X-Git-Url: https://git.decadent.org.uk/gitweb/?p=lca-dvswitch.git;a=blobdiff_plain;f=index.html;h=48d3612bd9baedaa5160a3de0996e3af497548f9;hp=3ee5fe00a70e0127e74a3737ab49a8ce1c2f1143;hb=eeae028954b1ea457db9d49f7471a3e101ca1fa7;hpb=92bdd3874a1f95b77a74c23ec61fa050dd131327 diff --git a/index.html b/index.html index 3ee5fe0..48d3612 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 @@ -36,7 +36,7 @@ @@ -45,7 +45,7 @@
-

DVswitch

+

Making great conference videos
on a budget

Ben Hutchings

@@ -80,17 +80,28 @@ A software system that supports video mixing, recording and streaming
  • - Designed particularly for the needs of technical conferences that - want to record and stream on a limited budget. Now used more - widely, often without streaming. + Primarily designed for free software conferences: + +
  • + Now used more widely, often without streaming
  • - Mixing is live - a requirement for streaming, and a way to - avoid the need for extensive editing after the event + Mixing is live - required for streaming, and avoids + extensive editing after the event
  • - Mixing is interactive - a requirement for good coverage of - presenters, audience and slides, but very limited in other + Mixing is interactive - required for good coverage of + presenters, audience and slides; very limited in other streaming software
    • @@ -107,7 +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 @@ -122,7 +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:

    @@ -168,10 +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. +

    +
    @@ -207,6 +222,12 @@ +
    +

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

    +
    @@ -235,13 +256,86 @@
    -

    Mixer

    - +

    Mixer UI

    + +
    + +
    +

    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 +
      • +
    -

    Mixer

    - +

    Further information

    +