X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=video.rst;fp=video.rst;h=4a0ae5cf52dad1b94fbe256379eb3f1431740479;hb=ebc1f8d4cd9128b057f385ae46fd15bdfa5c26ed;hp=c418e92a39e12b4fd24ece509dd0166e082baaca;hpb=fdc59442d0bc7cf50ac10c770a7f5d702e22fdd2;p=nageru-docs diff --git a/video.rst b/video.rst index c418e92..4a0ae5c 100644 --- a/video.rst +++ b/video.rst @@ -96,74 +96,5 @@ the next frame will resume playing. Integration with CasparCG ------------------------- -`CasparCG `_ is an open-source broadcast graphics system, -originally written by SVT, the Swedish public TV broadcaster. (In this -context, “graphics” refers mostly to synthetically generated content, -such as the score box in a sporting match.) With some coaxing, it is possible -to integrate CasparCG with Nageru, so that Nageru does the mixing of the video -sources and CasparCG generates graphics—CasparCG can also work as a standalone -mixer indepedently of Nageru, but this will not be covered here. - -The most straightforward use of CasparCG is to use it to generate an overlay, -which is then taken in as a video input in Nageru. To achieve this, the simplest -solution is to send raw BGRA data over a UNIX domain socket [#rawvideo]_, which involves -adding an FFmpeg output to your CasparCG configuration. This can either be done -by modifying your casparcg.config to open up a socket in your home directory -(you shouldn't use /tmp on a multi-user machine, or you may open up a security -hole):: - - - - 1 - unix:///home/user/caspar.sock - -c:v rawvideo -vf format=pix_fmts=bgra -f nut -listen 1 - - - - -or by setting it up on-the-fly through ACMP:: - - add 1 stream unix:///home/user/caspar.sock -c:v rawvideo -vf format=pix_fmts=bgra -f nut -listen 1 - -You can then use *unix:///home/user/caspar.sock* as a video input to Nageru on the -same machine, and then use e.g. *OverlayEffect* to overlay it on your video chains. -(Remember to set up the video as BGRA and not Y'CbCr, so that you get alpha.) - -CasparCG and Nageru does not run with synchronized clocks, so you will not get -frame-perfect synchronization between graphics and overlay; however, this is normal -even in a hardware chain, and most overlay graphics does not need to be timed -to the input more than through a few frames. However, note that it is possible -that Nageru lags behind CasparCG's graphics production after a while (typically -on the order of hours) due to such clock skew; the easiest solution to this is -just to use *change_rate(2.0)* or similar on the input, so that Nageru will consume -CasparCG's frames as quickly as they come in without waiting any further. - -There's also one usability stumbling block: *CasparCG's FFmpeg -streams are one-shot, and so are FFmpeg's UNIX domain sockets.* This means that, -in practice, if Nageru ever disconnects from CasparCG for any reason, the socket -is “used up”, and you will need to recreate it somehow (e.g., by restarting CasparCG). -Also note that the old socket still lingers in place even after being useless, -so you will *first* need to remove it, and CasparCG does not do this for you. -The simplest way to deal with this is probably to have a wrapper script of some -sort that orchestrates Nageru, CasparCG and your client for you, so that everything -is taken up and down in the right order; it may be cumbersome and require some -tweaking for oyur specific case, but it's not a challenging problem per se. - -Nageru does not have functionality to work as a CasparCG client in itself, -nor can your theme present a very detailed UI to do so. However, do note that -since the theme is written in unrestricted Lua, so you can use e.g. -`lua-http `_ to send signals -to your backend (assuming it speaks HTTP) on e.g. transition changes. -With some creativity, this allows you to at least bring some loose coupling -between the two. - -In general, the integration between Nageru and CasparCG leaves a bit to be -desired, and in general, the combination of CasparCG + Nageru will require -a beefier machine than Nageru alone. However, it also provides a much richer -environment for graphics, so for many use cases, it will be worth it. - -.. [#rawvideo] Good video codecs that support alpha are rare, so as long as CasparCG - and Nageru are running on the same machine, raw video is probably your - best bet. Even so, note that FFmpeg's muxers are not really made for - such large amounts of data that raw HD video produces, so there will - be some performance overhead on both sides of the socket. +This section has been removed, as since 1.7.0, Nageru has :ref:`native support +for HTML5 inputs `, obsoleting CasparCG integration.