[FFmpeg-user] Named Pipes

RLopez rlopez at netbox.com
Wed Feb 29 23:58:17 CET 2012


Well through trial and error I came up with this command line for piping
audio and video to ffmpeg though a command line.  I don't know if it's the
best way but it seems to work.

ffmpeg -f rawvideo -pix_fmt yuv422p -r 30000/1001 -s 720x480 -i - -f s16le
-ar 48k -ac 2 -i //./pipe/audio -vb 4M -y d:\clips\clip1.mpg <
//./pipe/video

-----Original Message-----
From: ffmpeg-user-bounces at ffmpeg.org [mailto:ffmpeg-user-bounces at ffmpeg.org]
On Behalf Of RLopez
Sent: Monday, February 27, 2012 4:53 AM
To: 'FFmpeg user questions and RTFMs'
Subject: [FFmpeg-user] Named Pipes

Hello,

I have been using a Windows binary version of ffmpeg for years(dated
7-7-2009) and recently upgraded to the latest Window build reference at
ffmpeg.org.  The link to the version I upgraded to is
http://ffmpeg.zeranoe.com/builds/win32/static/ffmpeg-git-b6ff81d-win32-stati
c.7z.  I am no longer able to use Named Pipes with the new version.  Did
something change in the calling convention.  This is the command line I use:

ffmpeg -f rawvideo -pix_fmt yuv422p -r 29.97 -s 720x480 -i \\.\pipe\mypipe
-vb 4000000 -y d:\m2vfiles\myvid.m2v

It works fine on the older ffmpeg but generates the errors below with the
latest version.  Could it be that the newer ffmpeg is trying to seek or
check the file size of a Named Pipe?  Is there a way to tell the newer
ffmpeg to read the file as a stream without seeking?  Any help would be
greatly appreciated.




C:\ffmpeg\bin>ffmpeg -f rawvideo -pix_fmt yuv422p -r 29.97 -s 720x480 -i
\\.\pipe\mypipe -vb 4000000 -y d:\m2vfiles\myvid.m2v ffmpeg version
N-37915-g6cb2085 Copyright (c) 2000-2012 the FFmpeg developers
  built on Feb 15 2012 20:52:28 with gcc 4.6.2
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-runtime-cpudetect --enable-avisynth --enab le-bzlib --enable-frei0r
--enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype
--enable-libgsm --en able-libmp3lame --enable-libopenjpeg --enable-librtmp
--enable-libschroedinger --enable-libspeex --enable-libtheora --en
able-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx
--enable-libx264 --enable-libxavs --enable- libxvid --enable-zlib
  libavutil      51. 39.100 / 51. 39.100
  libavcodec     54.  3.100 / 54.  3.100
  libavformat    54.  1.100 / 54.  1.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 62.100 /  2. 62.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    52.  0.100 / 52.  0.100
Truncating packet of size 691200 to 658433 [rawvideo @ 000000000201F7A0]
Estimating duration from bitrate, this may be inaccurate Input #0, rawvideo,
from '\\.\pipe\mypipe':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (Y42B / 0x42323459), yuv422p, 720x480,
29.97 tbr, 29.97 tbn, 29.97 tbc  [buffer @ 000000000201F710] w:720 h:480
pixfmt:yuv422p tb:1/1000000 sar:0/1 sws_param:
Output #0, mpeg2video, to 'd:\m2vfiles\myvid.m2v':
  Metadata:
    encoder         : Lavf54.1.100
    Stream #0:0: Video: mpeg2video, yuv422p, 720x480, q=2-31, 20000 kb/s,
90k tbn, 29.97 tbc Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo -> mpeg2video) Press [q] to stop, [?] for
help Error while decoding stream #0:0 Truncating packet of size 691200 to 1
Error while decoding stream #0:0 Truncating packet of size 691200 to 1 Error
while decoding stream #0:0 Truncating packet of size 691200 to 1 Error while
decoding stream #0:0 Truncating packet of size 691200 to 1 Error while
decoding stream #0:0 Truncating packet of size 691200 to 1 Error while
decoding stream #0:0 Truncating packet of size 691200 to 1 Error while
decoding stream #0:0 Truncating packet of size 691200 to 1 Error while
decoding stream #0:0 Truncating packet of size 691200 to 1
     .
     .
Repeat forever
     .
     .


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