X-Git-Url: https://git.decadent.org.uk/gitweb/?p=lca-dvswitch.git;a=blobdiff_plain;f=index.html;h=596114cb2864b6f4c34050ad606c92b2c3ca3490;hp=6a529133df6851776f00b978e779f5553403e42b;hb=1d7f8908beb4ce2ee765cd308e951aa9a37b43b1;hpb=a450ab8e09cff952020a72386505b7657728f7d9 diff --git a/index.html b/index.html index 6a52913..596114c 100644 --- a/index.html +++ b/index.html @@ -4,7 +4,7 @@ -DVswitch - Ben Hutchings - LCA2011 +Making great conference videos on a budget - Ben Hutchings - LCA2011 @@ -19,6 +19,9 @@ @@ -33,7 +36,7 @@ @@ -42,11 +45,34 @@
-

DVswitch

+

Making great conference videos
on a budget

Ben Hutchings

+
+

The author

+ +
+ +

What is DVswitch?

@@ -81,7 +118,8 @@ A general video editor
  • - An audio mixer (but it does implement audio dubbing and level monitoring) + An audio mixer - audio functionality is limited to dubbing and + level monitoring
  • A complete recording and publishing system @@ -96,7 +134,7 @@

    The 'DV' in DVswitch

    - The name refers to the DV formats used by many video cameras: + The name refers to the DV format used by many video cameras:

    @@ -142,10 +180,13 @@

    Overview of the system

    -

    - A simplified view of the typical components: -

    - + +
    +

    + This is a simplified view of the typical components. The system + is completely flexible as to which sinks and sources are used. +

    +
    @@ -167,10 +208,10 @@ Requires a script to coordinate mixer and source startup - an annoying complication -
  • - Improvement: tally lights -
    • +
  • + Later enhancement: tally lights +
  • Next release: sources run as RTP/RTSP servers and mixer connects to them as a client @@ -181,6 +222,12 @@
    • +
    +

    + DIF is the DV Interchange Format, sometimes referred to as 'raw + DV' although it is a container format in its own right. +

    +
    @@ -196,12 +243,10 @@
  • Original protocol: mixer runs a network server; sinks run as clients and receive DIF over TCP -
      -
    • - Improvement: sink reports whether it will record; mixer can - start, stop and cut recording -
      • -
    +
    • +
  • + Later enhancement: sink reports whether it will record; + mixer can start, stop and cut recording
  • Next release: file and pipe sinks built into mixer along with an @@ -211,13 +256,86 @@
    • -

    Mixer

    +

    Mixer UI

    -

    Mixer

    - +

    Mixer UI, annotated

    + +
    + +
    +

    Mixer internals

    + +
    +

    + To simplify the diagram, I omitted connection setup, tally light + and recording control, and the internal sinks that haven't been + implemented yet. +

    +

    + All these interfaces have limited-length queues. If a queue + fills up, frames have to be dropped - we must not block or use + unlimited memory! +

    +

    + The mixer clock thread maintains a frame clock at about 25 or + 30 Hz depending on the video system, constantly adjusted to + follow the audio source. +

    +
    +
    + +
    +

    Icecast streaming server

    +
      +
    • + Simple HTTP streaming server supporting MP3, Ogg Vorbis and + Ogg Theora streams +
      • +
    • + Each stream is provided by an authenticated source client or + relayed from another server +
      • +
    • + Relaying allows you to build a distribution network serving + viewers inside and outside the conference +
      • +
    +
    + +
    +

    Icecast distribution network

    + +
      +
    • + Internal master serves internal viewers and external master +
      • +
    • + Public servers serve viewers anywhere +
      • +
    • + Relaying restricted by password and/or firewall +
      • +
    +
    + +
    +

    Further information

    +