFmpeg git head.

Carl Eugen
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