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• Cannot stream video from VLC docker

  4 avril 2023, par Snake Eyes

  I have Dockerfile :

  


  FROM fedora:34

ARG VLC_UID="1000"
ARG VLC_GID="1000"

ENV HOME="/data"


RUN groupadd -g "${VLC_GID}" vlc && \
    useradd -m -d /data -s /bin/sh -u "${VLC_UID}" -g "${VLC_GID}" vlc && \
    dnf upgrade -y && \
    rpm -ivh "https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-34.noarch.rpm" && \
    dnf upgrade -y && \
    dnf install -y vlc && \
    dnf install -y libaacs libbdplus && \
    dnf install -y libbluray-bdj && \
    dnf clean all

USER "vlc"

WORKDIR "/data"

VOLUME ["/data"]

ENTRYPOINT ["/usr/bin/cvlc"]


  


  And then run :

  


  docker run -d -v "d:\path":/data -p 8787:8787 myrepo/myvlc:v1 file:///data/Sample.mkv --sout '#transcode {vcodec=h264,acodec=mp3,samplerate=44100}:std{access=http,mux=ffmpeg{mux=flv},dst=0.0.0.0:8787/stream.flv}'


  


  I get error :

  


  2023-04-04 12:19:11 [000055933c090060] vlcpulse audio output error: PulseAudio server connection failure: Connection refused
2023-04-04 12:19:11 [000055933c09d680] dbus interface error: Failed to connect to the D-Bus session daemon: Unable to autolaunch a dbus-daemon without a $DISPLAY for X11
2023-04-04 12:19:11 [000055933c09d680] main interface error: no suitable interface module
2023-04-04 12:19:11 [000055933bf26ad0] main libvlc error: interface "dbus,none" initialization failed
2023-04-04 12:19:11 [000055933c08d7a0] main interface error: no suitable interface module
2023-04-04 12:19:11 [000055933bf26ad0] main libvlc error: interface "globalhotkeys,none" initialization failed
2023-04-04 12:19:11 [000055933c08d7a0] dummy interface: using the dummy interface module...
2023-04-04 12:19:11 [00007f3b84001250] stream_out_standard stream out error: no mux specified or found by extension
2023-04-04 12:19:11 [00007f3b84000f30] main stream output error: stream chain failed for `standard{mux="",access="",dst="'#transcode"}'
2023-04-04 12:19:11 [00007f3b90000c80] main input error: cannot start stream output instance, aborting
2023-04-04 12:19:11 [00007f3b7c001990] stream_out_standard stream out error: no mux specified or found by extension
2023-04-04 12:19:11 [00007f3b7c001690] main stream output error: stream chain failed for `standard{mux="",access="",dst="'#transcode"}'
2023-04-04 12:19:11 [00007f3b90000c80] main input error: cannot start stream output instance, aborting


  


  I mention that I'm using cvlc and I can't stream that mkv file.

  


  I tried as well --sout '#transcode{scodec=none}:http{mux=ffmpeg{mux=flv},dst=:8787/}' but same errors.

  


  How can I solve it ?

  


• Server side video mixing

  16 mars 2014, par Nicolas Goy

  I have a serie of video files encoded in mpeg2 (I can change this encoding), and I have to produce a movie in flash flv (this is a requirement, I can't change that encoding).

  One destination movie is a compilation of different source video files.

  I have a playlist defining the destination movie. For example :

  Video file        Position        Offset       Length 
  
  little_gnomes     0               0            8.5
  
  fairies           5.23            0.12         12.234
  
  pixies            14              0            9.2

  Video file is the name of the file, position is when the file should be started (in the master timeline), offset is the offset within the video file, and length is the length of the video to play. The numbers are seconds (in double).

  This would result in something like that (final movie timeline) :

                 0--5.23|--8.5|--14|--17.464|--23.2|
  
  little_nomes   **************
  
  fairies               *********************
  
  pixies                           *****************

  Where video overlaps, the last video to be added override the last one, the audio should be mixed.

  The resulting video track would be :

                 0--5.23|--8.5|--14|--17.464|--23.2|
  
  little_nomes   *******
  
  fairies               ***********
  
  pixies                           *****************

  While the resulting audio would be :

                 0--5.23|--8.5|--14|--17.464|--23.2|
  
  little_nomes   11111112222222
  
  fairies               222222211112222222222
  
  pixies                           22222222221111111

  Where 1 or 2 is the number of mixed audio tracks.

  There can be a maximum of 3 audio tracks.

  I need to write a program which takes the playlist as input and produce the flv file. I'm open to any solution (must be free/open source).

  An existing tool that can do that would be the simplest, but I found none. As for making my own solution, I found only ffmpeg, I was able to do basic things with it, but the documentation is terribly lacking.

  It can be any language, it doesn't have to be super fast (if it takes 30 minutes to build a 1h movie it's fine).

  The solution will run on opensolaris based x64 servers. If I have to use linux, this would work too. But windows is out of the question.

• Stop doing this in your encoder comparisons

  14 juin 2010, par Dark Shikari — Uncategorized

  I’ll do a more detailed post later on how to properly compare encoders, but lately I’ve seen a lot of people doing something in particular that demonstrates they have no idea what they’re doing.

  PSNR is not a very good metric. But it’s useful for one thing : if every encoder optimizes for it, you can effectively measure how good those encoders are at optimizing for PSNR. Certainly this doesn’t tell you everything you want to know, but it can give you a good approximation of “how good the encoder is at optimizing for SOMETHING“. The hope is that this is decently close to the visual results. This of course can fail to be the case if one encoder has psy optimizations and the other does not.

  But it only works to begin with if both encoders are optimized for PSNR. If one optimizes for, say, SSIM, and one optimizes for PSNR, comparing PSNR numbers is completely meaningless. If anything, it’s worse than meaningless — it will bias enormously towards the encoder that is tuned towards PSNR, for obvious reasons.

  And yet people keep doing this.

  They keep comparing x264 against other encoders which are tuned against PSNR. But they don’t tell x264 to also tune for PSNR (–tune psnr, it’s not hard !), and surprise surprise, x264 loses. Of course, these people never bother to actually look at the output ; if they did, they’d notice that x264 usually looks quite a bit better despite having lower PSNR.

  This happens so often that I suspect this is largely being done intentionally in order to cheat in encoder comparisons. Or perhaps it’s because tons of people who know absolutely nothing about video coding insist on doing comparisons without checking their methodology. Whatever it is, it clearly demonstrates that the person doing the test doesn’t understand what PSNR is or why it is used.

  Another victim of this is Theora Ptalarbvorm, which optimizes for SSIM at the expense of PSNR — an absolutely great decision for visual quality. And of course if you just blindly compare Ptalarbvorm (1.2) and Thusnelda (1.1), you’ll notice Ptalarbvorm has much lower PSNR ! Clearly, it must be a worse encoder, right ?

  Stop doing this. And call out the people who insist on cheating.