[FFmpeg-user] Creating image stream from h264 and piping

[Adriano Todaro]

Hi all,

I'll try to describe clearly what I'm trying to achieve.

If I use this command:

ffmpeg -i 'rtsp://
user:password at 192.168.1.90:554/axis-media/media.amp?videocodec=h264' -vf
"select='eq(pict_type,I)'" -vsync vfr  thumb%04d.jpg

FFmpeg creates a series of JPEG images from the I frames of the original
video stream.

Now I need to pipe this output, but if I do:

ffmpeg -i 'rtsp://
user:password at 192.168.1.90:554/axis-media/media.amp?videocodec=h264' -vf
"select='eq(pict_type,I)'" -vsync vfr  pipe:1

I get the error:



ffmpeg version 3.1.4 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 6.2.1 (GCC) 20160830
  configuration: --prefix=/usr --disable-debug --disable-static
--disable-stripping --enable-avisynth --enable-avresample
--enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl
--enable-ladspa --enable-libass --enable-libbluray --enable-libfreetype
--enable-libfribidi --enable-libgsm --enable-libiec61883
--enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb
--enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus
--enable-libpulse --enable-libschroedinger --enable-libsoxr
--enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2
--enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp
--enable-libx264 --enable-libx265 --enable-libxvid --enable-netcdf
--enable-shared --enable-version3 --enable-x11grab
  libavutil      55. 28.100 / 55. 28.100
  libavcodec     57. 48.101 / 57. 48.101
  libavformat    57. 41.100 / 57. 41.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 47.100 /  6. 47.100
  libavresample   3.  0.  0 /  3.  0.  0
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
Input #0, rtsp, from 'rtsp://
root:avansig at 192.168.1.90:554/axis-media/media.amp?videocodec=h264':
  Metadata:
    title           : Media Presentation
  Duration: N/A, start: 0.040089, bitrate: N/A
    Stream #0:0: Video: h264 (Main), yuv420p(tv, bt709), 1280x800 [SAR 1:1
DAR 8:5], 25 tbr, 90k tbn, 180k tbc
[NULL @ 0x5590e4565b00] Unable to find a suitable output format for 'pipe:1'
pipe:1: Invalid argument



Seemingly because ffmpeg can't guess the output format anymore.

So the question is: how can crete a stream of jpeg images that I can send
through pipe:1?

I've tried to add something like "-f jpeg" but of course it didn't work.


Thanks in advance,

Adriano Todaro.